A while ago I stumbled on an interesting project over on the Technoblogy – an ATtiny85 continuity tester. I found the idea interesting, and decided to build a few of these testers myself, as I very often need to check continuity between two traces and not always is there a multimeter nearby. So the idea … “ATtiny13 continuity tester”
3D printed charger for Yi 4K camera battery
I own an action camera – the Yi 4K – and I am very satisfied with it. However, even though it has longer battery life than a GoPro, it still runs for only ~90 minutes on a single battery. For this reason, I bought a bunch of replacement batteries from Ebay for just 6 dollars/piece! … “3D printed charger for Yi 4K camera battery”
An interesting experiment: cooling a Cree LED on a normal FR4 PCB
Modern LEDs have enormous efficiency – up to 40 % – but this still means that if you mount a 5 W LED on a PCB it will generate up to 3.5 W of heat. In one of my recent experiments, I tried making a headlamp using a Cree XPG-BWT LED. I made a small … “An interesting experiment: cooling a Cree LED on a normal FR4 PCB”
Trace & via current carrying capacity on PCBs from JLCPCB
If you ever designed your own printed circuit board, you might have wondered “how thick does this trace needs to be?” or “how big this via needs to be?”. As always, you can try to Google it – however, you will find a lot of conflicting information, and that is why I ordered a simple … “Trace & via current carrying capacity on PCBs from JLCPCB”
Multicell Lithium Battery Charging & Balancing circuit
You probably know that charging lithium batteries isn’t particularly easy. But if you have just a single cell, you can get an IC to do this for you – the most popular being probably the TP4056 or the MCP73831 (you can get both of them from Ebay). But if you want to have a battery … “Multicell Lithium Battery Charging & Balancing circuit”
Lithium Battery Utility Board V1.2
I use lithium batteries a lot. However, they are not the easiest to use – you need a dedicated charging IC, complicated protection circuitry, boost module to power 5 V circuitry, switches, connectors… So I designed a board with all of these features. This is hopefully the last and final revision of my Lithium Battery … “Lithium Battery Utility Board V1.2”
An abandoned project: the STM32 watch
A few months ago, my watch broke. Instead of buying a new one, I decided to try to build a watch myself. Since I am not a mechanical engineer, I had to use electronics – 60 LEDs to emulate a classical watch face and some microcontroller to drive them. I was more interested in how … “An abandoned project: the STM32 watch”
Improved 18650 cell holder
I work with a lot of 18650 cells. And since I also test them a lot, I obviously need a good battery holder. So I tried buying some 18650 holders from Ebay, but these were just horrible – the cells were very hard to insert and remove, they used thin wires and the + terminal … “Improved 18650 cell holder”
Brymen BM867/869 interface cable
Recently I was looking for a good and precise digital multimeter to buy, and the Brymen 867, a 50000-counts handheld DMM, immediately caught my eye. It even had the PC interface I wanted, since I want to use it for some automated measurements. So after a bit of research, I finally decided to buy it … “Brymen BM867/869 interface cable”