DigiDash Speedo Input - Sine Wave?
Thread Starter
Tech Contributor
Joined: Oct 2008
Posts: 3,729
Likes: 190
From: Custer, WI
DigiDash Speedo Input - Sine Wave?
As some of you know, I recently converted to a 4L80E transmission.
I am using an EZ TCU as a controller. This TCU is capable of outputting a square wave signal, with variable PPM.
What I need to know is - did the Digidash use a sine wave input from the VSS in the 700R4?
I only have a single wire output from the TCU for use as a signal. From my understanding, the yellow and purple wires on the Passenger footwell connector that go to the digidash are some type of "VSS high" and VSS low"
I contacted Dakota Digital and they said their speedometer interface would work, but it's $80. Is there a cheaper way to convert square to sine, if that is what I need to do? How do I split one signal wire into two?
My car is an 85
Thanks for any help!
Jeremy
I am using an EZ TCU as a controller. This TCU is capable of outputting a square wave signal, with variable PPM.
What I need to know is - did the Digidash use a sine wave input from the VSS in the 700R4?
I only have a single wire output from the TCU for use as a signal. From my understanding, the yellow and purple wires on the Passenger footwell connector that go to the digidash are some type of "VSS high" and VSS low"
I contacted Dakota Digital and they said their speedometer interface would work, but it's $80. Is there a cheaper way to convert square to sine, if that is what I need to do? How do I split one signal wire into two?
My car is an 85
Thanks for any help!
Jeremy
Last edited by Pwnage1337; Oct 9, 2017 at 05:22 PM.
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 763
As some of you know, I recently converted to a 4L80E transmission.
I am using an EZ TCU as a controller. This TCU is capable of outputting a square wave signal, with variable PPM.
What I need to know is - did the Digidash use a sine wave input from the VSS in the 700R4?
I only have a single wire output from the TCU for use as a signal. From my understanding, the yellow and purple wires on the Passenger footwell connector that go to the digidash are some type of "VSS high" and VSS low"
I contacted Dakota Digital and they said their speedometer interface would work, but it's $80. Is there a cheaper way to convert square to sine, if that is what I need to do? How do I split one signal wire into two?
My car is an 85
Thanks for any help!
Jeremy
I am using an EZ TCU as a controller. This TCU is capable of outputting a square wave signal, with variable PPM.
What I need to know is - did the Digidash use a sine wave input from the VSS in the 700R4?
I only have a single wire output from the TCU for use as a signal. From my understanding, the yellow and purple wires on the Passenger footwell connector that go to the digidash are some type of "VSS high" and VSS low"
I contacted Dakota Digital and they said their speedometer interface would work, but it's $80. Is there a cheaper way to convert square to sine, if that is what I need to do? How do I split one signal wire into two?
My car is an 85
Thanks for any help!
Jeremy
Team Owner
Joined: Sep 2003
Posts: 25,377
Likes: 2,735
I believe DD is actually the less expensive of those out there. Speedo/cluster wants to see 4000 pulse. If anyone asks when you're shopping the VSS is a PM Generator that generates AC current.
Last edited by WVZR-1; Oct 11, 2017 at 09:12 AM.
Instructor
Joined: Jun 2015
Posts: 128
Likes: 13
converting the wave
from da google:
http://www.learningaboutelectronics....er-circuit.php
it's a low pass filter, probably a dollar or 2....the actual values of the capacitors and resistors might need to be changed.
you might need a oscilloscope to test out the circuit....
might be easier to buy a solution, depending on your interests....
good luck
http://www.learningaboutelectronics....er-circuit.php
it's a low pass filter, probably a dollar or 2....the actual values of the capacitors and resistors might need to be changed.
you might need a oscilloscope to test out the circuit....
might be easier to buy a solution, depending on your interests....
good luck
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Instructor
Joined: Jun 2015
Posts: 128
Likes: 13
I play with this electrical stuff just a little... just enough so I can sound like I know what I'm doing.
following your progress, looking pretty good.
Like some day, I want to build a tranny controller... Some day... most likely never happen..
Safety Car
Joined: Aug 2013
Posts: 4,427
Likes: 603
From: Minneapolis Mn
I don't know if this will help or not. My 86 was built with a 4+3, prior to my purchasing it the tranny was changed out to a Tremec TR3550. The speedometer apparently didn't work with the new tranny as installed. A Dakota Digital converter was wired into the speedometer wiring to allow the speedometer to work, which it does. Additionally it has an option to increase or decrease the signal being sent to the speedometer if adjustments are required. When I bought the car the speedometer was off several mph, using the adjustments on the DD adapter I was able to dial in the speedometer so it reads correctly.
One nice thing is if you ever change your rear end gear ratio or tire sizes and it throws the speedometer off you should be able to easily correct it.
One nice thing is if you ever change your rear end gear ratio or tire sizes and it throws the speedometer off you should be able to easily correct it.
Last edited by hcbph; Oct 11, 2017 at 03:14 PM.