Speedometer idea

djnutz

Member
May 14, 2010
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Sioux Falls, South Dakota
So I have an idea for a speedometer. I found this:

https://www.amazon.com/IZTOSS-Speed...rd_wg=gzaA7&psc=1&refRID=YA1DRGD0RCFBH0DQVKGF



It uses a reed switch and magnets to measure wheel rpm and that drives the mph on the display. It also has a wire to measure motor RPM and I am thinking it could be linked to the spark plug wire to measure the engine RPM.

Looking at the last image of the wiring diagram, it looks like the the speed can be calibrated to be mostly accurate.



This is how bicycle speedometers work, using magnets and reed switches. I have a few of those types of magnets that are made to mount on wheels spokes so it would be a simple case of making a mount for the sensor somewhere on either the front fork or the rear of the frame, depending on which wheel I want to use to measure the speed. I am thinking the rear wheel would make it easier to "hide" the sensor wire rather than having something zip-tied to the fork.

I also use the SBP shift kit with an internally geared rear hub. This uses a twist shifter. The twist shifter uses a metal tab that clicks into a detent in the plastic housing. I am thinking I might be able to add the wires to display the gear the bike is in as well.

I am wondering if I could make use of an in tank fuel gauge and connect that to this thing too....

Any thoughts?
 

djnutz

Member
May 14, 2010
30
2
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Sioux Falls, South Dakota
So here is the shifter for my IGH. I am thinking that it might be possible to add some copper tape to the red gear indicator and then 8 strips, one for each gear. Ground goes to the indicator, and one wire for each gear from the speedo shown above goes to each of the gears. Then the gear indicator on the speedo should in theory show me what gear I am in. I am using a trigger shifter for the clutch so I could possibly wire the neutral gear wire to that to show when the clutch is engaged...

 

Dan

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May 25, 2008
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Very cool!

Rode the short bus, here, so please forgive. If it is already a tachometer, I think that may be how it functions?

Or am I missing something? LoL, happens a lot.

But very cool. Really is fun part of this crazy. The tinkering and plotting.

Best of luck and thanks for sharing.
 

djnutz

Member
May 14, 2010
30
2
8
Sioux Falls, South Dakota
Very cool!

Rode the short bus, here, so please forgive. If it is already a tachometer, I think that may be how it functions?
From what I can tell, it looks like this is both a Tach AND a Speedo. The engine rpm is read off the spark plug wire and the speed is measured by a reed switch and wheel magnet setup.
 
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pjamin10

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Feb 18, 2019
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Question,
To power this display would you just need a 12v supply off the motor or would you need a battery too?