Monday, November 15, 2010

Hardboard: Death Metal \m/

So it turns out the springs won't cut it. I decided to haul the board with me one rainy day and ride it between classes. Pretty poor idea. First of all, the wide tire surface and the slickness of running water caused the board to hydroplane down some fairly steep slopes. The worst part was knowing it would happen. As I coasted down the hills of Georgia Tech, the board would oscillate violently. Turns out the springs were too soft and too responsive so a small semblance of a turn would soon be amplified to full extensions in a short period of time. I bailed off several times.

I put the board away for a few weeks and tacked other important things in the mean time. The finished Longpack for example.


I am a big fan of the blue shrink wrap. What I thought was really cool was how I could actually use the range on top of my stove to heat an area. It made me feel much safer than running a lithium battery under a flame.



The boards are in! Xo placed the order with Advanced Circuits and we received them as a strip of boards. I took a few of them with me to the Invention Studio one morning and cut them to size with the dremel tool.


The slot was also made through the ground plane to facilitate the edge of the nunchuk.


I also added some hall effect sensors to the hub motors. Three per hub motor, 120 degree spacing, attached to the tooth.



I'm not adventurous enough to try the flipped tooth method that Charles uses, although it would be much more convenient as I found out in the process.

Enough of that. THIS BOARD NEEDS TO HAPPEN NOW! I grabbed the deck and started prototyping resistive methods.

This plastic clip made from UHMW proved to be promising. The issue is that the truck angle is about 45 degrees, which means there is a 1 to 1 ratio between the person's movement and the trucks movement. With a person placing their weight on the edge of the deck, this means the resistive plug needs to exert 200-300 pounds of force without breaking or permanently deforming. Not an easy task.

Fortunately, these little guys did the trick.




These are also made from UHMW, but are taller and have additional bolt holes for more support. The older versions (also in the picture) have only two bolt holes, which twisted and widened after continual use.


What's left? Well next up is to solder the components to the boards. This should happen on Monday. My goal is to have this riding on Tuesday. How sweet would that be if I took the motor board to my meeting with Dr. Forest? =D

5 comments:

  1. i better get to ride this thing next time i'm in georgia.

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  2. Then hurry up and get back to georgia :P

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  3. It's hard to surmount the performance of the 45 degree reverse hanger poly bushings in nearly every longboard - cheap, durable, tunable, good linear response for a tight turning radius with no speed wobble up to the low 30s depending on the durometer of the rear bushing. It's a compelling enough implementation that it'd be a shame to settle for a substandard handling truck. I also wonder if you considered letting the axle stay with the stator - you could then sink the coil heat in the axle and truck itself. Fantastic job at any rate.

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  4. Very cool project, i've been checking out quite a few, your custom wheels are by far the coolest i've seen. I was wondering what were these motors like to push? Can you freewheel push the board with them off? or is there strong resistance? Just something I found with other electric skateboards is you cannot push them at all which was a bit weird.

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  5. Hi,

    Really a nice piece of work!

    I was wondering or the motors are mechanically stong enough to be used as Hub motors? Does the board actually works? I can't seem to find any updates about the hardbord.

    Thanks,

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