Forum Rule: Always post complete source code & details to reproduce any issue!
Results 1 to 16 of 16

Thread: Powering Teensy 3.2 and 144/m led strips using 5volt 10amp power supply

  1. #1
    Junior Member
    Join Date
    Jan 2018
    Posts
    12

    Powering Teensy 3.2 and 144/m led strips using 5volt 10amp power supply

    Hi im using a teensy 3.2
    https://www.pjrc.com/store/teensy32.html

    and the prop shield with motion sensors
    https://www.pjrc.com/store/prop_shield.html

    also im using 2 x 144/m led strip ws2812b, 5volts, soldered in parallel. cut slightly shorter so 127 leds on each strip. I need each led at basically max brightness.

    I also have a 5volt 10amp power supply to run the led strips and teensy board. but I dont think the teensy can handle 10 amps so I need to wire the strips to run with 10 amps max, and also with the same power supply power the teensy without blowing it up.

  2. #2
    Senior Member
    Join Date
    Apr 2013
    Posts
    1,935
    Running 10 amp across the board would not be a great idea, so one option would be to connect the strips to the prop PCB, then the power to the strip so Teensy and strip are drawing power from the same point. Also works to provide 5V to vin and strip positive.

    One related thought with 5V power is thinking about what happens when you connect USB power. You do not want the PC to be trying to power the LEDs - normal method is to cut the trace on the underside of the teensy to isolate 5V USB from 5V supply in your project but other ways to the same end.

  3. #3
    Junior Member
    Join Date
    Jan 2018
    Posts
    12
    Im not sure exactly what you mean. I have the teensy soldered to the propshield and the leds soldered to the propshield led driver pins. I then have a speaker coming off of the other end of the propshield where the audio pins are. and next to those pins I have a 5v and gnd wires coming off not connected to anything yet.
    Here is a pic of my project. Click image for larger version. 

Name:	IMG_2338[1].jpg 
Views:	37 
Size:	94.2 KB 
ID:	12820

  4. #4
    Senior Member
    Join Date
    Apr 2013
    Posts
    1,935
    So in this wiring scheme the 5ish amps the LEDs will draw flow through the propshield but not the Teensy? This is probably ok since I think the prop shield has heavy tracks joining the 5V together and a gnd plane.

  5. #5
    Junior Member
    Join Date
    Jan 2018
    Posts
    12
    but what if the leds end up needing more than 5 amps which from my testing so far they might be. It may be that a full 10 amps would run through the propshield, will it die? Also wouldn't the amperage run through the teensy anyways because of the solder joints?

  6. #6
    Junior Member
    Join Date
    Sep 2013
    Location
    NLR, AR
    Posts
    8
    Quote Originally Posted by GremlinWrangler View Post
    Running 10 amp across the board would not be a great idea.........

    But doesn't the board just pull the amps it needs? I search around some for this....and find some confusing , but informative, info....

    https://electronics.stackexchange.co...ted-for/175234

    ??????

    Thanks for additional clarification.....

  7. #7
    Senior Member
    Join Date
    Dec 2016
    Location
    Montreal, Canada
    Posts
    3,418
    if your pulling that kind of amerage over traces something is bound to heat up or burn out...
    leds need a dedicated powersupply, which you can run independant of your micro or in parallel as long as it goes to the same wire attached by VIN, this keeps the “pull” at the wires and not from the MCU.

  8. #8
    Junior Member
    Join Date
    Jan 2018
    Posts
    12
    Thats what im thinking I need is to power it separately but still from one power source. But im still confused on exactly how to wire it. Any clarification would be greatly appreciated.

  9. #9
    Senior Member
    Join Date
    Dec 2016
    Location
    Montreal, Canada
    Posts
    3,418
    the data pin can goto your prop shield or teensy pin as you wish, the power and ground from your psu can directly connect to the VIN of teensy (5V psu right?) to power them, also, you use the same wires (5v remember) to go straight to the led, basically in parallel, your just splitting power and ground, one goes to your setup, other to the leds

  10. #10
    Junior Member
    Join Date
    Jan 2018
    Posts
    12
    thanks ill try that, im currently awaiting my power supply in the mail. Thanks for all your help.

  11. #11
    Senior Member
    Join Date
    Dec 2016
    Location
    Montreal, Canada
    Posts
    3,418
    and dont forget to cut the trace that links usb power with VIN, or, an alternative is to use a data-only usb cable with has no power feed, or just strip the shielding off and cut the red wire, tape it off and happy testing

    this is to prevent both psu power and usb power sources from fighting each other

  12. #12
    Junior Member
    Join Date
    Jan 2018
    Posts
    12
    Im not sure where to cut on the back of the teensy 3.2

  13. #13
    Senior Member
    Join Date
    Dec 2016
    Location
    Montreal, Canada
    Posts
    3,418
    don't cut? just split the 5V PSU wire, one normally to teensy, the other to the led.

    if your referring to the VIN/USB trace, refer to this:

    https://www.pjrc.com/teensy/external_power.html

    Don't use brute force, and you can check with a DMM if the connection is severed or not before going ahead to use it

    Tony

  14. #14
    Junior Member
    Join Date
    Jan 2018
    Posts
    12
    I am talking about the cutting of the 5v pads to seperate the usb and power. but I cant see where it is on the teensy 3.2.

  15. #15
    Senior Member
    Join Date
    Dec 2016
    Location
    Montreal, Canada
    Posts
    3,418
    I posted the url for you...

  16. #16
    Junior Member
    Join Date
    Jan 2018
    Posts
    12
    I found the pads on the 3.2, there just off to the side a little

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •