Keep It Weird is an LED sign that my class made for our school’s hardware cabinet. Each student was assigned one letter of the sign. I made the letter “D”. For our given letter, we had to design our own schematic and circuit board using Eagle Software, and then mill (using the Othermill from Bantam Tools) or acid etch it. We then daisy-chained our boards/letters together to fabricate the sign. This was my first time learning how to create, design, and mill my own circuit board.
Using Eagle software, I first created the schematic of 19 parallel LEDs to be used for creating my letter “D” board. I used parallel as opposed to series, so that if one light bulb goes out it will not ruin the rest of them.
I then designed the circuit board and the electronic components to form the shape of the letter “D”. I made sure that there were header pins to attach to the “motherboard” in order to supply the power and ground. I also added 2 holes on the sides so that I can attach it to the cabinet.
Milling the circuit board that I designed on my own was pretty cool, and a lot of fun! Using the Othermill from Bantam Tools was pretty simple. The machine’s software easily connects with Eagle’s software as well.
I programmed the ATTiny85 with Arduino by first burning the bootloader. I uploaded the Blink sketch in the Arduino examples so that the LEDs on my letter “D” would blink.
After milling the board, I soldered all of the components onto the circuit board. One mistake I made which I have now learned from, is to check that your components are all working before soldering them onto your circuit board. I discovered later that a few of my LEDs were not working.
From the designated power and ground header pins, I connected my circuit board to the motherboard in the picture on the right. Our Professor created the schematic and designed the circuit board for the motherboard (see pictures below).
CONNECTING TO POWER AND GROUND
Once the letter “D” was connected to the motherboard, our Professor connected his power supply to the power and ground header pins on the motherboard, and daisy chained all of the students’ letters together.
ITP, Spring 2018
Homemade Hardware Class, Professor Andy Sigler