hybridfree/eevblog-posts huggingface dataset:
Spycatcher Direction Finding - Page 1
Forum section: electronics / beginners

author: Dasypus
author_rank: Contributor
timestamp: July 22, 2025, 03:33:00 pm
content: In Peter Wrights book "Spycatcher", he says, referring to tracking signals:"...Every radio set contains a local oscillator to "beat down" the incoming signal into a fixed frequency which can be much more easily filtered. The local oscillator always radiates sound waves as it operates, and it is the presence of these that reveal the presence of a receiver".Isn't it re-radiation back out the antenna at the LO frequency modulated by the sound?In the case of a TV detector van, of old, you would need clear access to the TV's antenna, so a radio inside a building would much more difficult to intercept?There are, to me, several "technical" statements made by the author that seem dubious, I also haven't finished reading it yet.Just wanted your thoughts on this particular statement, or indeed others if anyone has read the book.

author: iMo
author_rank: Super Contributor
timestamp: July 22, 2025, 03:50:33 pm
content: It depends on the construction of the radio set the spy operates.. You may detect with a sensitive equipment a radio which receives because is on, or/and receives at a specific frequency, that is feasible. There are usually 2-3 oscillators inside which are weak, usually shielded, but they radiate elmag waves (not the sound waves as you mentioned above). Those frequencies are detectable, but very weak.Some types of radio receivers radiate with a significant signal strengths, those are usually not recommended to use in general as they pollute the frequency bands.PS: you may even detect a radio receiver and/or a transmitter when is switched off from the power source - as its antenna circuits may suck in the energy of your detection oscillator when both are in resonance (on the same frequency)..

author: jc101
author_rank: Frequent Contributor
timestamp: July 22, 2025, 04:01:03 pm
content: I think that refers to RAFTER.A quick search and there is even a Wikipedia article on it.https://en.wikipedia.org/wiki/Operation_RAFTERAll part of the SIGINT world.
SQUARE NPTH HOLE (Opening) in PCB - Page 1
Forum section: electronics / beginners

author: caltroniks
author_rank: Newbie
timestamp: July 15, 2020, 05:25:17 pm
content: Hello Everyone.I am trying to make a SQUARE NPTH HOLE in PCB .This hole(opening) is for a light sensor .Light would fall onto the sensor through the opening.For this i was able to make a SQUARE hole using Hole editor .I did get a NC drill NPTH file for square HOLE. However when the drill file was opened in CAMTASTIC or ViewMate i am getting a round drill hole.Now normally a PCB fabricator will not have a SQUARE DRILL setup .as far as i know no one would have such as anormal practice.However can any one share info as to how i can show the SQUARE hole in Gerber or a drill file..?I am starting out with Altium Designer.Response much appreciated.Thank youA.Calvin

author: Benta
author_rank: Super Contributor
timestamp: July 15, 2020, 05:44:29 pm
content: You'll need to think about how PCBs are fabricated.There's a drilling machine that makes round holes (obviously), and the Gerber .drl file contains the positions and sizes of these holes.And there's a mill that cuts the outline of the board (mostly the same machine with a different tool).If you want an irregular hole in your board, you'll need to define it in the outline of the board. It will always have rounded corners, though.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 16, 2020, 05:47:06 am
content: You can get mechanically punched, or laser cut, holes in specific circumstances. If you want the board fabricated by whatever bargain basement proto fabs are out there, it's going to be milled, and you will have a corner radius.Tim
Square peg in a round hole  (pins) - Page 1
Forum section: electronics / beginners

author: Back2Volts
author_rank: Unknown
timestamp: September 13, 2016, 12:28:14 pm
content: Can you mix round and square 0.1" pin headers ? I mean insert square pin males into round pin females and vice versa ?

author: tooki
author_rank: Super Contributor
timestamp: September 13, 2016, 12:40:29 pm
content: In my experience, not really. The round male pins are too thin for square female, and male square are too big for round female.I use square for almost everything. (Also because round don't seem to be available for cheap on eBay in right angle versions).However, the round female are extremely good as component sockets, for example if you want to easily swap LEDs, capacitors, etc. on a PCB. And the round male pins work reasonably well, soldered to thin wire, to insert into IC sockets without damaging them.Beware, if you insert a too large pin (regardless of shape) into a round female socket, it will ruin the contacts inside and leave it loose. [Insert juvenile joke about loose female holes here.]

author: CatalinaWOW
author_rank: Super Contributor
timestamp: September 13, 2016, 10:51:36 pm
content: It frequently works once. But the reliability is definitely lower, and the times I have seen it work weren't challenging in terms of vibration, temperature or life.If you ever put the right shape in the hole you put the wrong shape in your chances of success are low.I would avoid it if there is any way you can.

author: Back2Volts
author_rank: Unknown
timestamp: September 14, 2016, 01:10:26 am
content: Thanks. I had tried with loosely with two unmounted headers and it looked like it would need brute force.Good to know.

author: Brumby
author_rank: Unknown
timestamp: September 14, 2016, 01:14:34 am
content: A general formula that I have observed with consistent results:Brute Force = Damage

author: CatalinaWOW
author_rank: Super Contributor
timestamp: September 14, 2016, 05:58:50 am
content: Quote from: Brumby on September 14, 2016, 01:14:34 amTrue. But a creative mind finds ways to make damage a positive. Someone like that invented the crimp connection. Someone else invented explosive forming of metals.Maybe someone creative can think of something positive in this case.

author: Brumby
author_rank: Unknown
timestamp: September 14, 2016, 08:41:29 am
content: Quote from: CatalinaWOW on September 14, 2016, 05:58:50 amThat sounds like a challenge - and one from which I'm curious to see what ideas may surface....
Square Wave 6 Step Commutation Resistor Network Values? - Page 1
Forum section: electronics / beginners

author: ericwil76
author_rank: Newbie
timestamp: August 10, 2024, 02:21:59 pm
content: Hello folks new here save the introduction gonna ask a lame question.I am designing a motor drive for a brushless motor and need to set the resistor network values for my 6-step commutation sensing. I understand how it works but not the formula to determine the resistor values to supply voltage to each pin on the MCU.The Vin or BAT voltage in this case for nets Motor A, B and C is (9 - 50.4V). This is 3-12S LiPo absolute low to high voltage cutoff ranges.The MCU can only input up to 3.3V's on Pins P0.0, P0.1, P0.2 and P0.3.I need safe resistor values so I do not over or underdrive the MCU pins. The Pin input voltage needs to be between +0.0V to 3.3V.I know how to calculate the forwarded voltage across a resistor but I am not clear on the formula for the network.Here is a picture of the network, the values listed are arbitrary and come from a reference design with different voltages.Any help is greatly appreciated.

author: trilerian
author_rank: Regular Contributor
timestamp: August 12, 2024, 07:54:16 pm
content: 3s-12s LiPo for a motor controller is a big range... From looking at what you are doing, I assume you are building a sensorless controller and you are going to use zero cross detection for rotor position. Ultimately you need to drop your max of 50.4V down to a voltage that can be seen by the mcu inputs. In reality the voltage will not quite be 50.4V, but it will be close. Looking at your diagram, look at R37 and R44, these two resistors make a voltage divider on phase A. R37 is R1, and R44 is R2. I would say something like 120kΩ for R1 and 7k5Ω for R2. You will need the same values for each of the 3 phases of the motor. Then the last bit on the left of your diagram are the resistors that tie all the phases together to create the virtual common. These just need to be high enough to limit current on them. I've used 33k-100kΩ. Then you will be comparing the phase wires to the virtual common to determine the zero cross. You may want to look into low pass filters for the signals as well, they are extremely noisy. Mind your low pass values though, it could change your perceived zero cross time.
Square wave current  amplifier for frequency generator - Page 1
Forum section: electronics / beginners

author: zanzeoo
author_rank: Contributor
timestamp: September 17, 2018, 10:41:54 pm
content: Hi everyI planning to make an current amplifier for my frequency generator.the main goal is to be able to generate a 10Vpp square signal with a resistive load of 33 ohmsI was thinking to do it with a mosfet pushpull and a laboratory dc power supply to generate +/- 5V , but i need some advices to do it proprelywhat are your advices ?
Square wave generator with variable frequency - Page 1
Forum section: electronics / beginners

author: tigrou
author_rank: Regular Contributor
timestamp: June 12, 2021, 09:00:17 pm
content: I have created a simple circuit based on this schematic to generate a square wave:It works great. I would like to be able to change the frequency depending some voltage input (eg : the higher voltage the higher the frequency).I have decided to replace RF by two mostfets in parallel (since it's AC) to be able to change the resistance depending voltage :Falstad simulatorIt does not work. Circuit does not oscillate anymore or at best give some weird signal with some high duty cycle.Either the way I set and control mosfets is completely wrong or their property values (eg: threshold voltage/beta) is incorrect.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: June 12, 2021, 09:22:27 pm
content: What happens if you simply apply a variable voltage to Vnat the junction of C and Rf? Like from the wiper of a potentiometer wired as a voltage divider between Vcc and ground?

author: ledtester
author_rank: Super Contributor
timestamp: June 12, 2021, 10:21:26 pm
content: You can find a classic VCO (voltage controlled oscillator) circuit with an operating principle similar to your original oscillator in this post:https://www.eevblog.com/forum/beginners/spikes-on-triangle-wave-in-vco/

author: Vincenzo
author_rank: Regular Contributor
timestamp: June 12, 2021, 10:26:01 pm
content: Ortry connecting the end of R1 that is going to ground to the control voltage, instead. Then play with the values of the three resistors (or do some good old algebra) to get the range you desire. Think of it as a Schmitt Trigger with an RC feedback network (use the famous charge-discharge exponential transient equations and the equations below)ledtestervery cool topic you referred to

author: ledtester
author_rank: Super Contributor
timestamp: June 13, 2021, 12:07:32 am
content: QuoteJust simulating the back-to-back MOSFETs in Falstad shows this V-I curve:(Falstad simulation of MOSFETs)Green trace is voltage across the pair, yellow trace is current.So the pair doesn't conduct when reversed biased. It acts more like a diode, not a resistor.

author: tigrou
author_rank: Regular Contributor
timestamp: June 13, 2021, 10:21:17 am
content: Quote from: ledtester on June 13, 2021, 12:07:32 amGood point. I should have tried something similar before.EDIT : I have tried all 3 configuration from thispagebut none of the works. It conduct in one direction but never both.Falstad simulation

author: ledtester
author_rank: Super Contributor
timestamp: June 13, 2021, 11:26:41 am
content: Found this:https://electronics.stackexchange.com/questions/550584/bidirectional-voltage-and-current-switch-using-mosfetsand this:https://electronics.stackexchange.com/a/484242/95488
Square wave inverter for Analogue Oscilloscope - Page 1
Forum section: electronics / beginners

author: Hex173t
author_rank: Contributor
timestamp: September 23, 2011, 04:57:51 pm
content: I did a search for oscilloscopes and square wave inverter and found it addressed for use with a Rigol model (thread Re: Using rigol DS1052E with Kensigton inverter back in Feb 11). Is there any difference in the analogue scopes such as the Tek 468? Sure would make me sad to kill it accidentally.Bill

author: Simon
author_rank: Unknown
timestamp: September 23, 2011, 05:09:18 pm
content: you really want a sine-ish inerter if the scopes psu works off a traditional transformer

author: Zero999
author_rank: Super Contributor
timestamp: September 23, 2011, 06:35:02 pm
content: I haven't done any tests with 'scopes but I'd suspect analogue would' be worse than digital.Most inverters nowadays at least modified sinewave. I don't think I've seen a squarewave inverter apart from the homebrew variety. Modified sinewave is slightly better but not much. The worst thing with squarewave is the peak voltage is equal to the RMS voltage so a 230V squarewave may not have a high enough peak voltage to power an SMPS which would be designed for 230VAC with a peak voltage of 325V. A modified 230V sinewave has a peak voltage of 325V and an RMS voltage of 230V so will be able to power an SMPs or an incandescent lamp with no problem. Another issue is the harmonics and RFI which will a squarewave than a modified sinewave.The reason why a digital 'scope will probably be better is that its power supply is switched mode so will be rectified to 325VDC anyway. There should be a good RFI filter to remove the harmonics generated by the SMPS anyway. An analogue 'scope will have a transformer connected to a rectifier and very little RF filtering.

author: Unknown
author_rank: Unknown
timestamp: September 23, 2011, 10:51:53 pm
content: My guess would be the same as Hero, a typical linear supply has much less RF filtering, since 50/60Hz ripple tends to dominate with a good quality mains supply.Be sure to consider the safety implications if your inverter doesn't supply the scope with a reliable and low-impedance ground connection, it would be sad to kill yourself accidentally.

author: Hex173t
author_rank: Contributor
timestamp: September 24, 2011, 12:01:19 am
content: Thanks for the responses! The consensus seems to be don't use this type inverter on an analog scope.Bill

author: tekfan
author_rank: Frequent Contributor
timestamp: September 24, 2011, 11:00:31 pm
content: Tektronix made a squarewave inverter with a battery pack that was designed for the 400 series.http://amplifier.cd/Test_Equipment/Tektronix/Tektronix_other/1105.htmlBTW the Tek 468 is actually a digital storage scope

author: Hex173t
author_rank: Contributor
timestamp: September 25, 2011, 12:14:14 am
content: Thanks Tekfan, beauty link.And that the 468 is a DSO was a draw when I was reading on what scope would suit my needs. And the work out from moving it around is healthySucker is heavy.Quote from: tekfan on September 24, 2011, 11:00:31 pm
SquareWave UPS to PureSine Wave, using EGS002 module?  - Page 1
Forum section: electronics / beginners

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: December 10, 2024, 11:25:00 pm
content: EGS002 module datasheetI have the schematic for an APC 500VA UPS. This UPS creates a "stepped approximation of a sinewave". Would it be easy to replace the original MCU with the EGS002? What sorts of problems may I come across?I can imagine:- The transformer being a problem due to the significantly faster switching speed of sPWM- Potentially higher losses in the FET's, due to the faster switching?- Loss of battery charging functionality? (I'd imagine the UPS would need to become a "double-conversion" UPS, as the EGS002 module only appears to help output 120v, and cannot detect a loss of power on the input?)-Anyone have any input? I'm not sure if there may be an easier way to convert a Squarewave UPS to PureSine? Thanks.

author: LinuxHata
author_rank: Frequent Contributor
timestamp: December 17, 2024, 04:45:01 am
content: I also had such ideas.As it turned out, it was much cheaper and practical in terms of time saving, to order a sine wave inverter from china.Of course, power rating is usually inflated 3-4 times, but this can be considered by use of simple math

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: December 17, 2024, 09:28:59 am
content: Hi,Quote from: LinuxHata on December 17, 2024, 04:45:01 amYeah, but be prepared for some noisy crap.I had to return the first two because to much disturbances(especially at the zero-crossing) and have a "4kW" Easun now.Good luck

author: J-R
author_rank: Super Contributor
timestamp: December 17, 2024, 09:49:18 am
content: I'm pretty confident your "stepped approximation of a sinewave" is literally just a single, simple square wave. At least it is on all the UPS units I've checked.The newest pure sine wave UPS units are worth upgrading to. Much longer runtime for the same Ah, better for equipment, and idle power draw is less due to newer regulations.

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: December 19, 2024, 04:38:15 pm
content: I'm mostly hoping to do this project for fun and to say "I did it", not so much for practically. I know I can buy pure-sine inverters for around $50USD, while the actual EGS002 module is about $7USD.
Squeegee size for a framed stencil with an effective area 19x29? - Page 1
Forum section: electronics / beginners

author: Savinda
author_rank: Newbie
timestamp: January 22, 2017, 04:38:23 am
content: Hi,I'm thinking of buying a PM3040 Neoden stencil printer and getting the 37x47 stencils from Seeedstudio. Neoden says that the printer comes with a 10cm squeezer; however we are planning on applying paste to a large panel. The effective area of the Seeedstudio 37x47 cm stencils is 19x29. Does this mean that we need a squeegee larger than 19cm? Is it possible to use a 10 cm squeegee and pass over sections of the panel instead?Thank you very much for your time,Savinda
SR latch and D flip flop - Page 1
Forum section: electronics / beginners

author: promach
author_rank: Frequent Contributor
timestamp: August 09, 2018, 02:22:37 am
content: How does the two SR latches resemble a resetable D flip flop ? Could anyone elaborate ?QuoteI am also not quite sure about the speed limitation as well...

author: Nusa
author_rank: Super Contributor
timestamp: August 09, 2018, 02:49:13 am
content: You haven't really described what it is you are having trouble with. I'd suggest searching for "flip-flip logic" and you'll get plenty of hits. Here's one to start with:https://en.wikipedia.org/wiki/Flip-flop_(electronics)If you want to know about a specific flip-flip, look at its datasheet. They're usually pretty useful.
SRAM missing address lines question - Page 1
Forum section: electronics / beginners

author: alank2
author_rank: Super Contributor
timestamp: February 21, 2018, 05:01:01 am
content: I've read that it doesn't really matter between say a Z80 and a 64K sram which address lines go where because it it will just store the bits and then retrieve them from the same location. Same with the data bits. (Obviously you can't swap an address bit with a data bit).My question is - does it make any different to the SRAM if you are reading all memory from 0x0000 to 0xFFFF whether the lines are in order or swapped. In the case of a sequential access, A0 would be toggling 32768 times for reading all memory and A15 only once. Electrically does it matter if A0 is connected to A13 and A15 is connected to A5? In this case the sequential access will look more random, but internally and electrically is it any difference to the SRAM?

author: ataradov
author_rank: Super Contributor
timestamp: February 21, 2018, 05:17:59 am
content: No difference at all. And Z80 is slow anyway, so it doubly does not matter.

author: basinstreetdesign
author_rank: Frequent Contributor
timestamp: February 21, 2018, 05:41:27 am
content: Quote from: ataradov on February 21, 2018, 05:17:59 amYup - no difference. The only "but" I can think of is if you are pushing the timing specs and looking for speed which is not promised then some odd re-arrangement of the address lines may work for you within a localized section of the address map, but that's it.
SRAM....Volatile or Non-Volatile - Page 1
Forum section: electronics / beginners

author: yoda_bear
author_rank: Contributor
timestamp: April 25, 2017, 03:22:49 pm
content: Is there a way to find out from the part number whether a SRAM component is volatile or non-volatile? In particular, a Cypress component.Thanks for any help.

author: Fgrir
author_rank: Regular Contributor
timestamp: April 25, 2017, 03:38:06 pm
content: SRAM is volatile unless there is a battery attached to supply power 100% of the time. That part has no built-in battery so you'd have to look at the rest of the board.

author: yoda_bear
author_rank: Contributor
timestamp: April 25, 2017, 03:40:35 pm
content: Thank you. No battery on the board

author: David Hess
author_rank: Super Contributor
timestamp: April 26, 2017, 09:28:33 am
content: Cypress makes some nonvolatile SRAM which does not require a battery or external power but the CY62137 is just a normal low standby power SRAM.
SRP420 Polyswitch - Polarized? - Page 1
Forum section: electronics / beginners

author: t1d
author_rank: Super Contributor
timestamp: April 30, 2019, 01:40:22 am
content: Re: Raychem SRP420-CKDXThis polyswitch has a blue stripe. Does that indicate polarity? Stripe = Negative; like a diode? I did not see this in the (Littelfuse?) Data Sheet...It was part of a rechargible battery pack.Thank you for your help.https://www.mouser.com/ProductDetail/Littelfuse/SRP420F?qs=%2Fha2pyFaduhgV%252Ba%2FiJna6ki%252B1dIWWm%252B5qgTUTuhWH90%3D

author: jeremy
author_rank: Super Contributor
timestamp: April 30, 2019, 02:46:28 am
content: I can’t imagine what would make it electrically polarized.It could just be used for some sort of machine vision, or be a mark on the tape roll to indicate the peeling direction (so that it can be loaded into a machine properly).
SS OPA buffer, how to handle output voltage swing? - Page 1
Forum section: electronics / beginners

author: Naluto
author_rank: Newbie
timestamp: July 25, 2018, 05:18:40 pm
content: Hello,I'd like to use a voltage divider in combination with an OpAmp as voltage follower / unity gain buffer turn an external 0...5V DC signal into a 0...2.5V signal and feed it into a 12 bit ADC (AD7927, Vref=2.5V). I planned on using a single 3.3V supply for the OpAmp and ADC. (5V USB > Buck > 3.3V)5V |R+----buffer-----adc_inRGND |I don't know what OpAmp I will use yet, but after reading a few datasheets (OPA376for example) I noticed:"At TA = 25°C, RL = 10 kΩ connected to VS / 2, VCM = VS / 2, and VOUT = VS / 2, unless otherwise noted."VCM Common-mode voltage range: V--0.1V ... V++0.1VVoltage output swing from rail: depending on the load up to 50mVIIRC the CM voltage is the voltage that is present at both inputs at the same time, so if I'd use it as a differential amplifier and had a DC offset on the signal.Question:Why does it say that the load is connected to VS/2 (sometimes called mid-supply)? Does that mean I have to give the input an offset voltage to make it operate around that mid-supply?And I read that when you exceed the output swing of the OPA, that you either get "non-linearities" or that the signal can even just clip off at some value.What does that look like in practice when I input a voltage of 10mV to the OPA? Would it always output at least the lower voltage swing, so +20...50mV? Or could it output 10mV, but if I increase the input to 11mV it could output 12mV for example? (non-linearity?)How are buffer circuits built regulary in applications? Do they use dual supply OPAs for that so they can get down to 0V? Or do you just live with the "dead zone" near 0V?Last question: Do you happen to know a good book in english or german where I could read about practical considerations when using OPAs in general / important circuits and stuff like the things I just asked above?If something about the questions is unclear, please let me know. Would be nice if someone could try to make me understand that.Thank you.

author: HB9EVI
author_rank: Frequent Contributor
timestamp: July 25, 2018, 06:27:49 pm
content: if you are talking about a 'buffer', you mean a unity gain amp, so an amplification of +1 - that means nothing else than 10mV on the input will produce 10mV on the output.there are opamps which get very close to the voltage rails - they are called rail-to-rail opamps; one example for your propose could be the MCP6281, it's a rail to rail input and output opamp; it can reach VSS down to a few mV above on the output
SS24 diode footprint for PCB? - Page 1
Forum section: electronics / beginners

author: ElectricPower
author_rank: Frequent Contributor
timestamp: November 21, 2021, 06:13:36 pm
content: I have ordered this SS24 Schottky diode:https://www.aliexpress.com/item/1005001452149989.html?spm=a2g0s.9042311.0.0.27424c4dk2OgKjI using EasyEDA and in library i do find a lot of versions with different sizes of SS24 diode. Can someone help me fin the right footprint for this diode please?

author: ElectricPower
author_rank: Frequent Contributor
timestamp: November 22, 2021, 02:43:36 pm
content: Someone?

author: wraper
author_rank: Unknown
timestamp: November 22, 2021, 02:50:40 pm
content: There is no single right footprint. You can open a datasheethttps://www.onsemi.com/pdf/datasheet/ss26-d.pdf(page 5) and select the closest footprint to that. BTW I don't suggest buying parts on Aliexpress unless there is no other choice. Those SS24 easily may have 5 times smaller silicon die than a genuine part from a reputable manufacturer.EDIT: listing says it's a DO-214AC (SMA) package and on the picture they look like so, not SMB as a usual SS24 should be. So you should use a smaller SMA footprint.https://eu.mouser.com/datasheet/2/80/20190621155523-2504768.pdf(page 4)

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 22, 2021, 02:54:24 pm
content: Any DO-214AC / SMA will do..?Tim
SSB transiter and receiver Tutorial/Explanation. - Page 1
Forum section: electronics / beginners

author: firewalker
author_rank: Super Contributor
timestamp: January 24, 2014, 09:39:43 am
content: Is there any analytic documentation for SSB transmitting and receiving? Not a mathematic analysis.I can find scattered informations for SSB transceivers, bit no one explains what happen inside every build block of the transceiver.Alexander.

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: January 24, 2014, 10:27:02 am
content: (blatant plug follows)Check out a few of these:The basic modules needed in radio circuits - Parts 1 & 2This is pretty much the simplest SSB transceiver you can getA commercially made SSB transceiverIf you want to start more basic, it's worthwhile understanding direct conversion receivers and DSB transmitters before SSB receivers/transmitters.A simple direct conversion receiverA simple direct conversion DSB transceiverAny questions? Ask them here.

author: firewalker
author_rank: Super Contributor
timestamp: January 24, 2014, 10:29:43 am
content: Thanks you! I will watch those asap.Alexander.
SSD1306 I2C Oled on Verilog - Page 1
Forum section: electronics / beginners

author: pieroc91
author_rank: Contributor
timestamp: October 31, 2018, 01:43:33 pm
content: Hi everybody.I'm doing a project on a Altera Cyclone IV FPGA based board, till i solve another projects i was trying to add a small oled ssd1306 based display but i couldn't find any pre-made library, or code, or anything...tryed to code it myself but there's no luck, does anybody tried to do it?Also as the main project could be quite memory demanding i was thinking about driving the display with an arduino and the FPGA only sending the necesary information in order to optimize memory usage.will be worth the effort of developing the ssd1306 on verilog or just hook the arduino?Thanks!

author: mrsteveman1
author_rank: Newbie
timestamp: December 23, 2018, 09:21:12 pm
content: I have an SSD1306 I2C module written in Verilog, but I suspect the design is the worst possible way to do itIt does work though, I can post the code on Github after Christmas.It was originally written and debugged using Lattice Diamond for the MachXO2 breakout (7000HE version), but I've synthesized it for iCE40 HX8K as well as Intel/Altera Max10. Italmostfits in an iCE40 HX1K like the iCEstick, but the framebuffer mapping logic is huge and inefficient.It waits 200ms after reset, sends the display initialization sequence, and then it just refreshes the entire screen over and over from a sequential 8192-bit framebuffer ram made up of 128-bit rows, mapped to the column+page ordering expected by the SSD1306. There are other drawing modes the display can be set to that might make things simpler and more efficient, but I haven't tried them yet.There's no logic for drawingtothe framebuffer yet. For development I just had it load a manually generated binary file into the framebuffer using$readmemb()so I could see if the pattern was being drawn correctly or not.
SSD1306 oled breakout, on portable atmega328 project - Page 1
Forum section: electronics / beginners

author: jawa_master
author_rank: Contributor
timestamp: September 15, 2023, 10:22:23 pm
content: Hello.I am working on making a wristwatch that will along with the time, show me tidal information.Its atmega328 based, with a DS3231 RTC, a Bluetooth module, pressure sensor, and an 0.96 oledFor the oled, i wanted to solder the flex cable directly to my own board, to reduce the thickness of the watch. I was a good boy, and actually made a test-board, instead of just ordering the final board right away. On my test-board (SSD1306 oled flex cable, and the required passives) i got the screen to work reliably.On the watch, however, it's not reliable at all. Occasionally, the screen will work as expected, and i can use the watch as intended. Then later it will turn on for a couple of seconds, before crashing, or not turn on at all. The buzzer, however, always work, so the problem seem to lie with the screen, and not the microprocessor. The only real differences between the watch and the test board, is that the watch uses 0603 instead of 0805, and that the 662k runs of a normal 3.7v lithium battery, instead of 5v.When the screen was non-cooperating, I tried running a continuous i2c scanner. It only shows the RTC at 0x68, until I give the flex-cable a bit of a squeeze around the I/O area, which makes it discover the address briefly. I have tried multiple times to reflow the solder, and even swapping out the entire oled, but to no avail. I even tried soldering up another board, being EXTRA tidy, with the IIC connected to a separate, known working arduino nanoThings im considering, but would like inputs on before i make alterations:The I2C pullups are connected to the 3-4 V of the lithium battery, while the screen is connected to the 3.3 of the 662K. Might cause issues ?I tried hooking my power supply up to the vcc and ground pins. This seemed to be a LITTLE more reliable. Could it be a power delivery issue ?EDIT: Looking at datasheets, i also added a 1uF cap on the in AND output of the 662K

author: DavidAlfa
author_rank: Super Contributor
timestamp: September 15, 2023, 10:39:29 pm
content: The pullups that way will increase current consumption, but won't cause damage, the excess voltage will get clamped by the ESD diodes in the pins.What you did with the HC06 is not good, leaving it floating!Better you used a p-ch fet as power switch for secondary circuits (Aka auxiliar), oled, pullups, sensors, modules etc.So the when the cpu goes to sleep most of the power can be turned off, only the cpu remains at the lowest power state, waiting for button press.You can also use n-ch to switch as high-side switches if wyou make a small charge pump with two unused mcu pins.You migh use any other commercially available charge pump, but they tend to consume more power.I did this in a smallrecent projectusing sod523 diodes, the thing was extremely small! (Also soldering them was PAIN).
SSD/HDD SATA 2.5 vs 3.5 voltage compatibility  - Page 1
Forum section: electronics / beginners

author: sairfan1
author_rank: Frequent Contributor
timestamp: August 31, 2022, 04:40:54 pm
content: I googled this question but my confusion did not go away so i thought to ask this question here.I do not own 2.5" SSD or HDD but while googling around i came to know they support 5V 1.2A (most commonly)I want to use some 2.5" SSD or HDD in desktop PC who has already installed 3.5" HDD, as we know standard power connector for SATA 3.5" HDD contains 12V & 5V wiresSSD 2.5" has same power connector but it supports 5V only, should I assume that its not taking in 12V in? or 2.5" can be only used in Laptops and may be small Pcs

author: samnmax
author_rank: Regular Contributor
timestamp: September 01, 2022, 07:41:37 am
content: Yes, you can use 2.5" HDDs in desktop PCs. In that case, only 5V is used and 12V pins are unused.
SSR Attempt - Page 1
Forum section: electronics / beginners

author: RyanG
author_rank: Regular Contributor
timestamp: March 01, 2017, 06:35:48 am
content: This is my attempt at a SSR to replace our old mechanical relays. The 12vdc is on when the machine is turned on. The 24vac is the current relay trigger. I don't know how the triac part of the circuit looks because I have never really done anything with them. The J connectors are screw terminals to replace the 8 contacts on the relays. The relays run motors. The terminals connected to the PNP are normally closed and the ones to the NPN are normally open. Does this thing look like it would work? If anyone has any improvements or ways to reduce the number of parts required that would be great.

author: bktemp
author_rank: Super Contributor
timestamp: March 01, 2017, 01:06:42 pm
content: I see many problems with this circuit:- This only works if there is no other connection between GND and 24V ac.- Q1 does nothing useful and could replaced by a piece of wire- The current is probably a bit too low for driving the optotriacs (check the datasheet, they require 5-30mA depending on the type)- When the 24V is turned on, Q2 sees a base-emitter voltage of ~20V, but it will break down and get damaged somewhere less than 10V. Also the switching point is not defined exactly, there is probably a period when both NO and NC contacts are open or shorted.- Using one optotriac for driving 2 triacs does not work.- You should add a snubber circuit for the optotriac.

author: RyanG
author_rank: Regular Contributor
timestamp: March 01, 2017, 09:47:58 pm
content: This is the only connection on the 24vac. I removed the original Q1. I forgot to remove it after I changed it around from my original layout. I reduced the resistors going to the optotriacs. I added 2 more optotriacs so each triac has its own. I also added snubbers for each of the optotriacs. What should I use in place of the BJT to turn that part on?
SSR buzzing? - Page 1
Forum section: electronics / beginners

author: ve7xen
author_rank: Super Contributor
timestamp: April 01, 2021, 08:38:23 pm
content: I have one of the counterfeit Fotek relays (it is labelled as a SSR40-DA 40A job) that are all over AliExpress, and figured it would be usable for a relatively low current (ca. 3A) mains switching job in a project. On wiring it up, I've noticed that it generates a (quiet but noticeable) 60Hz hum whenever mains is applied, regardless of whether the control lines are connected.I haven't actually used SSRs before, but this doesn't seem normal to me as what should be a solid-state part that shouldn't be passing any current or burning any power while off. Should I be concerned? It otherwise seems to be working as expected.

author: David Hess
author_rank: Super Contributor
timestamp: April 02, 2021, 12:08:49 am
content: The noise is likely from the snubber in parallel with the switching element.

author: Per Hansson
author_rank: Unknown
timestamp: April 02, 2021, 06:28:32 am
content: Quote from: ve7xen on April 01, 2021, 08:38:23 pmJust a technicality but this is not correct: when off most SSR's pass a milliamp or two.At least enough to brightly light a 230VAC LED, ask me how I know

author: Zero999
author_rank: Super Contributor
timestamp: April 02, 2021, 09:02:44 am
content: Quote from: David Hess on April 02, 2021, 12:08:49 amYes, especially if it's a ceramic capacitor, which is piezoelectric and will also be responsible for the significant leakage current.
SSR control of ?AC induction coil - Page 1
Forum section: electronics / beginners

author: jessoman
author_rank: Newbie
timestamp: September 25, 2021, 04:45:08 am
content: Hi all,I have used SSR'S in the past without issue.I have an induction cook top and I have disconnected the coil that does the heating and ran it through the load side of the SSR.It turns on once on initial signal from the microcontroller signal to the SSR, but when I send a low signal / turn the SSR off. The induction coil keeps getting powered and the SSR doesn't unlatch. ALSO within only a few minutes of running the thing goes well over 100 *C and deformed the plastic.The SSR light goes on and off but the coil remains heating, so I don't believe it's an input / control issue.The cooktop is 240vac 15Amp.I haven't just connected into the power button to turn it on and off because I want to pre set the power setting in the cook top board and it doesn't remember it it I turn it off and back on that way. I also don't want to overcomplicate it and write a switch to "push" multiple buttons.Combining my beginner knowledge of electronics and my research, I think it is something to do with the "zero cross trigger method" & something to do with the waveform voltage/current mismatch, meaning zero point is never hit, which stops the thing from releasing. Is this right?What is a simple & cost effective way of fixing this? I would like to PWM this coil, so I believe SSR is the go (more accurate power control of the coil). I don't think a mechanical relay would be suitable....SSR:https://www.ebay.com.au/itm/324173952564?chn=ps&norover=1&mkevt=1&mkrid=705-139619-5960-0&mkcid=2&itemid=324173952564&targetid=1281061181725&device=c&mktype=pla&googleloc=9068929&poi=&campaignid=10101784997&mkgroupid=117859315410&rlsatarget=pla-1281061181725&abcId=9300367&merchantid=115560435&gclid=CjwKCAjw7rWKBhAtEiwAJ3CWLDQBc1W3ttu_jNFNnzYw3XHwcdnTHiIFKahX1a8O-zvqs3dq7TrrzxoCKyMQAvD_BwEInductionhttps://www.internationalcatering.com.au/product/induction-cooker/Also, here is the cookers circuit diagram for the smart cookies. If any smart cookies can think of a way to "highjack" the circuitry to achieve this. With this, I would be happy to be able to turn the device on/off at max power.https://cdn-ice2018.pressidium.com/wp-content/uploads/2011/08/ICK3500-WIRING-DIAGRAM.pdfThanks for reading!
SST 29LE010 Programming - Page 1
Forum section: electronics / beginners

author: ironsniper1
author_rank: Regular Contributor
timestamp: August 28, 2020, 10:08:56 pm
content: Hey everyone, I have a device that has two of these SST 29LE010 eeproms that need to be programmed however the only programmer I have is a CH341A USB Programmer and was wondering if anyone knew of a cheap programmer I can use to program these chips?

author: oPossum
author_rank: Super Contributor
timestamp: August 28, 2020, 11:24:27 pm
content: TL866

author: ironsniper1
author_rank: Regular Contributor
timestamp: August 28, 2020, 11:42:27 pm
content: Quote from: oPossum on August 28, 2020, 11:24:27 pmis that the only one? a bit pricey for something i plan to only use once or one or two times a year if at all
ST 27C256B - CMOS or TTL ? - Page 1
Forum section: electronics / beginners

author: netdudeuk
author_rank: Frequent Contributor
timestamp: January 14, 2015, 10:40:55 am
content: HiI'm looking for some 32KB EPROMS for an NMOS 6502 project and have looked at the data sheet (http://www.thierry-lequeu.fr/data/27C256.pdf) for the ST 27C256B EPROM.However, there is talk about both TTL and CMOS levels. So, the question is, will these work ok with my NMOS 6502 and other TTL (buffer) chips, etc ?Thanks

author: amyk
author_rank: Super Contributor
timestamp: January 14, 2015, 02:59:16 pm
content: Look at page 5 - Vil, Vih, Vol, and Voh. The reason they mention both CMOS and TTL for Voh is because TTL usually needs more current sourced from its output than CMOS.

author: netdudeuk
author_rank: Frequent Contributor
timestamp: January 14, 2015, 03:44:15 pm
content: Thanks Amy.So, referring to the same V values herehttps://learn.sparkfun.com/tutorials/logic-levels/ttl-logic-levelsit looks like I'm good to go. Right ?

author: free_electron
author_rank: Super Contributor
timestamp: January 14, 2015, 05:57:03 pm
content: Quote from: amyk on January 14, 2015, 02:59:16 pmTTL does not take any current in for a HIGH level... it DELIVERS current for a low level.This is a common misconception.the input if a true TTL gate is the emitter of a transistor. if you apply a logic '1' no current goes in. if you pull it low you send the transistor in conduction.that is why you need to go as low as 2.4 volts anything above that does not turn the transistor on

author: netdudeuk
author_rank: Frequent Contributor
timestamp: January 14, 2015, 10:19:14 pm
content: So I'm good to go ?

author: amyk
author_rank: Super Contributor
timestamp: January 15, 2015, 03:54:58 pm
content: Quote from: free_electron on January 14, 2015, 05:57:03 pmThe transistor is leakier than the gate of a MOSFET.

author: SeanB
author_rank: Super Contributor
timestamp: January 15, 2015, 04:30:19 pm
content: All that means is that the drive out is enough to either drive a CMOS input to well within it's switching levels, ie over 80% and below 20% or over 4V and below 1V, under all conditions. It can also drive TTL to it's levels of over 2.4V high and below 0.8V low as well.Basically it will recognise any input voltage over 2.4V as high and below 1V as low. Outputs will drive to at least 4V with the rated load and will pull down to 0.8V with the rated load. Your typical TTL terminator is a 330R resistor to 5V and a 220R to ground, with the common point being the bus. Funny thing with the DIP and SIL terminators with plain resistors is they still work if put in backwards, just the floating voltage is wrong. This may not be noticed for a long time or may only give a very occasional random error.
ST 93C66 microwire EEPROM sniffing. - Page 1
Forum section: electronics / beginners

author: firewalker
author_rank: Super Contributor
timestamp: January 03, 2021, 11:05:40 am
content: I am trying to sniff the communication between a micro and an ST 93C66 EEPROM (93C66 6 ST K033M) of a vehicle instrument cluster. I am using sigrok (Pulseview), but everything I try there seems to be something strange to the communication.I desoldered the EEPROM, read with an eeprom reader and sniffed the protocol. Sigrok was able to decode as normal. So my logic analyzer work OK.Any hints?I am attaching the sigrok files.

author: Pokey
author_rank: Newbie
timestamp: January 25, 2023, 09:12:04 am
content: Hello. I have the same problem, did you solve it?

author: firewalker
author_rank: Super Contributor
timestamp: January 25, 2023, 09:27:26 am
content: No. I din;t had the time to further investigate the issue.Alexander.

author: Pokey
author_rank: Newbie
timestamp: January 25, 2023, 11:04:16 am
content: I solved this puzzle. In my case they are using hardware SPI in 16-bit mode in the microcontroller. The 93C86 memory expects a READ instruction which is 13 bits long. (SB (start bit)= 1, OPCODE = 10, ADDR = A9-A0). To align to 16 bits, the first 3 bits on MOSI are "0". Quote from datasheets: "If CS is high, but Start condition has not been detected, any number of clock cycles can be received by the device without changing its status (i.e., waiting for Start condition)." So the 93C86 recognizes the command only from the first bit in the "1" state. The protocol decoder in PulseView does not know this condition described in the documentation, therefore it cannot correctly recognize the communication. In attachment: Req. CLK Cycles 29 means 13 cycles per instruction + 16 cycles per data read.

author: firewalker
author_rank: Super Contributor
timestamp: January 25, 2023, 05:46:23 pm
content: Nice. Should I open a bug report to the sigrok?Alexander.

author: Pokey
author_rank: Newbie
timestamp: January 25, 2023, 10:19:57 pm
content: I think so. This is an oversight in the decoding protocol for this type of memory. The start condition is not only high on CS, but also high on DI on the rising edge of the clock.
ST Microcontroller - Page 1
Forum section: electronics / beginners

author: davidleverett30
author_rank: Contributor
timestamp: May 14, 2017, 05:15:44 am
content: I recently purchased a microcontroller and updated the firmware from the manufacturer via USB.I changed some of the code and recompiled the firmware, then uploaded it. Since then, I am unable to connect via USB. Have I bricked the device?I've ordered a ST-linkv2 programmer to try and re-load the original firmware using SWD.Is there another route I can take to get my device working again?

author: ataradov
author_rank: Super Contributor
timestamp: May 14, 2017, 06:10:10 am
content: There is no way to "brick" most modern microcontrollers.Don't waste your time with all those USB/UART bootloaders, real tools are cheap. Wait for your ST-link and it will program the device.
ST SOIC identification - Page 1
Forum section: electronics / beginners

author: donkey77
author_rank: Regular Contributor
timestamp: May 10, 2017, 08:36:03 am
content: Hi All,Hopefully someone will have an idea how to decode this chips markings. I am looking to repair a display panel that has an encoder input playing up. I suspect the voltage regulator but as the panel is still in operation I wanted to source components first as I won't get long for the repair before having to put it back into operation.Many thanksRich

author: wraper
author_rank: Unknown
timestamp: May 10, 2017, 08:51:44 am
content: LM224, L78M05

author: donkey77
author_rank: Regular Contributor
timestamp: May 10, 2017, 10:36:08 pm
content: Thanks very much Wraper. I'd worked out the voltage regulator although could find the exact one via the lower row of characters. I guess it's superseded now but shouldn't be an issue. May i ask what pointed to the missing 'I'm or is there a look up table somewhere? Many thanks again.

author: wraper
author_rank: Unknown
timestamp: May 12, 2017, 10:54:57 pm
content: Quote from: donkey77 on May 10, 2017, 10:36:08 pmIt's usual thing to omit first letters. Moreover I've seen such parts from ST before.

author: donkey77
author_rank: Regular Contributor
timestamp: May 22, 2017, 12:06:49 pm
content: Ah, ok. Learn something new every day. Thanks again