pictographer
Well-known member
I just smoked my first Teensy. I have a guess as to why, but I'd like help to avoid frying a second one. Also, perhaps someone else can learn from my mistakes.
Parts:
The rig had been up and running for a couple of weeks with no incidents, changing the lighting several times per day. Measured current with a Kill-a-watt and nothing seemed out of line.
I wanted to extend it from 180 to 220 LEDs. I unplugged everything. Connected the Teensy to my laptop as usual. Updated the sketch for 220 LEDs. Doubled the number of LEDs actually connected from 180 to 360. The sketch initially displays the LEDs at a minimal brightness.
Normally, I connect power last. This time I connected the power barrel connector and then connected the 4-channel connector to the APA102s. Smelled burning plastic. Unplugged power. Noticed the Kinetis processor was too hot to touch.
After letting the rig cool down, I tried again but making the power connection last. The rig lit up as per usual, but again the Kinetis was hot, so again I unplugged the power.
Unplugged everything and tried to connect it to the laptop. Tried holding the reset button while plugging it in several times. No device appears for it in /dev. The built-in LED flickers once very briefly when the power is first connected. The processor gets slight warm. The external power indicator LED doesn't light up, so I don't think my sketch is running.
From tip to base, the barrel connector has DI, CI, 5V, GND. This can momentarily connect 5V to GND as the plug is being inserted. I suspect that when I plugged in the LEDs, I briefly shorted 5V to one of the other inputs.
Here are some pictures of my wiring. Is there anything else you see wrong or that you'd do differently?
After I replace the Teensy, would I still damage anything by simply plugging too many LEDs in, even though most of the additional LEDs would be unused? At full brightness, 360 LEDs would be about 2x too much current for the power supply, but at minimal brightness of 8 (3%) it shouldn't be a problem. Should I be concerned about damage to the buffer chip or the LEDs becoming the source of new problems?
Will post the code if anyone thinks it's relevant. Thanks in advance.
Parts:
- Teensy 3.2 running FastLED at 12MHz with clock on 14 and data on 7
- 10A 5V power supply
- 74VHCT245N level shifter
- 180 APA 102 RGB LEDs
- 4-channel barrel jack driving the lights
- 2-channel barrel jack supplying power
- USB-A male connector normally plugged in to a wireless router.
- Momentary push button connecting the Teensy PROG to ground.
- LED through a current limiting resistor to Teensy pin 2.
- A5-V11 wireless router not connected at the time of the incident
The rig had been up and running for a couple of weeks with no incidents, changing the lighting several times per day. Measured current with a Kill-a-watt and nothing seemed out of line.
I wanted to extend it from 180 to 220 LEDs. I unplugged everything. Connected the Teensy to my laptop as usual. Updated the sketch for 220 LEDs. Doubled the number of LEDs actually connected from 180 to 360. The sketch initially displays the LEDs at a minimal brightness.
Normally, I connect power last. This time I connected the power barrel connector and then connected the 4-channel connector to the APA102s. Smelled burning plastic. Unplugged power. Noticed the Kinetis processor was too hot to touch.
After letting the rig cool down, I tried again but making the power connection last. The rig lit up as per usual, but again the Kinetis was hot, so again I unplugged the power.
Unplugged everything and tried to connect it to the laptop. Tried holding the reset button while plugging it in several times. No device appears for it in /dev. The built-in LED flickers once very briefly when the power is first connected. The processor gets slight warm. The external power indicator LED doesn't light up, so I don't think my sketch is running.
From tip to base, the barrel connector has DI, CI, 5V, GND. This can momentarily connect 5V to GND as the plug is being inserted. I suspect that when I plugged in the LEDs, I briefly shorted 5V to one of the other inputs.
Here are some pictures of my wiring. Is there anything else you see wrong or that you'd do differently?
After I replace the Teensy, would I still damage anything by simply plugging too many LEDs in, even though most of the additional LEDs would be unused? At full brightness, 360 LEDs would be about 2x too much current for the power supply, but at minimal brightness of 8 (3%) it shouldn't be a problem. Should I be concerned about damage to the buffer chip or the LEDs becoming the source of new problems?
Will post the code if anyone thinks it's relevant. Thanks in advance.