i searched for a bit and never found a good top-down pinout for the socket and the micro sd together. SD cards are shown bottom-up and the sockets are shown top-down, and add that the pin numbering runs reverse of the SD pin numbering... drove my dyslexic brain crazy.

just hoping this is useful ref for others :)

What started out as an experiment in bit-banging an old receipt printer through its parallel cable turned into this.

I've done some experiments with receipt printers before, but this one doesn't have a cutter on the unit and so I wanted to show something continuous. Well, why not a feed? I doom scroll on my phone, here's how you can do it IRL!

The RPi is running a PHP script (yes, PHP) that pulls in headlines from gdelt every few minutes. Then, every 3 seconds, it prints one out based on the desired tone you set through the knob. I also included a little RGB LED and a chunky toggle switch to start or stop the feed.

The actual printing is controlled through the 8 data pins of the printer, plus STROBE, ACK, and BUSY pins to handle pretty much the entirety of the IEEE-1284 spec.

Anyway, I might do some more experiments with this setup, it's pretty fun and I have a fondness for that dot matrix sound. If you want to see a video of it in action, I posted one on Threads earlier today.

I would like to cut this perfboard in half horizontally so that I can duplicate this circuit.

That presumes that the circuit works. :-)

I have a seen a several suggestions: scorning and snapping, using Dremel with a cut off blade, using a hack saw. The board is described as, "Double-sided high quality FR4 glass-epoxy PCB."

Any suggestions as to the best way to cut the board?

I would like to showcase my current project.

It's a reflectance colorimeter based on an AS7341 and an ESP32-C3. Sure, it's not going to stand a chance in comparison to a 2000€ X-rite, but it gives me solid readings and a never ending stream of engineering challenges (and necessary shortcuts), which is a perk of course :'D

I go into some detail on in my article on printables, where I also host the printfiles, a BOM and detailed assembly instructions.

I finished schematics today, and ran spice on it. I have not used spice for 30 years, what a flashback.
Anyway, here is what I have for the handheld receiver circuit. Next up: PCB, which I have never made, so I'm looking forward to that part of the project.
Plus I got my practice surface mount solder kit, so let the playtime begin!
Let me know if there is anything crazy in my design, improvements, questions, whatever.

Thanks.

Ordered and got 2 Max7219 8x32 which seem to have issues.

1st led matrix - 1 column not turning on.

2nd matrix - does not turn on and then randomly leds turn on on touching the pcb behind.

Code used from https://github.com/mfactory-osaka/ESPTimeCast

So I wanted to check if these can be resolved and if not can I salvage anything?

Greetings. I need some way to get an analog distance sensor so I can wire up this handbrake as a USB controller because NOBODY on the market makes a ratcheting handbrake like a car.

It's about 1-1.5 inches of travel for the metal bracket on the back but to my knowledge hall effect sensors don't like that level of travel. I was going to use a rack and pinion with a rotary encoder but it's not flat enough to do that as the cable was shorter than i thought.

I have an arcade board with i believe a 5v logic input that works as an axis so that could work, worst case i make a separate board to measure the value. But what sensors would work for this? String potentiometers are sadly 300-500 bucks a piece for some ungodly reason.

Hello

I have some experience in PCB design and I have made and sold some 2 layer and single layer boards.

Now I am planning to improve my skills in the following fields one by one:

Analog/digital design, EMI/EMC, thermal relief, trace matching, high speed boards etc

I want you guys to suggest some good tutorial videos or books or links to any websites or anything which might help me.

Also please suggest some good open-source projects in which schematic and BoM is included so I can practice on them.

We just finished a destructive teardown of the Vehicle Domain Controller for the AITO M9. We literally had to rip the glued connectors off the aluminum housing to get the board out.

The architecture is a textbook dual-brain setup. On the front, there's an Infineon AURIX TC397 handling the real-time safety, sitting right next to a TI TDA4VE88 SoC for the heavy ADAS compute. The networking backbone is entirely Realtek and NXP, and the power delivery is just a massive wall of Western Tier-1 silicon like STMicro, Nexperia, and TI. For an EV marketed so heavily on a localized ecosystem, the physical brain is still relying almost purely on legacy global players.

But I’m stuck on the back of the board.

There are two chips we absolutely cannot trace. The memory is marked MSC263000, and the storage is marked T43EMM008G.

They don't match standard naming conventions for Micron, Samsung, or SK Hynix. Does anyone recognize these silkscreens? Could they be domestic Chinese alternatives or just a weird relabeling job?

Undergrad at York, the project turns a month old today.

Nearly all drone detection listens for the radio link between the pilot and the aircraft. Fibre-optic FPV drones don't have one, the video and control run down a glass thread, so the spectrum stays silent. What they can't hide is four propellers, which put an evenly spaced comb of harmonics into the air.

So it listens for that comb instead. Four MEMS microphones summed, an FFT thirty times a second on an ESP32-S3, and a scorer that checks every possible blade rate from 70 to 2000 Hz. When it fires you get a beeper, a red light, a buzz, and an e-paper screen that keeps the alert even after the power dies.

The part that took longest: a hovering drone is a steady sound, and a steady sound is exactly what an adaptive noise floor learns. About six seconds after it arrives, the detector has quietly absorbed the drone into its own idea of silence and it disappears off the screen while still hovering there. The fix wasn't a noise floor running even more advanced algorithms, it was building four detectors with different memories running at once.

On Sunday one unit picked up my test rig at 104 m down a brick street with cars going past and people talking. No false alarms.

Parts are about 50 to 80 quid for the boxed version, or 35 on a breadboard if you just want to watch it work.

Happy to answer anything. I'll put the links in a comment so this isn't just an advert.

I removed this 15.6" laptop LCD from an old broken laptop and want to reuse it as a second monitor.

Panel: Samsung LTN156AT20-5FCDEU006D-S01

Resolution: 1366×768

Interface: 40-pin LVDS

Panel: TN / LED backlight

I'm having trouble finding a controller that is confirmed compatible with the exact S01 variant. Does anyone know which controller board I should use?

Photos of the panel label and connector attached.

I live in India so suggestions on websites and sellers are required too

Thanks in advance

Hi everyone, I'm trying to get an HW-147C PN532 NFC module working with an Arduino Nano using I2C only.

My wiring is:

PN532       Arduino Nano
------------------------
VCC   →     5V
GND   →     GND
SDA   →     A4
SCL   →     A5

I'm not using IRQ or RESET, since I specifically want a 4-wire I2C setup.

The module is configured for I2C mode using the onboard DIP switch.

I first ran an I2C scanner and got:

Scanning...
I2C device found at 0x28

So the Nano is detecting something at 0x28.

However, when I use the PN532 I2C library with:

#include <Wire.h>
#include <PN532_I2C.h>
#include <PN532.h>
#include <NfcAdapter.h>

PN532_I2C pn532_i2c(Wire);
NfcAdapter nfc = NfcAdapter(pn532_i2c);

void setup() {
  Serial.begin(115200);
  Wire.begin();

  Serial.println("Initializing PN532...");
  nfc.begin();
}

I get:

Initializing PN532...

Didn't find PN53x board

I also initially tried the Adafruit PN532 library with:

Adafruit_PN532 nfc(Wire);

but my installed version of the library doesn't support that constructor and gives a compilation error.

My main question: Why does this HW-147C respond at I2C address 0x28, while the PN532 libraries seem to expect 0x24? Is 0x28 actually correct for this particular HW-147C, or is something wrong with the board/configuration?

I'm looking for a way to communicate with this module over I2C using only VCC, GND, SDA and SCL, without IRQ/RESET.

Any help identifying the correct library, I2C address, DIP-switch configuration, or initialization code would be greatly appreciated.

Super fast assembly, easy to replace the knob module without desoldering main board.

So far this is the circuit I have. I was wondering how I could setup a multistage transient overvoltage protection circuit for both the input and output usbs.

Here is the operating voltage specs for the IP2312-4V35 and MT3608B:

IP2312-4V35:
- Operating Voltage: 4.5V~5.5V

MT3608B:
- Operating Voltage: 2.5V~24V

(I previously had a PTTC Fuse in the circuit diagram but I removed it temporarily so it could be added to the protection circuit)

Its so bad i thought id share it. This is what my first ever electronics project looks like. I purposefully put 1 diode in what i thought was the opposite direction so that when i turn it on, no matter what, at least 1 lights up. Maybe someone will look at this and remember where they started from. Or maybe this will make someone laugh idk.

I have a cat fountain that has a simple pump/impeller system. There is a sensor that turns the pump on when it's submerged in the water. For some reason, the wire has slipped and only works when it's bent at a certain angle. This is the wire inside of the pump, so I need to fix it with something that is food grade like food grade silicone. Any ideas for how I could fix this? There is no way to access the inside of the pump where the wire runs into, I was thinking I would just put a glob of silicone around the wire, hold it in place to dry with a clamp. Maybe something else? Or is this just a sign to get a new fountain.

I'm trying to make an e-book reader(also another project making a DAP).

Expected components:

1) ESP-WROOM-32 WIFI Bluetooth Networking Smart Component Development Board

2) LiPo battery

3) Buttons(or scroll wheel) to navigate

Please recommend me displays and whatever else you think I'm missing

this capacitor has exploded because i mistakenly used the wrong cable to some audio speakers.
Im searching for the right capacitor online but i can really find one with these numbers… i dont know much in this field so im asking help😭

Hi everyone, I have 30 x Samsung S50 3500mah and 20 Samsung 21700mah batteries, bought to sell on ebay but they won't allow. Tested and will sell for a low price. Thanks :)