The main impetus for this was to have a homebrew controller that actually featured an analog joystick, since there were few if any guides elaborating how to fashion one from an existing controller. I acquired a couple Parallax 2-axis joysticks with breadboard mounting capability to do the trick.
The Vectrex comes with a game in its ROM — Asteroids — thus you can play without needing a cartridge. However, with the traditional controller, this requires lots of button-mashing since it has no auto-fire feature. Using a 555 timer, potentiometer, and clever values within an RC circuit, I have given it the ability to auto-fire.
Several years ago, National Semiconductor came out with some very high performance, easy to use audio power amplifier ICs. I was in need of an extra amplifier so I could biamp some of my home-built electrostatic loudspeakers so I tried the LM3886 chip.
This part was chosen because of the ease of use, power output, turn-on and off thump suppression, low distortion, and built-in protection against shorts and thermal runaway. There isn’t much more to ask of a power amp than that. When driving electrostatic speakers, you can’t have too much protection!
The Pocket High Voltage Generator that I made a few weeks ago proved to be a very handy tool. I have been testing Zener diodes very often since I use many Zeners in 12V to 91V range.
However I wanted to give it a bit more power so that I can test Nixie tubes clearly – the previous design can only give less than 0.5 mA through most Nixie tubes, some digits don’t lit up completely.
I made some upgrades to the components to give it a modest 2 – 5 mA (depending on the voltage) output. While still keeping the same form factor.
After completing my VGA Generator project a while back, I’ve embarked on a new electronics project: building a simple 6502-based homebrew 8-bit computer on a breadboard. There are a bunch of similar projects online from which to draw ideas. Some projects set constraints such as only using contemporary parts of the 8-bit era, no FPGAs, no microcontrollers etc. In my case, I opted instead to keep the constraints minimal and the project simple.
What are you thinking — I am not trying to break any world record? My XYL asked me that question today — why are you building another rig? Followed up by a snide comment that I had so many rigs now why do I need another one. Well the answer plain and simple because I can!
For the longest time in the late 60’s early 70’s my success rate with homebrew SSB transceivers was miserable. At that time I lacked the more sophisticated test gear and let’s face it some of the technology wasn’t that great. Crappy Analog VFO’s were high on the list of impediments! I also had to work and to give a fair share of my time to the family — it is that balance thing.
But today that is all changed –better test gear, better technology like Digital VFO’s and a bit more time. The latest project is to demonstrate that some of the components out of boat anchors can indeed be reworked to provide a very modern, very capable rig.
Jesus Echavarria made this battery monitor and wrote a post on his blog detailing its assembly:
Here’s one of the design I do last year for a client. He wants to measure the voltage of a car battery and set a couple of alarms when voltage falls below a defined values. Also, he wants to put the device in the relay box of the car, so the design needs to have a relay form factor to easy integration. So, after a couple of iterations, here’s the final design of the battery monitor.
For a project I need to program a few microcontrollers in the same circuit. This meant I needed to plug the programmer around on the board a lot. This got annoying very fast. Therefore I decided to make a switch box. In my junk pile I found an old switch of a, parallel port switch. This has 4 positions and a lot of contacts. For the ICSP I only need 3. However in some circuits the supply voltage is not common. Hence, I chose to also switch the power supply connections. For the connections to the circuit boards I used DIN connectors, for the simple reason I have lots of these.
Anthony Lieuallen made this custom power supply and wrote a post on his blog detailing its assembly:
You might not truly be an electronics nerd until you build your own power supply. Either way, I’ve finally passed that threshold. As I’ve mentioned previously (and previouslier), I’ve been working on mine — very slowly, off and on — for most of a year. The bare start came with a guide posted to Hackaday about using nichrome wire to heat and bend acrylic plastic in straight lines, to make cases.
Our initial goal was to monitor power consumption in different parts of the house, and we quickly realized every household circuit would need to be monitored. After some research, small clip on current transformers, or CT’s, looked to be the best sensor for our application. Using CT’s, current draw and thus power on each circuit can be measured. The CT’s would be installed on the wires immediately leaving the circuit breakers in the standard household breaker box. CT’s work great for this because they’re completely isolated and nothing needs to be disconnected to install them.
Lies, damn lies and statistics.
You have a high school science fair and want to know how your project was perceived by the visitors. Modern online behaviour will direct you to “taking the online survey”. That requires an extra step for the visitors, usually by taking hold of their mobile device and fiddling with a small screen.
One problem you will encounter is designing good computer interaction and a proper look and feel on the tiny screen. It is a lot of work. A second problem is the distraction of using the mobile device with respect to the project being surveyed. The visitor will concentrate on the mobile device and that will diminish focus on the project for a moment. A third problem is anonymity and proliferation of data. Do we really need to be online and spread all that information one’s device sends?