I am afraid I don't know the total current draw, but I felt reassured by rsmls comment "in your project the total power draw is quite limited".
as I said above the project includes 35 pots, 32 buttons., 16 LEDs, 2 adafruit neotrellis (16 LEDs each. and 2 16X2 LCD displays.
The 16 LEDs will draw a maximum of 20mA each = 320mA
The Neotrellis are effectively 32pcs WS2812 with a maximum current draw of 60mA each = 1.92A
So worst case scenario with all lights fully on would be 2.2A or thereabouts. That's quite a bit, but....this scenario is exceedingly unlikely, because:
- It would mean on both Trellises, all 16 LEDs are ON at the same time and showing WHITE light.
- You would run your 16 LEDs at 20mA and they are all ON at the same time, which is unnecessary; you likely only need something like 5mA (you set the current with a limiting resistor which isn't shown in your schematic).
A more realistic estimate is that maybe half your individual LEDs are on and running at let's say 10mA = 80mA, and maybe 4 of the Trellis LEDs are on showing some kind of color, let's say 4x25mA = 100mA, for a total consumption of 180mA.
The buttons and pots draw a negligible amount of current. The microcontroller draws maybe 20-50mA worst case.
A pessimist would argue that the power supply is insufficient because the theoretical maximum power draw exceeds what the Teensy can be expected to deliver reliably. But in reality, it won't be quite as bad as the theoretical worst case scenario.
I am glad you mentioned that! I used the trellis in a previous project and I don't remember using a limiting resistor for that. That was the old trellis with only white LEDs, not RGB. I will check the adafruit documentation.
A pessimist would argue that...
You don't use those in combination with a resistor. The remark about the resistors is about your 16 individual leds that you control through the shift registers. You didn't draw the LEDs in the schematic, but they should have a resistor combined with them if you use regular leds.
Right... I have 4 220 ohm resistors for the 4 blue LEDs (which I'll use for headphone monitor indicators). The other 12 LEDs are combined with the silver buttons (see picture below). I am pretty sure (from the test I made with my multimeters and various searches on the web) that they have resistors inside. Hence I didn't draw them in the schematic, but thanks for pointing that out.
