Category Archives: DIY

Modified Heathkit HD-1410 electronic keyer

Dilshan Jayakody writes: HD-1410 is quiet popular iambic keyer which is manufactured around 1970’s by Heathkit. The original HD-1410 keyer is designed using 5 commonly available 74LS series TTL ICs and 8 transistors. Other than iambic operation it has an option to adjust sidetone frequency and support for (external) single-paddle key unit. In this project […]

USB to RS485

Marko Pavlin has published a new build: Testing of sensors with RS485 using PC without proper interface is not possible. Since RS232 interfaces are very rare, the interface should be hooked to USB. The interface between USB and RS485 can be soldered with one of the many FTDI interfaces with added RS485 driver, or bought […]

Project Hathor, a 2KV ring launcher

Check out Krux’s 2kV ring launcher, Project Hathor.  He writes: Have you ever wanted to shoot disks of aluminium forty five feet into the air at the press up a button? Do you like experimenting with high energy physics, and learn about things such as impulse generators, charge circuits, Lorentz force, electromagnetic induction, and how to […]

EMRFD Direct conversion 40m receiver in a tea caddy

Flathagen has made a DIY EMRFD Direct conversion 40m receiver in a tea caddy: I woke up one day eager to build something simple (at least I thought is was simple) and opened up the first chapter in EMRFD and decided to build the 40m direct conversion receiver. I already had most of the components in […]

Developing an IR remote and Software controller

Hardware Hacks has published a new build, a DIY Infrared remote for speaker: The idea is simple, we capture the IR signal from a remaining speaker remote and record the commands that get transmitted. We did this by connecting up our IR Receiver to the Arduino, the receiver has 3 pins and from left to right […]

Radionova 1 frequency synthesizer

Vasily Ivanenko has written up documentation on his Radionova 1 frequency synthesizer project: Frequency synthesizer for my Jupiter receiver — Радионова 1 — [ Radionova 1 ] Greetings! Most of my future homebrew radio projects will focus on building radio astronomy gear. Radio astronomy offers much fun + learning for the radio homebuilder — example topics include […]

Slider controller with auto-reverse and variable speed control

Paulo built a DIY electronic camera slider controller based on a small PIC microcontroller. It supports auto-reverse and variable speed: These motorized sliders share a common electronic controller design that provides speed control for the gear motor and also an auto-reverse feature using limit switches. In this article , I’ll go over the electronics and software for […]

Soldering pen

In this video Hans Peter demonstrates his soldering pen project: I’ve tried to compile a list of the things I still need to finish (not in order): – making a stand – making a casing – make temperature control via buttons – slow down LED pulse – general cleanup (in HW and FW) Project info at embryonic.dk site.

Automatic monitor brightness controller

Dilshan Jayakody writes: This is an automatic “monitor brightness controller” based on environmental light conditions. This system use USB port base sensor unit to measure the light level and control monitor brightness accordingly. We design this system to reduce the eye stress by matching the monitor brightness with environmental lighting. Project info at Dilshan Jayakody’s blog.

A 1-meter-diameter small transmitting loop for 7 MHz, part 1

qrp-gaijin has been working on a 1-meter-diameter small transmitting loop for 7 MHz: I’ve decided to try constructing a smaller, more traditional loop of 1-meter diameter. A smaller loop means smaller radiation resistance, and that means that small values of loss resistance become more significant. Great care must be taken in all aspects of construction to minimize […]

Mains 230VAC isolator

Jaanus Kalde has built an isolator box: Probing mains powered schematics is hard. Most oscilloscopes are earth referenced, so connecting ground probe to random spot of mains connected device will make a small explosion. Also there is the risk of electric shock by touching wrong part of the schematic while being in contact with something grounded like […]

(Nothing less than) The perfect tea timer

Michael from Acidbourbon has built the “perfect” tea timer project.  He wrote a post on his blog detailing its assembly: Maybe you just drink coffee, so this article might not catch your interest. However, if you enjoy a cup of black or green tea now and then, you’re likely familiar with the frustration of letting […]