The plan:
Multichannel datalogger
Necessary channels:
GPS
pulse counter
various resistor-type sensors (temperature, mostly)
Desired channels:
accelerometer
Talk over RS232 from other controllers
Write out all data to an SD card with not necessarily symmetric updates (need most data from GPS and accelerometer, all others can update less often.)
Super-bonus and probably the most difficult to achieve (for me anyway): Output to LCD or similar display some or all info
I do not know enough to do this myself and will need help. So here goes the rambling questions.
I could buy the Arduino and add the GPS shield and work from there, but I don't know how many channels will be left or if I could even get any remaining inputs to log to the SD card.
I could get the Boarduino and develop from there. Can you chain them together and have them report to a master controller to do the datalogging? It looks like I could chain Arduino shields together if I wanted, but what about the processors themselves?
What is the max sampling rate of the brain?
I think I can deal with any hardware manipulation pretty easily as that was my strong point in all my EE classes, but code is my weak point. I usually teamed up with a coder and a writer for the labs. I handled hardware, the coder coded, and the writer did our writeups. That would be why I didn't go for the EE minor. Anyhow what should I buy if I want to develop? I would think that if I can chain them together the boarduino would be the way to go. It is cheaper and easier to link because of the ease of use with a breadboard. If it were possible to link them, it would be easy to make a board with a master controller ready for add on modules to give me all the channels I wanted.
So, who wants to tell me I am crazy?
Arduino or BoArduino?
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- mooseheadm5
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- mooseheadm5
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OK, so this is what I gather from my initial research:
uart should let me talk over RS232 to other microprocessors with additional hardware. I may or may not care what they say, only that I can copy the received data to an SD card. In addition, I may be able to use this to run a display. Might I be able to interface with a CAN-bus (if I could find out what data I was looking for and how to extract it)?
I2C or TWI will let me have a master 'duino and various slave modules which can increase my available input channels. In addition, I may be able to run a display from this. I can have multiple masters here if necessary (but if it is, I don't yet know why.)
SPI is another type of bus that can only run one master but may have more simplified wiring and use less power.
I think that is pretty much what I understood. I have thought of a couple other things that I may need and will have to figure out how to build, but if they can just be chained onto the bus, there should be no problem adding any inputs I need. I need to figure out how to build an infrared pyrometer. I am sure the output of the device is simple and can be easily processed. Not sure if it would be cheaper just to buy one and figure out how to reverse engineer it or maybe just how to read the output of the circuit.
Next, I need to figure out how to build a yaw-rate sensor. That will probably require 2 accelerometers positioned a specific distance apart. I am not that interested in this, it is just a little icing on the cake.
uart should let me talk over RS232 to other microprocessors with additional hardware. I may or may not care what they say, only that I can copy the received data to an SD card. In addition, I may be able to use this to run a display. Might I be able to interface with a CAN-bus (if I could find out what data I was looking for and how to extract it)?
I2C or TWI will let me have a master 'duino and various slave modules which can increase my available input channels. In addition, I may be able to run a display from this. I can have multiple masters here if necessary (but if it is, I don't yet know why.)
SPI is another type of bus that can only run one master but may have more simplified wiring and use less power.
I think that is pretty much what I understood. I have thought of a couple other things that I may need and will have to figure out how to build, but if they can just be chained onto the bus, there should be no problem adding any inputs I need. I need to figure out how to build an infrared pyrometer. I am sure the output of the device is simple and can be easily processed. Not sure if it would be cheaper just to buy one and figure out how to reverse engineer it or maybe just how to read the output of the circuit.
Next, I need to figure out how to build a yaw-rate sensor. That will probably require 2 accelerometers positioned a specific distance apart. I am not that interested in this, it is just a little icing on the cake.
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so you want to know if your car is on fire or tipping over.
atmel makes some avrs specifically for living on the can bus. of course, you don't get the arduino environment, but if you just want to copy data to another processor how hard can it be... famous last words. although i love my arduinos, most of my code looks like plain old c, because i think plain old c is easier than the arduino api and certainly will run a tad zippier.
what kind of display are you after. a plain old alphanumeric lcd is easy to connect to an arduino. 3 control lines. 4 data lines. maybe another line for the backlight. 10k pot for contrast. it can also be done with 3 lines a shift register and a diode.
sounds like comms and a display will be the easy part. best save your fretting for talking to sensors.
atmel makes some avrs specifically for living on the can bus. of course, you don't get the arduino environment, but if you just want to copy data to another processor how hard can it be... famous last words. although i love my arduinos, most of my code looks like plain old c, because i think plain old c is easier than the arduino api and certainly will run a tad zippier.
what kind of display are you after. a plain old alphanumeric lcd is easy to connect to an arduino. 3 control lines. 4 data lines. maybe another line for the backlight. 10k pot for contrast. it can also be done with 3 lines a shift register and a diode.
sounds like comms and a display will be the easy part. best save your fretting for talking to sensors.
- mooseheadm5
- Posts: 79
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Close. Want to know if the tires are on fire or if the car is under or oversteering at a particular spot on a track. I think a simple display will be fine. Don't like the super large displays and prefer to stick with the stock gauges. So if the GPS reports often enough, I should know longitudinal acceleration. With lateral sensors I can determine lateral Gs and yaw rate. With IR pyrometers I will know if hte tires are about to explode. Talking over RS232 or CAN will feed me engine control data without tapping into individual sensors. Need the pulse counter for tach function. I have a standalone EFI (Megasquirt) that can feed out over RS232, but I may not always use that car. My brother wants this data for his car and he has CAN. Alternately, I just wire all my own feeds to the stock sensors. Looks like there are plenty of inputs on the Arduino. I think a pair would probably cover all my functions, if not just a single unit. Don't think I'll need to fret over any of the simple analog temp readings. Just found IR pyrometer modules that output PWM or SMBus. Sound feasable?
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- mooseheadm5
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This is good news. Unfortuantely, if you were walking around the track that would mean you stuffed your car, so hopefully it won't come to that. Anyhow, so I can have 4 of these IR modules very easily wired in checking tire temps, so no problems there. I may start by doing the boarduino with the GPS (I know it will require wiring because the GPS is an Arduino shield) and try the IR pyrometer and maybe drive a temp display and work from there. So now, do I get the USB or the DC? USB would be convenient for in-car programming if necessary, but DC would have the built in power circuit to run from the car without be having to build a regulator (but I should anyway.)
Please be positive and constructive with your questions and comments.