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Topic: Automatic Transmission Shifter Idea (Read 38775 times) previous topic - next topic

batuning

HI
CAN YOU SEND HERE A SCHEMATIC ..
AND PHYSICAL  WIRING ?

DblTrbl

Billdefish, yes, this is typical for controlling transmissions.  I've built a controller for my full size Corvette (4L80E) project.

So in your case, it's not that hard.  If you have a hall effect sensor on the shaft, you need to write an interrupt routine that captures the time that the hall sensor goes back to a high (or low).  Then subtract the previous time that the capture occurred from the current time and that gives you the time between shaft rotations.  Keep the interrupt routine very compact for high RPM operations. 

Use that difference in time to calculate RPM and shift accordingly.  I know that world record class engines have extremely fast RPMs (my guess is between 20,000 to 40,000 rpms), so you need a very fast processor or have an external circuit that divides the number of pulses by some factor.  If a standard servo can do the shifting, that part is a piece of cake.


mrburnette

Very good. For 45 cents at Mouser you can get a ULN2803 8-channel Darlington Array that can turn Arduino 5V to up to 500 mA of 50V (or 12V) = with built-in back EMF protection= given up to 50V (or 12V) external power capable of the load and a a heat sink on the chip.
You need 2 channels for your shift toggles. That leaves 6.
<...>
500mA may not be enough:
Reference:
Quote
The shift solenoid valve resistance should measure 19-24 ohms minimum when measured at 20°C (68°F). The shift solenoid current flow should not exceed 0.75 amps. The shift solenoid should energize at a voltage of 7.5 volts or more (measured across the terminals). The shift solenoid should de-energize when the voltage is one volt or less.

Natha

Hello
I am also new to arduino, but I would recomend this book on electrical engineering. It is only £10!

Hope it goes well.
Natha

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