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Survey - What's Your Prop Temperature? Cold, Warm or Hot? — Parallax Forums

Survey - What's Your Prop Temperature? Cold, Warm or Hot?

HumanoidoHumanoido Posts: 5,770
edited 2009-12-03 02:22 in Propeller 1
This is a survey to learn about the Prop chip's running temperature.
You can reply here. The choice is cold, warm or hot.
Please mention details. Ok, I will begin.

Cold (68 deg.) 40-pin dip chip
Using internal RC Clock, 12MHz
3-Volt battery, LED drawing 9 mA
1-Cog SPIN program to loop LED port on/off @ 1 Hz
Room temperature (68 deg.)
No fan, breadboard open to the air

humanoido

Post Edited (humanoido) : 12/3/2009 12:28:46 AM GMT

Comments

  • BradCBradC Posts: 2,601
    edited 2009-12-03 00:10
    humanoido said...

    Please mention the circuit used. Ok, I will begin.

    Cold.

    Temperature is relative. For anything meaningful you need hard data. Chip temperature, board temperature, ambient temperature, any air movement?

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    If you always do what you always did, you always get what you always got.
  • LeonLeon Posts: 7,620
    edited 2009-12-03 00:15
    It also depends on the number of cogs that are active, the package type, and the number of outputs and what loads they are driving. The length of a piece of string comes to mind.

    I did have one get quite hot a few days ago when I put over 9V across it.

    Leon

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  • HumanoidoHumanoido Posts: 5,770
    edited 2009-12-03 00:16
    BradC said...
    ...Chip temperature, board temperature, ambient temperature, any air movement?
    Room temperature, breadboard open to the air, no fan. Will add edit.
  • BradCBradC Posts: 2,601
    edited 2009-12-03 00:46
    humanoido said...
    Room temperature, breadboard open to the air, no fan. Will add edit.

    How did you obtain your temperature measurements?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    If you always do what you always did, you always get what you always got.
  • localrogerlocalroger Posts: 3,452
    edited 2009-12-03 01:14
    I find that at 80 MHz, running TV_text, 2 instances of fullduplexserial at 9600 baud (I think they spend a lot of time in waitcnt), the IIC driver for EEPROM access, and PropTCP (which has two full bore cogs running all the time) the chip draws about 100 mA and the DIP40 gets just barely noticeably warmer than ambient. The ethernet chip is also drawing about 100 mA and, being in a smaller package, gets a bit warmer.

    I have had demoboard chips (being very teeny in their SMT packages) get detectably warm just running TV_text and some serial cogs, but I've never felt a P8X32A get "hot" no matter what I did to it. Maximum power usage with all cogs going should be around 200 mA, less than 1 watt at 3v3. Having all I/O's maxxed doesn't raise this much because the max total current is only over the voltage drop of the output transistors, just a fraction of a volt. This is a level considered safe for plastic transistors like the 2N2222, which are about the same physical size as the SMT props.

    Of course, if you're overclocking or drawing 2 amps total from all the I/O's, all bets are off. But I'd say if your prop isn't comfortable to touch, you're probably doing something to it you shouldn't be doing.
  • Dr_AculaDr_Acula Posts: 5,484
    edited 2009-12-03 01:35
    Warm if running VGA (about body temperature). Cold if no VGA. DIP40 chip. (Tested with ambient 22C/72F. All bets are off when ambient is 44C/111F as we had recently. Then the koalas start dropping out of the tree outside our front door.)

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  • TubularTubular Posts: 4,717
    edited 2009-12-03 01:44
    Dr_Acula said...
    44C/111F as we had recently. Then the koalas start dropping out of the tree outside our front door.)

    Couldn't you fix that with a "low drop out regulator"? wink.gif
  • HumanoidoHumanoido Posts: 5,770
    edited 2009-12-03 02:22
    BradC said...
    How did you obtain your temperature measurements?
    I used a very simple and inexpensive comparison. A room thermometer was placed on the table next to the Prop board. After it settled, I then compared the temperature of the surroundings (table, board, components, etc.) to the chip, which appeared exactly equal.

    While this is part qualitative approach to temperature determination, it works quite well and has an differential detection accuracy of within 10 degrees. The margin of error of 10 degrees is certainly small enough to determine the approximate comparison between cold, even, warm and hot.

    If I want a more exact temperature determination in the future, when the component is significantly warmer or colder than its surroundings, I will use a Penguin Robot with an infrared heat thermometer (Parallax MLX90614 Infrared Thermometer Module with 10° FOV) directionally focused on the chip and simply read out the temperature on the computer screen.

    www.parallax.com/Store/Robots/WalkingRobots/tabid/129/CategoryID/21/List/0/SortField/0/Level/a/ProductID/438/Default.aspx

    www.parallax.com/Store/Sensors/TemperatureHumidity/tabid/174/CategoryID/49/List/0/Level/a/ProductID/539/Default.aspx?SortField=ProductName%2cProductName

    humanoido
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