Now I can test fit the indicator ligths on the top and the push buttons at the front edge -- all waterproof. It's a tight fit, but everything lines up nicely.
What's left is to complete the design of the PCB. From the limited space available, I expect there to be two PCBs stacked on top of each other: the top one for the display and MCU, the bottom one to interface with the lights, buttons, sensors, and the bike's wire loom.
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The next step is to drill out and clean up the holes, both from paint and deformation (the 3D print turns your circles into ovals, stretched along the stripes of the print).
After that I insert the rivnuts using a soldering iron. The larger ones are to attach the cockpit to the spoiler; the smaller ones will hold the PCB.
#3Dprint #FreeCAD #FreeCADFriday #DigitalCockpit #HondaMT #bikelife
I'm using a full system of 1K spray paints from #SprayMax here, which I apply wet-on-wet to achieve the best adhesion.
- degrease using IPA
- 2 layers of plastic primer
- 6 layers of spray filler
- some 400 wet sanding
- 3 layers of black top coat
- 2 layers of clear coat
The result is exacly what what I hoped for: a great finish without having to do a lot of sanding.
Time will tell how the paint keeps up against weather and wear.
The second 3D print of this digital-cockpit housing for the classic Honda MT moped/bike looks really nice and fits in the spoiler perfectly.
The print is rather streaky, so let's see if we can give it a nice finish that makes it smooth while at the same time keeps some of its underlying ()industrial) texture.
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Got it: isolated the DC ground wire from the rectifier up to the optocoupler per your description.
Thank you for pointing this out! saving prototype PCBs 😅
Fortunately, there are only three of these signals, e.g. tail/sidelight, low beam and high beam.
Alternatively, I could avoid this issue by connecting the power feed for the switches on the steer to the rectified power feed instead of the raw AC feed from the spool, but I cannot trust others that may be installing this digital cockpit to do the same. So better make sure that this input circuit works for both AC and DC.
Turns out that some of the lights -- old-school filament light bulbs -- are fed directly from a separate spool circuit on the stator, which means that alternating current (AC) is used there. So in order to light up the right indicator lights in the cockpit, each raw input from these lights will have to have its own rectifier block, TVS clamping diode and smoothing capacitor before it can be fed into the optocoupler.
The #KOSO sensor I'm using adheres to the 'JIS D 0203 S2' Japanese automotive standard, which means that a standardized table and some interpolation can be used to translate resistance to temperature. Reading the value from the sensor requires no more than a voltage divider connected to an ADC entrance of the MCU.
Connecting the temperature sensor for the (air-cooled) head on the other hand is surprisingly simple. The ring-shaped sensor is placed under the spark plug and its resistance decreases as the temperature gets higher (NTC).
Have been working on the input and output connections of the digital cockpit for the classic Honda MT mopeds. Isolating everything properly using optocouplers and MOSFETS takes quite some real estate. Now I understand why the control units for cars are so packed.
The good thing is that I can replace each set of four PC817 optocouplers with a 4-channel TLP291-4 optocoupler, and the pull-up resistors with resistor networks.
Offerman Industries