Hi,

I am trying to use and Arduino Mega 2560 to emulate various signals to an Instrument Cluster taken from a 2000 Nissan Maxima. The microcontroller will interact with a driving simulator.

So far on the Electrical/Electronic side this is what I have:

What is in bold is completed

• Power Supply
  
  Delta PMT-D1V100W1AA
  12V - 7A
  5V - 3A​
  ​
• Various 12V DC signals to control the panel's lights (indicators, warnings... 22 in total).
  
  Idea: Connect transistors connected to shift registers connected to the MC.
  Possible transistor: 8x ???
  Possible shift register: 4x ??? (Likely 8bit)
  One light per transistor. Each light is 1.4W incandescent.
  I mesured 11.94V @ 94 mA per light bulb. 1 bulb = 1 circuit (all in parallel)
  I need to find a combination that will allow me to use the MC to drive the SR that will trigger the Transistors. Providing power is not an issue but I am trying to make sure to saturate the transistors.​
• Speed Signal
  
  Need to create a 0.5V 7μA square signal. (0-400 Hz variable)
  Idea: Use the BOB-11420 from sparkfun.​
• RPM Signal
  
  Need to create a 5V 47mA square signal. (0-450 Hz variable)
  Idea: Use the BOB-11420 from sparkfun.
  Need to find a way to amplify the signal. (Op-amps probably?)​
• Fuel/Temp gauges.
  
  They are variable ground based (0-250 Ω)
  I wanted to use a digipot to control.
  Problem is that they are designed for much more resistance.
  I will probably end up using a servo to control a potentiometer mechanically.​

I only have little experience with electronics. As a mechanical engineer student, we had a class of electronics but it only covered op-amps briefly.
I am also attaching a plan/"schematic" of the solution. A better diagram will be uploaded soon.

Any suggestion is greatly appreciated.

 

How many panel lights are there? the Mega 2560 has a load of output pins so shift registers may not be necessary.

The Arduino is more than capable of generating square waves, just toggle a pin on and off and use a potential divider (2 resistors) and/or a transistor to get the voltage you need, so I don't think you need the BOB-11420.

As for fuel/temp gauges, what the variable resistor is doing is providing variable voltage/current to the meter so you could use a digital to analog converter (these are available as I2C devices so only need 2 pins); or you can get clever with PWM and a filter to generate a variable output voltage.

 

In total:

• 22 Lights
• 2 Square waves
• 2 Variable voltage/current
• 2 Inputs to determine if key is in on and/or start position

And thanks for the quick reply.

 

IIRC an Arduino Mega 2560 has about 54 digital I/O so no need for the shift registers and spare for the square waves which could either be implemented in software or via the on-chip timers.

I don't have much experience with Digital to Analog so may be someone else will be able to offer advice on appropriate chips

 

Can't you use the Arduino AnalogWrite() to create the variable voltage/current outputs?

 

Depends on the meter characteristics. AnalogWrite generates a PWM ouput from 0 to 100% duty cycle, so it is always 5V peak-peak but if averaged with a filter will generate an analog voltage.