Peter Rachow (DK7IH) built a 14MHz SSB QRP Micro-transceiver into a cigarette packet size case: This article describes the “Cigarette Pack” SSB QRP transceiver” for 14MHz that I first had mentioned some months before. Recently, when taking it from the shelf, the transceiver dropped to the floor and was severely damaged. This lead to serious […]
In this video Adam 9A4QV demonstrates his 2.4 GHz homemade helical feed for the QO-100/Es’Hail-2 satellite. Via RTL-SDR.
Sami Pietikainen has written an article detailing the build of his Bluetooth DAC using Raspberry Pi Zero W: My car comes with a built-in Bluetooth hands-free but unfortunately it does not support audio streaming. Luckily there is an AUX input available which uses a regular 3,5 mm jack. Perfect opportunity for a DIY project. I built the […]
Here’s a DIY vacuum pick-up tool for SMD components: This video describes a DIY Vacuum Pick-up tool for picking and placing parts from an SMD component tape. The basic design for this tool involves using a vacuum pump and a solenoid to control the vacuum to a handpiece under control of a foot pedal. Via SDG […]
DuWayne published a new build: While I was working on the power meter function for the latest version of the SNA, I used several fixed attenuators for checking linearity and calibration. It would be a lot easier if I had a variable step attenuator. I have several digital controlled attenuator modules that I bought one […]
Michael LeBlanc has a nice write-up on building a direct conversion radio receiver: In the late winter of 2018-19, I decided to build a receiver that would provide a performance improvement to the regen I built a couple of years ago. I wanted the radio to receive AM and SSB signals between 160m and 20m […]
B. Perry writes: I’ve always been fond of the popular Nixie clocks made from old surplus Soviet nixie tubes. Nixie tubes are no longer made, so they’re hard to acquire. Instead, I took inspiration from “Lixie” displays and made my own Nixie-inspired, LED-powered display. And in an unusual twist (for me, anyway), I didn’t make […]
Josh built this 6CY7 dual triode valve amplifier: I’ve always wanted to know what the “tube magic” was all about. There is much opinion in the science of music production, probably because music and its perception is highly personal and subjective. Ive always imagined that since transistor amplifiers were “perfect” with their large amounts of […]
Shawon Shahryiar over at Embedded Lab shared a how-to on making a SPL dB meter: Sound needs a medium for propagation or travel. It can’t travel in vacuum. Normally air is that medium but sound can also propagate in liquids and other states of matter. I am not going to lecture on how sound travels […]
The classic 555 timer on a breadboard: Here, I will show how you can make your own version of the 555 timer using just NAND gates, opamps , a transistor and a few resistors! Now, you may think what is the purpose of building this when you can buy the IC at very cheap rates. […]
Adam Zeloof made his own guitar pedal based on the Zvex Fuzz Factory: The Z.VEX Fuzz Factory is an amazing little fuzz pedal designed by musical and electrical wizard Zachary Vex. I was introduced to it through Matt Bellamy‘s unique guitar style, and fell in love with its out-of-this-world sound. While I was tempted to […]
A simple digital clock with PIC16F628A + DS1307: In this new project I am again using PIC16F628A microcontroller. The goal is simple digital clock with 7-segment LED display and the clock will have no additional functionality – no alarm, no seconds digits, no date. The latter can be added in the software though. For the […]
Here’s a great write-up on building a phase-locked inverter from mitxela.com: The input is at 50Hz and the output is at 60Hz. So for every 5 input cycles, we want to generate 6 output cycles. We will be synthesizing a sine wave in software, and there’s no reason not to go with a conventional lookup […]
Here’s a project log covering the build of a portable level 2 electric vehicle charger by Andrew Rossignol: This is a battery-powered EV charger that allows destination charging where L2 charging is not ordinarily available. This can be used as a range extender for electric vehicles with smaller batteries. This system has a ~7kWh battery […]
Ryan Flowers writes, “A fun project for every QRP enthusiast is an L-match tuner. We’ve built a couple here at MiscDotGeek and our latest build inspired Billy Dunn (AF5HD) to build a similar tuner. We have to say, this one turned out better than ours did!” More details on MiscDotGeek blog.
Davide Gironi writes, “The D01, litterally Discarica 01, is a guitar solid state amplifier build from salvaged parts.” See the full post on his blog. Check out the video after the break.
Dilshan Jayakody published a new build: The 1750Hz tone bursts are often used to trigger repeaters. There are several methods to build 1750Hz tone generators which including TC5082 divider, using MCUs, etc. In this post, I present another 1750Hz tone generator which I built using 74HC4060 high-speed 14-stage binary ripple counter and 7.168MHz crystal. In […]
DIY inline refractometer project from Anfractuosity: The idea of this project is to image the refractometer output, then convert the position of the blue line, to a digital reading, using image processing. The idea is to measure the brix of wort during mash and sparging, so that sparging can be stopped around 1.010 SG, to […]
Robert Gawron has made a new version of his radioactivity detector project and wrote a post on his blog detailing its assembly: In this post I will present a new hardware version of my sensor, older versions are described in part I and part II. In comparison to the previous one, sensitivity is roughly x10 […]
Eric Higgins has a nice build log on his Open Trickler project a bluetooth-enabled smart powder trickler from off-the-shelf parts for under $60: Fundamentally, this is not a hard problem to solve. Read the value from the scale, run a motor that moves powder into the scale, turn off the motor when the scale reads […]