hybridfree/eevblog-posts huggingface dataset:
Loop unrolling a SAR ADC - Page 1
Forum section: electronics / projects

author: nuno
author_rank: Frequent Contributor
timestamp: June 07, 2018, 11:37:44 am
content: The other day I was looking at the block diagram of a SAR ADC in a microcontroller's datasheet, and this thought came through my mind "uou, this is a loop, so loop unrolling should be applicable here, with high speed gains". And therefore immediately started to trying to design a "discrete" loop unrolled SAR ADC in simulation, in this case a 5 bit one. I frequently do this, just as a design exercise to better understand the design difficulties of doing this or that.Since I've put some time on it, I'll leave it here. I tried to use real components, but didn't manage to do a real sample&hold circuit, used a existing S&H/T&H component from LTspice's lib. There are 3 input test signals, to switch between them one has to set the series resistor of the selected one to 1 and the others to 1G. The output of the ADC goes to a "digital filter" to remove the "indecisions" and to a R2R DAC for visual comparison with the sampled input signal. The input signal is sampled at the clock's rising edge and result is available at the falling edge.After this I set out to look for references to loop unrolled SAR ADCs on the Internet, and found quite a few, usually in the context of IC implementation of ADCs.

author: coppice
author_rank: Super Contributor
timestamp: June 07, 2018, 11:59:53 am
content: The term you need for a search is "pipelined ADC". The earliest real world example I know of is the ADC Quantel made for the video processing market in the mid to late 1970s, so they are a very mature approach. They are widely used for fast conversion today.

author: David Hess
author_rank: Super Contributor
timestamp: June 07, 2018, 02:26:10 pm
content: Pipeline ADCs include subranging ADCs but there is no requirement that subranging ADCs be pipelined.What you have there is a subranging ADC which combines the worst features of a 1 bit per stage subranging ADC with the worst features of a successive approximation ADC.http://www.analog.com/media/en/training-seminars/design-handbooks/Data-Conversion-Handbook/Chapter3.pdf

author: nuno
author_rank: Frequent Contributor
timestamp: June 14, 2018, 11:37:37 am
content: Ah, so that's what pipeline ADCs are...Nice reading from analog, thanks
LoRA Antenna (920Mhz) on PCB - Page 1
Forum section: electronics / projects

author: mrpackethead
author_rank: Super Contributor
timestamp: September 12, 2017, 07:39:14 pm
content: Hi, i'm contemplating a LoRA design at the moment and i want to use a pcb based antenna, for reasons of cost. I can make some compromise on performance.Does any one know if it is possible to emulate a sleeved dipole using a a flat multilayer pcb? ( as opposed to using a a round sleeve )

author: krho
author_rank: Regular Contributor
timestamp: September 13, 2017, 05:07:57 am
content: I know that this is not the answer you are looking for but proant has some SMD antennae forthat purposeand the price on mouser is ~0,75US$@1000

author: BrianHG
author_rank: Super Contributor
timestamp: September 13, 2017, 08:53:38 am
content: I don't know if it's compatible with your particular LoRa chip-set, but read microchip's data sheet on their LorA module. They have a guide on how to construct a printed PCB antenna:https://www.digikey.com/product-detail/en/microchip-technology/RN2903A-I-RM098/RN2903A-I-RM098-ND/6823704I suspect you need to follow their PCB trace antenna EXACTLY...

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 13, 2017, 06:39:35 pm
content: How many layers are we talkin'?Sleeved dipole has up to three conductors in any given location, needing at least 5 layers. On a 6 or 8 layer board, you may have difficulty getting the right impedance between the outermost electrode and the "coax shield" electrode. (That region isn't impedance-critical, as far as I know (it's a shorted 1/4 wave stub), but a ridiculously low impedance would probably give higher losses and imbalance, and narrower bandwidth.)Nothing wrong with a good old F antenna, as far as I know!If you prefer a balanced design, a regular dipole, with a gamma match as balun, should do well enough. Or a folded dipole, even.If you want circular polarization (can be more omnidirectional), a phased patch / crossed dipole, spiral, or other design would be good. These will take up more board area, of course.Needless to say, you'll need either (and preferably both) an EM field analysis tool, or a few physical protos and a VNA, to qualify the antenna design; and regulatory approval for a new RF module.Tim
Lossy coaxial cables - Page 1
Forum section: electronics / projects

author: Earendil
author_rank: Regular Contributor
timestamp: December 23, 2015, 03:03:44 pm
content: I want to create my own logic probes for the Tektronix MDO3000. (I can't afford to buy the original one).But my issue is that it uses a lossy coaxial cable not just some regular coax.I can't seem to find any distributors for these lossy coaxes. I considered chopping up some cheap scope probes but since I want to create a 16 signal logic probe this would be pretty expensive.Do you have any idea where to buy these? Or any ideas how to substitute them? I considered creating a flat-flex PCB with discrete SMD resistances but that would also be pretty expensive and the usability would be pretty bad I think.For the probes' design see Howardlong's excellent tear down:https://www.eevblog.com/forum/testgear/mdo3000-hacking/msg765377/#msg765377

author: Marco
author_rank: Super Contributor
timestamp: December 23, 2015, 04:00:32 pm
content: Isthismicrocoax?

author: SeanB
author_rank: Super Contributor
timestamp: December 23, 2015, 04:09:35 pm
content: Looks like it is, too thick to be flat flex.

author: Marco
author_rank: Super Contributor
timestamp: December 23, 2015, 04:21:09 pm
content: From the manual it seems to have significantly less resistance, but they still call it lossy, should suffice.

author: Earendil
author_rank: Regular Contributor
timestamp: December 23, 2015, 04:29:24 pm
content: Quote from: Marco on December 23, 2015, 04:21:09 pmYeah, it's 0.067 Ohm per inch. For 84 cm that's only about 2.2 Ohm. It's still far better than nothing though.I bought one so I will see if it works. Thanks!

author: dmderev
author_rank: Contributor
timestamp: June 04, 2024, 12:41:29 am
content: If someone still interested, here you can get some:https://www.ebay.com/itm/156241170329
Lost Item Tag project with Atmega328p + nrf24l01+  - Page 1
Forum section: electronics / projects

author: builder01
author_rank: Newbie
timestamp: October 16, 2021, 02:19:06 pm
content: Hello,I'm trying to do a similar "tag" device that buzzes everytime I press a push button at a distance. Like those that can be used to attach to things you are usually misplacing.I have achieved most of the functionality with atmega328 + nrf24l01+. I want to implement a loop in the RX that sets the NRF to power down for shorts periods of time; this is to manage the amount of time is looking for radio (power saving purposes). I can send data by pressing an external push button to send a message ("ON") to RX , but after I set the NRF to go to sleep (setting the PWR_UP = 0 while on Standby-I), I wake it up by pressing the button and try sending another message, they don't get across anymore.I have made sure that the CE is properly pulsed after shifting everything out of MOSI while sending that2nd messageafter coming back from sleep. I really don't know how to debug this.I have attached the code (including the library) for you to reproduce my problem if you want to help. The library is an slightly modified version of this one:https://github.com/thehelvijs/nRF24L01-avr-bareminimumUsing TX and RX is simple with it and works quite well. My problem starts, as I said, when I try to send a message again after coming back from sleeping (setting nrf24_state(POWERDOWN) in the code to sleep).Thanks in advance for your help!

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 16, 2021, 07:09:49 pm
content: Just attach RFID/NFC tags to the items and then use a reader to scan for them?

author: builder01
author_rank: Newbie
timestamp: October 17, 2021, 08:11:28 am
content: And how can I make them buzz from 20-30m away?
LOTO practice(1): RC resistance-capacitance —— low-pass filter PWM to DC - Page 1
Forum section: electronics / projects

author: jiangtao.lv
author_rank: Regular Contributor
timestamp: May 12, 2020, 03:29:43 am
content: Resources used in the experiment: 1.5K resistor, 22u capacitor, oscilloscope, adjustable PWM wave.Note: The selection of resistance and capacitance does not need to be accurate, in fact, it is enough to combine a low-pass filter with a very low cutoff frequency. For example, our chosen value is equivalent to a low-pass filter with a cutoff frequency of 4.8 Hz.Two methods are described and practiced in the video. The first is software control of the duty cycle of the OSC482 with PWM to adjust the RC filter to generate DC. The second is to generate a square wave through the S02 signal source module, and manually adjust the amplitude of the square wave to change the DC value.Here is the video:https://youtu.be/ftgFqXiWJVA
Loud piezo siren driver - Page 1
Forum section: electronics / projects

author: gaminn
author_rank: Frequent Contributor
timestamp: May 10, 2020, 01:43:34 pm
content: Hi,I designed this piezo siren driver:I used parts of this siren:Namely transformer (it has 10 ohms primary resistance and 200 ohms secondary resistance) and the piezo transducer itself (it has 17 nF capacitance).I need approx 200 Vpp and this circuit is capable of generating it (actually, it can generate 300 Vpp). There is also very simple overload protect used in the driver. The piezo transducer itself has approx 1 - 4 kHz bandwidth.Would you somehow optmiize this circuit to consume less power, to be "more" EMC compliant, to have better overload protection (it would be nice max. current through transformer's primary winding can be set). Anything...Or is there some IC that can handle all of this?

author: Marco
author_rank: Super Contributor
timestamp: May 11, 2020, 03:55:02 pm
content: Only at resonance can a single switch drive the piezo without just turning a lot of energy in the piezo's capacitance to heat every time it switches on.A half bridge driver driving the transformer as a normal transformer, with a DC blocking capacitor and an inductor on the primary side to shave off some of the higher harmonics, would have lower losses.
Loudness of Audible Alerts IEC60601-1-8 - Page 1
Forum section: electronics / projects

author: cRash1001
author_rank: Contributor
timestamp: March 25, 2022, 05:35:58 am
content: IEC60601-1-8 states requirements for audible alerts in medical devices but doesn't state how loud should these alerts be. It distinguishes alerts based on priority into High, Medium and Low Priority, and says there should be a difference of 3-6dB between each of these alert sounds.I found medical audible alarms which are IEC60601-1-8 compliant with loudness between 85dBa to 95dBa. Link:https://news.thomasnet.com/fullstory/mallory-sonalert-audible-medical-alarms-meet-iec60601-1-8-standards-40002397I don't have access to the standard, and it would be really helpful if someone could provide me with some information regarding,1. For a medical device such as an X-Ray device which alert priority (High, Medium or Low) does the audible alert sound during an X-Ray exposure belong to?2. What should be a typical loudness level of such X-Ray Exposure Alert sound be?3. What is the loudness level (in db) of Low, Medium and High Priority sound for medical devices?

author: CaptDon
author_rank: Super Contributor
timestamp: March 25, 2022, 03:01:55 pm
content: I wonder if the joint commission for hospitals JCAHO would have any searchable rules or guidelines? They are the inspecting body we all fear working in BioMed (and everyone else from patient transfer to doctors hate to hear those words...surprise Jay-Koe inspection this morning). Best wishes in your search!!
Looking for a low angle led lens for 100w LED - Page 1
Forum section: electronics / projects

author: David97
author_rank: Contributor
timestamp: June 19, 2015, 09:45:24 am
content: Hi everyone. I have been playing with some cheap100W leds from ebay. Eventually I want to build a spotlight from one, problem is I cannot find a lens with a narrow enough be beam. I ordered one ofthese lensesat the same time, but it's still far too wide. I have also tried moving the lens further out, but it isn't big enough to catch enough of the light.Anyone know where I could get a lens/reflector that could be used for a spotlight?

author: ajb
author_rank: Super Contributor
timestamp: June 19, 2015, 03:21:45 pm
content: How narrow are you looking for, and how flat a field do you need? The trouble with the LED you have is that it's actually 9 individual LEDs arranged in an array, so if you try to use a single PC lens over the whole thing, you'll only have one LED in the focal axis of the lens. You'd probably have better results with an individual lens per die, but that'd be a fairly complex injection molded part given the close spacing of the dice. It may be possible to use a single multiple-element lens train to collimate all of the dice into a single beam, but getting an even field will be tricky.There's a How It's Made segment on ETC's Source Four LED fixtures which is informative. They use 60 Luxeon Rebels to produce an extremely high quality controllable beam that's competitive with 575W Tungsten fixtures. The LEDs are installed on a metal core PCB at the rear of the fixture, with an array of plastic lenses (one lens per emitter) fit over them. Then there's a hexagonal mixing tube lined with polished aluminum reflectors, capped off with a PC lens. After that is the pattern/iris gate, and finally the interchangeable lens tube that does the final beam shaping.

author: jmd2017
author_rank: Newbie
timestamp: July 31, 2017, 10:25:15 am
content: Hello, David. we are the lens manufacturer in CHina. we have the lens for spotlight as you looking for. pls visit our web:www.jmdlens.com

author: ConKbot
author_rank: Super Contributor
timestamp: July 31, 2017, 10:53:48 am
content: Those COB LEDs aren't meant for tight focusing. The ratio of the diameter of the lens or reflector to the effective die size determines how tight/focused/collmated the beam is. I.e a 2mm die on a Cree LED in a 4cm reflector and A 100w COB with a 20mm effective die width in a 40cm reflector will start to have similar performance.

author: firehopper
author_rank: Frequent Contributor
timestamp: July 31, 2017, 05:43:38 pm
content: actually I have one of these leds, if you look closely its 10x10 leds so 100 leds in side, 10 strings of 10 leds eachQuote from: ajb on June 19, 2015, 03:21:45 pm
Low battery cutoff board on ebay? - Page 1
Forum section: electronics / projects

author: Circlotron
author_rank: Super Contributor
timestamp: March 19, 2016, 11:28:05 am
content: A friend is building a box with a car radio, 2 speakers and an SLA battery. A portable high power worksite radio. What he needs is a ready made low battery cut-off board to stop the battery being discharged too low. it's just not worth me sitting down and building one from scratch, so does anyone know of a pre built on on ebay or similar?

author: davebb
author_rank: Frequent Contributor
timestamp: March 19, 2016, 12:44:37 pm
content: Hi I got one from ebay china about £2 it has a 30a relay and a small buzzer a pot for setting the cut-off voltage2 leds, problem is when it shuts off the 12v supply the board still took 400ma,could fit another relay so board turns off as well the press button to reset, I was going to use this on a 1.35ghz cofdm video rx box I made using a Cobham rx board with 2 down-converters, the box took 2Amps, I used a 5ah nmh batt, It is used for monitoring unmanned target boats, so would be in a noisy environment, so the design/engineer programmed me a small ATMEL chip and I switched 2 fets controlling 2 relays and used it as a charger aswell, and had the battery switch off at 10.4v the the led went red, then it was only taking 20ma,so it may well be worth making what you need,Dave

author: batteksystem
author_rank: Regular Contributor
timestamp: March 21, 2016, 10:04:03 am
content: Quote from: Circlotron on March 19, 2016, 11:28:05 amI sell ready made Low Voltage Disconnect for RV Deep Cycle Battery at very high price.http://www.ebay.com/itm/Low-Voltage-Disconnect-LVD30-12V-30A-Dual-Battery-Campervan-Solar-Fridge-Caravan-/301293456176

author: SeanB
author_rank: Super Contributor
timestamp: March 21, 2016, 11:34:06 am
content: Cheap one...http://www.ebay.com/itm/Low-Voltage-Disconnect-Module-LVD-12V-10A-Protect-Prolong-Battery-Life-/201543200472?hash=item2eece92ed8:g:hZkAAOSwf-VWUYzFand they will do free postage to NZ.
low capacitnace  relay? - Page 1
Forum section: electronics / projects

author: CopperCone
author_rank: Super Contributor
timestamp: December 10, 2017, 11:50:37 pm
content: I am looking to make a multistage amplifier (consisting of opamps and gain set resistors)What kind of relay should I use that has low open capacitance. Are there special designs?

author: CopperCone
author_rank: Super Contributor
timestamp: December 10, 2017, 11:55:46 pm
content: nevermind, it looks like RF relays fit the bill, they are just expensive.

author: dmills
author_rank: Super Contributor
timestamp: December 11, 2017, 11:26:17 am
content: Are you sure you need relays?They can be the right choice, but small signal switching is actually something that needs some care with relays if they are to work reliably.Jfets do well for audio sort of applications, or Hittite & Skyworks have product that does well at RF (and is usually cheaper then relays if the frequency and power level suit).Regards, Dan.
Low component count/basic component voltage booster (5V->14V only 2-3mA needed) - Page 1
Forum section: electronics / projects

author: ALonda
author_rank: Contributor
timestamp: May 08, 2019, 10:56:44 pm
content: Im working on a randomness source circuit based off of simple transistors with floating bases (breakdown effect?).But to give enough noise amplitude, they need to run at about 14V. Bot of them running only need ~2-3mA in total.I got a "voltage doubler" from a book, but it only outputs about 7-8V from 5V input. Its based of a simple 1kHz input to two transistors and 3 diodes.Since I am self-taught, not schooled, I dont know how to modify or build another circuit to boost it all the way to 14V.Im a perfectionist at heart so I am looking for a low component count, basic components circuit. Rushing off to buy a boost converter chip would feel like defeat. Likewise, using an off the shelf boost converter would feel the same.I hope some kind soul could help me find a solution to my problem.Thanks in advance,/A

author: mariush
author_rank: Super Contributor
timestamp: May 08, 2019, 11:13:13 pm
content: Have a look at MAX1720:https://www.digikey.com/product-detail/en/on-semiconductor/MAX1720EUTG/MAX1720EUTGOSCT-ND/2705019See page 10... voltage tripler ..Vout = 3 x Vin - 4 x diode voltage drops:https://www.onsemi.com/pub/Collateral/MAX1720-D.PDFlook into how these charge pump ics are made if you want to make one... but really, it's less than 1$...
Low Cost DC/DC Buck Converter... Requirements below.. Any Suggestions.. - Page 1
Forum section: electronics / projects

author: mrpackethead
author_rank: Super Contributor
timestamp: January 07, 2016, 04:16:29 am
content: i have a project were i will need a lot of DC/DC converters I need to downcovert from a nomimal 24VDC ( should be between 22 and 27V ) to 5VDC at 750ma.I need to acheive an efficency greater than 80%. Cost is likely to be the main constrainign factor.Anyone got any favourite Chipsets / setups that might do this?

author: mariush
author_rank: Super Contributor
timestamp: January 07, 2016, 06:42:16 am
content: Have a look at something likemax 26v inputAOZ1280 :http://www.digikey.com/product-detail/en/AOZ1280CI/785-1277-1-ND/2769845Cheap and works at high frequency, which means small inductors and ceramic capacitors & resistors so it's small footprint. Efficiency will be above or around 85%.If your input power is unreliable you should go for something else like these, which handle higher voltages but works at smaller frequencies which often means larger inductors, more pcb space used (but they're still quite high frequency:MCP16312 which does up to 30v :http://www.digikey.com/product-detail/en/MCP16312-E%2FMS/MCP16312-E%2FMS-ND/4079915orAOZ1282 which does max 36v :http://www.digikey.com/product-detail/en/AOZ1282CI/785-1613-1-ND/4147125
Low cost general PCB test fixture system/software/platform - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: April 13, 2022, 08:58:47 pm
content: Hi,are there any very low cost - perhaps open source - platform/system to be used with PCB test fixtures? Something general that can be customised. Like a state machine that generates certain analog and digital signals (defined through a PC interface) which are then applied to some contacts (i.e. pogo pins of a test bed) and then reads back signals form other contacts from the same fixture. Effectively recreating a low cost PCB test system.Something that would allow to use with a (DIY) bed of nails and setups quickly and easily instead of having to write custom code to control the PCB fixture test?Perhaps something Arduino based?Thank you

author: jbb
author_rank: Super Contributor
timestamp: April 13, 2022, 09:45:16 pm
content: Hmm. What kind of platform do you mean? We sort of have 3 domains: probing, electronics measurement, and test control.There are probably a few electronics measurements efforts out there. Maybe EEZ-DIB is worth a look as a platform? And Black Magic for JTAG programming/test?Test control is, I suspect, often a code-your-own effort. The EEZ crew are working on graphical stuff like EEZ-Studio and EEZ-Flow; I don’t know if that’s helpful.
Low Cost GSM & GPS Module/IC - Page 1
Forum section: electronics / projects

author: TG91
author_rank: Newbie
timestamp: April 29, 2021, 12:52:39 pm
content: Does anyone know what IC or module is used in super low-cost real-time GPS trackers, not the Bluetooth ones, the proper real-time trackers with a SIM card?I can't seem to to find any solutions that cost less than £/$4-5 even in volume yet you can buy devices such as this for £6:https://www.ebay.co.uk/itm/393223321792So yeah what module or IC is likely to be used in such cheap products?

author: amyk
author_rank: Super Contributor
timestamp: April 29, 2021, 11:39:05 pm
content: Mediatek MT62xx is relatively common.

author: technix
author_rank: Super Contributor
timestamp: April 30, 2021, 05:56:19 am
content: Orange Pi 2G-IoT + a cheap GPS + GLONASS + BeiDou GNSS module?Orange Pi 2G-IoT has GSM and application processor combined into one chip.
Low cost HMI touch panel ? - Page 1
Forum section: electronics / projects

author: David_AVD
author_rank: Super Contributor
timestamp: August 02, 2016, 02:57:30 am
content: I have an application for an LCD touch panel. The Nextion units are quite neat and the software is reasonably easy to use, but the processing and I/O are somewhat limited.What I'd like is one or two RS485 ports and the ability to do some processing on-board. The Nextion can spit out custom serial strings, but only seems that accept commands to directly control the various GIU components. There doesn't seem to be any way to accept serial data into a buffer and parse it for example.I could of course just use the Nextion panel as the GUI and do all the data processing on a separate board, but was hoping for a ready made solution.Other HMI units I've looked into are Kinco and Weintek, but they seem to be geared towards Modbus and PLCs. Are there other options out there?

author: rstofer
author_rank: Super Contributor
timestamp: August 02, 2016, 06:09:56 am
content: Use a tablet computer. If the Androids seem difficult to deal with, try one of the Microsoft Surface tablets. Lots of communications, simple to build GUI and plenty of development software. The 64 bit PC type platform would be ideal!A Surface 3 might do the job and it's only about $500. I know that seems like a lot but if it saves even 5 hours of development time, it's paid for! It's actually better than that because there was a cost for any other panel. If the difference is only a couple of hundred dollars, the payback in development time is just around the first coffee break.I retired but I still make my build vs buy decisions on $100/hr. Others may use a different number but the idea is the same - time is money!

author: prasimix
author_rank: Unknown
timestamp: August 02, 2016, 06:30:01 am
content: Check4D Systems, maybe they have something more appropriate for you but that is not in the same price range as Nextion.

author: David_AVD
author_rank: Super Contributor
timestamp: August 02, 2016, 07:50:15 am
content: The 4D Systems panels look interesting. just downloaded the IDE for them.As for using a PC (laptop / tablet) .... no, just no.

author: Kilrah
author_rank: Unknown
timestamp: August 02, 2016, 07:59:05 am
content: Another option, they have various versions:http://www.mikroe.com/mikromedia-hmi/50-cap/

author: David_AVD
author_rank: Super Contributor
timestamp: August 02, 2016, 08:48:46 am
content: Thanks for that. I've seen the dev kits advertised somewhere, but didn't realise they had a HMI panel.
Low cost LED driver for SSRs - Page 1
Forum section: electronics / projects

author: Cicada
author_rank: Regular Contributor
timestamp: November 30, 2016, 05:08:41 pm
content: HelloCan anyone point me to a fairly low cost, robust, easy to obtain driver to drive 8 of these SSRs (datasheet attached). I will be driving it with about 20mA per channel.The input side of such a buffer will be driven by a CPLD of which the outputs will be pulled high (through internal a 50k to 3.3V) during configuration. So with the inputs of the driver high the outputs to the SSR should be of.Any good options out there.Thanks

author: danadak
author_rank: Super Contributor
timestamp: November 30, 2016, 11:50:35 pm
content: This and a R array to limit current.http://www.onsemi.com/pub_link/Collateral/MC74AC573-D.PDFRegards, Dana.

author: Cicada
author_rank: Regular Contributor
timestamp: December 01, 2016, 06:46:21 pm
content: Quote from: danadak on November 30, 2016, 11:50:35 pmThanksA kind of similar device is this one.http://www.ti.com/lit/ds/symlink/sn74lvc07a-q1.pdfFor both they specify 24mA continuous output current. Does this spec mean you can have 24mA on all outputs? Taking into account that the maximum continuous current through Vcc or GND is 100mA.So I think my question is a general one. With buffers like these are you allowed to have all IO operate at their maximum rated current or is the spec only per output.Thanks

author: Zero999
author_rank: Super Contributor
timestamp: December 01, 2016, 08:17:03 pm
content: Quote from: Cicada on November 30, 2016, 05:08:41 pmWhy on earth do you want to drive them at 20mA? The datasheet for the solid state relay says they'll work at just 5mA. As long as the driver IC can deliver a total of 40mA then it will work perfectly.

author: langwadt
author_rank: Super Contributor
timestamp: December 01, 2016, 10:19:02 pm
content: Quote from: Cicada on November 30, 2016, 05:08:41 pmDatasheet specs 5mA, the CPLD should have no problem driving directly

author: Zero999
author_rank: Super Contributor
timestamp: December 01, 2016, 10:28:32 pm
content: Quote from: langwadt on December 01, 2016, 10:19:02 pmYes, just one SSR, no problem, but eight of them is another story, especially if the other outputs are already used to drive other devices.

author: Cicada
author_rank: Regular Contributor
timestamp: December 09, 2016, 04:13:26 pm
content: HiThanks to everyone for their inputsThis is the device I was looking for.http://www.ti.com/lit/ds/symlink/tpic6273.pdfNot to expensive as wellhttps://octopart.com/search?q=TPIC6273
Low-cost liquid level sensing - Page 1
Forum section: electronics / projects

author: jp430bb
author_rank: Contributor
timestamp: August 06, 2019, 01:49:23 am
content: I'd like to share a little experiment. I have an MSP430G2553 MCU with a long U-shaped loop of PVC-insulated wire (indicated by white arrow) attached to one pin. The loop runs vertically about 60cm into my basement sump pit. The TI CapTIvate capacitive touch-sensing feature sets up a relaxation oscillator on the pin and measures shifts in frequency when the capacitance changes. Increasing water level increases the capacitance, which shows up as a slow drop in counts in the plot below. When the sump pump runs, the water level drops in a few seconds, and the counts rise quickly.This setup has been going since October, 2018. It's satisfied my curiosity about how often the pump runs, how quickly the pit refills, etc. The shoulders on the profile during refilling seem to be real; I recorded video of a few refills and could see the water level rise quickly then slowly then quickly again.I definitely wouldn't count on this sensor to sound an alarm or control the pump. I've had better luck with it than I had with an ultrasound sensor pointed at the water surface, though.

author: floobydust
author_rank: Super Contributor
timestamp: August 07, 2019, 05:06:25 am
content: Interesting experimentthanks for posting. With a bit of work, it could be good enough for pump control.It looks like the sense electrode needs more (metal) area to get larger counts and more range. The wire's PVC insulation must be a factor, PVC dielectric constant is ~3 compared to water ~80, acting like an air gap is around the wire's conductor, so the capacitance is much less. Maybe more than one U-loop. That's my theory but I would have to model it or do the physic's math.A bare stainless steel rod or tube (with a coupling capacitor to prevent any electrolysis) would be worth trying.The graphs can predict failure of the pump, or float switch, drain hose etc.Although I had a start capacitor short and the pump was locked-rotor staying powered up, and heated up the sump water quite a bit. That was a weird failure. Another was the outlet drain hose popped off and water dumped right close to the foundation wall, and cycle time was crazy short. Every 10 minutes the pump was on but it wasn't raining out.You really need a high-high level alarm, pump run timer, as part of an embedded solution.
Low cost Load cell & RTD probe required - Page 1
Forum section: electronics / projects

author: embedded.world@aol.com
author_rank: Contributor
timestamp: March 28, 2014, 06:20:23 am
content: Hi,1. I am searching for low cost miniature load cell. Something of size ofhttp://www.omega.com/Pressure/pdf/LC307.pdfLoad cell which I searched for are whooping $200 & above.My load range is 250lbf. Excitation voltage 3.3V or 5V.Cost should be $50 - $100.2. RTD have to measure hot plate temperature +20C to +600C.I need a RTD already fitted with probe assembly.I have checked sensor on Omega & USsensor & asked for quote, meanwhile if anyone else have used RTD for such application can comment or suggest something.I am asking for RTD with probe assembly as earlier I bought RTD element separate & made own Stainless steel housing & then put RTD with thermoconductive powder inside SS assembly. I have noted that response gets slower & inaccurate . Probably I was not able to place sensor correctly inside SS.
Solved, obsolete. - Page 1
Forum section: electronics / projects

author: evb149
author_rank: Regular Contributor
timestamp: August 21, 2016, 03:24:00 am
content: Solved, obsolete.

author: janekm
author_rank: Unknown
timestamp: August 21, 2016, 05:36:36 am
content: http://www.hqpcb.com/offer blind hole and impedance control. Impedance control adds around 400 RMB to the cost, blind holes around 1400 RMB (so whether that's low cost is open to interpretation...). Those costs may vary depending on actual complexity of your requirements, that's just from their online calculator.I haven't seen any prototype service offering via-in-pad yet though.
Low cost PIR motion sensor IC - Page 1
Forum section: electronics / projects

author: Jester
author_rank: Frequent Contributor
timestamp: January 20, 2017, 02:24:27 pm
content: I have been asked to develop a low cost (<$5 in volume) PIR motion sensor for indoor close range use (< 5'). This is not used for an alarm so a false trigger once every 6 months would not be show stopper. I realize there are modules on eBay for about $1, however this not an option as it must be made in America and fit within an existing enclosure (~2" x 2")The components can be sourced from anywhere. Needs adjustable pick-up and drop-out time, can't be uC based in the sense that they don't want to have to program it in production.There are a fair number of IC's dedicated to PIR sensing, I'm looking for suggestions from someone that has done this before and has found a reliable, simple chip.Not sure if anyone has worked with BISS0001 these are super cheap at about $0.1 on eBay, I would have to find a reliable source other than eBay for production.Suggestions welcome

author: ataradov
author_rank: Super Contributor
timestamp: January 20, 2017, 10:39:18 pm
content: I would start looking at those doppler shift motion sensors. If you can figure out how it actually works and replicate the design, they can be pretty cheap.Here is what I'm talking about:https://www.eevblog.com/forum/rf-microwave/microwave-doppler-motion-detector-teardown/msg1099128/#msg1099128

author: holo
author_rank: Newbie
timestamp: January 21, 2017, 10:18:33 pm
content: I would check out the offerings from Elmos.http://www.elmos.com/english/products/sensor/passive-infrared.htmlI'm currently evaluating the E931.96 as it's extremely low power, needs virtually no external components and uses digital comms to a uC. So far it performs very well, better than a low power op-amp design we have used in previous products.You said you can't use a uC so maybe the E931.95 may be of more use as it's standalone and you program the time delay and sensitivity by setting a DC voltage on some of its pins.It may not be as cheap in production as rolling your own op-amp circuit but it does save a lot of development time!There are also 'proper' distribution channels for these chips - in the UK we are sourcing from Avnet.
Low Cost Programmable Decade Capacitor for Prototyping Convenience - Page 1
Forum section: electronics / projects

author: gerrysweeney
author_rank: Regular Contributor
timestamp: August 29, 2013, 08:01:10 am
content: Hi All,Following on from the Decade Resistor Board I made a couple of months ago I had a lot of requests to make a complementary decade capacitor board. I recently showed these in a blog article, you can see that through the link below. The capacitance can be programmed in the range of 100pF through 9.9999uF in 100pF increments. The tolerance of the capacitance is five (5%) percent.http://gerrysweeney.com/five-decade-programmable-capacitor-a-low-cost-solution/I also had a bunch of these made so if anyone would find these useful and wants one they are available to buy onhttps://www.tindie.com/products/gerrysweeney/five-decade-programmable-capacitor-100pf-to-9999uf-100v/Gerry

author: BiOzZ
author_rank: Regular Contributor
timestamp: August 29, 2013, 08:13:16 am
content: nice! some DIP switches would be nice but i think this would be nice in the on-the-go tool box!

author: Harvs
author_rank: Super Contributor
timestamp: August 29, 2013, 09:55:58 am
content: Nice. Quick correction in your post above, it's 100pF increments.When I first read that I thought dam, if only you had made it 100p instead of 1n. But alas, you did.

author: fpliuzzi
author_rank: Regular Contributor
timestamp: August 29, 2013, 04:43:58 pm
content: Thanks Gerry. Another nice little addition to my bench. Glad that you used 100V capacitors for this.Regards,Frank

author: gerrysweeney
author_rank: Regular Contributor
timestamp: August 29, 2013, 10:06:40 pm
content: Quote from: Harvs on August 29, 2013, 09:55:58 amThanks for pointing that out, corrected now :O

author: gerrysweeney
author_rank: Regular Contributor
timestamp: August 29, 2013, 10:07:29 pm
content: Quote from: fpliuzzi on August 29, 2013, 04:43:58 pmHi Frank,Super that you have one, thank you for your support.Gerry
Low cost shake sensor - Page 1
Forum section: electronics / projects

author: riscy00
author_rank: Contributor
timestamp: November 13, 2022, 11:13:36 pm
content: I'm looking for IC when shaken (tilt or similar) that generates a pulse to wake up MCU and do tasks then goes to sleep again. I preferred of shelve solution rather than I2C/SPI to config the device (I am just lazy). I do not like the mercury-tilt glass bottle style. I'm open to suggestions, it could be a wire loop with wire sticks, touching to pad.

author: Zero999
author_rank: Super Contributor
timestamp: November 14, 2022, 09:59:09 am
content: https://www.jprelec.co.uk/categories/components/switches-and-sensors/tilt-and-vibration-switches/comus-m1230-low-cost-non-mercury-tilt-switches/product/comus-m1230-low-cost-non-mercury-tilt-switches/800-528~800-528

author: 741
author_rank: Frequent Contributor
timestamp: November 14, 2022, 08:46:42 pm
content: Some years back,Elektormagazine printed a suggestion from a reader - the idea was to wrap a piece of conductive foam around a stiff wire, then create an outer electrode from copper tube. The foam is slightly distorted when the assembly is shaken, and this makes the resistance change.

author: DavidAlfa
author_rank: Super Contributor
timestamp: November 14, 2022, 08:49:56 pm
content: You have them with ordinary metal balls, not using mercury.

author: SiliconWizard
author_rank: Super Contributor
timestamp: November 14, 2022, 08:51:08 pm
content: Many MEMS accelerometers have that feature while drawing extremely low power. They usually need to be internally configured though, so require an I2C connection to the MCU beside the wake-up pin, which they also have.

author: DavidAlfa
author_rank: Super Contributor
timestamp: November 14, 2022, 09:00:35 pm
content: You also have spring-based sensors, like the SW-18010P.

author: Terry Bites
author_rank: Super Contributor
timestamp: November 15, 2022, 04:18:26 pm
content: SW-520D Vibration Sensor Metal Ball Aliexpress. $0.05. Cheap enough?

author: bidrohini
author_rank: Regular Contributor
timestamp: November 17, 2022, 07:13:35 am
content: If touching pad can solve your purpose, you can use ESP32. It has an in-built capacitive touch sensor.https://www.theengineeringprojects.com/2021/12/esp32-capacitive-touch-sensor.html
Low Cost signal tracer based on RD6006 Power Supply ?? - Page 1
Forum section: electronics / projects

author: dazz1
author_rank: Frequent Contributor
timestamp: October 13, 2022, 10:55:02 pm
content: HiBased on my reading of current eevBlog forum threads, there has been success using a arbitrary waveform sig-gen, or a programmable psu.This thread builds on the psu concept.I have a cheap and cheerful RD6006 bench top PSU.It can be controlled by a USB port and Windows PC. See this link:Has anyone looked at this option?

author: wrickert
author_rank: Contributor
timestamp: November 16, 2023, 07:18:58 pm
content: Sorry to necro-bump but I have been doing research on the RD6006 and I have a method to at least attempt this.There is a github project that can control the RD6006 via python. I've been playing with it for the last hour and does what it says on the tin.https://github.com/Baldanos/rd6006I dont know enough about signal tracers to say if this was a good one but its possible. Interesting stuff.
Low cost single channel analog oscilloscope and useful to view SPDIF signals. - Page 1
Forum section: electronics / projects

author: Lawsen
author_rank: Frequent Contributor
timestamp: June 06, 2011, 01:56:33 am
content: I am so poor that I use a single channel analog oscilloscope like these:http://www.electronickits.com/gold/CKOSCOPE10MHZ_Low_Cost_10MHZ_Oscilloscope.htmI liked them more than the digital storage oscilloscope like the Rigol.I have both in my bedroom. The PC motherboard is sending out SPDIF digital signals. I have figured a set up that will convert these to analog signal for my old speakers from a thrift store like condition, a dumpster. Microsoft and Asus BIOS in China changed my computer to send out only SPDIF digital signals. I will need a DAC, a circuit that changes SPDIF digital signals to analog by a Philips chip DAC converter. I am not happy with this, but no choice. I have not changed to Linux, yet. My analog speakers stopped working, because the Asus BIOS updates changed the audio output to SPDIF digital signals. Microsoft Vista adapted with the SPDIF driver software and made analog output incompatible. This computer will be silent for a few weeks, a month, until I figure a way to convert the SPDIF signals to analog and the needed cabling and DAC converter circuit board and steel cabinet to house it and a 6 to 9 V DC power supply. This came at the worse time, because of the great depression here.I have decided to add a sound card with a 24 bits digital to analog converter. I lost the use of a Firewire card, because the P5DV2-MX SE motherboard only has two PCI slots. It has one PCI Express 1.1, but I cannot afford the high end audio board that goes into that slot. The sound is restored with a common $30.00 sound card, a PCI card with Creative Labs chip set and surface mounted op amps. Updating the BIOS caused the motherboard to only output digital SPDIF signals at the audio jack that used to output analog audio. PCI slots are really important, never know, when I might need them. I was not impressed with the USB audio device, about as small as a key. It is too fragile and does not have much audio components in it, but that seem better selling and sound card PCI board. It is well worth the hassle to install it. Most computers output digital PCM, pulse code modulation signals at 1 MHz or less, so any analog oscilloscope can show that signal. I was wondering why my speakers did not work after the BIOS got updated. Updating the BIOS does not increase the RAM address capacity, that I am ignorant of. I learned that here. The board addresses 2.5 GB by experiment.Lawsen

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 06, 2011, 04:33:13 am
content: find the Asus Driver in the net, maybe it can change back the setting to output analog signal.

author: joelby
author_rank: Frequent Contributor
timestamp: June 06, 2011, 04:54:51 am
content: Yeah, it'll be a driver setting somewhere.It is *so* not worth your time to build a DAC. You can buy a USB sound card with stereo analogue outputs for a couple of dollars. A basic PCI sound card won't be a lot more.
Low cost transimpedance amplifier - Page 1
Forum section: electronics / projects

author: girishv
author_rank: Regular Contributor
timestamp: September 25, 2022, 02:36:44 am
content: I am a newbie in analog electronics. I need to build a Transimpedance amplifier for a photodiode.Frequencey: 10KHzPhotodiodeReverse Light Current: 1nAReverse Light Current: 3µA (Typical)I have TILM2902LVin my inventory.Architecture: CMOSChannels: 4GBW: 1MHzIB: ±15pAIOS: ±5pAI want to use LM2902LV as Transimpedance amplifier. I can limit the gain to stay within GBW limit and use additional channel for additional gain if need. Can I use LM2902LV?Girish

author: ledtester
author_rank: Super Contributor
timestamp: September 25, 2022, 03:25:48 am
content: Here is a TI app note on designing a transimpedance amplifier for amplifying the light-dependent current of a photodiode:Photodiode amplifier circuit - SBOA220Ahttps://www.ti.com/lit/an/sboa220a/sboa220a.pdf

author: Terry Bites
author_rank: Super Contributor
timestamp: October 03, 2022, 12:10:08 pm
content: https://tools.analog.com/en/photodiode/
Low-cost USB data isolation using a transformer? - Page 1
Forum section: electronics / projects

author: danieljfarrell
author_rank: Contributor
timestamp: September 04, 2024, 10:42:50 pm
content: Hi all,I'm looking at using thehttps://www.analog.com/en/products/adum3160.htmlfor isolating USB data, I would like full speed (12Mpbs) but actually slow speed (1.5Mbps) would probably be fine.But I'm curious why there is not a cheap high-speed transformer approach that solves the same problem. For example, a 1:1 transformer for the D+ and another for the D-. The transformers would slew the rise and fall of the edges, let's guess a 2ns rise/fall time, the USB clock rate is 1/(24Mhz) ~ 40ns gives the duration of the data high or low. As long as the transformer does not delay the rise time longer than 1/10th of 40ns = 4ns, then I think this should work. I don't know much about high-speed transformers, but I guess this is too much of an ask, or is it?There are a lot of transformer options for CAN, RS-232 etc,https://www.coilcraft.com/en-us/edu/series/understanding-and-selecting-isolation-transformersso why not USB?Happy to be educated

author: DavidJRobertson
author_rank: Regular Contributor
timestamp: September 05, 2024, 12:23:57 am
content: USB 1.0/1.1/2.0 (but not 3.0 onwards...) requires DC coupling on the diff pair, so a transformer alone will not work.

author: moffy
author_rank: Super Contributor
timestamp: September 05, 2024, 12:25:21 am
content: From my understanding USB also uses DC levels as part of the protocol and also for power demand levels, it's moderately involved.https://www.engineersgarage.com/signal-and-encoding-of-usb-system-part-5-6/

author: Irilia
author_rank: Regular Contributor
timestamp: September 05, 2024, 03:27:52 am
content: This is probably your best option.>https://a.aliexpress.com/_EQ7w56Z

author: danieljfarrell
author_rank: Contributor
timestamp: September 05, 2024, 09:04:00 am
content: Thanks everyone,I didn't realise DC coupling was in the specification for the data lines. Interestingly that is missing on USB-C so there might be some options there...That ADUM4160 board is virtually as cheap as just buying the IC.Thanks,

author: exmadscientist
author_rank: Frequent Contributor
timestamp: September 05, 2024, 10:07:58 am
content: Be mindful that USB-C connectors carry both the older D+/D- (aka USB1, USB1.1, USB2.0, Low Speed/LS/1.5, Full Speed/FS/12, or High Speed/HS/480) pairs and the newer SS (USB3.0 SuperSpeed/5Gbps aka ... okay, even this rant/joke has gone too far, just because it's a Universal bus didn't mean it had to get a whole Universe of silly nomenclature too) pairs.So just because you're using Type-C connectors doesn't mean you're free of the original data signals. They're just present together in parallel.
Low cost USB temperature sensor (DS18B20 over USB-UART) - Page 1
Forum section: electronics / projects

author: d-el
author_rank: Regular Contributor
timestamp: July 24, 2025, 03:41:12 pm
content: To provide testing, it was necessary to log the temperature of the device and the temperature of the laboratory.For these needs, a simple project was developed - 1Wire over UART. The sensor used is DS18B20. The hardware used is a USB-UART adapter of the CP2102, FT232, CH341 type with two external components.The connection diagram is shown below:Testing with 4 sensors:Output:Code:$ ./usb1wire /dev/ttyACM0Open: /dev/ttyACM0Found ROM: 28 48 49 94 0C 00 00 84Found ROM: 28 FA 0B D0 02 00 00 9DFound ROM: 28 EE 54 10 05 00 00 A3Found ROM: 28 C1 5B 3B 03 00 00 6BInit ds18b20 to 12Bit resolution, read TRIM1: 08, TRIM2: 74Init ds18b20 to 12Bit resolution, read TRIM1: 1F, TRIM2: DBInit ds18b20 to 12Bit resolution, read TRIM1: 3F, TRIM2: DBInit ds18b20 to 12Bit resolution, read TRIM1: 7F, TRIM2: DB25.4°C 25.4°C 25.6°C 25.2°C25.4°C 25.4°C 25.6°C 25.3°C25.4°C 25.4°C 25.6°C 25.3°C25.4°C 25.4°C 25.6°C 25.3°C25.4°C 25.4°C 25.6°C 25.3°C25.4°C 25.4°C 25.6°C 25.3°C25.4°C 25.4°C 25.6°C 25.3°CLink to code on githubhttps://github.com/d-el/uwb1wire.