hybridfree/eevblog-posts huggingface dataset:
Protecting 12V DC input - Page 1
Forum section: electronics / projects

author: deephaven
author_rank: Frequent Contributor
timestamp: August 03, 2012, 08:39:16 am
content: I have a board which uses a switching regulator with a Vin MAX if 20V. I run this with a nominal input voltage of +12V which is normally fed from an unearthed 12V mains power supply - the usual 12V 1A wall wart switching reg or similar. The input does need to handle up to 17V on the occasion that the source is a freshly charged battery pack. I want to provide protection for the situation where the user plugs the 12V in from the unearthed power supply when the supply is already plugged into the mains. This means it has to protect the input of my board from the induced AC volts on the connector which might touch the +12V input pin before the 0V connects. Looking at the specs of TVS diodes, it is difficult to find one which is safely above the 17V so that it doesn't normally turn on, but still provides the 20V protection needed by the regulator. Any suggestions on a good choice of protection device?

author: Mangozac
author_rank: Frequent Contributor
timestamp: August 03, 2012, 10:40:56 am
content: This is not an uncommon problem actually! Indeed the voltage range between when the TVS diode starts conducting and when it clamps is quite high.Earlier in the year an application I designed had a similar configuration as you. I ended up using a zener and MOSFET configured as a drain follower on the input to the switching regulator. Plus a TVS diode on the input to the circuit. The MOSFET drain is connected to the source (and TVS diode), the drain is connected to the switching regulator input. The gate is connected to the drain via a resistor and to ground with the reverse biased zener diode.This circuit effectively acts as a more precise voltage clamp, but still allows the TVS diode to take the brunt of the power dissipation for higher voltage spikes. It wasn't the most amazing solution (and you end up wasting a small amount of power in the MOSFET) but it worked for that application.I'd certainly like to hear how others deal with the problem!
Protecting a digital input in hostile EMI enviroment - Page 1
Forum section: electronics / projects

author: Jester
author_rank: Frequent Contributor
timestamp: January 11, 2025, 01:58:47 pm
content: Is the IP4220 next to useless in the circuit below?The T20F256C4 FPGA input is specified as -0.3Vmin, so I'm assuming the FPGA's input steering diode is Schottky.The IP4220 appears to use regular 0.7V type diodes.Pulse stream from thee encoder varies but 1.25MHz is probably a reasonable upper limit.I'm thinking pairs of Schottky diodes would actually help protect the inputs, perhaps CUS10S30 (Vf =0.23V)Problem is there are lot's of inputs and not a lot of board space.Suggestions welcome.https://www.digikey.ca/en/products/detail/nexperia-usa-inc/IP4220CZ6-125/1133526https://www.digikey.ca/en/products/detail/toshiba-semiconductor-and-storage/CUS10S30-H3F/5114299

author: AndersJ
author_rank: Frequent Contributor
timestamp: January 11, 2025, 03:06:10 pm
content: Define ”hostile”.

author: Jester
author_rank: Frequent Contributor
timestamp: January 11, 2025, 03:54:31 pm
content: Quote from: AndersJ on January 11, 2025, 03:06:10 pmGreat question....Close proximity to VFD; 2HP motor 240V 10A (fast edge, high current) so chassis ground is several volts at VFD chop frequency. Encoder wiring can only be separated to some extent.I'm thinking I should place a RS422 receiver between encoder and FPGA to act as a "buffer/fuse".
Protecting a Velleman relay board (K8090) for automotive use - Page 1
Forum section: electronics / projects

author: VinzC
author_rank: Frequent Contributor
timestamp: March 01, 2016, 01:02:40 pm
content: Hi all.I have aVelleman relay boardthat I need to protect somehow for use in automotive environment – battery nominal voltage is 12V. To cut a long story short such a board was installed in a vehicle and I need to do some post-sales maintenance and occasionally some repair. From what I've been told about the failure, I suspect the 5V regulator might be blown – the board still responds to the USB commands but the relays don't move, which typically happens when the power supply is disconnected... or something bad happened to the 7805. The board sinks up to 350 mA when all relays are on. The board is protected with a 5 Amp fuse in a dedicated fuse box.I'm considering some transient protection for the board but there's no obvious way I could hook something to it.I thought about replacing the diode rectifier bridge (D11-D14) with unidirectional TSV diodes, such as theTP6KE20AorTP6KE18AfromLittlefuse. The diodes maximum current is about 22 Amp and I'd like to clamp the input voltage of the 5V regulator to something like 20 volts due to the 1000µF/25V electrolytic capacitor.The TSV diodes aren't rated for power protection but the power protection diodes I found on digi-key are all SOT23 packages rated for 5V power lines, definitely not what I'm looking for. So is it worth replacing the1N4007(see page 10) with those TSV unidirectional diodes? Is the breakdown voltage OK or should I chose a higher value?Any hint/advice welcome.
Protecting an analog input from continuous overvoltage - Page 1
Forum section: electronics / projects

author: Jester
author_rank: Frequent Contributor
timestamp: March 12, 2021, 01:29:40 pm
content: I’m familiar with the PNP biased just below Vdd trick for protecting an analog input from continuous or long term over-voltage. I don’t imagine anyone offers the combined PNP and diode in a single package for convenience and/or space saving?

author: EmmanuelFaure
author_rank: Regular Contributor
timestamp: March 12, 2021, 05:56:59 pm
content: Maybe using a dual pnp transistor in a single package, the 2nd transistor BE junction used as the diode?

author: Marco
author_rank: Super Contributor
timestamp: March 13, 2021, 04:13:40 pm
content: The diode needs to be Schottky to keep the MCU ESD diode from turning on but still allow the input signal to reach the upper voltage rail, with a silicon diode it would be liable to start conducting too quick. A resistor divider can set the bias too, the Schottky just makes it supply voltage independent.For multiple inputs you could share the bias voltage.

author: langwadt
author_rank: Super Contributor
timestamp: March 13, 2021, 04:20:52 pm
content: Quote from: Marco on March 13, 2021, 04:13:40 pmthe input current is limited by the 10k resistor so for a single input the diode is probable not that critical, for multiple channels driving current through the esd diode might affect the other channels

author: Marco
author_rank: Super Contributor
timestamp: March 13, 2021, 04:23:24 pm
content: It's not about limiting, it's about how much current the PNP transistor would already be conducting at ~0.6V ... which is to say, far too much. It would distort when the input voltage gets near the rail.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 13, 2021, 05:26:17 pm
content: Don't push it to VCC. You can't reach a compromise between ESD diode bias (most ADC port pins specify +/-0mA), undistorted or accurate gain (E-B has significant leakage near breakdown -- granted, this isn't much of a problem at 3.3V, but can be at 5) and the softness of two diode drops.Simply run half the VREF (or whatever), and clamp to that. The ADC doesn't care about Vin > VREF, and VREF several diode drops below VCC avoids ESD diodes.The base bias may need to be larger anyway; using a somewhat beefier VREF (like a TL431 at several mA) covers that no problem.Tim
"Protecting" capacitive touch buttons from LED PWM signal - Page 1
Forum section: electronics / projects

author: 3dgeo
author_rank: Frequent Contributor
timestamp: February 26, 2019, 08:43:09 pm
content: Hi,I'm working on a project where I'm using cap touch buttons and RGB LED near them.I found that it's recommended to use 10nF bypass capacitors on LED leads to reduce LED power lines influence on touch pads.Each pin of a LED is PWMed – anode about 500 Hz, cathodes 100-200 kHz. Will 10nF cap do any good in this situation or it will mess things up?Currently LEDs are in the middle of the Tpad, but on a next revision I will add on top of LEDs another PCB (will be 2.4mm gap between PCBs) with Tpads and ground on a bottom to reduce influence.Don't know if this makes any different but TP ICs I'm testing isTTP229-LSFandTS20.Ideas?
Protecting Low Voltage Electronics From 220V AC Voltages - Page 1
Forum section: electronics / projects

author: bolodski
author_rank: Newbie
timestamp: December 06, 2017, 07:20:46 am
content: Hi All,I'm a newbie here. I'm currently working on a device that controls 220V AC equipments via an electromechanical relay. The relay and the low voltage electronics are all housed in one enclosure. The connections between my electronics and the relay are VCC, GND and CONTROL line for turning on/off the relay. In this setup, how can I protect my electronics from the AC voltage in cases like there is a faulty relay or that the AC wiring is shorted with the VCC, GND or CONTROL lines? Thanks!

author: leeatljs
author_rank: Contributor
timestamp: December 06, 2017, 10:15:05 am
content: The isolation between the relay coil and the relay switch should be adequate, providing PCB (or wiring) caters for a similar isolation gap.
Protecting Port Sensors During PCBA Wash - Page 1
Forum section: electronics / projects

author: KJeffriesTriad
author_rank: Newbie
timestamp: October 03, 2024, 09:56:09 pm
content: Need advice on proven methods to protect a sensor port (BMP384) during PCBA wash with chemistry. The rest of the PCBA must be completely free of flux for eventual potting/encapsulation or we would process everything no-clean. We have tried kapton over the port, with a water proof peelable mask over the entire sensor. Once cured, wash then peel the mask. This only works marginally. We have several sensors with damaged gel. Thanks in advance.
protection the boost converter - Page 1
Forum section: electronics / projects

author: majorloo
author_rank: Contributor
timestamp: February 08, 2018, 02:50:20 pm
content: hidoes any body know how can made a low cost protection for boost converter short circuits?

author: Siwastaja
author_rank: Super Contributor
timestamp: February 08, 2018, 03:45:10 pm
content: Every modern, proper boost converter control IC has this short-circuit protection already built-in.

author: majorloo
author_rank: Contributor
timestamp: February 08, 2018, 04:54:29 pm
content: i have been use tl494 and it doesnt have short circuits protection. can you suggest me a controller with two feedback (voltage and current) and short citcuits protection.

author: David Hess
author_rank: Super Contributor
timestamp: February 08, 2018, 10:04:08 pm
content: The easy way to add short circuit protection to a boost converter is to make it a SEPIC converter instead which has isolation of DC from the input to the output. This amounts to adding one capacitor and one inductor or more often using an inductor with two identical windings.

author: Zero999
author_rank: Super Contributor
timestamp: February 09, 2018, 09:30:13 am
content: Quote from: Siwastaja on February 08, 2018, 03:45:10 pmI think you're confused with a buck converter. It's not an easy thing to implement with a boost converter on an IC. Another switching transistor is required. Turning the main switching transistor off, will not stop current flowing through the coil and diode, to the output.Quote from: majorloo on February 08, 2018, 02:50:20 pmYes, a fuse, circuit breaker or PTC resistor.
Protection Circuit for Li-SOCl₂ Battery Pack in Ex ia IECEx Certification - Page 1
Forum section: electronics / projects

author: Smile2016
author_rank: Regular Contributor
timestamp: September 27, 2025, 04:23:35 am
content: I have a Li-SOCl₂ battery-powered device that I intend to certify under IECEx, with the design requiring Ex ia compliance. The battery pack itself will require certification.The application needs three cells in series to provide approximately 9.5 V, with a maximum circuit current of 100 mA.What would be the simplest compliant protection circuit ; for example, a combination of fuse, reverse-polarity diode, and PTC fuse that would meet Ex ia review requirements?

author: Smile2016
author_rank: Regular Contributor
timestamp: October 01, 2025, 05:43:00 pm
content: Is there anyone with intrinsic safety expertise ?

author: cburgess
author_rank: Contributor
timestamp: October 02, 2025, 12:20:20 pm
content: 30+ years..There's no substitute to getting to grips with the 60079-0 & 60079-11 standards.60079-0 gives some basic direction on cell types60079-11 provides details on battery construction and the type tests for certification, maximum permitted short circuit current etc.A key decision early on is whether you intend have the battery pack replaceable in an explosive atmosphere or not.Regarding circuit protection - there are two sides to consider in your design - ensuring the battery itself can't become an ignition source under fault conditions , and then protecting your circuit from the maximum current / power that the battery can supply under fault conditions.One quick pointer - the Li-SOCL2 cell has an assumed open circuit voltage of 3.9V - 3 cells takes you to 11.7 - which takes you into the "30V row " in Table 5 of the standard for creepage and clearance distances.

author: tszaboo
author_rank: Super Contributor
timestamp: October 02, 2025, 01:28:12 pm
content: Quote from: Smile2016 on October 01, 2025, 05:43:00 pmThere is, but the answer to your question is it depends.You have to specify a bunch of things. And read the standards.There are no easy answers. And we can charge a lot of money to answer those questions. IMHO it's not appropriate to aske them on a public forum anyway, because stuff can blow up, and you are going to be responsible for it.Your certification agency is going to charge tens of thousands of dollars for the certification of the product, just be ready to pay for questions.
Protection circuitry: Poor mans Fluke-like interface - Page 1
Forum section: electronics / projects

author: NivagSwerdna
author_rank: Super Contributor
timestamp: May 23, 2018, 11:41:59 am
content: The idea is this... I would like to develop a poor mans Fluke-like Microprocessor tester... one of the principals of operation of the Fluke is that the DUT buses are driven for a short period of time and then the result is sensed and latched. The resulting comparison is used to detect if the line had been driven OK and/or if the driven lines are affecting other lines... e.g. DUT data bus forced hi/low by defect or lines connected by defect etc.I have 32 I/Os (16Address, 8 Data and 8 Control) and each of these needs to have a protection diode to high and low (protect gadget from static?, 12V, -5V etc in the wrong place) and further I need a current limiting resistor on each (short on DUT) and then a further current limit resistor (one is a driven output the other is a latched sense input). See attached DaveCAD sketch.So I need 32*2 resistors and 32*2 diodes. That's 128 parts (with two ends!)These 64 I/Os (since each of the 32 lines have 2 taps) are at 5V TTL levels which then need to be translated to 3V3 to talk to my FPGA (this is my first FPGA project).I'm only a hobbyist so I hand solder everything... this is a bit daunting... are there ways to approach this to minimise components? e.g. DIL arrays of resistors and/or diodes? (The fluke original has custom for the diodes and resistors)Also... Any suggestions for the voltage translations? the sense lines are unidirectional into the FPGA; the data bus (eight) is definitely bi-directional and the address bus (16) is unidirectional out to the DUT. I have a few other control lines (<=8) which are ideally bi-directional.Thanks in advance

author: NivagSwerdna
author_rank: Super Contributor
timestamp: May 23, 2018, 01:35:51 pm
content: I have been looking athttp://www.ti.com/product/TXB0108which is a 8bit bidirectional level translation gadget.The TXB0108 claims to have in built ESD protection..... would such protection work if the input got connected to 12V? (i.e. I won't need any diodes)orSN74LVC4245A
Protection for the TPA3116D2 - Page 1
Forum section: electronics / projects

author: fabiodl
author_rank: Frequent Contributor
timestamp: March 16, 2020, 11:06:13 am
content: I am building an amp based on the TPA3116D2.I read that if I forget to attach the speaker / 1 wire slips away, there's danger of the LC filter enter resonance and fry the chip/capacitors.I saw some protections done by attaching two diodes, which lock the output of the filters inside the voltage rail (+Vf).I have two questions though.With reference to this schematichttp://www.ti.com/lit/ug/slou336b/slou336b.pdfAre right- and left- usually above ground? Or does the TPA3116D2 usually push right- and left- at negative voltages?The power supply can be as low as 5v. Does it mean that the chip can act as a "boost" converter?If the answer to any of these two questions is "yes", then I guess the diode protection I saw is unusable / impacts the performance (the second is less critical if the supply is high)

author: Zero999
author_rank: Super Contributor
timestamp: March 16, 2020, 11:35:14 am
content: You need to refer to the TPA3116D2 data sheet to answer those questions.http://www.ti.com/lit/ds/symlink/tpa3116d2.pdfThe output voltages from the TPA3116D2, to the speakers are always within the supply rails. Look at the internal schematic. Each output stage is simply a pair of MOSFETs, connected to either power supply rail. The only voltage, above the supply, is the gate drive to the high side N-MOSFETs. It enables the high side MOSFETs to turn fully on, connecting the output to the positive rail. The average voltage on each output will be half the supply voltage.

author: Prehistoricman
author_rank: Regular Contributor
timestamp: March 16, 2020, 08:02:24 pm
content: Quote from: fabiodl on March 16, 2020, 11:06:13 amPersonally, I wouldn't worry about it. You could add a light load (kilo-ohms) to be permanently attached if you're scared.Quote from: fabiodl on March 16, 2020, 11:06:13 amAll of the outputs will idle at half the supply voltage. This is known as a bridged amplifier configuration. Two single-ended amplifiers are used to drive the same load.These TI chips can usually go parallel-bridge as well, which is using the two bridged amplifiers driving the same load.Quote from: fabiodl on March 16, 2020, 11:06:13 amThe opposite. Class D amplifiers are essentially buck converters.

author: fabiodl
author_rank: Frequent Contributor
timestamp: March 17, 2020, 01:11:32 am
content: Thank you Zero999 and Prehistoricman, anything is clear now!
Protection from humidity and condensation - Page 1
Forum section: electronics / projects

author: girishv
author_rank: Regular Contributor
timestamp: December 18, 2022, 01:58:48 pm
content: I want to measure temperature and humidity in a refrigerator. I want to use a humidity sensor like Sensirion SHT30 series. I am going to use a thermistor glued to a piece of steel for thermal mass.The board will be placed in a small enclosure with slots to facilitate air movement. How do I protect the board from humidity, condensation and probably occasional spills?

author: coromonadalix
author_rank: Super Contributor
timestamp: December 19, 2022, 04:31:09 am
content: you have some pcb coating products, you can dip them or spray themhttps://www.techspray.com/the-essential-guide-to-conformal-coating

author: bidrohini
author_rank: Regular Contributor
timestamp: December 20, 2022, 03:39:26 am
content: I think you need to make an enclosure like this:https://www.instructables.com/Building-an-Electronics-Enclosure/

author: girishv
author_rank: Regular Contributor
timestamp: December 20, 2022, 07:32:17 am
content: Quote from: bidrohini on December 20, 2022, 03:39:26 amI will have a enclosure large enough to fit the PCB. I can't seal the enclosure as I am using a surface mount humidity sensor. I will go with conformal coating as suggested by @coromonadalix

author: Miti
author_rank: Super Contributor
timestamp: December 20, 2022, 08:51:28 am
content: I guess it’s common sense but I’ll say it anyway. Don’t coat the humidity sensor.

author: girishv
author_rank: Regular Contributor
timestamp: December 20, 2022, 09:37:25 am
content: Quote from: Miti on December 20, 2022, 08:51:28 amNo harm in saying itOf course, I will not coat. I am trying to figure out a way to cover the humidity sensor. I would appreciate very much any advice on that front.

author: Miti
author_rank: Super Contributor
timestamp: December 20, 2022, 09:43:52 am
content: Mask it with masking tape and spray, don’t dunk the board.
Protection of device against automotive transients, reverse voltage - Page 1
Forum section: electronics / projects

author: WCarp
author_rank: Newbie
timestamp: September 15, 2020, 06:56:38 pm
content: I was wondering what would be suggested to properly provide protection of a electronic device with a 5 V low power regulator and LED driver against automotive transients, and reverse voltage that is connected to an automotive starting battery. A TVS diode could be used but should it be bidirectional or unidirectional. A Schottky diode could be used for low voltage drop first in line for reverse voltage protection but it would have to withstand the clamping current of the TVS diode. Would it be be necessary to include a resettable fuse if the transient lasted too long and exceeds the power rating of the TVS diode? The device I need to protect will have probably 18 gauge wires approximately two feet long connected to the battery.Thanks

author: David Hess
author_rank: Super Contributor
timestamp: September 15, 2020, 08:45:29 pm
content: Quote from: WCarp on September 15, 2020, 06:56:38 pmIn front of the regulator, I would use two diodes in series to protect against reverse voltage, in case one shorts, and then a high voltage series transistor which operates as a preregulator in front of the regulator, which also serves to distribute the power dissipation between the transistor and linear regulator if used. Since protection is series instead of shunt, there are no conditions that cause excessive input current.If overload can be continuous, then fold-back current limiting or shutdown should be included.In some applications the linear regulator can be left out and the series transistor used as the regulator.
Proteus design pcb layout problem - Page 1
Forum section: electronics / projects

author: zzlong94
author_rank: Contributor
timestamp: April 04, 2018, 02:30:15 pm
content: I had some problem with my pcb layout design using Proteus 8 edition.The layout of my pcb design have the shape and the name of the component i had placed.Any method to remove the name and the shape of the component to prevent it from short circuit?thx.
Protoboard Gerber files for SBC-85 8085 Single Board Computer are now available - Page 1
Forum section: electronics / projects

author: Ccandrews
author_rank: Contributor
timestamp: March 26, 2020, 06:22:13 pm
content: For anyone that has one, is building, or is interested the the 8085 single board computer system, the Gerber build files for a prototyping board are now on the project website.http://sbc-85.com/Regards
Protocol for programming PEEL chips - Page 1
Forum section: electronics / projects

author: fabiodl
author_rank: Frequent Contributor
timestamp: January 23, 2020, 08:04:10 am
content: I am interested in programming a PEEL18CV8, but I find no programmer that supports it.I would like to have a try in developing one.I see that back in the day there were self made oneshttps://www.americanradiohistory.com/Archive-Poptronics/90s/90/PE-1990-01.pdfhowever I do not know the protocol. Does anyone have any information about?

author: up8051
author_rank: Frequent Contributor
timestamp: January 23, 2020, 10:47:48 am
content: If you interested in build own programmer this documents should be helphul.But it is for PEEL18CV8/16CV8 not PEEL18CV8Z (zero power).Regards,JarekCPS.I have some (>100)pcs spare PEEL18CV8ZP and programmer for them Labtool48.

author: fabiodl
author_rank: Frequent Contributor
timestamp: January 23, 2020, 01:47:10 pm
content: Thank you very much!Probably you already know this, but on the wayback machine I found thishttp://web.archive.org/web/20040402000557/http://ictpld.com/In case there are some documents you don't have already

author: up8051
author_rank: Frequent Contributor
timestamp: January 23, 2020, 02:07:58 pm
content: Unfortunately, the links to the other algorithms are broken (18CV8Z, 22CV10).I only have printed data book "ICT Product Data Book 1999/2000"and install disc for "ICT Place DOS", WinPlace 2.0" and "WinPlace 2.1"Currently, I do not use these chips anymore, I have left from the previous production .

author: lluchiari
author_rank: Contributor
timestamp: June 30, 2020, 03:06:20 pm
content: Hey Guys...i need help to an old program here.... I'm young and I never programmed any SPLD! I need to make my own programmer for an PEEL22CV10A but the documentation is rare! I found some App Notes with help of wayback machine but It seems to be a secret how they program EPLDs! ICT company was incorporated to DIODES and I asked them about information and they said that they bought the company 10 years ago and this product was outdated on that time!Anyone knows how to read and program this PEEL22CV10?

author: Beta_vulgaris
author_rank: Regular Contributor
timestamp: November 22, 2022, 01:34:15 pm
content: Quote from: lluchiari on June 30, 2020, 03:06:20 pmWhich appnote? I only have PEEL16CV8, PEEL18CV8 and PA7540. Also, PALCE information can be found athttps://dewey.petra.ac.id/catalog/digital/detail?id=16353.
Protocol of available phone touchscreen - Page 1
Forum section: electronics / projects

author: Jaunedeau
author_rank: Regular Contributor
timestamp: October 01, 2022, 07:11:15 pm
content: Hi,some capactiv touch screen (only the touch panel, without the screen) that can be bought as replacement parts for phone at low price (<5€ one aliex) have a chip on the flex pcb that comes with it.are there some cheap, easy to source and flat (no curved borders) touch screens which have a well known chip that could be used with an MCU so it can be used with cheap MCU with few ADC pins ?Thank you,John.
Prototype board for 50 way IDC header socket. - Page 1
Forum section: electronics / projects

author: djsb
author_rank: Super Contributor
timestamp: October 31, 2021, 02:15:32 am
content: I need to make a dummy load for the A6 power supply on my HP8563E spectrum analyser. I want to put a 50 way (2 rows of 25 pins) 0.1 inch pitch socket similar to this onehttps://www.digikey.co.uk/en/products/detail/3m/3433-6302/416597on the prototype board. Are there any prototype boards available that can be used easily with a socket of this type? The socket above is on the actual power supply, so I would need a 50 way ribbon cable as well as another socket and 2 matching plugs. If there is something that I can fit an edge connector to, that would be good.I need a board that I can fit big power resistors to. Also, can ribbon cable be bought that already have the 50 way plugs already attached? This would save me buying the tooling, although I'd normally use a vice to fit ribbon cable to the socket. Any ideas, advice and insights welcomed. Thanks.

author: Nominal Animal
author_rank: Super Contributor
timestamp: October 31, 2021, 05:21:56 am
content: Quote from: djsb on October 31, 2021, 02:15:32 amI do believe that connector was often used in computers for internal 50-pin SCSI connections. So, check if 50-pin SCSI internal cable is what you need; they're cheaply available (<$10). The housing with the male pins having a slot in the middle about two pin spacings wide is a dead giveaway.It's basically almost the same as used on IDE/PATA (40-pin IDC), but with 50 pins.My own approach (I'm just a hobbyist!) is to use a longer ribbon cable, and cut it in half. Using one half, separate the leads a bit, say about 2cm. These cables have a 0.05" pitch (have to have, these being IDC with two rows of pins at 0.1" pitch), so if you have a stripboard or veroboard with standard 0.1" pitch, you can solder odd wires to one side, and even wires to the other side, or even two different boards. Crude and cheap, but so am I.Alternatively, a standard 0.1" pitch 2×25 male header pin block will mate with the female connector IDC cable just fine. If you don't like crude, that is.
Prototyping component holder - Page 1
Forum section: electronics / projects

author: cowasaki
author_rank: Frequent Contributor
timestamp: February 29, 2020, 09:50:56 am
content: I'm looking for ideas for some kind of holder for components. such as caps and resistors. I'm building a valve amplifier experimentation kit for the 3D printer so there will be equal sized blocks for 9 and 8 pin valves, tone stack, reverb unit etc etc. For the tone stack you might wish to change the fixed resistor and or cap values. I've sorted how I will do the pots.....Any ideas?

author: tautech
author_rank: Super Contributor
timestamp: February 29, 2020, 09:54:31 am
content: Wiper style IC sockets ?

author: cowasaki
author_rank: Frequent Contributor
timestamp: February 29, 2020, 10:01:18 am
content: Quote from: tautech on February 29, 2020, 09:54:31 amYes that was one idea as was headers like arduinos have. I'm trying to find the best options. I hope to produce lots of modules of a standard size (plus some half and double sized). So that you can quickly prototype a new valve amp design whilst keeping the dangerous voltages at bay.

author: tautech
author_rank: Super Contributor
timestamp: February 29, 2020, 10:11:33 am
content: You could probably blank every second hole off to give adequate separation but still components will be close together or go real agricultural and use screw terminal chocolate blocks.Then again there are mains push connectors but not sure if they're available in PCB mount.Have a look at the Phoenix catalogue.https://www.phoenixcontact.com/online/portal/nz?1dmy&urile=wcm:path:/nzen/web/main/products/entry_page/entry_page

author: cowasaki
author_rank: Frequent Contributor
timestamp: February 29, 2020, 10:22:37 am
content: Quote from: tautech on February 29, 2020, 10:11:33 amThanks. Not wanting things to be PCB mount. Point to point will be ideal...... When I'm in valve mode I have to shun those horrible "circus boards". I have to compartmentalise my electronics

author: ChristofferB
author_rank: Frequent Contributor
timestamp: February 29, 2020, 02:18:45 pm
content: What about IC sockets or tiny breadboards mounted on tube bases, fitting in additional tube sockets?The component assemblies could then be put in cardboard/aluminium tubes for aesthetics, soldered into more rigourous plug-in modules free-wire or perf board or similar.
Prototyping in process... - Page 1
Forum section: electronics / projects

author: slateraptor
author_rank: Frequent Contributor
timestamp: November 23, 2011, 08:29:09 am
content: It's been an interesting learning experience thus far. Still have a bit to go; 95% code from this point forward.All rails stable on load, FPGA boots and configures, VGA outputs.When all is said and done, a complete redesign without haste and deadline is in order.

author: BravoV
author_rank: Super Contributor
timestamp: November 23, 2011, 08:59:31 am
content: Looks great, what does it do ?

author: slateraptor
author_rank: Frequent Contributor
timestamp: November 23, 2011, 09:14:48 am
content: Quote from: BravoV on November 23, 2011, 08:59:31 amI thought the sockets were a dead giveaway.With a bit of VHDL savvy and a pinch of luck, a cycle-accurate NES emulator largely inspired by the work of Dan Strother and Brent Allen, and fueled by the countless others that have contributed reverse engineered data onnesdev.parodius.com/throughout the years.http://danstrother.com/fpga-nes/The main difference is 1) all hardware was designed from the ground up, and 2) I'm working solo on this project with a tight deadline (everyone in my class either thought my project was lame or ran away screaming by the complexity when I proposed the project late August).

author: Balaur
author_rank: Unknown
timestamp: November 23, 2011, 09:42:04 am
content: Quote from: slateraptor on November 23, 2011, 09:14:48 amHey, the famous sockets! I'm glad to see that you managed to fit them. Did you ground the pins or did you drill larger holes?Nice project and kudos to you for your work ethic and enthusiasm.Quite complete as well. I can see:- discrete (i.e. not POL) switching supplies - not the easiest solution, but it shows your determination- the FPGA with its oscillator, JTAG port and adequate decoupling- 6 bits resistor ladder DACs for the VGA- modular construction- a LED on the FPGA board. Is that the DONE led?Hey, show us the middle board too!How is the sound generated?Congratulations and many nice wishes for easy development and debugging!Cheers,Dan

author: Balaur
author_rank: Unknown
timestamp: November 23, 2011, 09:45:16 am
content: By the way, what's the Bluetooth for?

author: slateraptor
author_rank: Frequent Contributor
timestamp: November 23, 2011, 09:57:20 am
content: Quote from: Balaur on November 23, 2011, 09:45:16 amhttp://upload.wikimedia.org/wikipedia/commons/1/1d/Wii_Remote_Plus.jpgMore details when time permits. I intend to publish all my work online NLT next summer.
Prototyping wire - Page 1
Forum section: electronics / projects

author: gaminn
author_rank: Frequent Contributor
timestamp: January 10, 2020, 04:14:51 pm
content: Hi,I use this wire for prototyping:It is 0.3 mm diamater solid tinned copper wire, overall diameter 0.7 mm, silicone insulation (so it can withstand high temperature during soldering).I'm running out of this cable. Do you have any idea where this can be bought?

author: edavid
author_rank: Super Contributor
timestamp: January 10, 2020, 04:28:52 pm
content: Are you sure it's silicone insulated? It looks like regular 30AWG Kynar insulated wire wrap wire. Kynar is kind of hard and waxy, rather than soft like silicone. It's a lot easier to strip.P.S. If you want tips on where to buy things, you shouldn't set your country to 00.

author: tooki
author_rank: Super Contributor
timestamp: January 12, 2020, 04:11:57 pm
content: Quote from: gaminn on January 10, 2020, 04:14:51 pmThis vendor sells 26AWG (0.4mm diameter) solid wire with silicone insulation. But I’m sure its overall diameter is much larger than 0.7mm (they don’t specify).https://www.aliexpress.com/item/32880626533.htmlWith that said, I agree with edavid that your wire is unlikely to be silicone. Silicone insulation is comparatively weak, so it tends to be thicker than PVC insulation, which in turn is thicker than Kynar (PVDF), Tefzel (EPFE) or Teflon (PTFE) insulation, since those materials are tougher. Alas, those materials are also a lot more expensive, making such wire rather costly. Best bet for those is to get them from military surplus. (I need to go back to Los Angeles so I can go to Apex, which sells such wire by the pound!)

author: gaminn
author_rank: Frequent Contributor
timestamp: January 14, 2020, 08:39:35 pm
content: You are right, it is probably not silicone, it is not soft. But definitely it is high temperature resistant, it does not burn when I touch it with my solder at 350 °C.I'm from central Europe, Czech Republic. Not sure why there is 00 as my location - in my profile here I have location filled with my country.

author: nctnico
author_rank: Super Contributor
timestamp: January 14, 2020, 09:02:12 pm
content: It is very probably teflon coated wire. That is very common for prototyping.
Protron / SpectronIQ PLTV-4250 Service Manual or Schematic? - Page 1
Forum section: electronics / projects

author: Kilohurtz1
author_rank: Newbie
timestamp: June 05, 2013, 08:31:12 pm
content: Hello, I'm new to EEV... recently found the YouTube channel and this is my 1st post here... look like some great info all the way around.. Thanks to Dave and all for sharing your knowledge.. I'm a Network Consultant / Engineer by trade, but also an electronic hobbyist as well.. by no means a professional, but find my way to fixing a lot of broken stuff..I have acquired a SpectronIQ PLTV-4250... same as Protron PLTV-4250... been looking for a Service Manual or Schematic... no luck.. apparently this set is a real turd.. (guess they all are when they are broke huh?) The set powers on, but it makes a screeching noise from the speakers and has some screen distortion now.. found a couple bulging caps on the power supply board... I plan to replace all the caps`anyway... but i suspect the screeching is coming from the mainboard... anyway, if anyone knows where i can get a service manual/schematic or has any experience with this unit.. I'd appreciate any input... looks like most of these met their demise when the PSU caps went... don't think many lasted long enough to develop other issues.. I'd like to try to save it to use in the garage/shop..ThanksKilohurtz1

author: marshallh
author_rank: Unknown
timestamp: June 05, 2013, 09:22:32 pm
content: High volume mass market products like that have such small margins nobody bothers with service manuals except maybe the more established brands like Sony, Panasonic, Toshiba, etc.Order repacement caps that are low-ESR only. Your vanilla radio shack crap will just go belly up in short order.Look through digikey or mouser for low-ESR series like Panasonic's FC and FM series.You may spend $20-40 on this and it still may not fix everything. Just so you know
Proximity-Based RFID System - Need Advice - Page 1
Forum section: electronics / projects

author: Enthusiastic Student
author_rank: Newbie
timestamp: September 03, 2013, 06:07:38 am
content: Hey everybody,I'm new to this forum so forgive me if it is incorrectly posted or anything like that.PS I'm no beginner in microcontrollers but RFID is brand new to me.I'm trying to create a system where whenever someone carrying an RFID tag got close enough, a microcontroller would be able to sense it. I can program the microcontroller to carry out the desired tasks without help though. The system must respond whenever the tag and reader are within about 4 or 5 feet from each other. I would like the tag to be passive if possible and if it is not then how to keep the power draw to a minimum. Also, the power consumption of the reader is fairly irrelevant. Ideally, I would like to find a good kit that comes with what I need that I can just program or find a few parts that work well together that I can improvise. Does anyone know of a good kit for this or have any advice/thoughts?Thanks in advance for any help and I apologize for my lack of aptitude.
Proximity detection for a keyboard? - Page 1
Forum section: electronics / projects

author: 3dgeo
author_rank: Frequent Contributor
timestamp: June 07, 2020, 01:10:12 pm
content: Hi,I would like to hear suggestions on a simple solution how to implement proximity/hand over detection in a keyboard I'm designing.I have a steel plate under keycaps, so I was thinking about capacitive detection, but I don't know how well it would work in real world situation...Idea is to use it to turn on/off backlight, I know this could easily made by detecting key press, but I want a bit more sophisticated solution, even if it will add few bucks to the BOM.All suggestions are welcome.EDIT:This is what I'm looking for:Find on Google:"When something approaches, such as a steel disk or a hand, the impedance changes. When the impedance passes a certain threshold, the controller will know to turn on/off the backlight" (green PCB – "Santiago proximity detector"):

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 07, 2020, 03:21:47 pm
content: IR LED one one side of the keyboard coupled with an IR detector on the other side. Modulate the light to make it resistant to ambient light and look for changes in IR reflectivity.There's also radar and sonar, but those are likely to cost substantially more than an IR LED and detector. PIR is another possibility.

author: 3dgeo
author_rank: Frequent Contributor
timestamp: June 08, 2020, 07:48:11 pm
content: Thanks for your reply,I had IR in mind, but sensors will be visible and relatively unprotected.I think I will try duplicate Logi keyboard approach.
Proximity sensor anyone use MTCH101 or MTCH105? - Page 1
Forum section: electronics / projects

author: Jester
author_rank: Frequent Contributor
timestamp: July 25, 2017, 09:31:52 pm
content: Hi,I need to add two proximity switches (just on and off) to a device, to be implemented as pads on a PCB with solder mask over top (Think common on/off household light switch)I can use 2 x MTCH101 (with no guard trace) or use one MTCH105 (with a guard trace). The layout will be easier if I can use 2 x MTCH101 layout wise as all routing will be done on one side (solid ground plane on touch side of PCB (other than the two sensor pads) so that is my preferred solution, however if the no guard trace solution is likely to be overly sensitive to false triggers I will use the MTCH05.Does anyone have experience with these parts in a real world application?https://www.digikey.com/product-detail/en/microchip-technology/MTCH101-I-OT/MTCH101-I-OT-ND/3872305http://ww1.microchip.com/downloads/en/DeviceDoc/40001793C.pdf
Proximity sensor for "inteligent storage" system - Page 1
Forum section: electronics / projects

author: jayx
author_rank: Regular Contributor
timestamp: November 30, 2023, 10:13:22 pm
content: I plan to build a sort of "inteligent storage" system. It supposed to detect if a small plastic container is in the slot or not. There will be about 100 containers in an array. I thought I can use an array of infrared proximity sensors on I2C bus for detection of the containers, but what I've found so far seems to be quite sophisticated with a distance measurement and over 100mm of range, or simple present/not present sensor, but without I2C. Maybe someone can suggest a specific component?

author: MarkT
author_rank: Frequent Contributor
timestamp: November 30, 2023, 10:20:07 pm
content: I2C devices typically support a few addresses at most, often just 2, so 100 sensors isn't going to fly. This is probably an application for a multiplexed array of sensors.

author: Buriedcode
author_rank: Super Contributor
timestamp: December 01, 2023, 07:36:51 pm
content: Or a few sensors pointing toward the front of the draws, with one IR LED per drawer. Turn on one LED at a time and the sensors can pickup where the object is base don time. Bit like how old light guns worked on Tube TV's.

author: Ian.M
author_rank: Super Contributor
timestamp: December 01, 2023, 08:55:13 pm
content: Old-skool would be microswitches with series diodes so they could be read individually, possibly in a 10x10 matrix, though for ease of coding it an 8x13 matrix would be preferable. Drive the 13 row line from two 74HC138 chips so only one goes low at a time, controlled by four output bits from a 16 bit I2C I/O expander (or direct from your MCU), and read out which switches are closed (low) from an eight bit input port with pullups on the same I/O expander( or your MCU).

author: jayx
author_rank: Regular Contributor
timestamp: December 08, 2023, 10:57:52 pm
content: Thanks for the ideas. I thought about switches, but thought it wouldn't be very reliable solution. I've found some inexpensive sensor BROADCOM APDS-9930, but quickly found out that it has fixed I2C address! Then I've looked at other similar sensors, every one I've checked had fixed addressI guess that's what MarkT meant, wondering what's the point of I2C then?Anyway, today I've been printing some documents on a large office printer/scanner and noticed that the scanner has automatic paper size/orientation detector in the form of three sensors. I thought it's exactly what I was looking for, I'm tempted to take it appart to see how they are connected, would be surpriced if each one is on a separate I2C.
Proximity Sensors and RFID tag project brainstorm help. - Page 1
Forum section: electronics / projects

author: TheWinterSnow
author_rank: Contributor
timestamp: December 16, 2015, 03:10:49 am
content: I want to build an alarm system that can alert users through email, text or audio alarms in certain locations if a person or large object comes within range of a proximity sensor. The caveat is that I don't want it to go off all the time so I want to utilize RFID tags that if within range of the transceiver and proximity sensor, has a password that prevents the alarm from going off.The proximity part is not that much a big of deal, however the use of RFID tags is. I am not aware of there being commercially available RFID tags that can be programmed. Since I REALLY don't want to deal with the idea of making my own I want to know where I could get RFID devices that can be programmed to communicate with certain deviced and be programmed to hold passwords.

author: AustinEngy
author_rank: Regular Contributor
timestamp: December 16, 2015, 03:24:30 am
content: This project sounds like you could really use a WiFi enabled MCU development board. I've used a Particle Photon in one of my college classes and along with some Google Scripts and IFTTT stuff you can really get creative with your interactions with the world from the MCU. Here's a link to someone who asked a question on the Particle forums about RFID stuff with this dev board.https://community.particle.io/t/what-rfid-readers-do-you-recommend-to-use-with-the-photon/12977There are lots of other IOT dev boards out there, so you can really use whatever you're most comfortable with. It looks like there are quire a few products out there for RFID interaction with microcontrollers and they seem pretty universal.

author: TheWinterSnow
author_rank: Contributor
timestamp: December 16, 2015, 04:04:07 am
content: I do want to use WIFI. The issue that I am having right now is the fact that I want to have a master Arduino inside a secure area within WIFI distance of the sensing Arduino boards outside. I need to be able to multi-plex each sensor and listen to each device in almost real-time.If I have a wifi master device and I have multiple slave devices how do I setup the slave devices to connect to the master device and how do I get my master device to connect to my main internet wifi router?
PS/2 keyboard behaviour - Page 1
Forum section: electronics / projects

author: Dan Moos
author_rank: Frequent Contributor
timestamp: March 12, 2019, 02:45:27 am
content: Trying to get a PS/2 keyboard controller working. Right now I just have the keyboard hooked to power and a scope.With just power, and pull ups on clock and data, the keyboard is sending a byte of data every ~60 mS.The data it sends is always 11 clock ticks (as it should be), and its a stop bit (0), 8 data bits that are always 55 hex, a parity bit (1) and a stop bit (1)I feel like I need to reset the keyboard or something. If it helps, I'm using one of those Digilent PS2 adapters, which has built in pull ups. I'm aware that the rev 1 of that little board had an incorrect silkscreen. I'm confident my wiring is correct. Everything its HIGH between data bursts as it should.As an aside, this is for a homebrew 6502. I am willing to skip the PS/2 interface completely, and tie into the keyboard matrix to do it manually. Is there a standard to how those are laid out on the zebra strip? I know I can brute force figure it out, but I'd rather not!

author: magic
author_rank: Super Contributor
timestamp: March 12, 2019, 12:07:00 pm
content: There is no standard matrix layout. It isn't simple either, traces make zigzags to avoid ghosting in common key combinations.0xAA is self-test-ok, maybe you've got the bits backwards?At any rate, I would just connect it to some host and see what it does to initialize it and do the same.If you kb supports it, you could avoid dealing with the idiotic extended scancodes and things like 0xE0 0xF0 0x7C 0xE0 0xF0 0x12 by switching to scancode set 3. Google it, I guess.editThis is my favorite, highly detailed reference on old PC keyboards.https://www.win.tue.nl/~aeb/linux/kbd/scancodes.htmlSee table in 1.2 for non-scancode messages the keyboard may send.Chapter 12 deals with commands you can send to the kb.Chapter 10 is scancode maps in various scancode sets. Use set 2 for compatibility with any random keyboard, use set 3 to save your sanity if you can.Whenever they speak of translated/untranslated, untranslated is the raw bits from the wire and translated refers to what software sees after the bits pass through the byzantine hardware of the PC. Ignore this nonsense when building your own host.