Basic Feather 32u4 questions for an e-badge

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strredwolf
 
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Basic Feather 32u4 questions for an e-badge

Post by strredwolf »

I got a few questions over the Adafruit Feather 32u4. The context is that I'm building (again) a e-badge system using the 3.5" touch screen to display several con badges on a rotating basis. The images are decoded (ether BMP or TGA) straight to the display (although making a dedicated format could work, depending on how powerful the GPU is on the display). Right now I'm testing using a 3v3 Trinket Pro and a LiPo backpack.
  • If I ground the En pin, will it turn off both the 32u4 and anything tied to the 3v3 pin? It wasn't clear in the tutorial since it says it'll turn off the 3v3 regulator but I don't know if there's anything tied to it.
  • Is the touch screen too much of a power draw, or do I have to PVM the backlight to 50% and have a fine control over the RESET on the touch screen?

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adafruit_support_mike
 
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Re: Basic Feather 32u4 questions for an e-badge

Post by adafruit_support_mike »

strredwolf wrote: If I ground the En pin, will it turn off both the 32u4 and anything tied to the 3v3 pin?
Yes.
strredwolf wrote:Is the touch screen too much of a power draw, or do I have to PVM the backlight to 50% and have a fine control over the RESET on the touch screen?
The regulator can put out 500mA, and most small TFT backlights run between 75mA and 100mA, so you should be good.

strredwolf
 
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Re: Basic Feather 32u4 questions for an e-badge

Post by strredwolf »

Okay, I'm wiring up the Feather to the TFT touchscreen. It looks like I have some code changes, since I'm more used to the Uno and this is more like the Leonardo.

Here's how it's looking so far:
https://www.dropbox.com/s/0bl61mgvtuvh0 ... 1.JPG?dl=0

strredwolf
 
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Re: Basic Feather 32u4 questions for an e-badge

Post by strredwolf »

The Feather controls the board nicely! It's now going through the demo test loop. Next step, the BMP test.

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Re: Basic Feather 32u4 questions for an e-badge

Post by strredwolf »

MILHOUSE! :D

Image

First try too! Image from Kathi Burke via Threadless. Unfortunately sold out! https://www.threadless.com/product/5504

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adafruit_support_mike
 
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Re: Basic Feather 32u4 questions for an e-badge

Post by adafruit_support_mike »

Looks good!

strredwolf
 
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Re: Basic Feather 32u4 questions for an e-badge

Post by strredwolf »

Yep. I'm now tweaking the spitftbmp example to rotate through several PPM files. NetPBM PPM format is much simpler than BMP, and since it's all full screen, there's some code savings there. I may have enough room to code in a file transfer protocol based on XMODEM.

But I have a case to build for it!

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Re: Basic Feather 32u4 questions for an e-badge

Post by strredwolf »

PPM code's in, and I did a test with a 2500 mAh battery...

5 hours before it started shorting. Hmmm, we need 12 hours, and a good way of halting code. The former, go for a 6600 mAh battery...

...the 100 mA charge current is limiting that. 66 hours? Oy veh. Is there any way we can increase that on the Feather? Or is that a hardware change?

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adafruit_support_mike
 
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Re: Basic Feather 32u4 questions for an e-badge

Post by adafruit_support_mike »

You're speaking in shorthand. I'm sure those statements mean something to you, but I need more context to understand them.

strredwolf
 
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Re: Basic Feather 32u4 questions for an e-badge

Post by strredwolf »

I think I gave too much fluff there, confusing you.

Here's my question: Is there a way to charge the attached lipo faster than 100 mA, or is the charge circuit limited to that?

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Re: Basic Feather 32u4 questions for an e-badge

Post by adafruit_support_mike »

The 100mA limit is set on the board, but you could change it by replacing this resistor:
rset.jpg
rset.jpg (70.97 KiB) Viewed 1329 times
The existing value is 10k, but you can drop it as low as 1k.

The charging current is 1000mA * 1000/Rset, so 1k would set the current to 1000mA, 2k would set it to 500mA, etc.

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Re: Basic Feather 32u4 questions for an e-badge

Post by strredwolf »

Whew! Talk about tiny! But at least it can be done.

Project update for those who were curious: I've gotten a Printrbot and printed up a case! I also took the second Feather Basic I had and soldered up a more compact version. Some shots here.

I actually soldered the switch up-side down so it pokes out the back, and used the 2200 mAh lipo so it fits in the case. The case (after some knife work to trim out some spillage of the filament) fits tightly with the two halves, and doesn't need screws.

There are two downsides. First, the SD card is basically permanently installed, so I need to code up a transfer protocol (XModem-1K?). The second downside is that it can only run for 5 hours, but then I have a small stick USB battery, plus I can make the 6600 mAh lipo be the backup for it. More stuff to get from Adafruit!

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Re: Basic Feather 32u4 questions for an e-badge

Post by strredwolf »

My last post here on this topic. Have a Github repo of all my files! https://github.com/STrRedWolf/ebadge-Arduino

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Re: Basic Feather 32u4 questions for an e-badge

Post by adafruit_support_mike »

Nice! Thanks for posting it.

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