07/29/2016 at 23:30 •
I recently got a message from a 'community manager' at hackaday.io requesting that I post more pictures of bright. I threw together a rough prototype on a breadboard with an arduino pro mini, but ultimately didn't want to post pictures of it. I wanted something impressive-looking that would attract attention (and skulls) to my project. So, I took a couple hours out of a rainy day to assemble a 'dead bug' freeform circuit that would more or less be electrically similar to the final version of bright. I used an attiny85 because I already have a few of those on hand. It's my first attempt at deadbug style design, and while the main reason I built it was lack of any protoboard, I have to say it looks very cyberpunk-ish and intriguing.
I'm crossing my fingers that it will work, given that I didn't even test out the schematic beforehand to make sure everything was OK, nor have I written a single line of code. However, the hardware will be the easy part of this project-it's essentially a fancy blinkinlight, but the software is going to take a little while. I'll have to do a quick sketch in arduino before porting the code over to GCC and optimizing it to take up as little space as possible while still looking like a semi-realistic candle.
The schematic is above. I didn't feel like spending another half hour on EAGLE so I sketched out a rough draft on paper in 5 minutes. The thing on the left is my attempt at drawing an LDR (I don't know what the symbol is). I probably won't be making very fast progress on this project; I'm working on a paid freelance job while working fast to finish up #bioloop, all before school starts.
07/26/2016 at 19:33 •
I searched around for small, low cost microcontrollers that would be ideal LED candle drivers. At the very least, I needed something with 5 i/o pins, including one ADC pin for a light sensor. It was tempting to pick something from the tiny*5 family, simply because the Arduino IDE support is so good, but it would come at a cost in terms of volume production.
Name price/1 (USD) price/1K (USD) MSP430G2131 1.51 0.55 STM32F030 1.37 0.62 ATTINY102 1.44 0.62 MSP430G2252 1.59 0.67 LPC822 1.64 0.75 ATTINY13 1.84 0.85 EFM32ZG110 1.36 1.01 ATSAMD09 2.32 1.09 ATTINY25 2.74 1.27
(prices are based off digikey as of 7/25/2016 and may change)
It's interesting to see how much processing power a dollar (or less) can buy in volume. Even light ARM cores are cheaper now than hobbyist mainstays like the ATTINY25. The microcontroller I'll probably go with is the ATTINY102, because of it's low cost. Besides, I've always worked with ATTINY chips. And lack of Arduino IDE support will provide the right amount of motivation for me to finally learn C.
The other challenge is the fact that I can't seem to find the ATTINY102 in stock anywhere on the internet. The official dev board is available, but not the actual IC. I can improvise and work with the TINY85, which I already have on hand, hoping that the 102 will go on sale or Atmel can provide me with free samples :).