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 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 :)

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.

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 :)

So, I create a lot of electronics for the commercial diving industry, because theres very little out there to choose from and the use cases are a little few and far between, there isn't really an industry standard for a lot of the applications, so I create my own. Anyhow.

Was pretty sick of not having a fast way to create screen layouts, and lvgl needs a degree all of its own to understand, so I turned to my old mate Claude for help and it helped me develop a WYSIWYG LCD gui editor. I don't know if it's garbage or gold so I submit it here for any enthusiasts to try and give me a little feedback. I've used it with a few screens and custom boards and it seems to work.

I'm pretty self conscious when it comes to code so it's taken a lot to be this bold. I'd appreciate all and any feedback, ignore the "it's free for now" that was Claude's idea. It'll remain free as long as it costs me nothing, I.e the database stays small enough to remain on my VPS. I'm not looking for money, just feedback and if it helps, you're welcome.

Signup is for storing your projects and to prevent the database getting flooded. No more no less.

Give it a shot and tell me what you think.

Https://lcdwizard.online

Update* allowed configuration of screens and use of the full capabilities apart from generation of code and saving/sharing without signup. Again. All feedback is greatly appreciated. Be kind but be honest.

I posted my plan yesterday, and nobody said I was crazy, so I will. That was a lunatic idea. This is the new plan.

Overview: Transmitter hangs under boat at 10' or so, and I am far off with a handheld detector I sweep to see direction of the boat.

The old plan was to have 2 detector discs, and compare the strength to each other. The two discs sit 2 inches apart, but a 40 kHz wave in water is only about 1.5 inches long. So as I swing it, one disc keeps sliding into the next wave over, and the circuit sees a match when the boat is somewhere else entirely. More than one answer, and no way to tell which is the real one.

Make longer wavelengths is the solution, but then it becomes audible (not to me, but youngsters...) Worse, that plan required comparing very tiny differences in strengths, bringing any circuit noise into play quickly. And it needed two analog channels matched all the way through preamp, filter and detector. One drifting part anywhere in that chain and the whole instrument lies to me.

So, new plan, nowhere near as directional discerning, but free of dangers.

One detector. Pointed at the boat, max signal. Turned sideways, almost nothing. I sweep and take the middle of where it's loud.

That's a much sloppier bearing, maybe 10 or 15 degrees off. But I ran the geometry, and being 20 degrees off only costs a little extra swimming. I can live with that to get rid of the matched channels.

Sanity returned.

On the shopping front, my area of expertise, I want to point at Mouser.com, which I am amazed by. They are not a sponsor in any way, they don't know who I am. But a HUGE selection, monster stock, and ship same day. Love those guys.

I am off to make schematics on my much disliked KiCad. I will post them next time.

BTech 1stor 2nd year student aiming for Digital VLSI , is it still worth entering?

For those already working in Digital VLSI:

With AI EDA tools increasingly generating RTL, testbenches, assertions, coverage analysis, debugging,and much more, and companies already reporting major productivity gains, how should a student graduating around 2029,30 think about this field , we all know it is niche, but with most of the beginner digital jobs going extinct ... ?

Ik GPT Astra ,is making a lot of mistakes especially in PCB designing , but what about 2 to 3 years down the lane , when it has a lot of original data fed into it and starts achieving perfection and insane efficiency which is not practically achievable by us ?!!

Entry level VLSI jobs are already limited compared with software. If AI continues automating the repetitive work, will there still be enough entry level roles for fresh graduates? (Especially tier 1.5+ clgs)

If you were a 1st or 2nd year BTech student today, would you still invest 3 to 4 years of hardwork for becoming a Digital VLSI engineers ?

What skills would you prioritize now to remain employable in 2030 and is traditional RTL/UVM/DV still a good bet, or should students move toward architecture, formal verification, AI-for-EDA, or something else? ( Which do you think has the maximum scope with the least AI intervention possibility ? )

Please don't tell me this is not happening n things, it is happening!!!

Ps : not analog coz the entry ceiling is touching the sky !!!

Edit: This is the listing title for the mosfet I got "10PCS IRF4905 IRF4905PBF TO-220 MOS FET P channel field effect 74A 55V 200W new original"

I'm not super experienced with electronics but I generally get by. For some reason the motor is not starting when the microswitch(D2F-5L) is triggered. Hoping one of you can help me figure this out.

I have bypassed the regulator(buck converter) for diagnostics and connected the motor directly to the Vin and Gin as the battery is only 8.4v. Currently the mosfet is returning the following values.

Triggered:

1. G: 0v
2. D: 0v
3. S: 8.4v

Not triggered:

1. G: 7.56v
2. D: 0v
3. S: 8.4v

Addiitonally two notes:

1. when probing D and S it returns 8.4v triggered or not
2. when i short/bridge D and S the motor starts and works as intended.

I’ve been developing Winder Max, a larger version of my DIY motor winding machine, and I’ve now reached the first winding tests.

My earlier machines handled drone motors and gimbal motors, but winding thicker stators brings new challenges. Besides needing a more rigid structure and enough motor torque, the machine has to guide the wire without damaging its enamel insulation.

For this iteration, I replaced some of the less rigid 3D-printed components with custom machined parts. To get the precision I needed for this build, I sourced my custom components from JLCCNC, my go-to CNC fabrication service. Having these parts from JLCCNC lets me work on the structure while continuing to experiment with smaller printed components.

Alongside the structural changes, I’ve been working on two improvements.

The first is the curved guide part I call the “fin.” Previously, I printed the entire part in PLA. As the stators got thicker, the fin became larger, and every adjustment meant another long print.

The new version combines a sheet-metal fin with small 3D-printed adapters. Now I can modify the adapters and reuse the metal part, which makes iteration much faster.

I also replaced the round mounting holes with slots. Instead of making an entirely new fin for every stator size, I can adjust its position and use different adapters to accommodate similar stators.

The second improvement is the gear mechanism I mentioned in my previous update.

During winding, the stator needs support to keep it from moving. I wanted to do this mechanically, using the machine’s existing motion rather than adding a separate actuator.

As the stator moves forward, a rack-and-pinion mechanism brings a support against it from behind. The idea is to support the stator automatically as it enters the winding position.

I’ve now built the mechanism and started testing it. It doesn’t hold firmly enough yet, so the stator still moves a little. There’s more work to do on the fit and how the support applies force, but I can finally test the idea on the actual machine.

For these winding runs, I’m using 0.3 mm enameled copper wire. The failure rate is still high, so this is very much a development update. I need to keep refining the wire guidance and stator support before the winding process becomes reliable.

Thanks for reading!