S2000 Cluster in 86 Corolla ?? pro's plz

[Project D]

thanhngo can you give us some details about the imputs ?

You said "RPM signal needs 12V square wave"
ok, but with which frequency / duty cycle ? (@ rpm, because I think the frequency varies with the rpm, right ?)

same question about the VSS

I lost many hours to try to find how this thing work (with a NE555 and many setup...)
but I found nothing (and that realy irritated me )

So if you can provide at least this thing that will be realy helpful for everyone

[thanhngo]

RPM 12v:
30-400hz with 50% duty cycle.

Speedo 5v:
0-8000hz, 50% duty cycle.

ECT pwmish 5v:
high, low
1 bar (always on)
30ms, 1197ms
2 bars
30ms, 1034ms
3 bars
30ms, 553ms
4 bars
30ms, 368ms
5 bars
30ms, 274ms
6 bars
30ms, 182ms
7 bars (red)

The speedo will be the challenge. Rough formula for speed (y) and freq(x) in mph
y = 0.0373x - 1.9642

[Project D]

PERFECT, Thanks
(I will try this tomorrow )

[Project D]

thanhngo, are you sure about the 30 to 400Hz for the RPM ?
(I don't had the time to try at my work, sadly to busy)

Theoretically if we have 1 pulse/rev that mean 150hz for 9000rpm
with 2P/R we have 320hz for 9600rpm (so less than 400hz)
and wit 3P/R @ 400hz we only have 8000rpm

[thanhngo]

Very rusty with this as I haven't looked at it for awhile but thats what I have written down on my notes. It'd help get you to produce a close frequency to test your circuit.

If you are looking for offshelf options: (adds up few hundred $)
Tacho: SGI-8 from digital dakota
ECT: modifry ECT chip
Speedo: Electronic Speedo Corrector (powerful one that can multiple at least 10x - not +/-100%).

Did you get the signal running? I used a Mofset to produce the 12V voltage signal.

Got my engine running so im back on the tacho proj to finish it.

[Project D]

Okay today I have done my "homeworks"
I will upload pictures I have taken after my work :wink:

So :
- Tachometer:
810rpm @ 27hz to 8900rpm @ 296.65hz
so 2 pulses by rev
and it seem to work with less than 12v

-Speedo:
like you said it's not perfectly linear
I have something like 7820hz for 300km/h

Edit:
pictures !!

Tacho:






Speedo:


131km/h @ 3500hz (display show 3.500Khz not 3500Khz ^^)

[thanhngo]

Nice, drools at equipment - you should have no problems building this. Did your rpm start flashing when it hits 9500rpm?

I'm doing the wiring on the car atm to hook up to the 20v engine. Gonna connect the Tacho soon and running off 1/4 IGF signal from the COPs. Thinking:
Signal -> Schmitt trigger -> freq multiplier x 4 -> Logic Mofset - > Tacho

Sorry I don't have diagrams etc as I've been doing it mostly on the breadboard and blindly trying it

Speedo:
VSS sensor - > Schmitt trigger -> Controller -> Freq Divider -> Tacho In
* need a RC filter to remove noise at higher speeds
* incorporated 2 trimpots to adjust speedo for changes in tyres/diff ratios/gearbox etc
* Frequency Divider used to overcome hardware limitations/resolution of pwm signals of 10bit freq

ECT:
ECT -> Controller (ADC) -> temp gauge
* couldn't figure out a way to use single wire as I think the factory uses a Capacity so I used 2 wire toyota thermistor used wired in voltage divider with 51R

Toyota Thermistor recordings
Temp ADC (heatup) ADC (Cool down) ADC (Sustain)
60 55 78 73/76
65 62 89 83/87
70 73 103 97/98
75 86 117 111/112
80 102 133 125/129
85 116 149 142/143
90 135 165 162
95 154 180 177
100 172 193 196
105 225 217/219
110 239

[Project D]

thanhngo Wrote:Nice, drools at equipment - you should have no problems building this.

Actualy that's not mine, I don't have the money to afford it: it is the equipment of my work.
I'm in prototype department (CAD / mechanical stuff) and electronics stuff is in another department
so I can't use it every day, only during the lunch time.
And I'm a crap in electronics :lol:

Quote: Did your rpm start flashing when it hits 9500rpm?

Yes

[Project D]

thanhngo Wrote:If you are looking for offshelf options: (adds up few hundred $)
Tacho: SGI-8 from digital dakota
ECT: modifry ECT chip

Speedo: speedohealer V.4
http://www.healtech-electronics.com/

[thanhngo]

I looked at that one originally as it has the specs for it. Only thing I didn't like about buying all these adapters is that $ adds up and that you have 3 different adapters but it'll certainly work for those who don't want to build their own. Oh and the Modifry ECT works with S2000 sensor.

Tested the prototype tacho on the engine and my above circuit works. I tried bypassing the controller and it didn't work as the IGF signal has a very short duty cycle Thus I had to capture the falling edge and regenerate the signal. Probably could tap into IGT but i'd rather not.