Forum Rule: Always post complete source code & details to reproduce any issue!
Results 1 to 8 of 8

Thread: Power both Teensy 3.2 and Octo board

  1. #1
    Junior Member
    Join Date
    Jan 2021
    Posts
    3

    Power both Teensy 3.2 and Octo board

    Hi guys,

    For a permanent light art installation I am using Teensy 3.2 and 6 60led led strips.

    I have a teensy 3.2 with an octo board soldered on it. I have cut the connection for usb power, so the Teensy should only get power from the external PSU. When I power only the octoboard the Teensy is not powered. Therefor I connected also 5v power to the teensy and now everything works fine.

    Is this a goog solution, powering both the octoboard (5v and GND and the Teensy (a14/DAC and GND)with 5v and ground cable? Or wil this malfunction after some time?

    Best, Rob

  2. #2
    Senior Member
    Join Date
    Feb 2016
    Location
    Australia
    Posts
    273
    I'm pretty sure powering the octoboard at 5v & gnd connection should power the teensy 3.2 through vin.
    If it doesn't you've blown up the teensy 3.3v regulator. Are you saying you are putting 5V on pin A14 and the teensy is working?

    I'll wait to see someone explain how that is working but I would be interested if you could measure the 3.3v line and tell me what your getting.

    I'm gunna say not a reliable setup.

  3. #3
    Junior Member
    Join Date
    Jan 2021
    Posts
    3
    Quote Originally Posted by Gibbedy View Post
    I'm pretty sure powering the octoboard at 5v & gnd connection should power the teensy 3.2 through vin.
    If it doesn't you've blown up the teensy 3.3v regulator. Are you saying you are putting 5V on pin A14 and the teensy is working?

    I'll wait to see someone explain how that is working but I would be interested if you could measure the 3.3v line and tell me what your getting.

    I'm gunna say not a reliable setup.

    See attachment for my set up.

    I get 4v from the 3.3v pin (the pin in between GND and VBat)

    Without this my Teensy board dus not power up and does not receive power from the Octoboard. I cut the line between VIN and VUSB.


    Click image for larger version. 

Name:	IMG_7113.jpg 
Views:	12 
Size:	217.8 KB 
ID:	23474

  4. #4
    Senior Member PaulS's Avatar
    Join Date
    Apr 2015
    Location
    Netherlands
    Posts
    533
    Gibbedy is right, when you power the Octoboard, the Teensy board should be powered over the Vin pin.
    Something is definitely wrong; you should read ~3V3 on the 3V3 pin. Don't power the Teensy on pin A14/DAC please.

    Click image for larger version. 

Name:	IMG_7113.jpg 
Views:	9 
Size:	204.0 KB 
ID:	23475

    Paul

  5. #5
    Junior Member
    Join Date
    Jan 2021
    Posts
    3
    Quote Originally Posted by PaulS View Post
    Gibbedy is right, when you power the Octoboard, the Teensy board should be powered over the Vin pin.
    Something is definitely wrong; you should read ~3V3 on the 3V3 pin. Don't power the Teensy on pin A14/DAC please.

    Click image for larger version. 

Name:	IMG_7113.jpg 
Views:	9 
Size:	204.0 KB 
ID:	23475

    Paul
    Hi Paul,

    Thanks for your reply. I checked the power on the 3.3v pin according to Gibbedy's request. Why is the teensy not powered by the Octoboard? I get 0V when I check the GND and Vin pins on the Teensy, but 5V when I check the GND and 5v pins on the Otoboard. Do I need to wire the Teensy also to the Vpin and ground pin? That means these pins (on the teensy) are connected to the octoboard on one side and to the external power via a wire on the other side.

  6. #6
    Senior Member PaulS's Avatar
    Join Date
    Apr 2015
    Location
    Netherlands
    Posts
    533
    Did you solder *ALL* the Teensy pins on the back of the Octoboard?
    If you power the Octoboard with the red [+5V] and white [GND] wire, you should see that +5V also on the Teensy pin Vin. If not check you soldering.

    Paul

  7. #7
    Senior Member PaulS's Avatar
    Join Date
    Apr 2015
    Location
    Netherlands
    Posts
    533
    After soldering, using an ohmmeter, you should measure less then 1 ohm between the indicated pins:

    Click image for larger version. 

Name:	Octo.png 
Views:	10 
Size:	163.8 KB 
ID:	23476

    Paul

  8. #8
    Senior Member
    Join Date
    Feb 2016
    Location
    Australia
    Posts
    273
    Cutting vin-vusb connection stops your board being powered up through the usb plug. Vin still works as normal. That is you put 3.6-6v on it and your teensy gets supplies with 3.3vdc through its onboard regulator.

    I do t know the electronics, but youíve found that putting 5v on A14 pulls the 3.3v line up through some resistance on that pin. Lucky itís working but can I ask... did you try vin directly before jumping to a14? If you did and you get no 3.3v on the 3.3v pin your regulator is fried.
    Run an external 3.3v regulator is the solution to that.

Posting Permissions

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