I am going to use a Trinket M0 with a Neopixel ring (16 LEDS’s). I understand that the Trinket needs a voltage of 3.3v DC but the Neopixel needs 5v DC. If I get a power supply for the Trinket at 3.3v (and I’ve not found one yet) will I get 5 v at the Trinket USB for the Neopixel?
If I need 3.3v for the Trinket can any one suggest a suitable one.
Many thanks in anticipation
There are 5V trinkets.
I do believe you can power the M0 via the USB jack with a 5V supply? Or a lipo battery. The 5V gets regulated to 3.3v, same deal for the LIPO battery. That’s not going to help you with your 5V Neopixel though.
Thanks for your reply.
So if I get something like a Raspberry Pi power supply (which are 5.1 v) to provide the power to the Trinket will I get 5 v for the neopixel from the usb connection?
I “think” you will get +5V at the pin marked USB if you power it with 5V via the USB jack. Adafruit usually lists what each pin does but I couldn’t find that info for the M0. The logic signal to the NEOPIXEL is still going to be 3.3V though. That may work, or might not? You’d have to try to see. They drive those NEOPIXEL’s from a Raspberry PI and it uses 3V logic so I’m thinking it will work.
This is still one of those do so at your own risk deals. Honestly, I can’t see anything being damaged, it just might not work.
I “think” you will get +5V at the pin marked USB if you power it with 5V via the USB jack.
This is correct, see the pinout section of Adafruit’s guide for more information. You won’t get 5V if you power it with 3v3: there is a regulator which will step 5V from the USB down to 3v3, but it doesn’t boost 3v3 up to 5V.
The signal voltage will indeed be 3v3 but that’s actually almost always enough to drive Neopixels anyway. Strictly speaking Neopixels will run on 3v3 power too, just a little dimmer, but don’t try to power them from the 3v3 pin on the Trinket: the converter which supplies the 3v3 only puts out about 500mA, which isn’t enough for 16 Neopixels at full whack. Power them from the USB pin.
Assuming that you’re using CircuitPython to run them, check Adafruit’s Circuitpython Neopixel guide page. Just be aware that the Trinket M0 doesn’t have as much storage space as some of the boards, so rather than installing the whole library bundle you may just need to copy over the files you’ll actually use.
Must be having “one of those days” I looked for that and missed it. =(
Easily done! One of the things I realy like about Adafruit is that they do publish these guides, usually attached to their shop product pages. It makes figuring this stuff out so much easier, unlike random eBay pages where you’re lucky if they have any information at all.
The pinout info is really handy. I have several of their powerboost’s in use and don’t use the USB port for power in. I don’t even bother soldering it on. I also make use of the enable pin to turn it off and just leave the battery charger on.
And their RTC tutorial is pretty well the only one that works 100% reliable for me.
Thanks for your reply guys - makes it much clearer - will give it a go…!!