Wednesday, January 13, 2016

New year, new device

Finally got most of the kinks worked out of the Pebble as CGMS project.  Above is the device with it's charging stand.  Completely removed the phone component.  Added all the calibration functionality to my pebble.  Some screen shots from the emulator:

For calibration values, you can choose 80-190 in 10 mg/dl steps.  I also added a 15 minute snooze for alarms.  Entering anything is a two step process to avoid issues with accidentally pushing the buttons.  This will probably see more work, but for now, you click an action then scroll back to the top and choose Enter.  Finally broke my watch code up into libraries, much happier with it now, and it's easier to maintain.  Maybe I'll let my iOS developer license lapse now.  I really dislike xCode, I spend more time proving to it that I'm an authorized developer, than I do coding.

For the circuit, I realized I was better off with the Wixel, since it handles running it's radio and a 115k Serial connection.  Almost no room for a program on the Wixel, but I only had to cram in a function to blast out 2 packets to the pebble every 5 minutes.

A picture of the packed circuit board:

I'm very happy with this.  I no longer have to keep track of the phone.  Also both the boards I'm using are pretty awesome at their jobs.  The Bluetooth board easily covers the house, and pairing is automatic, handled by firmware.  No more disconnects from blocking the device.  The Wixel is also much better at pulling in signals than my CC2500 devices.

I did the PCB on a CNC router this time.  Just barely worked, luckily this is a simple circuit.  I should be able to do better on the next PCB I route.

One downside for now, is I can only get the Classic Pebble and Pebble Steel to pair.  There is something different with the Pebble Time and what it expects for Pairing.  There are quite a few parameters for the RN41 so I have a few other options to explore.  On the upside, while the Classic is fairly ugly, it has nearly a 5 day battery life.


  1. Where do you go from here? Is the quest done?

  2. I'm messing with BLE Central, I still want control of the newer Pebbles. After that, I've got robots and a million other garage projects to get back to...