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Power for the Spinneret — Parallax Forums

Power for the Spinneret

David BetzDavid Betz Posts: 14,516
edited 2013-11-09 20:48 in Propeller 1
I'm finally getting around to powering up the Spinneret that I bought ages ago and I'm trying not to fry it. The documentation says that you can supply between 4 and 9 volts to J6 pin 2. I have a wall wart that says it outputs 9 volts but when I measure it not connected to any load I get 14.55 volts. Is there any chance this will damage the Spinneret or will the in-circuit voltage drop down to the 9 volts that the wall wart says it produces? Secondly, is there any danger in powering the Spinneret at the extreme 9 volt end of its range or is it better to choose something a bit lower?

Comments

  • Don MDon M Posts: 1,652
    edited 2013-11-09 11:34
    The data sheet for the regulator used on the Spinneret (NCP1117-3.3) states a maximum input voltage of 20V.

    However- this is a linear regulator so the higher the input voltage the more heat it will disperse. So the best rule of thumb is the lower the better. I would suggest 5V. I use cell phone USB changer wall warts that I find at garage sales for $1 or less. These are well regulated at 5V and usually around 500 - 1000 mA.

    Hope that helps.
  • ctwardellctwardell Posts: 1,716
    edited 2013-11-09 11:37
    According to the schematic and BOM you should be OK to try it.

    The NCP1117-3.3 regulator spec says up 20V input and the 10uF capacitor on the input is listed in the BOM as >=25V.

    That said, if the voltage stays above 9V with the circuit connected I would change to a lower voltage wall wart.

    Main issue is power dissipation of the regulator at high input voltages.

    C.W.
  • Mike GMike G Posts: 2,702
    edited 2013-11-09 13:04
    This is a timely thread as repurposed Spinneret power supply seems to be on the outs. Today I snipped the connector of a 6V 1000mA wall wart with the intent to use as my new Spinneret power supply. I measure the voltage close to 10V. OTOH, the repurposed cell phone charger specs show 5V and it measure 4.99V.

    I'm wondering why the 10V out with a 6V spec?
  • David BetzDavid Betz Posts: 14,516
    edited 2013-11-09 13:07
    Mike G wrote: »
    This is a timely thread as repurposed Spinneret power supply seems to be on the outs. Today I snipped the connector of a 6V 1000mA wall wart with the intent to use as my new Spinneret power supply. I measure the voltage close to 10V. OTOH, the repurposed cell phone charger specs show 5V and it measure 4.99V.

    I'm wondering why the 10V out with a 6V spec?
    I know almost nothing about electronics but my guess is that there is no load on it when you just measure the output with a multimeter. The USB charger is probably regulated so it measures close to 5v.
  • David BetzDavid Betz Posts: 14,516
    edited 2013-11-09 14:29
    Just to play it safe I bought a 6v wall wart and it measures at 6.1v even when unloaded. I connected it to my Spinneret and sure enough the green power LED comes on! A minor success but at least I've done *something* with the board I probably bought a year or two ago. Does anyone know if anything comes pre-programmed into a Spinneret from the factory? I didn't find any code on the Spinneret page in the Parallax store.
  • Don MDon M Posts: 1,652
    edited 2013-11-09 14:30
    Mike G wrote: »
    This is a timely thread as repurposed Spinneret power supply seems to be on the outs. Today I snipped the connector of a 6V 1000mA wall wart with the intent to use as my new Spinneret power supply. I measure the voltage close to 10V. OTOH, the repurposed cell phone charger specs show 5V and it measure 4.99V.

    I'm wondering why the 10V out with a 6V spec?

    Mike- it all depends whether or not the power supply is regulated. It may only be a transformer, bridge rectifier and a capacitor in the 6V wall wart. The 10V is the OCV (open circuit voltage) or no-load voltage. It's saying that up to 1000mA the voltage will probably go down to 6V whereas the chargers for cell phone are a switching regulated power supply so they are regulated to 5V. Measuring 4.99 is ok :)

    The label should indicate they type of supply it is.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2013-11-09 15:49
    One caveat with the Spinneret's power supply: if you're using a daughterboard with it, the supply has to be a regulated +5V.

    -Phil
  • NWCCTVNWCCTV Posts: 3,629
    edited 2013-11-09 17:00
    David, When it is working this site is a GREAT place to start. It guides you through being able to light up an LED via your web browser. The Spinnernet Web Server Forum is also full of great projects and help threads. And no, I do not believe there is anything pre programmed. If there is I wiped mine out but had fun playin around with the servebeer site. Mike G is very helpful if you run in to problems.
  • David BetzDavid Betz Posts: 14,516
    edited 2013-11-09 20:48
    Thanks for the pointers Andy!
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