Using the ATtiny85 Chip to Control Halloween Props
While wasting time one day I ran across a Google search item titled: "How-To: Shrinkify Your Arduino Projects". I was hooked. This little chip was incredible, and cheap. For under $2 you can get something that can have a pushbutton and control up to four things. This covers nearly 90% of everything we do at the haunted house. How could I not find many uses for these.
Of course like normal I went overboard building the PCB to go along with the tiny little chip. I think the first circuit board I built cost around twenty bucks. Since an Arduino Uno is only around $30, maybe $35 with S&H, not really a big savings there. It did include three transistor circuits to handle the higher current of multiple LEDs, built in programing pins, including the capacitor and a couple of diodes to prevent damaging various power sources. The programming pins are a nice touch though. Unless you perfect the program in a mock up it's kind of a pain to remove and re-insert the chip everytime you want to tweak the program.
I purchased ten of these chips from Mouser, after you calculate in the S&H they are around $1.80 each. I found some locally, they cost me $2.40 each, plus about $20 in gas to go get them. However, it was at a really cool electronics store, so I had fun looking through a lot of interesting stuff. For under $10 you can make a pretty cheap controller that at a push of a button will active a couple of LEDs and run a sound file from an audio player.