Building A Digital Instrument Panel

[mishu 0]

Hello everyone,

 

it's been a while since I've posted here, the main reason being I haven't had much time to work on the car.

But now I'm back, hopefully to start this project. I'm trying to build a digital dash and display all the collected information on a LCD.

I have a 1.1 TU1 1990 205 GR, and was wondering which sensors I could read information from? I read the instrument panel wiring article on the main site, which helped a lot in figuring most of the wires out. Then I took the dashboard out and was able to figure most of the other stuff out as well.

My question is:

 

Does anyone know whether the TU1 engines have water temp. signals (and any others) AND what their values are?

 

Except for the on/off signals (beam/light/indicator/battery/etc.), which I've been able to figure out by looking at which bulbs the circuit leads to, I hope someone can help with the values of the gauges. Being a GR model, it only has a fuel gauge (and a clock), but I suspect there might be some other signals which are not displayed (although the wiring arrives at the dash). The main thing would be the water temperature..

 

I've figured out the resistance values on the fuel sensor, so that's sorted.

 

I've attached the wiring I've figured out so far below, maybe someone knows what the other wires are for.

 

Thanks!

 

mishu

[mishu 0]

Does someone at least know the water temperature voltages that the sender, um, sends? I'd like to know at least what is too hot, too cold and normal... thanks

[cybernck 402 1 Cars]

water temp sensor (as well as other sensors) are actually variable resistors

(the resistance varies with temperature obviously) and this coupled with the

voltage present on the gauge make the gauge give out temp readings .

 

 

for instance, on a 205 GTI, water temp gauge sensor behaves like this:

• 0°C = 8.60-8.75 kΩ
  
  
• 24°C = 2.79-2.84 kΩ
  
  
• 100°C = 155-160 Ω
  
  

hope this helps .

[mishu 0]

Of course it helps, I'll be testing my results to see whether they match those. Thanks!

I also managed to figure out the resistor values for the fuel gauge. If anyone needs those values, just let me know and I'll post them.

[Scottieb 0]

I'd be interested Mishu, I've just started designing my own digital 'pod' for my track/hillclimb car.

 

Scott

[mishu 0]

On my 1.1 GR model's dash, I got the following values (when supplying the display gauge with the following resistance):

 

220Ω ... 0

124Ω ... 1/4

68Ω ... 1/2

41Ω ... 3/4

10Ω ... 1

 

What are you planning to use for reading the speedo cable RPM? I haven't finished my design yet, but I'm thinking of using a magnet and a Hall sensor (the idea came from an older post on this forum, so I can't take credit for it).

[cybernck 402 1 Cars]

i would get and use an electric speed sender from a later 306 as it seems much easier and straightforward!

[Sandy 191]

106 1.3 Rallyes (and some others) have combined electronic and cable speed sensors.

[VisaGTi16v 1]

The Visa GTi had a cable drive up to an electronic sender that sat by the bulkhead in the engine bay so it only transmitted the last foot. All other Visa's were cable all the way????!

[jackherer 543]

The Visa GTi had a cable drive up to an electronic sender that sat by the bulkhead in the engine bay so it only transmitted the last foot. All other Visa's were cable all the way????!

 

Someone at citroen did too much acid in the seventies or something. That reminds me of my old CX, it had a slider for the heater by the handbrake, if you moved it you'd hear an electric motor turning the actual knob inside the dashboard