Shiny Motorcycle Computer

We’re rather surprised at how popular it has become to build your own motorcycle computer. [Mario Mauerer] tipped us off about his shiny motorcycle computer (translated) for his Yamaha XTZ 750. It uses an ATmega644 microcontroller to pull a variety of data together and display it on this white LED backlit display. He connected a flow meter to the fuel line to monitor gas consumption. Oil temperature is captured by inserting a brass tube (containing the sensor) through a hole in the oil cap and soldering it in place. Water temperature is gathered by measuring the external temperature of one of the cooling lines. [Mario] uses a rotary encode with a click function as the control interface device, and a battery backed real time clock keeps time.

A quick look at the PCBs tells the tale of good circuit design. But we do wonder about catching the reflection of the sun in that shiny bezel.

19 thoughts on “Shiny Motorcycle Computer

  1. Definitely took some skill, more of a build than a hack, but I’m not complaining, this is awesome!

    Though it’s interesting that he’s german(?? it looks german), but did the UX in english… most of it’s great cause it’s only one or two words, but he might want to get a proof reader to wean out the things like “Fuel Consumpted:” (unless he did that on purpose.) ;-)

  2. @Mikey: Regarding the choice of language on the display. It might’ve simply been out of convenience. I’m Swedish and when I play around with LCDs or other stuff that requires me to output text I usually stick to English. Why? Because it’s often a bit of a pain in the ass to add support for our extended alphabet. In Sweden we have three additional characters after “z”, namely “åäö” or “ÅÄÖ” in caps.

    These characters appear “out of order” in the ASCII table so you have to add logic to handle them separately. By sticking to English you can get away with being a bit lazy :)

  3. Not a bad job. Though, this really isn’t necessarily what I would call a computer. It’s more of a monitoring device. The computer controls the EFI, spark timing, etc.

    Excellent build, though.

  4. Here’s a thought that I had along similar lines.

    Ditch the gauge cluster altogether and install a transparent lcd in the helmet.

    Not sure what a back light would do during night driving.

  5. Hi Guys,
    Thanks for the commendations!
    I chose english as my menu language because some words were a bit shorter and fitted better.

    What`s wrong about “Fuel Consumpted”? How should it be written? :-D (As beeing from Switzerland, English isn`t my mother tongue…)

  6. @Mario

    “Fuel Comsumption” is correct, my guess is that you’re using “consumpted” because it’s “fuel used”, but the grammar is different :) if you want to keep the form then it would be “fuel consumed”, but it wouldn’t make sense.

    – Eirinn

  7. Just a fix to my previous post.

    Fuel Consumption if you want to display how much fuel is being consumed at the time.

    Fuel Consumed if you want to show how much fuel has been used.

    Blargh :D just trying to help. Awesome build you’ve made!

  8. I’d say that its a great project. I like the concept and how it was packaged. I would suggest that you paint the aluminum flat black and find a bezel cover that won’t reflect sunlight in your eyes.

    BTW, I ride a 1976 BMW R75/6.

  9. I don’t think the reflection will be a big deal. My bike has chrome all around the instrument cluster and I never have had it reflect into my eyes.

    One thing I would use would be a digital speedometer, then you could make it give you 0 to 60, quarter mile times, ect. But then again I think just the stop watch would get me into enough trouble.

    Nice build!

  10. It’s an interesting exercise, but the values generated & displayed aren’t worth much beyond a way to start a conversation…

    1)The “fuel flow” measurement will be, at best, an educated guesstimate. Consumer-level flow-metering hardware used in this manner will be less accurate than a the tank-level gauge. If the meter-spec is actually good enough for the task, it still needs to have its’ flow-measuring accuracy calibrated and verified after it’s been installed in the system that’s being monitored. No calibration means that you’ve made a somewhat unreliable fuel tank level indicator.

    PS: Good flow meters measure mass, not volume. :)

    2)The accepted ways for measuring oil temp require that the probe be immersed in the oil that’s down in the sump. The described method is measuring the temp of the air/oil mist that’s being created by the spinning clutch backet. It’s influenced to some degree by the oil’s heat downstairs, but the biggest influencing factor in the area you’re measuring so-called “oil temp” is the air going past the outside of the engine as it cools the clutch-side of the crankcase. You’ll get a temperature indication, but what it means is dubious.

    Nice try, but the wrong approach. Fwiw, simply inserting the probe deeper into the engine from the oil-fill hole won’t help either.

    3)There’s a similar issue with measuring the temp of an external coolant line. A better way to measure the coolant’s REAL temp would be to have the temp sensor/pickup attached to the radiator’s lower reservoir, and insulating it so the only temp seen by it is the coolant temp within, not the atmosphere blasting past it on the other side.

  11. Thanks for your points, but:

    1.) I calibrated the flow meter directly in the bike and achieve a accuracy of 5% at the gas station, which is pretty much enough for the desired task, as the original motorbike hasn`t any fuelgauge at all.
    A much bigger problem is the fact that the fuel travels back and forth in the fuel lines with every revolution of the engine because the fuelpump works with the vacuum generated by the engine (inlet suction), i guess it will be better if i mount the flowmeter between pump and carb and not before the pump…gotta do that next season.

    2.) The engine got a dry sump lubrication and guess where the sensor is – right – in the oil tank. So this is the best place to measure the oil temperature, because the engine is ready to do something when all the 4.5 liters of oil are heated up – which is exactly what the sensor tells me. (it takes about 15km/10mi for the oil to get up to ~60°-70° celcius)

    3.)Yes, the water temp sensor isn`t optimally placed. But when i built it i didn`t have the time to drill a hole into a radiator screw.
    But the Water temp isnt`t of very much interest; The bike has its own water temperature gauge.

    Greets from Switzerland

  12. Any chance of uploading schematics and layout? I really like your project, top notch! Makes me want to mod my motorcycle! Then again I still have a 1970 Honda CB350 I’m restoring, maybe that will get a computer in it some day :)

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