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Oil temperature — Parallax Forums

Oil temperature

geologeekgeologeek Posts: 8
edited 2008-04-02 23:09 in BASIC Stamp
Hi there i hope some of you kind people can point me in the right direction!

I have a stamp unit and at the moment it is just gathering dust!

Therfore i was hoping to put the unit to good use and create a temperature probe to detect the temp of the oil in my VW beetle and have it light a light when it reached a temp of 120 degree celcius or there about!

Anyone know if this is possible and could they point me in a direction of a high temperature probe/thermister capable of temps upto about a max of 200 degrees?


yours,

levi

Comments

  • FranklinFranklin Posts: 4,747
    edited 2008-03-31 19:45
    Most sensors for autos (oil temp) use variable resistors. You should be able to interface with that. Get an old one from a junkyard and do some testing.

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    - Stephen
  • geologeekgeologeek Posts: 8
    edited 2008-04-01 17:08
    thanks franklin but i was hoping more to create a dipstick probe in place of the original dipstick.

    maybe placing a thermistor or other into a hollow tube and sealing the ends. but am unsure if the oil will be too hot for the thermistor?

    any sugestions?

    Levi
  • geologeekgeologeek Posts: 8
    edited 2008-04-01 19:44
    Could someone please have a look at this and say if its feasible?

    http://www.farnell.com/datasheets/77163.pdf

    Can the stamp deal with such high temps? (not that it will get hot - but deal with the calculations?)



    thanks in advance,

    levi
  • ercoerco Posts: 20,260
    edited 2008-04-01 19:57
    Levi: Oil temp in my '67 Corvair 140 gets well above 200 on a hot day, maybe pushing 230. Whatever you make should be tested to higher temps than you expect. IMHO you're looking for trouble sticking a probe down the dipstick tube for a couple reasons. First, you run the risk of breaking something off (wire, thermistor, tube, epoxy, etc) that will fall into your oilpan and get picked up and mashed through your oil pump rotors. Second, you'll need probe wires long enough to take your dipstick in & out to check your oil. These will inevitably get brittle as they get flexed and thermally cycled mercilessly in your engine compartment (if not sucked into the fanbelt!). Stephen makes a good point to find a standard screw-in-the block temperature gauge. Any Pep Boys/Auto Zone type store will have a variety to pick from, then you'll have some testing and calibration to do. Alternatively, you can buy a water temp gauge kit complete with sender; oil temp measures just like oil temp.

    BTW, I bought two iron/constantan thermocouples a while ago to install as cylinder head temp gauges, but haven't put in yet. One day, before I die... Thermocouples have their own peculiarities and must be installed properly to give useable results. And they are not accurate enough for oil temp measurement.

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    ·"If you build it, they will come."
  • FranklinFranklin Posts: 4,747
    edited 2008-04-02 01:52
    www.parallax.com/Store/Microcontrollers/BASICStampModules/tabid/134/txtSearch/thermocouple/List/1/ProductID/96/Default.aspx?SortField=ProductName%2cProductName

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    - Stephen
  • geologeekgeologeek Posts: 8
    edited 2008-04-02 16:53
    Thanks for the sugestions!

    Franklin you have hit the nail on the head! i will look to see if they deliver to the UK or have a distributer over here!

    erco - sorry i forgot you guys deal in farenheit - i was talking celsius - and if the oilt got to the 200 degree mark i am sure my engine would be more than fried! Im sure 120 would be the top end of the needed range which would be about the 240 farenheit you suggested!

    The reason i wanted to use the stamp is i want it to light different colour at different temps (dont like guages - want minamalistic) and i also want to try and control a few other things should there be program space left!

    thanks again!

    levi.
  • Shawn LoweShawn Lowe Posts: 635
    edited 2008-04-02 17:31
    Levi-
    That sounds cool! An RGB led that would be blue when the engine is cold to red if your overheating!

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    Shawn Lowe


    Maybe I should have waited to do that......
  • geologeekgeologeek Posts: 8
    edited 2008-04-02 21:01
    thats the idea shawn! just got to figure out how to do it!

    cant remember exactly what stamp unit i have - think a BS2 (got a whats a microcontroler kit with a servo and other bits)

    theres got to be a reasonably simple code to figure this out!
  • ercoerco Posts: 20,260
    edited 2008-04-02 23:09
    Levi: Of course, if you just want to light LEDs up, at various temps, you don't need a Stamp. Use an Autozone resistance temp sender in a voltage divider with a LM339 quad comparator (costs ~ $1) to give you 4 LED outputs that you can calibrate once and for all. Or get two 339s and drive 8 LEDs for a bargraph display. Cheers!

    http://www.elecfree.com/electronic/4-level-voltage-detector-by-lm339

    http://academics.vmi.edu/ee_js/Teaching/ee223/materials/Lab%204%20%20Comparators.pdf

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    ·"If you build it, they will come."
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