Month: June 2014

I’ve been using this cheap $4 AVR programmer to upload Arduino code to bare AVR chips.  The only issue is that it uses the 10-pin programmer interface, which takes up a lot of PCB real estate on my projects.  Instead, I wanted to use the more efficient 6-pin connector standard.

I looked on eBay for a cheap 6-pin programmer, but they don’t appear to exist.  All I find are the same programmer I have, but with an awful, gigantic, ugly adapter that’s designed to go on the project side:

Fig.1: Lame adapter for losers.

So you run a giant fatty 10-pin ribbon cable and have this thing jutting out of your project.  That suuuuucks.

Instead, I developed a tiny (half inch square) PCB designed to accept the programmer on one side and a 6-pin ribbon cable on the other.  Because it’s so small, it’s crazy cheap to fab with OSH Park ($1.60 for three), and the headers cost virtually nothing.  Now I can snap it into my programmer and use 6-pin cables, or pop it out and use 10.

I over-engineered mine, hot-gluing the exposed conductors and rounding the corners, but really, none of that’s necessary.

You can get the Eagle design files on GitHub, or order one from OSH park.

I’m going to be making a large 7-segment display clock later, and I needed a control board for it.  Rather than purpose build something, I set out to make a generalized board I could reuse with various projects based on the Arduino-compatrible ATtiny84 microcontroller.

The result is the TinyBuddy: a general host PCB for the ATtiny84. Features two buttons (plus reset), a power LED, activity LED, 16MHz crystal for accurate timekeeping, and USB or DC barrel jack for power. The pins are one-to-one correlated to the pins of the bare chip, so it’s a drop in replacement on a breadboard.  While the prototype (pictured here) used micro-USB for power, I designed a second revision that uses entirely through-hole parts for easy construction. It can be fabricated for about $7 through OSH Park!

You can find the Eagle design files for it on github, or order it directly from OSH Park (Rev1 with micro USB, Rev2 with barrel jack).

Some build history after the break.  Continue reading TinyBuddy: A host board for the ATTINY84→

I just picked up a Teensy 3.1, which is an ARM development board that can speak Arduino.  OSH Park was running a special where I could tack one onto my order for a few bucks.  It’s pretty neat.

The only downside is that the design doesn’t have pin labels on the top of the board.  This makes it really tough to use in a breadboard.  To fix this, I made a label to stick to it to call out the pins — posting here in case someone on the internet could use such a thing.

Here’s the PDF, as well as the Microsoft Publisher source file.  Unlike the photo, the linked label has the name of the board written in text rather than in ballpoint pen.

This is a guest post from my friend Rebecca on her adventures building her own Ax Clock. -Tyler

This blog post came about because I saw Tyler’s Ax Clock post and wanted one for myself. He wrote a nice blog post about it, but I didn’t know enough to make it myself so I asked him to help me. As we were making the clock, Tyler asked me if I would like to make a guest post on his blog. I was not sure if this was a good idea because a) Tyler has already made a post about this same project and b) I know basically nothing about electronics or programming. This did not stop me from immediately agreeing to do it.

Full story after the break.  Continue reading Ax Clock Part 2→