Automatically re-connecting low-voltage cut-outs for 12 and 24 volt battery systems

KA7OEI writes: In a previous post I described a simple circuit that provided a low-voltage cut-out that could be used in a battery-operated system – see the article “A latching low-voltage disconnect for 12 volt lead-acid and lithium batteries”. That circuit – intended mostly for lithium-based batteries – required manual intervention to “reset” the device, […]

Homemade injection transformer for PSU loop analysis

Adil Malik made a DIY injection transformer for PSU loop analysis: Recently, I have been designing some SMPS and required some hardware to measure the actual loop response of the complete converters. People familiar with this area will probably know this can be done breaking the feedback loop of the converter and injecting a small […]

Building a Power-over-Ethernet (PoE) power supply using a DPS5005 module

Dr. Scott M. Baker has designed and built a PoE-powered lab power supply using a DPS5005 and custom PoE board: The DPS5005 is a DC-DC converter. It can accept an input voltage from 0 to about 55 volts or so, and will regulate an output voltage up to about 1 volt below the input. This […]

Homebrew 500 watt HF power amplifier

Jeff (K6JCA) has written a series of posts describing his homebrew project 500 watt HF power amplifier: I started this project back in 2016 — I had finished my Automatic Antenna Tuner (seen in the upper-left of the picture, above) and a PA project that would integrate into my FPGA-SDR and ATU system seemed like […]

Internet connected fire/smoke alarm project

Martin Harizanov blogged about his cheap DIY IoT smoke detector: This project is an upgrade to a previous project of mine – the DIY IoT smoke alarm. It is a more advanced version that uses dedicated hardware rather than the generic “Funky” project + external components. In essence, the module integrates into cheap smoke detectors […]

Nano current meter based on an ATtiny84

Johnson Davies published a new build: This project describes a simple low-current meter I devised to check the sleep current of different microcontroller circuits, such as ones based on AVR microcontrollers. It’s capable of measuring currents of between 10µA and 30nA with reasonable accuracy, using an ATtiny84 and a few other low-cost parts Project details […]

DIY Analog resource monitor for your PC

Sasa Karanovic posted detailed instructions of how to build a physical dashboard for your PC, that is available on GitHub: The overall architecture is very simple; There is a python script that is running on a PC and collects CPU, memory, network and GPU usage. Then, it sends that information over serial COM port to […]

Pogo pins + laser cutter = test fixture

Eric Gunnerson made this DIY pogo-pin test jig: I decided to build a pogo-pin test jig, and since the approach I came up with was different than the other approaches I’ve seen I thought it would be worth sharing. I’m going to be targeting my laser cutter for fabrication, though I could have chosen to […]

FM stereo radio receiver with RDS

Dilshan Jayakody has published a new build: This tuner circuit is a quick prototype which I build to test the RDA5807M FM radio tuner IC. RDA5807M is a single-chip tuner IC with RDS and MPX decoder, and it equipped with I2C interface for control. This receiver builds around Atmel’s ATmega16A 8-bit MCU. The output stage […]