Hockey Stick GPS Tracker.
Canadian Tire supports Team Canada in the Winter Olympics with a campaign that saw a special hockey stick travel across Canada and then on to Korea.
tl;dr. I built a tracking device hidden inside the shaft of a hockey stick, that counts how many times it’s been tapped and phones home its location.
This is one of the toughest challenges I’ve faced — build technology that will fit inside the shaft of an ice hockey stick, actively phoning home it’s location and number of times its been tapped on the ground, using very low power as it won’t be charged for the 4 weeks of the campaign.
At first glance this seems like the perfect job for a Particle Electron, but it turns out to be a little too big, and is too power hungry to be considered for this job. Instead, Adafruit’s Feather platform was to play a starring role, with it’s diminutive size making it perfect to slide into the shaft of a hockey stick.
By using the base unit of a Feather 32u4 we immediately had access to a wide selection of libraries that work out of the box. I chose the Feather with the onboard FONA to provide us with a data connection over available Rogers’ 2G network. By default the FONA chip is always on, which would make it too power hungry, but by cutting a trace contact on the back of the board, the FONA chip will only power up when sent a 2 second pulse to the KEY pin. This meant I could disable the FONA chip completely when we weren’t trying to phone home.
For location I used Adafruit’s Ultimate GPS Featherwing, which is designed to stack atop the Feather, but there wasn’t enough space inside the stick for this, so instead I laid the two boards end to end and connected them with jumper cables. This board has a true ‘power disable’ control line (labelled EN) that I used to completely cut power to the GPS module when not in use. GPS antennas are directional and ideally have line of sight to the sky, so I ended up adding an external antenna to give us better reception which equated to shorter times from powering up the GPS to being connected to enough satellites to get an accurate location, which in turn led to lower power usage.
The result was a very low power system, that would power up the GPS every hour to grab its location, and connect to Canadian Tire’s API twice a day to upload it’s location and the number of times the stick had been tapped.
My desk at Performance Solutions!
Fabrication of the stick was taken on by the endlessly talented folk over at Performance Solutions, who located a vibration sensor near the blade of the stick that tracked taps, and was calibrated so that random bumps of the stick wouldn’t be enough to mistaken as false positives. I added a LED display to the system which Performance Solutions embedded into the handle of the stick to display the number of taps.
Preventing my own Y2K bug.
This display is actually just a dense grid of bright white LEDs, which means that when nothing is being displayed, it’s not drawing any power. I added code to detect if the number of taps to be displayed was more than the 5 characters that fitted on screen at the largest size type, and reduce the size of the text to fit the larger number. The running total is backed up in EEPROM memory so that if the battery dies, or if the processor crashes, it can reload the number of taps on startup.
Overall the campaign was a huge success, with more than 22 million media impressions for the Golden Stick, with coverage in 50 media outlets. Also, the social videos featuring the stick received 40% engagement, whereas the client’s videos normally get about 7-8%.
We all play for Canada.