So I wanted a small clear container to hold my mini projects. I found these Amac plastic boxes at The Container Store and they are fairly inexpensive. The 1"x2" ones are about $0.59 apiece. So I bought a clear one and a smokey one.
Taking some quick measurements, I created a simple board in Autodesk Eagle Cad:
I built the board around the ATmega328P since it's what's used in the Arduino UNO(s), it fits in the design, is easy to solder up, has an internal oscillator, and is generally compatible with Arduino IDE and most other tools. Ie, it's accessible and easy to work with, and you can get it fairly cheaply. Also, I had a bunch on hand and wanted to use them up. :)
In the layout above:
- 1 x 10pin ICSP for programming the chip
- 1 x 4pin I2C header for controlling I2C devices like OLED/LCD displays, sensors, expanders, etc.
- 1 x 0805 SMD RESET pullup resistor under the ATMEGA328P IC. Generally good practice to have a pull up, but you an omit this if you're feeling brave. :) A 4.9K - 15K resistor value is fine.
- 2 x 10pin expansion headers. I made sure that both have VCC/GND, and both have 2 PWM pins. Otherwise, one has the serial RX/TX and the other has all of the ADC pins now used up by the I2C.
- First one:
- Second one:
- First one:
Top copper pour is VCC and bottom copper pour is GND. Corners are rounded to ease fitting into cases. Layout and spacing is straightforward. Silk screens help with identifying which pins do what.
Top of PCB as visualized by OshPark:
Bottom of PCB as visualized by OshPark:
Update: March 27th, 2017
Just got the boards from OshPark. Woot!
Here, the batch of boards from Oshpark are stacked/placed near the 1"x2" plastic box/enclosure I designed for.
I had undersized the board a bit, so there is plenty of wiggle room in the main body of the box. I probably could have sized it to fit snugly, but I think that the clearance lets one route wires, if need be.
LOL. The whole 6 board order fits inside of one 1"x2" box with room to spare.