Lukas Fässler has designed and built an MPPT solar charger: One of my main goals with this design is to archieve very low standby current, somewhere in the tens of microamps. The basis for this is a low-power buck on the basis of a Texas TPS62120 where the microcontroller can switch the output voltage between […]
Category Archives: DIY
Arduino Mega EPROM programmer
An Arduino Mega Eprom Programmer project from Robson Couto, that is available on github: Recently, I acquired a SNES, but it only came with a bootleg Mortal Kombat cartridge. In my search for additional games, I stumbled upon a growing trend of repro cartridges being sold on various second-hand websites. These cartridges, which often have […]
Automatic volume tracking for a TV
An automatic volume tracker by KA7OEI: It occurred to me that I did have a reference on which I could base an outboard volume control: The internal speakers of the TV. I surmised that I could “listen” to the audio level coming out of the speakers and based on that, adjust the volume of an outboard amplifier. […]
RC2014/LL and RC2016/10
Scott Lawrence has written an article detailing his Z80 homebuilt computer, the RC2014: The RetroChallenge is upon us again! This time around, I plan on working on my Z80 homebuilt computer, the RC2014. (Website for RC2014, Order a RC2014) For a few months now, I’ve had my RC-2014 computer built, and modified to be an RC2014/LL […]
40 dB attenuator
A 40 dB attenuator project by Hartmut DK5LH. Hartmut uses the attenuator to measure the power of his transmitter (2 watts) with a power meter for -80 dBm to -10 dBm The attenuator is used to reduce the output power of the set to a value that is less than 0.1 milliwatt. (-10 dBm) More details at PA1B’s […]
μPC1237 based 2 channel speaker protector
Dilshan Jayakody has published a new build: When working with expensive speaker system, speaker protector is an essential item to avoid any damages to speakers. In this project we build low cost speaker protector by using NEC’s μPC1237 IC. The circuit in this project is based on μPC1237 datasheet and it is specifically modified to […]
DIY Desktop CNC with an Arduino
Bob Davis has been working on rebuilding his DIY CNC machine: I have been busy rebuilding my DIY CNC machine. It will be all metal when I get done. It will also include a USB interface, likely an Arduino. None of my computers have a parallel port these days. So something has to be done to […]
ICS501 simple frequency multiplier
Scott from SWHarden has published a new build: Today I made a high frequency multiplier using a single component: the ICS501 PLL clock multiplier IC. This chip provides 2x, 5x, 8x (and more) clock multiplication using an internal phased-lock loop (PLL). At less than a dollar on eBay, $1.55 on mouser, and $0.67 on Digikey, […]
Homebrew dummy load
A simple DIY dummy load project from Flathagen: I have created a simple 50 Ω dummy load to test transmitters. I also added a simple RF diode detector so I can measure the peak voltage, and calculate the power. The dummy load consists of eight 100 Ω resistors rated at 2 W so the load […]
R2-D2 build
Bithead942 blogged about his R2-D2 build: To really bring R2-D2 to life, I knew I had to do some great sturff with electronics. I started with a Taranis X9D controller and a pair of X8R receivers configured for a full 16-channels. I chose this platform mainly for its versatility, but also because I wanted to […]
Mini CNC 2D plotter made from an old DVD drive and L293D motor shield
Sandeep_UNO posted detailed instructions of how to make this mini CNC 2D plotter using scrap DVD drive, L293D motor shield and Arduino. Project instructables here. Check out the video after the break.
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, […]
Breadboard line driver module
Scott from SWHarden has published a new build: Line driver chips are one of my go-tos for quickly amplifying digital signals because they’re so fast to drop in a breadboard and they provide a strong output with very high impedance inputs and need no external components. Individual buffer of the integrated chip can be paralleled […]
Outmoded Sequencer project
LuckyResistor made a miniature music machine -the outmoded sequencer project and wrote a post on his blog detailing its assembly: I just started an interesting new project: The Outmoded Sequencer Project. It is an minimalistic music machine. You can use a 8×8 “programming” matrix to create simple melodies which are looping endlessly. This melody can […]
Dekatron tubes controlled by Arduino
Flathagen writes: Interfacing dekatron tubes with a microcontroller is fairly easy, once you understand how the tubes work. Threeneuron’s Pile o’Poo of Obsolete Crap provides the necessary background information and schematics for making this work. I used two russian OG-4 tubes. I prefer the orange look of the neon tubes rather than the purple look […]
Light following bristle bot
Facelesstech made a light following bristle bot and wrote a post on his blog detailing its assembly: There is one thing missing from all my projects so far…..Something that moves. Bristle bots are very similar to hex bugs but are built from toothbrush heads and pager motors. I thought the idea of bristle bots was […]
25 watt hybrid EL84 tube amp
Ray Ring from Circuit Salad has published a new build, 25 watt hybrid EL84 tube amp: This is my new hybrid guitar tube amp which utilizes a solid-state input stage, DSP reverb, and solid-state phase splitter. Only the push pull, class AB output stage utilizes tubes, namely two EL84’s run at 390 volts with cathode bias. […]
A low-voltage disconnect for 12 volt lead acid and lithium batteries
KA7OEI writes: The avoidance of overcharging is usually pretty easy to avoid: Just use the appropriate charging system – but overdischarge is a bit more difficult, particularly if the battery packs in question don’t have a “protection board” with them. Lead acid batteries (almost) never come with any sort of over-discharge protection – one must […]
DIY ECG with 1 op-amp
A DIY ECG made from single op-amp (LM741) and 5 resistors by Scott Harden: I made surprisingly good ECG from a single op-amp and 5 resistors! An ECG (electrocardiograph, sometimes called EKG) is a graph of the electrical potential your heart produces as it beats. Seven years ago I posted DIY ECG Machine on the […]
DIY PCB inspection microscope
Saulius made a DIY PCB inspection microscope and wrote a post on his blog detailing its assembly: Despite how good microscope you have, stand is still very important part of final assembly. And while there are many commercial ones made of cast iron, they might cost more than a microscope head itself. I decided to make stand […]