Input filter and preamplifier – Jupiter modular receiver

Vasily Ivanenko blogged about his input and RF preamplifier build: Above — Build of the input and RF preamplifier stage. I put in a 0 or 6 dB attenuator right at the input. That’s double-sided Cu+ board with copper vias joining the 2 surfaces intermittently and also at crucial ground points. Project info at QRP HomeBuilder blog.

DIY USB power bank from laptop battery

A DIY USB power bank made from an old laptop battery from DoItYourselfGadgets: A situation many can relate to: an empty smartphone battery and no outlet around! That’s exactly why I recycled an old laptop battery into an USB power bank. This article will show you the basic powerbank circuit consisting of Lithium cell charging circuit, […]

40 meter XCVR size of an business card with 1 watt output, 7.000 to 7.150 MHz coverage

A business card size homebrew 40 meter XCVR project from Ray Ring: I tweaked my previous XCVR design to use push button tuning and made the board layout extremely compact. I improved the side tone injection to be absolutely  perfect – not too loud, full break in and no clicks. I went ahead and integrated my switch […]

Programmable relay switch using PIC MCU (revised version)

Raj has documented his DIY programmable relay switch using PIC16F1847 microcontroller: Here are the summary of the features that this programmable relay switch has: On-board +5V voltage regulator (operates at 9-15V DC input) OFF and ON time setup for the relay operation Option for cyclic run (maximum 100 cycles, after which the timer stops automatically) […]

La Skala Arduino controlled ladder attenuator

Dimdim has designed and built his own stepped ladder attenuator, controlled by an Arduino: A few years ago I had an encounter with a ladder volume attenuator. I loved hearing the relays clicking away as they dialed-in the desired attenuation. Ever since then I wanted to design and build one for myself. The years passed, with […]

110v temperature controlled soldering station build no. 2

Mike Doughty from PCB Smoke shared his DIY 110v temperature controlled soldering station in the project log forum: This project is build number 2 of a 110v temperature controlled soldering station. It is a follow-up post to the project that I was working on last October. Blog post with complete details here. This version has […]

flip-flop/BCF project

Ray over at the diyAudio forum has been working on his flip-flop/BCF project: I’ve just finished a project to roll up the developments into a more ‘finished’ build, feeding the balanced outputs from the flip-flop board into a Broskie BCF buffer stage. I’m using Nicks MJ Statistical Regulator for the B+ and one of Andrew’s indirect filament […]

INA219 current sensor DIY Breakout board

A INA219 current sensor DIY Breakout board project from Juan Ignacio: Another small board, this time for a INA219. The INA219 is a high-side current shunt and power monitor with an I2C interface. For testing I used Rei VILO library with a MSP430G2553 and Energia, and I measured the power consumption for this simple circuit. Project info […]

Paint Machine, a printer that prints small bitmaps on the street

Alex Weber has posted a new project on building a DIY Paint Machine, he writes: Here is my latest creature, the Paint Machine. It’s a machine the prints simple bitmaps with spray chalk on the street or sidewalk. Some of the key features: *dimension: width: 220cm, length: 38cm, height: 24cm, weight: 12kg *printing speed: ca. 0.036 km/h […]

Lab LED constant current controller board

Ladvien blogged about his Lab LED constant current controller board project he made using DirtyBoard PCBs: A little lab controller PCB I’m working on. It centers around four high-power constant current circuits meant to be driven by an Atmega328’s PWM. I hate working on anything mechanical in dim light; comes from dropping parts down under […]