Ever thought about building your own race lap counter? Well, now you can. Knog teamed up with the guys behind the legendary Mission Crit race in San Francisco to develop and build a Knog lap counter made entirely out of Blinder Mob bike lights for the race. You can check out Mission Crit's step by step guide to building a lap counter below. Enjoy.
Mission Crit was stoked to hear back from KNOG about teaming up for the spring 2017 edition of the race, and we were even more interested when KNOG presented the challenge of coming up with a cool way to showcase their bike lights. we’d been working out how to source a lap counter for the race, so the idea of making one out of KNOG bike lights was a pretty logical connection to make. with some help from the innovative team at AKQA San Francisco, we’re pretty happy with what we put together.
Step 1: investigation - breaking stuff is always the best way to start a project, right? We busted open a few of the lights to figure out how we could hack their on/off function. we soon realized that we didn’t actually need break the lights open; we could hack the lights just by stripping away the rubber casing on the on/off button with an x-acto knife and soldering wires to the button leads so that we could short the lights with the program we’d write.
Step 2: soldering & laser cutting - at the local tech shop, we cut the rubber casing away from the on/off buttons on each light, soldered wires on each side of the button leads, and etched the KNOG logo into an acrylic panel with a laser.
Step 3: programming - using Node.js, we wrote a program targeting the lights in such a way that they would form digit patterns and using a presentation clicker let us count down on button press from whatever number we set.
Step 4: frame construction - we opted to make the lap counter frame out of pvc piping so we could use the bike light’s straps to easily mount them. once assembled, we drilled holes in the back of the frame for the wires at the spots where the bike lights would sit, and then spray painted the whole frame black.
Step 5: hooking up - we connected the light wires to the relays, which were then connected to the raspberry pi that would parse the presentation clicker clicks to run the program we’d written to count the laps down.
Step 6: Assembly - this was super labor intensive; we determined what the light placement would be and trimmed wires accordingly, then threaded them through the corresponding holes and out the back of the frame. The KNOG logo was mounted in the frame using zip ties, and the relays were placed in a cardboard box in an attempt to contain the guts of the device a little.
Step 7: Action - the lap counter set up on the race course, blinding everyone from across the street. having digits burned into your retina is a small price to pay to be able to keep track of a kick ass race though, right?
Special thanks to Nate Waddington and Nick Mitrousis of AKQA San Francisco, and to RP Cuenco for their enthusiasm and technical expertise. We could totally R&D this baby and get it on the back of a pace bike in subsequent races. just sayin’.
- Clare (Mission Crit)