V_88:
Hi Sembazuru,I want to thank you for guiding me through the XBee code. However, this is not over. My project needs me to measure RPM and also the exhaust gas flow rate.
I am not finding any sensors which can be interfaced with Arduino, and which can withstand the temperatures of the exhaust gas for the flow rate measurement.
For the RPM, I ordered the Hall effect sensor A3144.
Here is the link from Ebay :
http://www.ebay.com/itm/like/251114199126?lpid=82I guess I could use the digital pins on the board for this one. But do you have any ideas for the flow measurement?
V_88:
Hey Sembazuru,I wanted to ask about this. I found a MAF sensor, and I am thinking this is more suited to my application than the MLX90614.
If I understand it correctly it measures the temperature and the flow rate right?
A MAF sensor might be good for the exhaust but as I've said before, I don't have the experience to be able to tell you exactly what sensor you need. I'd try contacting a sensor vendor (like my suggestion for Omega), or try contacting the manufacturer of a sensor you think might work and have them verify that it would work.
You need to explain to them exactly what you need to measure, and that you will be reading the output of the sensor with a 5V microcontroller with either digital (I2C, SPI, or pulses) or 10bit ADC (I don't know of "Arduino" would mean anything to them). If this is for a school project, mention that and you may get an educational discount.
Remember, for hall effect sensors you need to have a magnet mounted to the moving part that passes close enough to the sensor to trigger it. I understand the theory of hall effect sensors, but I've never set one up. Unfortunately, I'm not sure if you can rely on any technical support from an e-bay retailer. It can't hurt to ask, but I wouldn't expect any. (It's not like DigiKey, Newark, SparkFun, AdaFruit, etc. that have engineers on staff to assist with customer technical support.)
That hall effect sensor that you mentioned, I haven't dug up a manufacturer's datasheet on it yet (look up the part number on Octopart, and you should find one), but if the e-bay description is true it needs 24V to power it. I would expect the output signal to potentially be greater than the 5V allowed by the Arduino, and 24V is more than is normally available on cars so you would have provide a power supply on the car for it instead of using the car's existing power supply (the battery) passed through a regulator to lock at a voltage less than 12V to provide a stable voltage instead of the 12-14V that the battery/alternator puts out.
I've been thinking... Wheel RPM? Are you sure it isn't engine RPM? Because of the transmission those two things are completely different...