Reviving a destroyed Pint

  • Routed out a few mil off the u-profile I got and it fits!.. ugly, but fits.
    Router table was a quick DIY mess made of old desk pieces which make a lovely surface for routing. Had a bit of chatter but that was mostly down to me feeding too fast and not applying consistent pressure... Still did the job mind you.

    This is only the first pass in which I just remove some material on the inside to fit over the housings and axle mount.
    -Next one is to shave down the internal depth to 10mm since it's about 5.8mm too big.
    --After I'll cut the edges down at around a 53.5 degree angle so they line up with either bumpers.
    ---Lastly I just need to drill all the holes for the bolts and countersink a handful. Since I already modelled the rails I an just print some templates and drill away.

    The edges will still be flat however I can 3D print a curved facade piece to replicate the shape of the Pint then glue it on. I'll finish machining the rails first before doing so, no point making it pretty before knowing it can survive later testing.


    Edit: Okay I got a little impatient and put the axle bolt holes in. Like a glove~
    Even better it holds my weight fine. Can bounce on it (with my foot barely bridging the gap between the rails) and no signs of twisting with the battery in place.

  • @Lia Lol... Is that an oculus rift? Who are you?

  • @NotSure Valve index headset with the old vive wands :)

  • @NotSure it's true, @Lia's last name is Stark.

  • So last week I was attempting to cut the depth of the rails but my Jigsaw blade kept walking so had to buy an aluminium cutting disc for my circular saw.
    Although I made a mess it worked like a charm after setting up a guide for the saw. Excuse the notches on the lower right side of the rail, it's from where the jigsaw walked but after removing the corners it's not that bad.

    With the depth cut to size I made a jig to angle the rails so they could be cut right.

    Needed to notch out part of the lower rail so it doesn't interfere with the bumpers

    Like a glove

    Slapped those on and seem to fit just right, turns out they're pretty strong as is. Still need to make all the mounting holes and cut out where the button and charge port will go.
    Will make a facade to recreate the curved rail edge so it matched the bumpers and holds the lip of the pads.

  • @Lia those socks look warm!

  • @NotSure Warm indeed :) Probably going to be a little too warm for them soon (fingers crossed).

  • @Lia -- You are giving that Pint a better life! The process is clear and inspiring to watch!

  • @blkwalnutgrwr Glad it's entertaining to follow along :)
    Hoping to rip around on it soon, the footpad sensor is next on the list and should be the final step if nothing fails.

  • Haven't forgotten about this, just had a few side projects that needed my attention before I set off finishing the Pint.

    One thing I've been working on is a DIY footpad sensor. All the OW's appear to use what's known as an FSR sensor either side of the footpad which when pressure is applied it completes the circuit. I won't bore you with a technical explanation of these however if you want to take a look there are a handful of pages that go over them, fewer explaining how to make a reliable one...

    Why not buy one? Well the largest FSR's I could find had an active area of 45mm x 45mm which is tiny. If you use 2 each side of the pad you still have some very small contact points with them not really being designed for this sort of thing. I needed something more durable. Being unable to find a place that would cheaply make a custom FSR as a one off I opted to just DIY it as is the theme of this Pint rebuild.

    As with most FSR sensors I'll be using metallic traces with a layer of velostat above them separated by a small air gap that keeps them disconnected. Maintaining this air gap is difficult. Failing to do so results in ghosting. Overdoing it and you'll have a pad that might deactivate mid-ride.

    I cut the traces out by hand from a 0.1mm copper sheet. That was fun...not! To stop the traces lifting I'm using 4mm wide double sided tape to attach them to the 3d printed lower plate which is only 0.4mm thick (2x 0.2mm 3d printed layers). Built in is some tiny vertical walls on the upper layer to help prevent the traces ever bending into each other.


    Using some electrical tape to make sure the ends of the traces never lift and touch the velostat. Then some double sided tape around the edges to attach the spacer that will introduce an air gap. It's 0.3mm thick (single 3d printed layer) which should be enough to prevent it ghosting and require a decent amount of pressure to activate.


    I won't use the whole single sheet of Velostat in the final so both pads can act completely independent of each other. With a single piece it's possible under some edge cases that both pads regardless of which side is active could stick on.

    Hoping it's reliable enough to last and not kill me while riding. If it's anything else like my other creations it will at least give me a decent injury before I finish it. All my most trusted and favourite creations have done so in the past. I like to think of it like a creator/creation bonding exercise ;)


    Enough with the footpad sensor, wanted to move onto attaching the controller housing to the rails. Needed to use a guide to make the mounting points on the rails for the controller so made a little template to give me guide holes.

    Worked a treat however I don't have M4 bolts that are short enough to not poke out so going to order some.


    Got special plans for the power button. Going to replace it for something a little cooler. Already tested and got the solution almost there but just need to implement it. If it works I won't need to drill a hole in the rail for the power button.

  • @Lia said in Reviving a destroyed Pint:

    I cut the traces out by hand from a 0.1mm copper sheet.

    exacto blade and stencil or snips?

  • @NotSure Tried using an exacto but it dulled too often and began to tear rather than cut.
    Printed off a template, stuck it down then just used a pair of sharp scissors to cut it in the end. Was thin enough to not take a lot of effort.

    Using scissors did introduce twisting in the traces so I had to give them a good flattening for a while with the double sided tape helping keep them flush.

  • @Lia -- Thrilling it is to watch your process and progress!

  • @Lia You should definitely get the “Badass/Genius” badge for this achievement. This project has been fun to watch.

  • @blkwalnutgrwr @HanahsDax Glad it's fun to follow along :)
    Hopefully going to get more done tomorrow and maybe spin up the motor for the first time (without it detonating like last time).

  • Did lots more testing today. 2 steps forward one step back sort of deal though.

    I have managed to replace the power button with one that is operated by magic!

    Okay it's not Magic, it's a magnet. More specifically a reed switch replacing the stock switch with a magnet hidden underneath the OW logo on my gloves.

    Why did I do this? I have no idea but I did it and it works!
    On the plus side it were to ever break it's not like there is any large metal attached to it that could bash the PCB >.>


    Now onto if the board actually works...
    Well Yes But Actually No.png

    The board does and sort of doesn't work. It'll turn on, boot correctly and if I bypass the footpad I can prime the board. I can even get it to move BUT.... oh my god the noise that comes from that poor motor!

    Typically noise like that on the Onewheel is a loose hub bolt. I can assure you these are cranked down so I don't think it's that. It could possibly be the controller/battery wiggling around as those are still press fit into the rails.

    Assuming it's not that it seems like I'll be taking the motor apart, I have 3 suspects as to what's causing the noise. In order of what I think is most likely:

    1. Bad bearing(s). Considering the absolute state of the hub I wouldn't hesitate to suspect one of the bearings has died. The fact that when pressure is taken off the left side it gets quieter leads me to believe the right bearing might be shot. It does spin cleanly though so I have doubts.
    2. Damaged cabling between the controller and motor hub. I think the 3 main wires that control the 3 poles are fine but I wonder if maybe one of the sensor wires could be damaged and thus it cannot perfectly locate what position the motor is in which could lead to vibrations as it bounce back and forth between the unknown positions.
    3. Faulty Hall sensor. If one of the sensors has died then the same theory from #2 applies as these actually read what position rotationally the motor is in.

    I don't suspect the controller electronics. If it had a fault I'm sure it would have manifested itself in earlier testing.

    Regardless of that, congratulations Pint OW131223 for "passing" your first test ride on the road to recovery.

  • @Lia said in Reviving a destroyed Pint:

    a reed switch replacing the stock switch with a magnet hidden underneath the OW logo on my gloves

    You've discovered the solution for someone hopping on our boards and taking off! Let them get up to speed, then shut it down!!! @Lia, you should repost this on the theft prevention thread . . . :D

  • @OneDan Good idea, I'll finish up the designs for the printed parts and add a post there.

    It's unbelievably simple to do. Just the switch alone and some silicone around it would suffice if looks weren't a factor.

  • @Lia sounds like an old vacuum but it works! Very cool.

  • @NotSure Not a happy noise at all. I'm sure it's something simple though, just got to find the cause.

Log in to reply