After replacing the drive transistors on both boards of both channels and diode testing everything and verifying shorts and opens, it was time for a safe power up. With a current limited bench power supply, it was time to verify leakage and drive for all 4 units, and they all passed.
Next up, ohming out the transformer and using the variac to get some live values. But that’s next week.
What is everyone else working on?
Pictured, one channel, set up to measure the current from the pnp side, just 0.1uA or 100nA (the absolute smallest reading on my DMM). Possibly rounding up to that value. One of 8 measurements taken. The small chunk of wood from a laser cutter (kerf finder) was used to keep the alligator clip from touching/shorting to anything.

I'm working on a few design tweaks to boost the stable output power to 1W.

Hi everyone, I want to make a simple system that detects if anyone is present in the room. If the room is empty for some time, it should automatically turn off the lights and fan. I’m looking for practical ideas and suggestions. Here are some specific questions I have: Sensor: Is PIR sensor enough or should I use mmWave presence sensor for better detection (even if person is sitting still)? Hardware: Can I use ESP32 + relay module for this? Any recommended relay modules that are safe for controlling fan and lights? Code: Any simple example code for presence detection + automatic turn off after some delay? Power & Safety: How to safely connect the relay to AC switches? Any tips for beginners? Improvements: Is it better to make it completely offline or also add WiFi control through phone? Any circuit diagrams, code examples, or advice will be very helpful. Thanks in advance!

ESP32 #PIR #mmWave #HomeAutomation #IoT #EnergySaving

Now into the 4th episode(video/article) and I've tested 18 irons with full details on:
- Input watts
- Time to melt solder
- Temperature accuracy
- Handle temperature after 30 mins
- Whatever I notice during practical testing

RESULTS FROM OCTOBER 2026 TEST ROUND

What did not test well:

• Fanttik T1 Max: After the last video, where I found it was 70-80°C over the selected temperature (Set to 350°C, but would hit 420°C) the vendor sent me a replacement unit. Sadly, it's identical. I did 8 readings over 7 minutes and it ranged from 378° to 448°C.
• Fanttik T2 Max: They fixed the temperature issue, perfectly accurate. Sadly they removed everything that made the original so good. No soft grip, takes proprietary tips, hard to read the temperature, included usb cables does'nt support its 27W on cable, etc...

What did test well:

• Alientek TB1: 2.5s to melt solder on cable and 5s on battery, the fastest I’ve tested. It takes standard C210 tips. It ran about 20°C under out of the box though, so if you own one of these you may want to check yours. On the negative? Battery only lasts about 1.5-2 hours depending how you use it.
• FNIRSI DWS-P2: a battery soldering station was accurate out of the box, battery is replaceable. Some of their stuff I've rated poorly recently, but this is a good one, at least in my view, would be interested to see other peoples opinions. The only thing I don't like is the plugs are quite plasticky, but don't feel like they'll break.
• FMCHIP FM03: Super cheap iron, around 20 bucks or so. Great for someone who only solders occasionally. T65 tips, measured 60W at input, temperature fairly accurate, and was just pleasant to use. I actually used this cheapie more than any other during testing.

Full test results, heaps of charts, photos of tests, etc are on the article here:
https://cheerful.cheap/video/best-portable-soldering-irons-nov2026/

Hey guys,

I saw an ad for a sleek car fragrance diffuser mounted under the glovebox. Concept was cool, but it was ridiculously overpriced (and turned out to be a drop-shipped Alibaba item with huge huge markup)

I was thinking of putting something together using a piezoelectric atomizer like in the photo and a ESP32 board and using my 5v USB female inside the glovebox as power and of course it would be PETG

I don't want to drill holes though

My question how would I start regarding the 3D design

And how will the piezoelectric atomizer perform with perfume oils

Original ad I saw https://www.alibaba.com/product-detail/Car-Air-Freshener-Electric-Auto-Air_1601207635100.html

When two linear actuators lift the same platform, differences in travel speed can cause one side to get ahead of the other.

Possible approaches include adjusting motor speed, adding a mechanical linkage, switching to a stepper-driven setup, or using position feedback to correct the difference.

For anyone who has built a setup like this, what worked reliably over time?? At what point did keeping two actuators in sync become more trouble than redesigning around a single drive?

Fan of my guitar amp broke during our tour and I found the part online but it’s missing the connector. Can someone help me which connector this is and where to find it? (US)

Edit: I could only put one picture. Video of the connector in the comments

Hello! I'm just getting started in assembling electronic projects. I'm working on a way to light a standalone tree with string lights. Basically, I have a tree that I can't stretch an extension cord to.

I bought some twinkly programmable/addressable lights that I love. However, they have an AC connector; the company doesn't make a non-AC connector. Currently, I have a Milwaukee tool battery plugged into a converter and that powers the lights. Obviously, I'm converting from DC to AC I don't know how many times and losing time between charges.

PLUS, the inverter doesn't have a timer. And it stays on when the twinkly lights use their timer to turn off to conserve power.

I have two battery ecosystems: Milwaukee and Ego. What I want is something that I can switch out at the lights every several days to a week.

Would you assemble two portable power stations to switch out. Or build a box that allows you to attach and switch out the ecosystem batteries, either ego or Milwaukee?

And thoughts on how?

I maintain feuristic, an independent custom firmware for the Trezor Safe 3. The project reuses an existing device’s screen, two buttons and USB connection to provide authentication and smart-card functions instead of a cryptocurrency wallet.

No replacement PCB or case modification is part of this project. The work is in the firmware: FIDO2 passkeys, OpenPGP/PIV operations, OTP codes and AES-GCM, with configuration and confirmations on the device.

There are two Safe 3 revisions, requiring different binaries: T2B1 uses an STM32F427 and T3B1 uses an STM32U585. The normal USB mode exposes FIDO HID and CCID. Temporary modes provide serial time synchronisation and QR-image import through a FAT12 volume; returning to normal restores the authentication interfaces.

The source is GPL-3.0-only, with build instructions and a documented first physical T2B1/macOS test campaign. T3B1 physical testing remains unfinished.

This is an unaudited development project. Installing erases the wallet and permanently removes original manufacturer attestation. It is intended for spare hardware with disposable identities. There is no cryptocurrency wallet or seed migration, and the project is not endorsed by Trezor/SatoshiLabs.

Source and documentation

I’m sharing it as an example of changing an existing device’s use through firmware. The repository documents what was physically tested and what is still pending.

I am adding stuff to my cart, I asked chatgpt for an general overview on it, rn I have some breadboards, jumper wires, resistor and capacitor assortments along with an ESP32, since I wanna work with it. I am not really sure what else to add in it, because I don't know what I want to get deep into. It also suggested getting LM358, LM393, NE555, 74HC00 and 74HC14 ICs, and says I might be interested in stuff audio amplifiers, codec or signal-processing circuit, things combining multiple subsystems. Making a cyberdeck from scratch is an idea I have, but before that I don't have clear idea of what components to begin with.

Previously I had played around with an arduino, leds, and basic sensors and stuff; But I kinda wanna move on from toy projects and learn and make some practical stuff.
A measurement instrument or oscilloscope-related project

I’ve been trying to fix this Xvive U4 receiver. The headphone jack was very tightly stuck in the socket. Much effort made to remove manually, but didn’t budge.

I disassembled the unit and got the socket component desoldered to try getting the jack out. Eventually had to get the socket opened up and pop the whole thing out. The barrel was firmly stuck, and attached to the barrel was a small tab that was the sleeve connection and 6th pin on the PCB (see the socket with 5 pins and one hole, and barrel with broken off tab).

Lots of hassle to end up with a tiny break that ends my repair for the moment. I’m going to enquire about warranty/replacement since the fault was caused by normal use, but obviously my disassembly and meddling will likely void this. The unit was bought new less than a year ago AFAIK.

I need advice or recommendations on where to look for replacement parts. The jack socket component seems fairly generic, but the barrel and sleeve tab could maybe be specific to Xvive products.

Any other guidance on how best to proceed would be appreciated!

TLDR; Need to find replacement parts for Xvive U4 receiver, specifically the 3.5mm socket barrel.

Made this as a small projec i wanted to do for a while. Features: 3 encoders, 9 action buttons and 1 layer/page switch button. Supports multiple layers and multiple pages per layer. So you can have layer photoshop and under that pages for brush, adjustments… smart layer switching per application ( if photoshop is focused it will automatically switch to that layer for example). Each key can be: combo, macro, app launcher, website launcher, system config, microphone config, volume mixer config and OBS config. Also made a companion app for it that lets you easily set it up the way you like it. Would like some feedback on it.

Hello, are there members here who had successfully used this smart energy meter here in the Philippines (see picture)? I bought this popular gadget in Lazada and Shopee but there is no way I can ask the buyers' feedback there. Meanwhile, for whatever reason electricians and engineers whom I talked to are hesitant and afraid to install this in our house panel because of unfamiliarity. It promises to be  useful for monitoring purposes (for determining inverter and battery capacity for future solar installation; for Meralco consumption  counterchecking; etc.).

If any Quezon City-based electrician had successfully installed this, your service will be highly appreciated (kindly pm me).

Thank you.

http://docs.rs-online.com/24e3/0900766b8144c28b.pdf

Am trying to do a pcb with an sd card for storage but I am not familiar with working with them so I wanted some second opinion on whether the connection is right and if I missed something.

I’ve successfully implemented point-to-point wireless image transmission using two custom-designed LR2021 nodes at Makerfabs.

Traditional LoRa sensor applications focus on small data packets; this demo explores the LR2021's capabilities for larger data transfers. 

I used two nodes equipped with Makerfabs-designed LR2021 modules; I've successfully demonstrated point-to-point wireless image transmission. All the transmission information can be shown on the OLED display.

Technical Highlights

• High-speed FLRC: Supports PHY data rates up to 2.6 Mbps.
• FLRP Protocol: Supports high-speed burst transmission, data segmentation, acknowledgments, and retransmissions.
• Flexible Applications: Enables exploration of larger data transfers, including images, firmware updates, and remote monitoring.

Ongoing Research

With basic wireless image transmission working, I’m now evaluating actual transfer throughput, effective communication range, link reliability under interference, and power consumption during high-speed bursts.

I’d love to hear your thoughts and ideas on LR2021. What applications would you explore with it?