The P0 SOM is based around the BCM43362 WiFi chipset and uses a STM32F205 as the brain. The STM32F205 firmware is open source and on github.
I set the device up through my iPhone. The setup process with Tinker app was seamless in setup. I ran into issue when I tried flashing through the build.particle.io with the LED blink example the device would go into an infinite flash cycle (flashing magenta LED). I would then have to soft-reset the device to push it back into WiFi Host-mode so I could pair it again.
I also ran into some issues with my unit out-of-the-box. Generally, the serial operation was flaky with frequent 'Serial Error' messages.
I ended up having to flash to the latest firmware (0.4.5) using dfu-util. This resolved the issue with poor serial operation and inability to flash from the cloud-based IDE.
The code syntax interface is 'Wiring' similar syntax so easy to pickup if you've used the Arduino. Now onto the fun stuff, the demo....
I threw together a project when I got back this evening. My girlfriend has been leaving her hair straightener on in the mornings and will text me to check and turn it off before I go to work. So, I thought I'd whip up an AC relay example to showcase how rapid and easy the development is. The whole thing took me about 1 hour to put together. I could probably condense this all into a single PCB and replace the mini-USB breakout used for power by an integrated AC-DC +5V module recommended on this electronics.stackexchange post. A block diagram of the setup is shown below. I used the Tinker iPhone app to control the device. The D7 GPIO pin on the Photon is connected to the Powertail Switch 2 AC relay + input.
Required Parts:
1. Sparkfun mini USB breakout. - $2
2. Apple AC-to-DC 5V USB wall plug. - $10
3. Spark Photon Eval Board. - $20
4. Powerswitch Tail 2. - $26.00
Some pictures of the prototype:
