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Anything not specifically related to the Speeduino hardware. Eg sensors, bluetooth, displays etc
By Jcrotts
#40775
Can a GM 7/8 pin module correct a vr sensor signal or would I still need a vr conditioner to get a usable signal to the speeduino board?
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By PSIG
#40777
Yes, the GM modules and many other similar modules may be used as VR signal conditioners. I have tested the GM 4-pin and 7-pin to output a 5V square wave (using the on-board pullup) to Speeduino up to 24000 rpm on the bench. PCB settings are Hall with pullup ON.

David
By Jcrotts
#40778
I have a 36-1 trigger wheel. Do I have to use the gm 7/8 setting or can I use the missing tooth setting with it just as a conditioner?
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By PSIG
#40805
You're just using it as a remote conditioner module with its output digital 5V, so Speeduino sees it with the Hall setting. Use other settings, e.g., 36-1, as-usual.

Be sure to verify your VR polarity and manually test your VR with the module in order to verify if you need a rising or falling setting for the signal. In other words, depending on the specific module and pullup used (or not), the output to Speeduino may mirror the VR signal (VR high outputs as 5V high) or inverted (VR high outputs as low). This is important in order to read the correct tooth edge for a signal that processes correctly, and most VRs with missing-tooth wheels will need to read the trailing edges of the teeth, so the signal shows the missing tooth properly.

If all of this is seeming too complicated (really it's not), you can also just install everything, then use Tooth Logger in TunerStudio to check for a proper signal. But know that can have its own frustrations (is it wrong sensor polarity or wrong edge?), so I prefer to test each item before installing so I know it's right, and no worries about that part of setup. Do your thing!

David
By vandea05
#40924
Hi David, I'm curious why the Speeduino needs a 5v pullup if the 7/8 pin module puts out a 5v square wave? What am I missing?
By pazi88
#40925
vandea05 wrote:
Thu Feb 13, 2020 9:34 am
Hi David, I'm curious why the Speeduino needs a 5v pullup if the 7/8 pin module puts out a 5v square wave? What am I missing?
In many cases, the output from sensor is just grounded when tooth is seen, so 5v pull up pulls the voltage to 5v when output is not grounded, leading to 5v square wave. Not familiar with GM stuff, if that's the case, but still.
By vandea05
#40926
I understand the concept of ground triggering, yes. However, these specific modules apparently (as mine are yet to arrive) put out a 5v signal. From http://gpzweb.s3-website-us-east-1.amaz ... eNotes.txt

"R outputs a squarewave, pulsed DC signal based on the input signal to the P terminal. The signal at P is converted from AC to pulsed DC in the AC-to-DC-converter. A positive signal at P, above a threshold, will produce a positive 5v DC pulse. Below that threshold, the converted signal will be near zero volts. The converted signal then goes through a buffer before it is output to the R terminal. The signal at the R terminal is typically routed to the ECM (electronic control module) of the car. In the ECM, dwell and timing adjustments are made to the signal."

Which is why I'm asking David why the pullup is still necessary, or indeed if he's used that output from the module.
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By PSIG
#40933
vandea05 wrote:
Thu Feb 13, 2020 9:34 am
Hi David, I'm curious why the Speeduino needs a 5v pullup if the 7/8 pin module puts out a 5v square wave? What am I missing?
That depends on if you are using terminal C or R. C is always safe, as the pullup voltage is from Speeduino. R may be safe, but you need to test the voltage it outputs at all reasonable supply voltages in order to ensure it remains below 5V (5.5V absolute max), or you can fry the processor input. Some have tested at closer to 6V. ;)

David
By Jcrotts
#41132
Doesn't the module have built in base timing? How do you bypass that to get a signal on pin C to the speeduino? Wouldn't the signal be off by whatever the base timing is?
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By PSIG
#41264
Base timing is not in the module. It is achieved by adjustment of the distributor housing position. What you're probably thinking is the switching from fire-on-signal to ECM-triggered advance control. Set your base timing, use Trigger Angle to tell Speeduino where 0BTC is, then tune with the Spark table. Refer to the Wiki GM 7/8 Pin section if using it for firing the coil, and using Bypass.
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