Order Parts and PCB: Version 2.1 of the board can be found on (Osh Park). Make sure you check the box for "2 oz copper, 0.8mm thickness." This will get the right impedance for the 50-ohm trace to the antenna. This is a complex build requiring many SMD components. Many components are standard ICs and passives that can be found on this list, but there are a couple components that must be special ordered:
- The MKL02Z32 must be purchased with the teensy bootloader pre-burned in it from here
- The RFM69HCW must be the 915 MHz version to match the antenna
SMD Solder: This is NOT EASY. The density of this board is very high. The components have very small pin pitches and some CAN ONLY BE REFLOW SOLDERED. For example, the microphone pins are underneath the part have cannot be accessed with a soldering iron and there is a ground plane under the Teensy.
I recommend building this in steps. Populate the Teensy LC chip, it's bootloader chip, the crystal oscillator, and the reset switch. This will allow you to get the teensy up and running before waisting time with other components. If the teensy doesn't work, nothing will work. You can bypass the 3.3V regulator and use a bench power supply to connect to the 3.3V power pin (and ground of course).
Test the teensy by connecting to it on your PC and making sure you can program it with some example code or simple blink code. If you can take to it you are good!
Next, or if you don't have a bench power supply, populate the 3.3V regulator and it's associated components. Test it with a multi-meter.
Now populate each sub-system and test is along the way if you can.
- Accelerometer (you can use the Adafruit LIS3DH test code to make sure it is working)
- Battery Charger (not critical)
- Microphone (this is the hardest component to solder. YOU HAVE TO REFLOW THIS. I use a toaster oven.
- Speaker driver
- Speaker on back (Make sure you add some insulating tape underneath the Speaker to make sure there are no shorts)
- Wireless TX/RX. This should be done last as it is the easiest part to do and takes up the most space. Make sure you add some insulating tape underneath the RFM69HCW to make sure there are no shorts.
Once you have populated all of the components, you can program the Teensy with the Communicator software. You can also try the unit test codes that I have posted.
- Install LATEST Arduino IDE: https://www.arduino.cc/en/main/software
- Install TeensyDuino Software: https://www.pjrc.com/teensy/td_download.html
- Open the code in the Arduino IDE and choose 'Teensy LC' as the board (Tools->Board)
- Click the Upload/Program button
- You may have to hit the reset button to get it to program