[PSIG]

Those are diagnostic LED indicators. LED1 is on if the board has power. LED2 flashes when a signal is passed. At cranking or low speeds, you can see the flashes, but at higher rpm, it just looks brighter 'on'. Below is my prototype of the SSC (Single Signal Conditioner) for VR/Hall/Opto showing the LED flash when a trigger signal is passed to Speeduino. If you see flashes the board is working, but if you then see no rpm, then the problem is on the Speeduino board, or tune settings. Diagnostics.

David

This old and crappy video was to show the extremely low rpm sensing of the SSC prototype directly from a distributor VR sensor (not through the factory module), which are normally difficult to read at very low rpm. The diagnostic LED shows the signals for each cylinder are being processed and sent to Speeduino which become a blur quite rapidly as rpm rise (click link if it does not appear here):http://efistuff.orgfree.com/PostHost/VR ... R-v1FR.mp4
http://efistuff.orgfree.com/PostHost/VR_Module_H-VR-v1FR.mp4

[Ceeloo Yello]

David,

Thank you for the info in that case the LEDs are a great addition and I guess could really be added to either of the other designs.

[Ceeloo Yello]

I'm also starting with fuel only so I'm doing the same sort of "head scratching" as you

Thanks for the moral support

[dazq]

As promised a photo of my external opto board that fits in the ex-relay box

[Ceeloo Yello]

Wow that brings me back to High School electronics class

[dazq]

Wow that brings me back to High School electronics class

Simple works, that's been running since 2005 with other efi experiments!!!!

[Ceeloo Yello]

V3 - fixed NickZ LED to 5V, added LED between pin 1 and 2, changed LED BOM to 3mm

New Download
http://www.mediafire.com/download/4705s ... z/Opto.fzz

In the schematic for Dazq's board D12 seems to be backwards as compared to other schematics posted, can someone tell me which way is it supposed to be mounted?

[dazq]

This is the actual schematic I followed to build my units. Not my design but they work

[PSIG]

I would think it should work fine without the Zener diode like the other two. There are a couple of oddities about that MS circuit, and the Zener is one of them, in that the way it's used all it does is reduce the input signal by 5.1 volts — not shunt it to 5.1V.

David

[Old Grey]

I tried to make all the designs similar so you can see the differences easily, but must have got dazq's D12 Zener upside-down.

Page 3 pic and upload file has been corrected.