Gear Indication and Manual mode questions

[spoolinsteve]

Howdy again. I have two questions that revolve around using the AMS-1000 boost controller.

The AMS-1000 uses a 0-5 volt signal to identify what gear the transmission is in. Are there any such provisions on the factory 4l80e which I could use or make a gear indicator box from? I was hoping to leave the transmission in drive while at the track. I was thinking of using signals from the shift solenoids or something to accomplish this.

If that is not possible I can use the dakota digital box if the transmission was manually shifted. I was thinking of using switches on the right pins to trigger "manual mode." Is that safe to use at the track? Will lock up still function..etc etc.. I would think this is the easiest way to accomplish my goals.

Thanks,
Steve

[slow67]

One problem is they solenoids are operated by a ground signal, not a +12V.

[spoolinsteve]

Good info, that is what I have found through the research I have been trying to do. Its another bump in the road but still could be used through some sort of homemade electronic box do-dad. I hope...

[joecar]

How does the AMS-1000 interpret the 0-5V signal...?

[spoolinsteve]

I believe (since I did not buy yet) It has an input wire for the 0-5v signal. You then put the car in each gear and press some buttons on the screen to calibrate the unit. When it sees whatever constant voltage was programed into it, it will assume you are in that gear.

Ie 1.2volts =1st 1.9v=2nd 2.1v=3rd and so on I think it can detect a 0.1 change in voltage and be calibrated to see up to 6 gears.

[joecar]

The 4L80E and 4L60E have two shift solenoids, this gives a total of four combinations (representing four gears);

each solenoid signal is either 0V (on) or floating/12V (off);

if they are floating, then each signal needs a pull up resistor (pulls the voltage up to 12V when the signal is off);

then you would need a 2-bit digital-to-analog-converter made from a resistor ladder and possibly an op amp...

for example:
http://zone.ni.com/devzone/cda/tut/p/id/13237
http://www.allaboutcircuits.com/vol_4/chpt_13/3.html
http://www.baron58.com/DAC.htm

The op amp will allow you to scale the output voltage range independently of the input voltages.

How versed are you in electronics...?

[spoolinsteve]

I am not versed well....haha well here goes?
I have 3 5v op amps leftover from a 5v buffer project for a non lsx vehicle. Their data sheet can be seen here: http://www.ti.com/lit/ds/symlink/opa2340.pdf Would they work even though the solenoid operates on 12v? The are model OPA340PA

Obviously I will have to do math to figure out the resistors... But, here is my first attempt after sifting through google and your links. Do I need diodes anywhere? How wrong does this look?

http://i536.photobucket.com/albums/ff326/prot00ning/GearIndicatorIdeasA.jpg

[joecar]

More like this:


http://img196.imageshack.us/img196/5346/gearindicatorideasa.jpg

[joecar]

The two vertical buffers can be CMOS inverters/buffers powered by 12V... or maybe they can be left out.

[joecar]

The key points are:
- the op amp mustuse negative feedback loop;
- the resistances at the summing point must be R and 2R;
- the ECU grounds the signals to turn on the solenoids, and floats them to turn off;
- the pull up resistors pull the signals up to 12V when the ECM turns them off;

[joecar]

Actually might have to use a non-inverting config, do this by swapping the op amp inputs (and add a resistor to the ground point).

[joecar]

Like this:

http://img828.imageshack.us/img828/5346/gearindicatorideasa.jpg

[joecar]

Yes, then you have to use math to figure out Ry, Rx, R.

[spoolinsteve]

I wish I could send a hug via the mail.

[spoolinsteve]

Joecar do you suggest using a 10k or 33k resistor for the pull ups? I really don't know a ton about electronics and I don't want to hurt the pcm with too much current.

[joecar]

I think 10K should be good.