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Power for the propeller demo board — Parallax Forums

Power for the propeller demo board

chris joneschris jones Posts: 391
edited 2009-11-11 08:18 in Propeller 1
Hello

i wanted to know if there is any way i can power the propeller demo board with a battery pack or if parallax sold a battery pack for this purpose
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Comments

  • BradCBradC Posts: 2,601
    edited 2009-10-27 15:21
    chris jones said...
    Hello


    i wanted to know if there is any way i can power the propeller demo board with a battery pack or if parallax sold a battery pack for this purpose

    Sure. 4AA batteries in a 6V pack will do it nicely.

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    lt's not particularly silly, is it?
  • Mike GreenMike Green Posts: 23,101
    edited 2009-10-27 15:26
    RadioShack sells a nice enclosed 4 x AA battery holder with wire leads and an on-off switch. They also sell the plug needed (2.1mm ID / 5.5mm OD). Don't try to run the Demo Board with 4 NiMH rechargable cells. They'll only produce 4.8V at most. You need 5.5V or more for proper operation.
  • chris joneschris jones Posts: 391
    edited 2009-10-27 15:28
    ok do you think i can use a 9v lith ion single cell battery?
  • Oldbitcollector (Jeff)Oldbitcollector (Jeff) Posts: 8,091
    edited 2009-10-27 15:36
    Depending on what kind of I/O devices you will use. I got around 4-5 hours output to TV using a nine.
    The "lith ion" cell you mentioned will likely do a little less. Use the same connector that Mike mentioned.

    OBC

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  • BradCBradC Posts: 2,601
    edited 2009-10-27 15:38
    chris jones said...
    ok do you think i can use a 9v lith ion single cell battery?

    Well, 9V will work nicely, but I'm gagging to see how you get 9V out of a single li-ion cell [noparse];)[/noparse]

    Personally I have a 2.1mm plug hanging out of my benchtop supply and regularly throw between 8-13V at my proto and demo boards.
    At 13V the regs get a it warm but still within specs (and they are too small to cook an egg anyway)

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    lt's not particularly silly, is it?
  • RsadeikaRsadeika Posts: 3,847
    edited 2009-10-27 15:38
    Yes, I think that you should be alright. I have been looking at the Li battery packs that Sparkfun sells, probably would have to do barrel plug adapter for the battery pack, and away you go.

    Ray
  • WBA ConsultingWBA Consulting Posts: 2,938
    edited 2009-10-27 15:44
    I use a 9.6v Ni-Cad battery pack from an RC car that I found for $5 on the WallyMart clearance shelf. Works great and it is a flat pack just a little wider than the demo board so I set the demo board on top of it.

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  • photomankcphotomankc Posts: 943
    edited 2009-10-27 15:54
    If you can find one.... a 6 cell battery holder will make a real nice NiMH pack and it's voltage levels stay within range pretty well all the way through it's discharge curve. I sure appreciate being able to recharge batteries vs. tossing them and they are useful everywhere.
  • chris joneschris jones Posts: 391
    edited 2009-10-27 16:03
    does anyone have a place that sells the dc cable that i need i went to the radio shack web page and did not find it.But i did find it at this location but its about $20 to ship 2 cables.

    [url=][/url]·
  • potatoheadpotatohead Posts: 10,261
    edited 2009-10-27 16:30
    If you can't find a place that makes sense for the little plug, go visit your local thrifty type store. Dollar stores, Goodwill, etc...

    In the dollar stores, they have a totally cheapo electronics section. Most of the stuff is Smile, but there are lots of connectors, bits of cable, etc... for a buck.

    Personally, I prefer the thrifties. Many of them have an "electrical" section, where who knows what you will find. For sure, there will be a wall, or basket, or drawer chock full of used wall power adapters. Score one or two of those for cheap, power your Prop, and get a spare plug.

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  • DufferDuffer Posts: 374
    edited 2009-10-27 16:31
    Chris,

    Check your "junk drawer". You probably have and old "orphan" wall wart with the right sized plug. Maybe you're like me and just can't throw away something that still works even though you don't know what you'll use it for.

    Cut off the cable,·using a meter, find and mark·the wire that goes to the center contact (that goes to the battery +), wire it up to your battery holder and you're all set.

    If all else fails, save the $20 shipping and the cost of the cables and go buy a cheap wall wart with the right sized plug and "liberate" the cable as above·(take your demo board with you and find one that fits).

    Duffer
  • potatoheadpotatohead Posts: 10,261
    edited 2009-10-27 16:37
    There is one other good alternative.

    See if there are any surplus stores where you live. If there is one of these near by, how they operate is they take "inventory" off of other peoples hands, then process it (or not, LOL!!), then sell the stuff rock bottom.

    The one near me is just excellent. They've got a ton of stuff, and it's just the place for getting components, plugs and other stuff to work with. $5 takes home a very interesting bag 'o goodies.

    This is worth looking for IMHO. Once you know the place, it's perfect for that "I need X on saturday" kinds of things.

    Being a little willing to scrounge make the hobby fun actually. It's always a little adventurous, and often leads to those "happy distractions" that sometimes turn out to be great things. At the least, you will have some sources lined up, and that's never a bad thing.

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  • VaatiVaati Posts: 712
    edited 2009-10-27 16:56
    I power my prop(s) with 7.5 volts... I got a 5xAA battery pack that Terry Hitt had at the Prop E Expo, and I found a 2.1mm barrel power plug on the freebie table, so I just connected that to the battery pack. It lasts a lot longer than a normal 4xAA would...

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  • fisiofisio Posts: 38
    edited 2009-10-27 20:51
    you can do it quietly, but attention to the polarity,
    because in demoboard do not know why the designers
    have omitted a diode like a 1N4007 to protect the card
    from the inversion

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  • chris joneschris jones Posts: 391
    edited 2009-10-28 14:38
    ok i have put a order in for the supplies i need another question about the power for the board, i have an external lith ion charger and i want to get the voltage that coming from that device and display it or store it how can I hook power wires into the board to get voltage readings?
  • Rob7Rob7 Posts: 275
    edited 2009-10-28 15:09
    Chris,
    For portable use I used a 7.2V. 1700mAh, 6 cell battery that you can pick up at any hobby shop.
    I have several of these I use in my R\C cars and tanks. They work great !
  • Mike GreenMike Green Posts: 23,101
    edited 2009-10-28 15:25
    @fisio - The diode is not needed because the voltage regulator used is designed to withstand reverse polarity power connections without damage to itself or the equipment suppled by it.
  • chris joneschris jones Posts: 391
    edited 2009-10-28 15:37
    ok so i dont need to hook any wire into the board. will the propeller chip tell me the voltage tghats comeing through it. the overall goal here is to find a way to monitor my battery to make sure there is power.
  • VIRANDVIRAND Posts: 656
    edited 2009-10-29 08:59
    One trick I discovered though it should be obvious to many is putting a zener diode in series with an LED,
    and since our voltage is so low we can use a regular diode or two instead. Certain LED's,
    especially the older not-superbright yellowish green ones turn on suddenly instead of gradually.
    The diodes have a voltage drop (regulator) effect, which can change the light-on voltage of the LED.

    Because (SOME) LEDs have that noticeable light-up threshold, it is easy to make bargraph voltmeters with them
    and just a pair of resistors (which may be a variable resistor) for each one.

    So, you could have just one LED indicating good power close to 3.3 volts,
    and maybe also another one which goes out just before the circuit starves and battery dies.

    As far as I know only older yellow green LEDs have a good threshold effect
    and the red ones fade gradually, BUT I haven't thought of trying to use newer ones the same way,
    so feel free to experiment. I just can't recommend the idea of using a green LED for "good power"
    PLUS a red one for "prepare for death" for these reasons.

    I have used diodes to inform microcontrollers of impending battery death but not for the Propeller yet,
    though I'm sure it would work. All that needs to be done is connect diodes to a pin and when they
    cannot pull down the pin anymore then the voltage is too low. They sell power watching chips but
    diodes usually only cost me a penny or two.
  • Toby SeckshundToby Seckshund Posts: 2,027
    edited 2009-10-29 09:05
    You would have to emulate an A/D channel with the sigma/delta way. The actual battery volts would have to be divided to be within the measuring range ie 0V to 3.3V. I have done the same thing with AVR stuff, but they have the benefit of inbuilt A/Ds. There are objects available for external A/D chips.

    That or just have one preset "alarm" level by using the transisition point of an input.

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  • chris joneschris jones Posts: 391
    edited 2009-11-02 16:43
    Will anything happen to my chip if my battery thats hooked to the board cant run the board. i have a battery but i am not sure if the propeller chip will have a chace to shut itself down.
  • Mike GreenMike Green Posts: 23,101
    edited 2009-11-02 17:01
    The Propeller normally uses a built-in brown-out detector which will reset the chip (and keep it in reset) when the input voltage becomes too low to reliably power it. You have to tie /BOE low (to ground) to enable the brown-out detector which I think triggers at supply voltages below 2.7V.
  • chris joneschris jones Posts: 391
    edited 2009-11-10 02:08
    i have a 7V Lith Rechargeable battery and i can not get itto power the propeller is there something i am doing wrong or do i need more power lets say a 10V.
  • chris joneschris jones Posts: 391
    edited 2009-11-10 16:23
    any updates or comments?
  • chris joneschris jones Posts: 391
    edited 2009-11-10 22:57
    has anyone hooked a battery to there propeller if so what was used size battery etc...
  • StefanL38StefanL38 Posts: 2,292
    edited 2009-11-10 23:17
    yes a comment,

    do we all have chrystal balls to look inside what you did wrong ??? NO !!

    to state the obvious things:

    did you check for the right polarity ?

    did you check for "cold solderings" (beeping through the wires)

    did you check the voltage of the battery when it is connected to your protoboard ?
    maybe the voltage brakes down if it is connected to the protoboard

    did you check the current flowing from the battery to the protoboard when connected ?

    If it REALLY has 7V it is 1V MORE than the schematic says so it should work (6V-9V)
    testing-incoming-voltages.png
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  • chris joneschris jones Posts: 391
    edited 2009-11-10 23:46
    i understand that noone has a chrystal balls to look inside what i did wrong. i must be asking all my questions wrong, i have a volt metter it all current from battery are correct around 7V.

    thanks for helping "StefanL38" i feel that i am wasteing everyones time with my dumb questions.
  • Mike GreenMike Green Posts: 23,101
    edited 2009-11-10 23:53
    People have used all sorts of batteries for their Propeller. I've generally used 4 x AA Alkaline batteries with a Protoboard and Demo Board with its 5V Low Dropout regulator. I've used 5 x AA NiMH rechargables as well. I've briefly used a 9V Alkaline battery and once used a 12V Lead-Acid Gel Cell being careful about the amount of current drawn (to avoid heating up the regulator too much). Some people have directly used a 3V Lithium cell without a regulator.
  • chris joneschris jones Posts: 391
    edited 2009-11-11 00:04
    i will take a picture of my setup and see if that helps
  • StefanL38StefanL38 Posts: 2,292
    edited 2009-11-11 00:22
    good idea with the picture.

    Your just wasting your own time beeing unprecise in your question

    You are working in too many different places at the same time
    You put together a lot of code and to me you seem to be still a bloody newbee.

    Concentrate on the battery-issue OR concentrate on the test serialconnection code

    You can believe me. Doing the things one after another instead of parallel will lead you much faster
    to the target
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