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 […]
Author Archives: DP
How to make analog sensor readings with digital I/O pins
Edward Mallon wrote an article describing a technique he used to make analog sensor readings with digital I/O pins: Will this method replace our pin-toggled oversampling? Perhaps not for something as simple as a thermistor since that method has already proven itself in the real world, and I don’t really have anything better to do […]
Teardown of an Amrel PPS 35-2 programmable power supply
Kerry D. Wong did teardown on a single-channel Amrel PPS 35-2 programmable power supply: A while back, I did a teardown on a dual-channel Amrel PPS-2322 programmable power supply, and was quite impressed by its solid construction. Recently, I found another Amrel power supply on eBay and this time it is a single channel version […]
#FreePCB via Twitter to 2 random RTs
Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week: Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch […]
DIY IoT garage door opener
Ludzinc wrote a series of posts detailing his IoT garage door opener. See the full post on Ludzinc blog.
App note: Keys to high flexibility
Ever wonder why some wires used on moving attachments last long? Cicoil who innovate the flat ribbon cable has done a lot since early computers on hi-flex wires. Link here Most industrial wire is made up of multiple wire strands, called ‘base strands’, rather than being made of a solid piece of metal. Multiple strands […]
App note: Insulating and Jacketing Materials
Different application calls for different insulations, heres a great info on different insulation and jacketing materials from Calmont wire & cable Inc. Link here Today’s wire user has a wide range of plastic insulating materials to choose from, and yet the selection of a particular dielectric for a specific application frequently is a trade-off in […]
Free PCB coupon via Facebook to 2 random commenters
Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three […]
Custom NES cartridge – Harambe’s revenge
Troy Denton and Brad Taylor made a USB reprogrammable NES cartridge: Initially, Brad and I wanted to make a PCB that could do some very ambitious things, requiring either a very capable processor, or an FPGA device. We began down this path, but soon realized that we were biting off much more than we could […]
Monitoring GNSS constellations with Galmon using the LimeNET Micro Ublox-M8 module
Luigi Freitas (PU2SPY) writes: In this blog post, I will explain how I managed to get a GNSS multi-constellation monitor called Galmon working on my LimeNET Micro. The Galmon project is a crowdsourcing tool developed by @PowerDNS_Bert to monitor the health status of GNSS constellations including the GPS, GLONASS, BeiDou and more notably Galileo. The […]
ESP32 LoRa sensor monitoring with web server (Long Range Communication)
Rui Santos posted detailed instructions of how to build an ESP32 LoRa sensor monitoring with web server: In this project, you’ll build a sensor monitoring system using a TTGO LoRa32 SX1276 OLED board that sends temperature, humidity and pressure readings via LoRa radio to an ESP32 LoRa receiver. The receiver displays the latest sensor readings […]
#FreePCB via Twitter to 2 random RTs
Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week: Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch […]
Understanding and repairing the power supply from a 1969 analog computer
Ken Shirriff writes: We recently started restoring a vintage1 analog computer. Unlike a digital computer that represents numbers with discrete binary values, an analog computer performs computations using physical, continuously changeable values such as voltages. Since the accuracy of the results depends on the accuracy of these voltages, a precision power supply is critical in […]
A homebrew all-in-one RTL-SDR with screen and control knobs running on a mini pc
In this video, Pablo Sala (KI7OJL) shows how to build your own all-in-one receiver based on an RTL-SDR. Via RTL-SDR.com.
Drive an MCP49XX series DAC with an AVR ATmega
Davide Gironi writes: Driving that IC is pretty simple, expecially if you have a dedicated SPI hardware interface, like many microchip has. The ATmega8, used in this example has a dedicated SPI Control Register (SPSR) that one can use to setup the SPI interface. This library can drive more then one MCP49XX of the same […]
4116 RAM tester
niq_ro shared a DIY 4116 RAM tester using Arduino. More details on nicuflorica blog. Check out the video after the break.
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 […]
A look inside a Marconi signal generator
A closer look at a Marconi Instruments signal generator @ jaeblog: Recently I got a Marconi Instruments 2019 signal generator, capable of generating signals from 80Khz up to 1040Mhz. It can also modulate these signals with AM, FM and more. This instrument is from the mid 80s and is, as far as I can test, […]
Make an amazing $6 digital radio with an old ESP8266 and a VS1053 decoder
Mike Diamond @ whatimade.today has written an article on how to make a low cost digital radio with an old ESP8266 and a VS1053 decoder. See the full post at whatimade.today.
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 […]