Thread: Arduino Modular Engine Sensors Unit (~$50)

Originally Posted by stirlsilver

Just some quick input from me. From the times when I was playing around with microprocessors to monitor sensors and control devices. I found one of the single biggest issues with this sort of system on a car is filtering out noise, especially on a petrol engine.

If you are planning on feeding a voltage signal to the analogue inputs, I think you will need to consider having some low pass filters in your circuitry to filter out ignition noise out of your signals. Or convert the voltage signal to a 4 to 20mA current signal at the sensor, run the signal cable to the location where you have the Arduino (inside a shielded box) and covert the signal back to a voltage. A current signal is much more immune to noise when compared to voltage so shielding and filtering isn't quite as important.

Also, another area which I tended to have issues with was getting a nice clean power supply to the microprocessor. The power supply on a car (again especially petrols) is very noisy and can cause microprocessors to behave strangely due to noise getting through the voltage regulators to the chip. So again, you may need to consider a nice filtered supply in your design to get the chip stable.

I really like the idea of the project, and I may implement something using an arduino on my project car also.

On a side note, for anyone that has an OBD enabled vehicle, you can consider simply hooking in a OBD to bluetooth adaptor (or OBD to USB ) and use an Iphone or Android device to run an app called Torque. I use it all the time in my car to monitor coolant temperature (along with other sensors) and also set some alarm trigger points on the sensors also should something go wrong.

We have had the same issues with the sparkfun datalogger based systems we have developed. All our sensors are pressure and temp, and not relying on or grounded to any of the vehicle or vehicle electrics. We thought that using 12V-5V and 24V-5V power supplies would remove the noise, but it was not the case. The noise meant that the datalogger would log 2x or 3x the max range of the sensor connected to that port - so completely useless - not just a bit of noise in the data. For our applications it was easiest just to switch to running the whole system from batteries instead...

Took me a while to get started, but I've been playing around over the last week. Started with the example "paint" app and changed a few things here and there to better understand the code.



Then I started drafting up some screen ideas. Initial thoughts are each sensor value can be "Green" "Amber" or "Red" status which would be the background for that cell. Starting with just 4 sensors, but can split the screen into however many needed. Haven't figured out what the menu options will be available yet but I'm thinking the black dot in the middle could be the menu button.

The colours are a bit "fluro" for my liking - I'm sure I can make them nicer - but it's a starting point.



Now I need a sensor or something to connect so I can start reading/displaying real data.

Originally Posted by haydent

I bought a couple off head bolt k thermo couplers off Ebay that I don't need. I can send you one of you Pm me your address. Bear in mind you'll need a op amp circuit for these.

Originally Posted by haydent

im now waiting on a particular opamp type to use in the circuit

Did you find an op amp? Any links for these sensors/op amps you can send me?

Re: the head bolt coupler, do you know the bolt size needed?

I'm thinking something like this for head temp:

Thermocouple Sensors K type 18mm id Washer for Cylinder Head Temperature (CHT) | eBay

Just need to find the bolt size first...

Originally Posted by Judo

I'm thinking something like this for head temp:

Thermocouple Sensors K type 18mm id Washer for Cylinder Head Temperature (CHT) | eBay

Just need to find the bolt size first...

thats the ones i have, you can have one if you want, just pm me your address.

im still awaiting on the op amp, it seems to have been lost in post, so i have to reorder.

as for thermocouplers' you will have to build a little circuit to go with them to amplifiy the signal.

Originally Posted by isuzurover

However we do have applications where we need to control 240V devices... Does anyone have experience with any 240V relays and relay drivers?

Yeah, I've used various types over the years in different applications - CEBus, etc. A good source for them in Australia is security alarm system wholesalers - they are used to drive home lighting, security lighting etc when the alarm is tripped. Alarm systems run on 12V, so the relays are specifically designed for just the application you describe.

Originally Posted by Dougal

Can you make a stepper motor driver version so we can replace crappy factory instruments with ones that work? Thinking rev counter, fuel and temp.

I can do the hardware side, just need stuff to drive it.

I worked on something like this quite a few years back, using an 8051 microcontroller, but the premise is much the same. It's actually reasonably straightforward - either read the resistance of the analogue senders or pop in digital senders, and start generating a square wave for each gauge. It has other benefits too, such as being able to smooth out signals from the fuel sender, matching different gauges to the stock fuel sender, so on and so forth.

In my opinion, a combination of stepper motor driven gauges and an LCD display would be the ideal. Gauges for normal usage, plus the LCD displaying additional information, logging data, flashing bright red when tolerances are exceeded etc. I'd imagine that you'd have to integrate a multiplexer into the design to accommodate all of the digital inputs and outputs, but again that's very straightforward.

I need to get me one of these kits, ASAP

Ahhh very cool,

I'll have to upload the code to the unit I've built anyone had any luck with the obd2 integration?

Alex

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Originally Posted by mike_ie

I worked on something like this quite a few years back, using an 8051 microcontroller, but the premise is much the same. It's actually reasonably straightforward - either read the resistance of the analogue senders or pop in digital senders, and start generating a square wave for each gauge. It has other benefits too, such as being able to smooth out signals from the fuel sender, matching different gauges to the stock fuel sender, so on and so forth.

In my opinion, a combination of stepper motor driven gauges and an LCD display would be the ideal. Gauges for normal usage, plus the LCD displaying additional information, logging data, flashing bright red when tolerances are exceeded etc. I'd imagine that you'd have to integrate a multiplexer into the design to accommodate all of the digital inputs and outputs, but again that's very straightforward.

I need to get me one of these kits, ASAP

Thanks Mike, I might call on you for ideas later on. Basically I want to drive needles to keep the factory look. No other reason.