Securing the bike computer ancilliaries

The bike computer ancillary box (containing the battery, reset switch, and connections for the magnet sensor) was placed directly behind the front wheel truck. This ensured the smallest length cable possible to the bike computer.






The original road test used blue tack to hold the magnet sensor to the truck axle. The bike computer was actually supplied with cable ties to secure it to the fork of a bicycle. These cable ties are also ideal for securing the magnet sensor to the truck axle.

Invalidating my board warranty (again)

Previously I had drilled and chiselled  a recess in the board  to house the bike computer. To keep this area water tight (I didn't want the lovely Canadian ply to start separating or get swollen due to water ingress), I took the nearest paint pot to hand and painted the recess area with black paint.

Now that the bike computer was ready to be mounted onto the long board, I had to  drill another hole in the board in order to feed the bike computer cable through.



Not, a good looking result, but then again this area is covered by the bike computer. And here is the result:

Electrical repurposing of a bike computer

Regular readers of the blog will recall that I removed the back of the bike computer enclosure to reduce its thickness (I didn't want to have a chance of kicking it off). Removing the back lid  meant that the battery, the wire points connecting to the magnet sensor, and the reset switch  had to be removed. All these components required a home remote from the new slimmer bike computer. I had planned that the "home" comprising a small plastic enclosure would be positioned on the underside of the long board.

First off, I carefully soldered six wires to the existing connection points on the back of the bike computer PCB. Two wires (purple and brown) for the magnet sensor, two wires (blue and green) for the reset button, and two wires (black and red) for connecting to the battery.

Now, electrical connections on a skateboard have to be quite robust since even  riding on normal tarmac road the board is subject to a lot of vibrations. This is where UniBond 100% power glue comes in. After doing  a quick electrical test with a multimeter to confirm good solder contact for the wires and that I had not introduced any shorts, I put a big dollop of UniBond glue on the back of the PCB. I made sure that all the wires were submerged in this glue.  After 24 hours the result was a layer of resin (couple of mm thick)  on the back of the PCB securing all the wires. 

The next step was to source an enclosure for housing the battery, reset button and magnet sensor connections.This was a generic off-the-shell small plastic box available from an electronic component supplier. Once the box was delivered  I was then able to cut a piece of vero-board to fit within the box and populate it with a battery holder, reset switch and screw terminal PCB connectors.I made wire connections from the switch and battery to the terminal block connectors. I also fitted a rubber cable sleeve to the side of the box in order to reduce any strain on the bike computer cable and magnet sensor cable feeding into this box.

From the bike computer newly soldered in cable, I wired in the black and red wires for the battery, the green and blue wires for the switch. I took the existing magnet sensor cable and wired that to the brown and purple wires of the cable. 

Hey presto, I had a working bike computer. Each time I waved a magnet near the magnet sensor the LCD screen showed a "cycling" graphic.Moving the magnet close and far way in quick succession resulted in the mph reading changing!

Its time to mount all on the board!

Keeping the bike computer snug

A little bit more sand papering and the recess I made will be  a 1:1 fit for the bike computer!



Next step is to attach the wires to the PCB in order to connect to a separate box under the longboard. This box will house a board for mounting the battery, bike computer reset switch and the connection points for the magnet sensor.

Probably voiding my VoLo-E board guarantee!

Removing the bottom half off the bike computer casing means I can actually embedd the top half of the computer bike into the longboard by making a recess in the board ply to house the bike computer. This will mean that the bike computer will protrude from the surface by around 6mm.

All along I have been worried about the positioning of the bike computer and not wanting to reduce the strength of the board. So I positioned the recess at the top of the board away from any loading. The fact that I don't need to drill through all the plies should also be a positive thing in terms of keeping the board strength.

First, I placed the top half of the bike computer onto the top of board and drew round it in order to get the the shape for the recess perimeter. Then I arranged a  drill in my drill press so that it could not extend by more than 6mm into the board surface (I didn't want to go all the way through the board!). Then I drilled about 40 holes within the drawn out shape boundary. After that, I got a Stanley knife to cut out any remaining bits in-between the holes and used some sand paper to try clean it up a bit. Oh boy I must have definitely destroyed any sort of product guarantee I had from VoLo-E. The work in progress can be seen below:

Bike computer

Readers of this blog will know that I am slowly converting a cheap Halfords bike computer for use with my electric longboard.  The bike computer I bought  functions when it is docked in its cradle. Unfortunately when placed on top of the long board it sticks out more than 20mm from the longboard top surface. There is therefore a high risk that it gets knocked off when I am carrying the longboard on the train or I may even kick it off accidentally  when jumping off the skateboard.

Previously I had taken apart the bike computer with a view to see if I could reduce the height by removing the bottom half of the bike computer. I also wanted to do away with the docking rail. Well, by removing the bottom half its possible to reduce the total height to just 10mm. The plan is to make a recess in the skateboard to house the bike computer. However, I do have to put the battery somewhere else now. This will be accomplished by putting the battery and internal reset button in a separate box under the long board and connecting wires from the box to the PCB. The image below shows the disassembled bike computer. I have drawn a red circle around the bike computer part I will use.Other than the battery everything else in the image will be discarded.

Back on the skateboard in December !!!!

I had previously  thought  that  November would be my last month for skateboarding due to the weather. The weather was cold this afternoon but sunny and dry. So I charged up my skateboard  and  went skate boarding in the back streets. I didn't have  a particular destination to go, so  this was a  fun experience because it was without time limits. As was the case in the summer people were still stopping with prolonged gazes as I whizzed by. Funny, I would have thought electric skateboards are familiar sight to the public now.