I am playing with a Trinket 3V and NeoPixel 144 RGB strip. I have the strip soldered and working, but I want to experiment a little.
The "scanner" code is working great but it is only powering 5 LEDs at a time. Can I power more than 5 at a time? Can I light up all 144 or 22 or is that pushing what voltage is available? I am asking before I try it in case I might screw something up.
Trinket 3v and Larsen Scanner Shades
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- adafruit_support_rick
- Posts: 35092
- Joined: Tue Mar 15, 2011 11:42 am
Re: Trinket 3v and Larsen Scanner Shades
How are you powering the LEDs? From the trinket? You will need a separate power supply for the NeoPixel. NeoPixels require up to 60mA each, which adds up really fast. A 144 pixel strip can use up to around 8.7 Amps
Be aware that you will have a problem if you power the NeoPixels at 5V. The 3.3V data signal from the trinket is not high enough to reliably drive the neopixels.
You can power the NeoPixels at 3.3V (or at 3.7V from a LiPo battery)
Or, you can use a level shifter to bring the data signal up to 5V
Or, you can use a 5V trinket.
A trinket doesn't have enough RAM for 144 NeoPixels. Max is about 100, but can be less, depending on the RAM requirements of the rest of your sketch..
Be aware that you will have a problem if you power the NeoPixels at 5V. The 3.3V data signal from the trinket is not high enough to reliably drive the neopixels.
You can power the NeoPixels at 3.3V (or at 3.7V from a LiPo battery)
Or, you can use a level shifter to bring the data signal up to 5V
Or, you can use a 5V trinket.
A trinket doesn't have enough RAM for 144 NeoPixels. Max is about 100, but can be less, depending on the RAM requirements of the rest of your sketch..
- iguanaman
- Posts: 73
- Joined: Sat Mar 19, 2016 4:48 pm
Re: Trinket 3v and Larsen Scanner Shades
This is a Pro Trinket 3V 12mHz. I am powering it through a lipo battery backpack using a 150 mA 3.7v.
I was able to run all 144 using the RGBStrandTest Sketch though the Trinket got warm so I stopped that. I cut the NeoPixel strand to 29 LEDs and have them installed now in some sunglasses. Seems to work okay with the Larsen scanner sketch. I was able to get the scanner sketch to run all 144 (ran all the way down and back) for several hours without an issue of course only 5 are ever lit at one time.
I was able to run all 144 using the RGBStrandTest Sketch though the Trinket got warm so I stopped that. I cut the NeoPixel strand to 29 LEDs and have them installed now in some sunglasses. Seems to work okay with the Larsen scanner sketch. I was able to get the scanner sketch to run all 144 (ran all the way down and back) for several hours without an issue of course only 5 are ever lit at one time.
- adafruit_support_rick
- Posts: 35092
- Joined: Tue Mar 15, 2011 11:42 am
Re: Trinket 3v and Larsen Scanner Shades
So you're running them off the 3.3V output of the Pro Trinket? Yeah - that should be fine for Larsens. You're maybe only pulling 60-ish mA total.
Definitely not a good idea for strandtest.
Definitely not a good idea for strandtest.
Please be positive and constructive with your questions and comments.