hybridfree/eevblog-posts huggingface dataset:
STM32U5 vs ESP32 for my project - Page 1
Forum section: electronics / beginners

author: davegravy
author_rank: Regular Contributor
timestamp: December 26, 2021, 06:25:07 pm
content: Hi All,I bought an ESP32 and builtthis Hackaday projectwith it. It's a sound-level meter with a I2S MEMS microphone as an input.The system functions fine except the power draw is higher than I'd like. The lowest I can frequency scale the ESP32 while remaining stable is 80MHz at which point the power draw is about 20mA@5V = 100mW. I'm curious to know how easy it is to further reduce it by using different MCUs.I was looking at the STM32U5 which has SAI connectivity that I think supports I2S. The U5 series claims 26uA / MHz, and assuming I'd need the same clock rate that translates to 2mA@3.6V = 7.2mW. That's a huge reduction and seems too good to be true. I realize one clock frequency of one MCU is not equivalent to one of the other in terms of processing capability, so how can I reasonably evaluate this and select an appropriate device? Is the only good way to purchase discovery boards and try it out?

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: December 27, 2021, 01:38:20 am
content: Unfortunately the ESP32 doesn't support SPI/I2S and/or DMA in light sleep. You could use a separate chip to buffer the I2S and send the data through to the ESP32 in batches. Then the ESP32 would use ~1 mA when in light sleep.The STM32U5 is a far more powerful chip. Particularly if you're doing floating-point ... the ESP32's hardware float is anaemic. Even for integer, the ESP32 has half the performance per core per Hz of an nRF528xx for example. This is based on Dhrystone benchmarks, which various individuals perform and publish the results of.The ESP32 has many disadvantages, but as you know its advantages (cheap, many peripherals, easy to develop for) often outweight them if you play to its strengths.
STM8 SWIM pin as output/Debug - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: November 08, 2014, 10:37:17 am
content: 1. I have STM8S003F3 & want to use its debug pin as output.So I will configure it my code.2. Will that make debug option dead?On next power up, will I be able to debug the code?? Because pin will already be configured as output by that time

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: November 08, 2014, 11:15:16 am
content: I haven't used 8bit swim but use the swd for the stm32 range. So I haven't read the datasheet.you should be able to intercept the chip on boot to debug it.but you will need to debug it without the pin being used as a gpio.wrap the pins initialisation in#ifndef debug// set pin as output.#endifobviously while in debug mode you cant use this pin as normal gpio, but this way you can debug the rest of your code and hardware.

author: Kjelt
author_rank: Super Contributor
timestamp: November 08, 2014, 01:53:57 pm
content: For SWIM debugging no, you need to continuously keep communicating to the device so you can not configure it during debugging as a hard output for instance.For final product, it also is kinda tricky so I never do this but it should be possible.The problem I encountered in the past was that the SWIM signal is high frequency (order of 10MHz) so for instance a small capacitance on that pin can already inhibit the use of SWIM programming/debugging.So my advice is to breadboard your design first and do a lot of testing before putting it in a real product. For hobby purposes you can always make a jumper or small switch.

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: November 19, 2014, 05:20:29 am
content: I checked it & working.But for now, in professional boards I won't use SWIM pin
STM8S003F3 Integrated development environment options - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: June 14, 2020, 01:19:44 pm
content: 1. I am using STM8S003F3 & exploring options for IDE available. It has 16Kb flash, which ide is free for 16KB?2. There are options here:https://www.st.com/en/microcontrollers-microprocessors/stm8s-series.html#tools-software3. I am using IAR 3.11 which is limited to 8KB now for free version. Didnt it used to be free for upto 16KB for previous versions?I checked IAR website didnt find where to download old version and see which was free till 16KB flash?

author: rhodges
author_rank: Frequent Contributor
timestamp: June 14, 2020, 04:00:50 pm
content: Since you want an IDE, I don't know if this is very helpful, but...I have been using SDCC for some time now, and I think it is excellent for STM8.http://sdcc.sourceforge.net/I use SDCC, EMACS, and make as my development environment.I use stm8flash and $2 to $3 ST-LINK V2 USB programmers to program the chips.I have a number of STM8 libraries, projects, and example programs on github:https://github.com/unfrozenThe libraries use some inline assembly for speed or size, so they need SDCC.But feel free to browse the code and use what you want.
STM8S003F3 Interfacing with WS2811, external crystal required ? - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: July 10, 2017, 05:41:28 pm
content: 1. I need to interface STM8S003F3 with WS2811. I want to know if external crystal is required for it or not, as WS2811 has very tight timings. I prefer to generate timing through NOP's for delay using inline functions2. As STM8S003F3, Accuracy of Internal oscillator = +-5% over all temperature ranges.3. WS2811 specifies:a) T0H = 0.5?s ±150nsb) T1H = 1.2?s ±150nsc) T0L = 2.0?s ±150nsd) T1L = 1.3?s ±150nse) RES = Above 50?s4. With 16Mhz crystal, time for NOP is 1/16Mhz = 0.0625usWith on left end of accuracy -5%, time for NOP is 1/(16*.95) = 65.79nsWith on right end of accuracy +5%, time for NOP is 1/(16*1.05) = 59.52ns5. Are below calculations for NOP's are ok? I think internal oscillator can also be used.6. a) T0H = 0.5?s ±150nsvariation allowed around 0.5us is +-150ns i.e = 0.35us to 0.65usNOP's in T0H = 0.5?s / 0.0625us = 8Taking 8 NOP will generate = 0.5usvariation with +5% accuracy = 8 * 59.52ns = 0.476usvariation with -5% accuracy = 8 * 65.79ns = 0.526usSo well within specs hereb) T1H = 1.2?s ±150nsvariation allowed around 1.2us is +-150ns i.e = 1.05us to 1.35usNOP's in T1H = 1.2?s / 0.0625us = 19.2Taking 19 NOP will generate = 1.1875usvariation with +5% accuracy = 19 * 59.52ns = 1.131usvariation with -5% accuracy = 19 * 65.79ns = 1.25usSo well within specs herec) T0L = 2.0?s ±150nsvariation allowed around 2.0us is +-150ns i.e = 1.85us to 2.15usNOP's in T0L = 2.0?s / 0.0625us = 32Taking 32 NOP will generate = 2.0?svariation with +5% accuracy = 32 * 59.52ns = 1.905usvariation with -5% accuracy = 32 * 65.79ns = 2.105usSo well within specs hered) T1L = 1.3?s ±150nsvariation allowed around 1.3us is +-150ns i.e = 1.15us to 1.45usNOP's in T1L = 1.3?s / 0.0625us = 20.8Taking 21 NOP will generate = 1.3125?svariation with +5% accuracy = 21 * 59.52ns = 1.25usvariation with -5% accuracy = 21 * 65.79ns = 1.382usSo well within specs heree) RES = Above 50?sSo number of NOP's should be so that,at minimum clock time it should have at-least 50usi.e 50us / 59.52ns = 840 NOP'shouldTime for 840 NOP's at Min time 59.52ns = 840 * 59.52ns = 50usTime for 840 NOP's at nom time 62.5ns = 840 * 62.5ns = 52.5usTime for 840 NOP's at max time 65.79ns = 840 * 65.79ns = 55.263us

author: edavid
author_rank: Super Contributor
timestamp: July 10, 2017, 05:53:11 pm
content: Quote from: Vindhyachal.takniki on July 10, 2017, 05:41:28 pmIt doesn't have tight timings, just a confusing datasheet:https://wp.josh.com/2014/05/13/ws2812-neopixels-are-not-so-finicky-once-you-get-to-know-them/
Stm8s003f3  Pin as SPI MOSI and use MISO as GPIO - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: May 27, 2020, 12:52:22 pm
content: 1. I am using Stm8s003f3.In it a slave SPI device is connected, which only inputs data, it dont output any data so MOSI is only used.2. My question is can I use remianing MISO pin as GPIO? since MOSI is used after configuring SPI, will it automatcially configure MISO also?Or i can use it as independent GPIO?
STM8S003F3 reset pin 10K connection required or not? - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: July 31, 2020, 01:36:56 pm
content: 1. I am using this MCU STM8S003F3. Datasheet says dont need to conenct 10K pull-up on reset. So option B in image below2. In demo board they have option A, but 10K is not mounted.3. But i have noticed some times their MCU dont start, i doubt placin 10K would be better? Which is ok?Or option C to be used, it may limit any inrush current.4. What is more preferable?

author: rhodges
author_rank: Frequent Contributor
timestamp: July 31, 2020, 04:22:08 pm
content: I would go with just the capacitor. "The reset network shown in Figure 37 protects the device against parasitic resets." (9.3.7)The internal pull-up is around 40k or 50k, so you could speed it up with a 10k external resistor. Figure 37 shows a Schmitt trigger, so the simple RC should be fine.
STM8S003F3 reset pin - output frequency - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: February 27, 2015, 06:21:05 am
content: 1. I have made a circuit using STM8S003F3.I don't understand somehow when I probe reset pin of MCU, it is giving 12Khz freq output.Thus I am unable to program/debug the MCU.2. I have removed everything else from board. Just +5V supply & MCU.MCU supply is decoupled by 0.1u & 1u caps.Vcap pins is decoupled by 1uF cap.Reset pin is decoupled by 0.1uF cap.That's it . Nothing else on circuit.3. I have probed VCC pin of MCU, I get clean +5V across it.Probing Vcap pin gives +2V clean.I have also removed 0.1u cap from reset pin & then checked the bare pin but same result.Edit: I have also changed 2 MCU but same results

author: Psi
author_rank: Super Contributor
timestamp: February 27, 2015, 06:30:30 am
content: Looking at the datasheet the watchdog can be set between 64ms and 75us.75us is ~12khz, coincidence? i doubt itEither your code, or the option bytes, are enabling one of the chips watchdogs and it's not being cleared. It will keep tripping every 75us (or whatever its set to) and pull RESET to ground, then repeat.Quickest way to confirm is put some watchdog clear commands into main().

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: February 28, 2015, 06:32:52 am
content: Problem is its fresh piece I have soldered.Due to reset pin frequency, I can enter my code into it. Debugger replies that it cannot communicate.

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: February 28, 2015, 07:52:30 am
content: Problem solved. By mistake I had connected 1pf at vcap pin instaed of 1uF.
Stopping Solid State Relay Leakage Current - Page 1
Forum section: electronics / beginners

author: Con Current
author_rank: Newbie
timestamp: June 05, 2016, 06:09:08 pm
content: HiI'm hoping someone can guide me to a solution to stop my SSR from leaking current.The problem is that every 5 seconds I get a flash from the security light when it's not powered, on reading the data sheet I believe that it's caused by a 3ma current leakage from the SSR.I've read some other topics and believe a resistor (2.2ohm 10watt) may help, I'm not confident that I would pick the right resistor and put it in the correct location.SSR:- Fotek SSR-10DASecurity Light: LED, 10 Watt, 240v ACI've included a picture of the circuit, any assistance appreciated.

author: Ian.M
author_rank: Super Contributor
timestamp: June 05, 2016, 06:22:57 pm
content: Use a mechanical relay!There is NO practical way of stopping the leakage current, you can only divert it, which wastes power. You could try a 330nF Class X2 capacitor across the light's L and N terminals, which will keep the voltage across the light due to the leakage current under 30V, which may be enough to stop it flashing.

author: electr_peter
author_rank: Unknown
timestamp: June 06, 2016, 08:26:40 pm
content: As mentioned above, all one can do is to shunt/direct current around the lamp or use mechanical means. Methods like R+C in parallel to both SSR and lamp or shunt resistor across the lamp are suggested hereResults depends on lamp internal construction, no guarantees methods above will work perfectly in your specific case. Just be careful with component values, ratings and installation quality - if done incorrectly, it can be much worse or even dangerous from fire/electrocution perspective.Sometimes lights starts flashing randomly even with mechanical switches (because minuscule amount of leakage current is flowing) - DPST switch or capacitor (or C+R) in parallel should solve such issue.

author: Con Current
author_rank: Newbie
timestamp: June 06, 2016, 10:29:11 pm
content: Ok, thanks Ian.M and electr_peter, I looked at Big Clives Fotek SSR breakdown but didn't see this one about the LED lights.I'll try a mechanical relay, it's probably going to be safer in the long run.Cheers
Stopping spurious pulses on write strobe - Page 1
Forum section: electronics / beginners

author: hotdiode
author_rank: Newbie
timestamp: June 17, 2023, 05:14:59 pm
content: I have an Altera EPM7128SLC84 CPLD connected to the following pins of a FTDI UM245R device (parallel to USB converter)1. UM245R WR : Active high input, parallel data strobed into the device on the falling edge.2. UM245R TXE# : Active low output indicating there's room in the transmit FIFO. Goes high when the FIFO is full after too many write pulses.I observe the TXE# status pin keeps going high as if a data was being continuously strobed into the device, filling up the FIFO. This happens even when the CPLD is not writing anything. In fact, I can force the pin low by changing the Verilog design and I still see the FIFO fill up spontaneously.Touching the WR pin with a logic analyzer probe or oscilloscope probe stops this entirely. So I couldn't directly monitor the WR pin. In fact touching a jumper wire of about 3 inches to the WR pin also stops this!I tried adding 2.2K pull-down resistor to WR. But the problem persisted with no improvement or change. What solved it completely was to add a 47pF capacitor to ground on the WR pin near the UM245R. What is happening here and why did adding the capacitor solve it? The 2.2K pulldown is still in place so I don't know if that is unnecessary yet.I went through a bunch of old schematics for other products and noticed it's common to have a pF-range capacitor to ground on edge sensitive signals, so while I can see this fix is a real thing that is done on commercial devices, I'd really like to know what the root problem was and how this change is resolving it.I did try swapping both parts out with known good ones and the problem persisted, and I've used this same circuit on other projects with no problems. Not sure what is different this time around. The parts are on a four layer board with a solid ground and 5V power plane and the rails look clean, and every other edge sensitive signal for other ICs work fine. Plenty of decoupling at every Vcc pin too. It's just the UM245R to CPLD part of the circuit that has this issue.
Store display initialization commands on FPGA's config flash - Page 1
Forum section: electronics / beginners

author: soFPG
author_rank: Frequent Contributor
timestamp: April 25, 2021, 12:22:20 pm
content: Hello,I would like to store display initialization commands on a flash IC (e.g. Winbond SPI) such that an FPGA can fetch these commands and then starts executing them once its configuration is loaded.My plan is to store these commands on the same flash where also the configuration bitstream of the FPGA is stored (the FPGA I plan to use is a Xilinx XC3S200 with a bitstream size of <= 2MBit).Now, this means that somehow I have to get these commands on the SPI flash. I thought about a microcontroller who receives (e.g. via USB/UART converter) and writes these commands to the flash.My question is: How can I design the wiring between the FPGA, flash and controller such that both devices can access the flash safely?In general: is this a good idea?

author: soFPG
author_rank: Frequent Contributor
timestamp: April 25, 2021, 12:37:05 pm
content: Hi and thank you for your answer.What I am particularly worried about is whether a wrong pin configuration on the FPGA or microcontroller (or combination of both) can lead to a short circuit (e.g. if the FPGA is reading configuration via an input pin while the microcontroller is configured as output GND / VCC)?

author: rstofer
author_rank: Super Contributor
timestamp: April 25, 2021, 03:08:24 pm
content: I just use initialized BlockRAM (or distributed RAM). The configuration of BlockRAM is stored in the SPI Flash along with the rest of the bits. It is done in the HDL source code.A better way is to have the contents of BlockRAM come into the design from a file. Look at the attachment to Reply 14 here:https://www.eevblog.com/forum/fpga/risc-v-evaluating-on-fpga-board/That is hamster_nz's code. He is active on the FPGA forum.I use that loader to get a program into the memory of a soft-core CPU at build time.If you wander around in that thread, you will see where the Xilinx dat2mem utility can be used for pretty much the same thing BUT... You need to know the actual physical layout of the BlockRAM and if other components are using BlockRAM, this takes some sorting out. Doable but ugly!https://www.xilinx.com/support/documentation/sw_manuals/xilinx14_7/data2mem.pdf
Store timer event for best resolution - Page 1
Forum section: electronics / beginners

author: A2
author_rank: Contributor
timestamp: July 29, 2014, 04:47:30 pm
content: I am using STM32F205RBT6.I have to start a timer when a particular event happens. This I have done in programming.After that interrupts comes on 3-10 other pins. Now I have to measure the time between:1. Start & interrupt on pin 12. Start & interrupt on pin 23. Start & interrupt on pin 3 (total of 10 pins)1. What I am doing that when a start occur I run the timer & whenever any pin transition occur (I had set up 10 pin interrupts for all pins), control go that ISR read the counter value in it & return.Only drawback in it that on evry interrupt timer go to interrupt & then read the value & come back, this waste as control push register on stack, go to ISR . I want to know is there any better way to do that?
Storing Mechanic UV curable solder mask. - Page 1
Forum section: electronics / beginners

author: HobGoblyn
author_rank: Unknown
timestamp: May 03, 2020, 05:53:28 pm
content: Just got a syringe of UV solder mask.Possibly a stupid questionThe syringe appears to be clear(ish) hence can see the green solder mask in it.Does this need to be stored in the dark? My thinking is that UV light will be coming in windows etcThanks

author: Ian.M
author_rank: Super Contributor
timestamp: May 03, 2020, 06:18:20 pm
content: What does the product datasheet say? Certainly if you want to push the limits of its shelf life, leaving it on the window sill would be a bad idea.

author: rdl
author_rank: Super Contributor
timestamp: May 03, 2020, 10:25:48 pm
content: If no kids or stupid adults are around, I'd put it in a jar or zip lock bag and store in the refrigerator.

author: HobGoblyn
author_rank: Unknown
timestamp: May 03, 2020, 10:37:00 pm
content: Thanks.Couldn’t find any data sheet for this brand.Not sure I will be allowed to store in the fridge.I like the zip lock bag idea.

author: Ian.M
author_rank: Super Contributor
timestamp: May 03, 2020, 10:59:00 pm
content: Refrigeration certainly help extend the shelf life of most one component polymerising resins, but some are very moisture sensitive, so if you can refrigerate them, its advisable to put them in a well sealed container with a generously sized desiccant sachet and replace or regenerate it as nessercery (depending on container volume and how frequently its opened) to keep it active. I wouldn't trust a zip-lock bag to seal well enough, though one can be helpful to protect other items in the fridge from cross-contamination from the exterior of the container.Chemicals, non-human-food organic materials etc. should *NEVER* be stored in a food fridge. Get a mini-fridge just for the workshop, permanently mark the doorCHEMICALS ONLYUNSAFE FORFOOD OR DRINKso it cant be put back into food service and don't be dumb so *DON'T* keep your sodas and Hershey bars in it! If you've got small kids, add a padlock and hasp. You *NEVER* want to be in the situation of having to find the MSDS sheet and rush your kid to the hospital because they made a PB&J sandwich with that 'funny jelly' from Dad's fridge.
Storing that damn soldering iron. - Page 1
Forum section: electronics / beginners

author: Geooorge again
author_rank: Newbie
timestamp: October 21, 2014, 12:42:40 pm
content: Hi, total newbie here. I'm not a an engineer, not even a hobbyist one. I just have a cheapy soldering station for the odd job of soldering a cap or fixing something.And i'm always curious on how to store the thing for long term. In some places i've seen the "tin it and save it" and on others the "wipe it clean". Heck i'll put it in the freezer in the end.

author: CrashO
author_rank: Unknown
timestamp: October 21, 2014, 01:06:47 pm
content: Clean and Tin it before storing. Then clean before use and retin.

author: Tandy
author_rank: Frequent Contributor
timestamp: October 21, 2014, 01:30:30 pm
content: Wipe the tip clean on a damp sponge to remove all the gunk and then lightly tin the tip. Don't try cleaning with abrasive such as wire wool or sand paperas most tips consist of a copper base material, plated with iron to prevent erosion and abrasives will remove the coating exposing the base metal.

author: Geooorge again
author_rank: Newbie
timestamp: October 21, 2014, 02:15:26 pm
content: Thanks. And yes, my tip is copper plated, i'm only using a soft sponge.

author: compet17
author_rank: Regular Contributor
timestamp: October 25, 2014, 10:43:22 am
content: Copper plated? Normally the cheap tips are made of copper with NO coating. Get an iron plated copper tip, it will last almost forever. Unplated copper tips will dissolve rather quickly in contact with tin and lead, no matter how good you care.The benefit of pure copper tips is that they can be cut, filed and sanded into any form until there is nothing left.I clean my tips on a moist (not too wet) sponge and then I switch the iron off. Never had problems.

author: Geooorge again
author_rank: Newbie
timestamp: October 27, 2014, 08:50:09 am
content: It's a soldering station from Velleman. For 25 euro i thought it would be a cheap knockoff knowing that stations usually go for 3-4 times as much?

author: compet17
author_rank: Regular Contributor
timestamp: January 02, 2015, 12:32:37 pm
content: I would recommend the Weller WS81 station which I have at home. It has 80 Watt power and heats up in 10 sec. Of course it is a bit more expensive at Euro 300.-But you can use the tips for many many years without worrying about procedures. And there is a wide choice of tips for any application.

author: ConKbot
author_rank: Super Contributor
timestamp: January 02, 2015, 12:59:51 pm
content: If the iron isnt in your hand, then it should have a decent sized blob of solder on the tip, hot or cold. If you have a lot of solder on the tip while its hot, then the solder will oxidize instead of the tip, so you can easily wipe it away, add a small amount of solder to tin the iron to do your joint, wipe it to get any crud from the pcb off, re-tin it with the blob and put it back in the holder. Turn it off/unplug it, let it cool with the blob on there, and its still there when you turn it back on.
Storing tubes of ICs - Page 1
Forum section: electronics / beginners

author: dorkshoei
author_rank: Frequent Contributor
timestamp: February 09, 2021, 07:45:43 pm
content: I have a large number of tubes of 0.3" ICs. 74 series etc.The threads I've found via searching talk about dumping them all into those organizers with X rows of Y small bins.Does anyone have a good storage system for storing the plastic "tubes". I don't mind cutting the tubes into shorter lengths.Right now they are all in a plastic tote and each time I need a specific value I spent ages rummaging through the bin to find the correct tube.And a picture is worth a 1000 wordsThanks

author: Benta
author_rank: Super Contributor
timestamp: February 09, 2021, 08:07:21 pm
content: Cardboard tubes as used for poster storage, cut to lenght fitting the IC tubes, or a bit shorter.Place them horizontally on top of each other in a cupboard or a shelving system frame, they will form a nice beehive pattern.Stick in your IC tubes. If you want, you can tack small cardboard signs with the IC names to the ends of the cardboard tubes.Cheap and easy.

author: edavid
author_rank: Super Contributor
timestamp: February 09, 2021, 08:10:38 pm
content: I find that what takes time is squinting through the tube to try to read the IC markings. Maybe this is obvious, but if you put nice bold labelmaker labels on both ends of the tube, it's much easier to pick out the one you want. You could use different color labels or color coded tape to make this even easier.If that's not good enough, you could get some mailing tubes and group them that way.

author: nfmax
author_rank: Super Contributor
timestamp: February 09, 2021, 08:24:24 pm
content: When I had need to store IC tubes, we used metal cabinets of drawers, the kind used for storing paper and stationery. The drawers were A3 size, and an inch or so deep. There is a label holder on each drawer: related parts go in a common drawer
Storing videos from a camera directly in an SD - Page 1
Forum section: electronics / beginners

author: bjancj
author_rank: Newbie
timestamp: June 09, 2022, 01:24:20 pm
content: Hello, I am working on a camera system that has to record a video and store it in some type of memory.The main constraint here is space: it has to be very small, ideally less than 4x4x6cm, and lightweight. I found a camera that uses a USB 2.0, but I need a way to record its output.Any ideas are greatly appreciated.Thank you

author: Jester
author_rank: Frequent Contributor
timestamp: June 09, 2022, 02:27:11 pm
content: I picked up one of those super cheap eBay cameras that records directly to a SD card. Seems to work okay. It has motion sensing and can be setup to record on power-up.

author: bjancj
author_rank: Newbie
timestamp: June 09, 2022, 02:31:02 pm
content: can you tell me the model so I can check it out myself?

author: bjancj
author_rank: Newbie
timestamp: June 09, 2022, 05:34:49 pm
content: Long story short, this thing has to fly, so it has to be very, very lightweight (max 100g) and it has to not consume much power. I will definitely look into dashcams and see what I can find.

author: ledtester
author_rank: Super Contributor
timestamp: June 09, 2022, 08:24:57 pm
content: Quote from: Jester on June 09, 2022, 02:27:11 pmWhat I think Jester is talking about is something like the "SQ11" or what pops up when you search aliexpress for "minicamera":https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20220609122143&SearchText=minicamera&spm=a2g0o.productlist.1000002.0There's a bunch of different models so make a thorough search through the listings.Quote from: bjancj on June 09, 2022, 05:34:49 pmThe cube cameras are very lightweight - the one I got weights 9 grams. Also note that mine didn't record any audio.
STP1612PW05 LED driver - Page 1
Forum section: electronics / beginners

author: alizare368
author_rank: Regular Contributor
timestamp: June 18, 2019, 02:22:31 pm
content: HiI used these codes to run the RGB LED DRIVER(stp1612pw05), but it does not work.Code:#define SPI_SCLK_LOW_TIME 200#define SPI_SCLK_HIGH_TIME 1uint16_t SPI_1(uint16_t byte_out){uint16_t byte_in =0;uint16_t bit;for(i=0;i<16;i++){//LE pin is lowHAL_GPIO_WritePin(GPIOB,GPIO_PIN_9,GPIO_PIN_RESET);for (bit = 0x8000; bit; bit >>= 1){/* Shift-out a bit to the MOSI line */HAL_GPIO_WritePin(GPIOB,GPIO_PIN_4,(byte_out & bit) ? GPIO_PIN_SET : GPIO_PIN_RESET);/* Delay for at least the peer's setup time */for(int i=0;i<SPI_SCLK_LOW_TIME;i++){}/* Pull the clock line high */HAL_GPIO_WritePin(GPIOB,GPIO_PIN_5,GPIO_PIN_SET);///* Shift-in a bit from the MISO line *///if(HAL_GPIO_ReadPin(GPIOC,GPIO_PIN_8)==1)//byte_in |= bit;///* Delay for at least the peer's hold time */for(int i=0;i<SPI_SCLK_HIGH_TIME;i++){}/* Pull the clock line low */HAL_GPIO_WritePin(GPIOB,GPIO_PIN_5,GPIO_PIN_RESET);}//LE pin is highHAL_GPIO_WritePin(GPIOB,GPIO_PIN_9,GPIO_PIN_SET);HAL_Delay(1);}//return byte_in;}while (1){SPI_1(0xffff);}
stp9nk50zfp replacement - Page 1
Forum section: electronics / beginners

author: DaZero79
author_rank: Newbie
timestamp: November 27, 2021, 06:33:56 pm
content: Hi together and greetings from Germany.I was checking a TV that won't turn on for a friend and found a dead resistor (0.1Ohm) on the main power supply (Sony APS-299) and connected to that resistor on the second board (Sony DPS-76) 2 shorted mosfets.My problem is that the original mosfets are hard to get here. So, I looked for some replacement.The original is an stp9nk50zfp (Link to Datasheethttps://www.mouser.de/datasheet/2/389/cd00002970-1796061.pdf)I've found an available replacement ( Link to Datasheethttps://asset.conrad.com/media10/add/160267/c1/-/en/000162527DS01/datenblatt-162527-vishay-irf840apbf-mosfet-1-n-kanal-125-w-to-220ab.pdf)From the Pins/Voltage/ ID it looks good for me but the timings are slightly slower.I don't have much experience in power supplies, so can someone check if my choice is at least reasonable and how I can find out such things in the future on my own?Many thanks in advance for your help

author: edavid
author_rank: Super Contributor
timestamp: November 27, 2021, 08:21:55 pm
content: The original parts are readily available:https://www.tme.com/us/en-us/details/stp9nk50zfp/tht-n-channel-transistors/stmicroelectronics/

author: DaZero79
author_rank: Newbie
timestamp: November 27, 2021, 10:50:25 pm
content: Thanks edavid,I've created an account there but the standard delivery time seems to be 8 weeks for that mosfet.( at least if I want to ship it to germany)

author: edavid
author_rank: Super Contributor
timestamp: November 28, 2021, 12:20:40 am
content: Quote from: DaZero79 on November 27, 2021, 10:50:25 pmWhoops, I somehow didn't notice they were out of stock.You linked to Mouser before, is it a problem to order from them? How about Farnell or RS?See:https://www.findchips.com/search/stp9nk50zfp

author: DaZero79
author_rank: Newbie
timestamp: November 29, 2021, 03:35:03 pm
content: That is a cool website, I've bookmarked it but sadly most of them ship from US or China.So long and expensive (22.5$ ) shipping. Maybe I have to deal with customs as well.I think I'll try my luck with the replacement part.Thanks for the cool website and your help.

author: wraper
author_rank: Unknown
timestamp: November 29, 2021, 03:58:42 pm
content: QuoteThe part you asked about has uninsulated case, original part number has fully insulated (covered in plastic) TO220FP. If uninsulated case is ok, STP9NK50Z are in stock at TMEhttps://www.tme.com/us/en-us/details/stp9nk50z/tht-n-channel-transistors/stmicroelectronics/Don't buy any replacements from China, it's not needed, and very likely you will receive counterfeits.

author: .rpv
author_rank: Contributor
timestamp: December 01, 2021, 09:08:50 am
content: Hi, the ST store has on stock:https://estore.st.com/en/stp9nk50zfp-cpn.htmland has flat rate shipping at 5.99usd
Strain gage array - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: April 12, 2015, 07:23:45 am
content: 1. What is meaning of array of strain gages.2. I have read here,http://www.ni.com/white-paper/10636/en/Does it mean a load cell which have array of strain gagesor they can be connected in array. If yes what is configuration, how they are connected in array?
Strange analog readings. - Page 1
Forum section: electronics / beginners

author: cameronasmith
author_rank: Newbie
timestamp: April 07, 2014, 07:10:23 pm
content: Hi Guys,I have an INA125 plugged into a breadboard (i read that this might be a problem) with a strain gauge connected to an Arduino analog pin.When I take readings it seems to jump around. For example:101, 102, 101, 101, 102, 101, 101, 101.Is this normal for a strain gauge? And can anyone recommend a way to not make the signals so erratic.Thanks,Cameron.

author: PA0PBZ
author_rank: Super Contributor
timestamp: April 07, 2014, 07:13:03 pm
content: I don´t see a problem here: imagine that the signal is 101.5, what readout would you suspect?

author: cameronasmith
author_rank: Newbie
timestamp: April 07, 2014, 07:19:08 pm
content: Hi, paopbz,I'm sorry, I don't think I explained it very well. If I put a 100gram weight on the scale. The reading will jump around like:202, 201, 201, 202, 202, 201.If I put a 101 gram weight on the scale I will get something like this:203, 202, 203, 203, 203, 202.You can see how this can become a problem when weighing in 1 gram increments.I really need it to just give me one reading.Thanks,Cameron.

author: KJDS
author_rank: Super Contributor
timestamp: April 07, 2014, 07:44:04 pm
content: You will always have some variation due to noise.Just display an average.

author: lewis
author_rank: Frequent Contributor
timestamp: April 07, 2014, 07:47:46 pm
content: You need some digital averaging! I use an IIR filter like this:http://electronics.stackexchange.com/questions/30370/fast-and-memory-efficient-moving-average-calculationThink about why the reading will jump around and why you will never get a single consistent value.

author: PA0PBZ
author_rank: Super Contributor
timestamp: April 07, 2014, 08:03:47 pm
content: Quote from: cameronasmith on April 07, 2014, 07:19:08 pmI think you did explain it very well, just look at my answer again and think about it...

author: kfitch42
author_rank: Frequent Contributor
timestamp: April 07, 2014, 08:56:43 pm
content: Expanding on the concept a bit more, this is a case were noise can be a good thing. By using an average you can get a more precise reading than what you get with a single reading.Think about those cheap digital oral thermometers, they can take quite a while to give a reading ... but the ones they use at the doctor's office only take a couple seconds.This is because the cheap ones are using a cheaper/noisier sensor and wait until the average settles down. The more expensive ones at the doctor's office use a better(more expensive) sensor so they don't have to average for so long.
Strange AVR UPS - Page 1
Forum section: electronics / beginners

author: sam1275
author_rank: Frequent Contributor
timestamp: May 14, 2015, 05:09:20 pm
content: Hi everyone.I posted this as a post in another thread but no one answers... So I decided to go a new thread.I have a UPS with AVR function, some article says it's like a auto transformer, it select the right coil to output a stable voltage even if the input voltage varies.But last time I took it apart, but the AC input is connected directly to AC output, I do found a big transformer-like unit, but the output doesn't go through it, and among the wires the battery is connected to the "transformer".How can the AVR regulate the voltage if it's like this? It really make me feel strange... Any ideas?Thank you.

author: cpt.charlie
author_rank: Contributor
timestamp: May 14, 2015, 10:05:14 pm
content: I don't know if it's possible, but the UPS might be injecting a voltage to correct a low AC, but if you are talking about a cheap UPS, the AVR function could be fake.Dave explains some basics about UPS at this video:AFAIK the active line UPS must pass through the transformer
Strange behavior ESP next to wireless power coil? - Page 1
Forum section: electronics / beginners

author: symbianas
author_rank: Regular Contributor
timestamp: April 06, 2025, 01:38:36 pm
content: Hi, I have Cat Fountain which pump is wireless powered with a coil. I have attached ESP8266 to control it. Switch every 5mins on/off, added motion sensor also some WS2812 LED's. It seem to work ok at first. but then I have noticed that ESP keeps rebooting, LED lights sometimes flicker randomly, motion sensor keeps triggering constantly... Sometimes it ok, sometimes not...I am wondering is this the coil interfering ESP?Or its more like power supply issue?

author: JustMeHere
author_rank: Frequent Contributor
timestamp: April 06, 2025, 04:47:26 pm
content: The ESP will tell you why it rebooted in the startup data.

author: symbianas
author_rank: Regular Contributor
timestamp: April 07, 2025, 05:54:13 pm
content: Quote from: JustMeHere on April 06, 2025, 04:47:26 pmWell I see that reset reason is 0 which means:REASON_DEFAULT_RST = 0, /* normal startup by power on */Does not help a lot, but it keeps rebooting randomly...
Strange Behavior of brand new BRYMEN BM869S when checking TRIAC - Page 1
Forum section: electronics / beginners

author: Kaluluka
author_rank: Contributor
timestamp: April 25, 2022, 03:56:16 am
content: Hi!Today I discovered strange (at least for me, but maybe I’m wrong) phenomenon, when i was checking BTA16-600B Triac with Brand new Brymen BM869S: when in diode mode and Black Lead (Common) at Anode1 and Red Lead at Gate it shows 0.1804 Volt’s (like Zener Diode), any other DMM shows around (Give or Take) 0.4500 Volt’s.Maybe I do no’t understand something right and someone has explanation for this?If I check power Rectifier (Diode) it shows normal value.Please Check attached picturesP.S. All the measurements are taken with same Leads on all DMM and with same Triac.Regards,

author: Kaluluka
author_rank: Contributor
timestamp: April 25, 2022, 04:09:24 am
content: More Pictures:

author: jonpaul
author_rank: Super Contributor
timestamp: April 25, 2022, 08:35:55 am
content: Normal: Check the triac internal form and specs.Gate and anode do NO behave like an ordinary diode.Use another better brand of meterJon

author: wraper
author_rank: Unknown
timestamp: April 25, 2022, 08:45:32 am
content: G-A1 acts more like a resistor, not like a diode. Brymen probably uses lower current in diode mode, hence you get lower voltage drop reading.

author: Kaluluka
author_rank: Contributor
timestamp: April 26, 2022, 03:26:15 am
content: THANKS for all the Reply's!I will test this further.....Regards,
strange behaviour Grundig Oscilloscope Mo 32-30 Mhz - Page 1
Forum section: electronics / beginners

author: nhouza
author_rank: Newbie
timestamp: May 07, 2019, 01:19:26 pm
content: hi guys! i recently noticed this strange behaviour in the osscilloscope Grundig Oscilloscope Mo 32-30 Mhzand was wondering if you have any idea why this happens?cheers1)https://youtu.be/GLAxl15RRFQ2)https://youtu.be/iFIPja0De1g

author: nhouza
author_rank: Newbie
timestamp: May 15, 2019, 07:33:52 pm
content: ideas anyone?
Strange behaviour of RIGOL DS1054z - Page 1
Forum section: electronics / beginners

author: Windows9Professional
author_rank: Contributor
timestamp: February 18, 2020, 05:02:58 pm
content: So I've used my DS1054z intensively in the last few days since I wanted to calibrate a shunt sense resistor and today I've noticed a very strange behaviour of my scope:Every time the scope switches from 500mV/div to 200mV/div (with 1X attenuation) I hear a relay switch, which is pretty normal. The strange things start when you switch into 200mV/div:!Some! fast changes in voltage result in capacitor charging curves/slopes, which completely dissapear when switching to higher voltages/div.These are visual in picture 1This does not happen with 10X probe attenuationI wanted to add an negative offset to the waveform as seen in picture 1 to get a better view on the charging slopes, but as I turned the offset knob on my scope, the curves disappeared (picture 2). They seem to vanish proportional to the offset I add. I cant imagine how this happened, since I always thought the offset knob was just a software adjustment that basically slides the waveform up and down the screen.I figured all of this out, when I was scoping a 50% duty cycle pwm signal from my atmega8 (picture 3)So does somebody have an idea if my scope is broken, or if this is just an effect of an 1X probe?Note: When I turn off the output of my lab power supply, the charging curves disappear, while my signal gets shown without a problem for half a second (till the internal caps of my supply have discharged), so is this some kind of ground loop problem? (my PSU is linear & has an isolated output)Picture 1:https://ibb.co/72kp79YPicture 2:https://ibb.co/pZPF8L5Picture 3:https://ibb.co/vZ48PCX

author: StillTrying
author_rank: Super Contributor
timestamp: February 18, 2020, 06:28:29 pm
content: Quote from: Windows9Professional on February 18, 2020, 05:02:58 pmWhen you've got a lot of the waveform well off the screen it's quite normal to see some strange curves when the waveform reappears on the screen, it's just the analogue amp parts recovering from the overload.Here's a Siglent example I remembered.www.eevblog.com/forum/testgear/siglent-sds1000x-series-oscilloscopes/msg1208426/#msg1208426QuoteThat works as well, same thread.www.eevblog.com/forum/testgear/siglent-sds1000x-series-oscilloscopes/msg1210522/#msg1210522A Rigol one.www.eevblog.com/forum/testgear/rigol-ds1054z-vertical-distortion-problem/So I don't think it's broken.

author: Windows9Professional
author_rank: Contributor
timestamp: February 18, 2020, 07:14:19 pm
content: Thanks, im pleased to hear that I didn't break my scope
Strange component in a laptop battery - Page 1
Forum section: electronics / beginners

author: rexxar
author_rank: Frequent Contributor
timestamp: July 06, 2014, 03:58:37 am
content: I had just opened an old netbook battery to rip out the cells when I saw something weird. My first thought was that it was some sort of FET without a plastic case. I guess it could be a temperature cutout, since it's glued on top of two MOSFETs (with actual cases), but it's got three legs?

author: rs20
author_rank: Super Contributor
timestamp: July 06, 2014, 04:01:10 am
content: Wow, that's an awesome-looking component! Thermometer sounds like a reasonable guess; thermometers can have three legs. I'm sure someone else has a more definite idea of what this is, though.

author: mij59
author_rank: Frequent Contributor
timestamp: July 06, 2014, 04:22:54 am
content: It could be the controller chip.

author: peter.mitchell
author_rank: Super Contributor
timestamp: July 06, 2014, 04:42:05 am
content: my money is on a fuse. either single element with heater or dual element.

author: Rerouter
author_rank: Super Contributor
timestamp: July 06, 2014, 04:43:53 am
content: If your referring to the device with the orange spot, it is the sensor for the coulomb counter chip mounted beneath it (high current bidirectional shunt)

author: What_NZ
author_rank: Regular Contributor
timestamp: July 06, 2014, 08:03:10 am
content: It's a fuse, most likely this typehttp://www.us.schott.com/epackaging/english/cutoff/sh_type.html

author: amyk
author_rank: Super Contributor
timestamp: July 06, 2014, 09:44:00 am
content: Agree, it's a dual heated fuse.http://battery.newlist.ru/images2/Fuse.pdf
Strange discrepancy in transistor measurents - Page 1
Forum section: electronics / beginners

author: camurgo
author_rank: Newbie
timestamp: September 08, 2018, 06:00:55 pm
content: I have a bunch of PNP and NPN transistors here (CBC327-25, C559B, BC560b, BC549, CBC328-25, BC640, BC546b, C550C, BC547b, BSR50, C32725, C32716, C556B, among others).I also have two Fluke multimeters (87-V and 289), and several Chinese brands (Peakmeter PM8236, Borbede BD-168B, Zotek ZT219, Elecall MK72).While measuring base-emitter and base-collector resistances, consistently across all transistors I get around 0.5 MOhms with the flukes and around 6 MOhms with the Chinese brands.Anyone knows why that is?

author: iMo
author_rank: Super Contributor
timestamp: September 08, 2018, 06:17:13 pm
content: It could be the meters use a different current while measuring the R.

author: Signal32
author_rank: Frequent Contributor
timestamp: September 08, 2018, 06:23:42 pm
content: It is not strange at all, it is very expected.You are basically measuring a diode by measuring B-E of a transistor.The meters are using different voltage to measure the resistance.Put one meter in resistance mode and the other in voltage measure mode and connect the leads to see what voltage they are using.So, using a higher voltage will end up showing less resistance, because of this:http://www.nlreg.com/diode.htmWhat the meter is doing is applying a voltage, and seeing how much current is flowing.

author: David Hess
author_rank: Super Contributor
timestamp: September 10, 2018, 06:50:58 pm
content: Meters usually apply a current and measure the voltage.PN junction "resistance" is strongly non-linear with current so different test currents result in different resistance measurements. The voltage drop changes by 60 millivolts per decade change in current so for example:600mV 10mA = 60 ohms540mV 1mA = 540 ohms480mV 100uA = 4.8 kohms420mV 10uA = 42 kohms360mV 1uA = 360 kohmsSome meters have a "low ohms" mode where they use a very low test current and low input range so they can measure resistance which are in parallel with PN junctions without activating the PN junction.

author: bson
author_rank: Unknown
timestamp: September 11, 2018, 10:09:27 pm
content: It makes no sense whatsoever to measure non-constant resistances with a DMM. Itcanbe useful for semiconductors when you know what the exact current is, especially if the current can be adjusted. For example if you're experimenting with biasing a diode as a switch, or measure channel resistance vs gate voltage on a MOSFET.

author: David Hess
author_rank: Super Contributor
timestamp: September 13, 2018, 03:27:57 am
content: It is not quite useless; it can test for shorts and opens and sometimes bad leakage. With some practice, the emitter and collector can be distinguished.
Strange filter behaviour - Page 1
Forum section: electronics / beginners

author: dog80
author_rank: Regular Contributor
timestamp: December 13, 2012, 02:41:28 pm
content: I am doing a frequency sweep of a typical ADSL filter using a scope and a generator as shown here:The filter has a Line input on one side and Modem and Phone outputs on the other side. I am feeding the output from the generator to the input of the filter andI have set up the generator 1 Hz to 1MHz, 1 second linear sweep and 1 Volt peak to peak.When testing the Modem output, things go as expected:But when testing the Phone output it seems I am getting out almost twice the input voltageWhat is going on here?

author: dog80
author_rank: Regular Contributor
timestamp: December 13, 2012, 02:50:44 pm
content: And here I am doing a sweep from 1Hz to 32Khz, all other settings the sameIt reaches a peak at around 31KHz and then starts to attenuate. But I still have a 1Vpp and the output is about 1.8Vpp

author: peter.mitchell
author_rank: Super Contributor
timestamp: December 13, 2012, 03:28:45 pm
content: I'm pretty sure the modem output is relatively unfiltered and it is the phone that is filtered, because all the interference the phone would cause is in a range the modem would not use.Basically they would do a low pass on the phone side i guess?

author: SeanB
author_rank: Super Contributor
timestamp: December 13, 2012, 05:56:38 pm
content: Load the output with the expected line impedance of 600R and do it again. The filter is showing how important matching input ( and more importantly) output impedance is. The filter is normally very simple, a choke in each line and a capacitor after the filter to attenuate the ADSL signal and more importantly provide isolation from the ADSL signal and the phone input capacitance which otherwise attenuates it quite well. If unloaded it will ring as it is then basically a series RCL circuit.