A longboard speed and distance computer


Why should cyclists have all of the fancy toys? Bicycle computers are very common these days but you won’t find similar hardware for skateboards and longboards. [KobraX22] isn’t taking it lying down. He built this speed and distance computer for his longboard. It doesn’t use very many components and should be easy to install.

The device monitors the rotation of one of the wheels by mounting a reflectance sensor on one of the trucks. It points toward the inside of a wheel which has a piece of black tape on it. Every time the tape passes it prevents the IR led from reflecting back at its paired receiver. This lets the Arduino count the revolutions, which are then paired with the wheel diameter to calculate speed as well as distance traveled. Of course the wheels wear down over time to so frequent riders will have to take new measurements at regular intervals.

[KobraX22] went with a QRB1114 sensor. It costs less than $2 and doesn’t require him to embed a magnet in the wheel like a hall effect sensor setup would have. It also shouldn’t interfere with any other fancy wheel hacks you’ve done, like adding a POV display.

[via Reddit]


  1. Mark says:

    Anyone know where to source a QRB1114? Digikey and Sparkfun don’t carry them anymore.

  2. ColdTurkey says:

    a quick google search upturned this and only this


    Unfortunately for me to get this in the uk it will cost me upwards of £25

  3. Art Barrios says:

    Here are some similar Sparkfun IR / Phototransistor sensors:



  4. dave says:

    arduino, lcd, sensor, additional supprt parts… why wouldn’t I just use a gps or smart phone?

  5. lmn says:

    QRB1114 is obsolete part, search for a replacement


  6. Cool project and nice work! I have to be a butt, but beyond the joy of making you can do this really cheaply and easily with a $20 bell bike computer. The wheel diameter calibration goes down to longboard sizes. Big advantages are you already have a moisture and vibration resistant device. Challenges are maintaining wheel balance after mounting the magnet, finding an epoxy to mount things that can resist that much vibration, and either shortening or storing the enameled wire.

    I was able to pull it off using an 1/8″ riser mounted on top of dropped through Randall IIs with the wire zip tied to the underside of the riser and the bikeputer base screwed and marine epoxied to the top.


  7. Yeah, the GPS on my phone sucks. I use it with Glympse and half the time it’s teleporting me all around the city…

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