On Saturday, June 11, 2016 I had a chance to show off 5 of the Raspberry Pi designs I’ve been working on.
In preparation for a Kickstarter, I’ve been assembling designs that showcase the versatility and usefulness of the “Pi Platter” board I’ve been working on. Dan Julio, the other engineer on the project, and I are both members of the Boulder Hackerspace aka Solid State Depot. The Boulder Hackerspace was invited to the Denver Mini Maker Faire at the Denver Musieum of Denver Museum of Nature and Science.
The Pi Platter board is designed to give the Raspberry Pi Zero, as well at the other models of the Raspberry Pi additional features such as
- Additional USB ports
- Solar Li battery charging circuit
- Real Time Clock as well as additional I/O such as PWM outputs and analog inputs
Because the Pi Platter is so versatile, it’s important to showcase some of the ways you can use it. Currently, I have 5 demo designs.
- Raspberry Pi Zero with eInk display and solar cell showing time, battery voltage, and voltage graph
- Raspberry Pi B+ with mini touchscreen running python games
- Raspberry Pi Zero ver. 1.3 showing binary clock on a 8×8 LED matrix display
- Raspberry Pi B+ Security System with motion detector, 4×4 membrane keypad, camera and 2×16 LCD display
- Raspberry Pi 3 with 1TB hard disk
However, because I only have one demo Pi Platter board, I was only able to make one of the designs battery (and solar) powered for the faire. Two key features of all the designs is that they are battery powered and that the GPIO connector is available for HATs – that is daughter boards that fit on top of the Raspberry Pi. The Pi Platter connects through 4 pogo pins to the bottom of the Raspberry Pi Zero and through USB to other Raspberry Pi models.
The Saturday at the faire was a good way to make connections and talk to hob nob with fellow makers.
I was contacted through the Boulder Hackerspace by someone who wanted help building a Raspberry Pi security camera. We finally settled on the design being a cross between a PiLarm and system that sends pictures to your phone.
The hybrid system has:
- 4×4 membrane keypad for issuing commands
- Magnetic door sensor
- PIR motion detector
- 2×16 backlit LCD status display
- WiFi module
- And of course the the Raspberry Pi and Camera Module
I had a nice aluminum case that fit the display left over from a previous commercial design.
There where some “gotchas” in getting the Python code to work. It was not possible to just mix and match code from the two reference designs.
- Sending the MMS picture does not work with Wheezy, but only with Jessie because Wheezy’s Python 2.7.3 is incompatible with the Twilio import. Jessie provides Python 2.7.9, which works.
- The magnetic door sensor and PIR motion detector code triggered interrupts. This can interfere with the display code if not carefully structured.
- While a code block may work fine by itself, when you combine them you can put quite a demand on the processor. Scanning the matrix keyboard left little time to do anything else.
However, when all was done and said, the final design did a great job of detecting motion or an opening of a door, then taking a picture and texting it to a phone.
A possible next step is to rework this system using a Banana Pi D1, once we can figure out how to reprogram it.