Hi, I was just wondering a few things about the arduino uno and its capabilities.
I would like to use my arduino to monitor and control my sensors and other things in my car. Is the uno capable of running multiple sensors like voltage, temperature, etc. can it also at the same time be used with a BT shield to control switches? Also can I have it output all this info to an lcd? I have the ultimate MC pack. Could I use the lcd in it and be able to switch between all the sensors to print the results on the lcd? Thx in advance for any help
Temp sensors, Voltage from batt and voltage from alternator, Vehicle speed sensor, would also like to be able to read oil temp sensor, intake air temp sensor... pretty much would like to be able to read real values from all my sensors.
Another thing Id like to do is build a software fuse bank, where Id be able to set hard limits that would, if overloaded disable the circuit and light a led or send a push notification to my phone or lcd. Can this be done with arduino? I dont know what other hardware Id need for this.
Be sure to put automotive surge suppressors between the auto electrical system and any electronic devices. Voltages range from about 4.5 V (during starting) to 16 V, with occasional spikes of hundreds of volts.
jremington:
4.5 V (during starting) to 16 V, with occasional spikes of hundreds of volts.
Spike of "hundreds" of volts... maybe if...
There's no regulator on the alternator.
There's no battery to absorb the voltage spikes.
Quite frankly i think it's a myth, if what you say is true Car Radios, lights etc would all blow but clearly this is not true yet you expect me to believe my car radio has supression diodes to prevent 200+ volts dc (it is rectified after all)...
Its no myth that you can get massive spikes on the power supplies. Most of the noise comes from the ignition LT circuit. Electronics designed for use in a car have to be designed to deal with that noise. There can also be a lot of radiated electrical noise picked up on long cable runs. Digital signals typically need shielded cables to protect against that.
Anyone who thinks this is a myth is invited to read this article from the engineers at Pololu, who demonstrate circuit-destroying 40 volt spikes from a short piece of wire being powered up. Pololu - Understanding Destructive LC Voltage Spikes
In automobile electrical systems the problem is much worse. Here is a professional summary from Tyco: http://www.digikey.com/Web Export/Supplier Content/Tyco_8004/PDF/Tyco_AutoNetwork.pdf
BioCyd3:
Hi, I was just wondering a few things about the arduino uno and its capabilities.
I would like to use my arduino to monitor and control my sensors and other things in my car. Is the uno capable of running multiple sensors like voltage, temperature, etc. can it also at the same time be used with a BT shield to control switches? Also can I have it output all this info to an lcd? I have the ultimate MC pack. Could I use the lcd in it and be able to switch between all the sensors to print the results on the lcd? Thx in advance for any help
Jeremy
any sensor with simple voltage or resistance changes can be monitored, but you'd have to plot a voltage or res table for yourself and make reference to it in order to output any of the data on whatever way you choose to display the information.
example: o2 sensors on older non-lambda/uego equipped cars are narrowband (as opposed to wideband on new cars like VW) have a range of 0-1v to determine lean-stoich-rich oxygen/fuel ratio. You would need to know what the O2 content is at 0v and at 1v and perhaps 0.5v and plot the values in between. (This is inaccurate though, and thus wideband is what you should be using if this is what you intend to control).
Same goes for resistance based cylinder head temp, coolant temp, or intake air temp sensors. If you know the peak value and the min value, and some of the values in between that you can get by correlating current resistance/voltage and current gauge readout using factory gauges, then you can plot your own table and input those into arduino for output on another display.
is this what you're trying to do?
if you want to get even more complex, you can find out how your crank or cam angle sensor works and even get an ignition timing read out.
you can also do interesting things like increase or decrease voltage going to a mass air flow sensor in order to increase or decrease fuel compensation. but that might only work on older non-obd1/2 cars.
So I haven't had major problems with spikes (that I know of) so far. But this worries me. Should I add a Zener and maybe a pptc to my circuit to protect from these spikes?
jremington:
Anyone who thinks this is a myth is invited to read this article from the engineers at Pololu, who demonstrate circuit-destroying 40 volt spikes from a short piece of wire being powered up. Pololu - Understanding Destructive LC Voltage Spikes
In automobile electrical systems the problem is much worse. Here is a professional summary from Tyco: http://www.digikey.com/Web Export/Supplier Content/Tyco_8004/PDF/Tyco_AutoNetwork.pdf
Link 1 does not have a regulator nor a 12v battery.
It seems like a 3 cent Zener would handle the hundred volt spikes. Their "Polyzen" device looks like just a fuse and a Zener. Pretty expensive at that. I expect my device to already be on the other side of a fuse, and the 7805 voltage regulator should handle minor spikes. But I might add a 3 cent 20 volt Zener to handle any higher spikes, and a normal diode to handle those negative spikes.
Big spikes on automotive power lines are fairly rare events, but manufacturers like Tyco and Littlefuse produce surge protection devices that are intended to protect automotive electronics for the entire life of the vehicle. Thus, they are designed for worst-case scenarios and are accordingly expensive.
Incidentally, one failure mode of the Zener is a short, so there should be a suitable fuse in line with the power input. Pretty cheap insurance!
