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DELETED (Inactive)
3 Posts |
 Posted - Oct 15 2003 : 10:58:27 AM
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I have been trying to calculate a circuit for measuring tyre temperature of tyres on a road car, with the intention of having the values displayed by 7 seg display (2 displays for each of the 4 tyres, max temp of 99deg C)
I was gonna use thermistors to sense the temperature, can any of you guys think of a better idea?
If not, wud u have any advice for me on how to make this circuit work well?
matt
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BEatonNo1
Nobel Prize Winner
USA
1133 Posts |
Posted - Oct 15 2003 : 8:08:53 PM
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well if you plan to use a thermistor, then you would need to figure how to get juce to the tire. a electrically isolated ring with a brush.
another option would be to use an infared or laser temperature sensor.
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Kale
Nobel Prize Winner
Canada
795 Posts |
Posted - Oct 15 2003 : 10:37:37 PM
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Yeah, I could see that using a temperature measurement circuit in a spinning tire would be difficult: How do you connect to it?
Brushes and the like induce a bit of signal noise, but an RC filter should be able to handle it: you're really only interested in the DC component of the signal.
Get a good thermistor linearization circuit of the internet.
Use a microcontroller with and A/D converter built in to read the voltages from the circuit and convert the readings into something to put out onto the 7-segment displays.
www.microchip.com
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Oct 16 2003 : 09:12:14 AM
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You can buy this product commercially. It just uses RF and a small battery. No idea where to find it, but Google should turn up the answer. The real challenge is making it light enough not to effect the balance of the tire...
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n/a
DELETED (Inactive)
3 Posts |
Posted - Oct 16 2003 : 11:34:50 AM
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I have already designed a spring loaded brush mechanism, its gotta be spring loaded cos hte tyre grows a bit when its turning fast. The thermistors i am intending to use are linear as far as i know. Im kinda new to the electronics tho. I was thinking about hte infra red, but the cheapest sensors are like $300 each!
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BEatonNo1
Nobel Prize Winner
USA
1133 Posts |
Posted - Oct 16 2003 : 12:11:49 PM
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well if you plan to use a microcontroller it would be an option to make the ir temperature sensor yourself
There are ICs that convert the voltage from the thermistor to a digital number, that could be fed to a bcd to decimal converter driving the display.
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Oct 17 2003 : 11:32:56 AM
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I would think the brush mechanism will not last long. Ever raced slot-cars? If so, then you know how often the brushes need to be cleaned and replaced. RF is the way to go.
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n/a
DELETED (Inactive)
3 Posts |
Posted - Nov 10 2003 : 4:45:44 PM
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so you guys reckon its best to make a seperate sensor for each tyre? with a "ship to shore" style transmitter?
If so, could any of you guys be kind enough to steer me in the right direction with it? I know very little about electronics, but really want to learn.
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BEatonNo1
Nobel Prize Winner
USA
1133 Posts |
Posted - Nov 10 2003 : 6:19:08 PM
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I think I would use a thermocoupler so that the circutry could be put as close to the center of the wheel as possible then make the circutry so that you had a tone whose pitch varies dependant on the temp of the tire. then you would feed that into the transmitter. the hard part is going to be decoding the information into the temperature....one way would be to use a frequency to voltage IC and feed the tone from the recever into this then calculate the temp from that.
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Nov 12 2003 : 2:34:00 PM
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This system is available commercially from tirerack.com
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n/a
DELETED (Inactive)
9 Posts |
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tyre temperature sensor
