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By Bruceynz
Hi Everyone,

I am in the process of building up a 6.1 Hemi and I want to speeduino it! I need to get this crank trigger wheel sorted before I bolt it together.

I am unsure if the factory 6.1 crank trigger wheel will work, it has missing teeth plus a section with no teeth.

Here is a photo of one here ... M_0541.jpg

User avatar
Almost. You need to request a 36-2-2 decoder. It should be a fairly simple mod to existing decoders, so post your request on the decoders thread and perhaps on Slack for one of the code wizards to see.

Speeduino only reads one edge on each tooth, ether rising or falling. It does not care if the teeth are filled or cut-out, they are still just missing teeth for a duration between the selected rising or falling signals. If you look at your wheel below, you can see an example of using falling-edge detection (green and orange lines), and that Speeduino will see the same duration from one falling edge to the next, on both sides of the wheel. That makes it a basic and symmetrical 36-2-2 trigger wheel.

You can perhaps see that if rising-edge were used, the results would be the same, but Trigger Angle would be shifted CCW by (360/36)/2=5°. The black lines were only to verify how far out-of-square (distorted) the image was. Hope that helps.

MOPAR_36-2-2.png (265.04 KiB) Viewed 752 times
By Bruceynz
Hi David,

Sorry for the dumb question but where is the decoders forum, I had a look and search but no luck.


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