Addressable LED Collar

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Things
Posts: 36
Joined: Mon Aug 26, 2013 3:47 pm
Location: Cairns, Australia
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Addressable LED Collar

Post by Things » Thu Jun 11, 2015 3:30 am

Have seen plenty of the boring light up dog collars you can get, and thought they needed a bit of a rework. I had a whole bunch of addressable LED strip left over from Christmas and thought, why not? :D

I am looking at perhaps selling these at some point, but still have a bit of work to do in regards to enclosures, as it'll probably need something custom.

I have custom designed the PCB to fit nicely atop a 400mAh single cell LiPo. It runs an ATTiny85 (which I'm just now finding is going to be pushing it flash memory wise, but should be doable) with a V-USB based bootloader, a LiPo charger IC, and a boost converter. It's controlled entirely from a single pushbutton, and so far has 4 user define colour modes, adjustable brightness, and 3 fixed animated patterns.

Currently testing the battery lifetime, and so far I'm up to 45 minutes with the battery voltage at 4.04V, running a rainbow scroll effect at a fairly high brightness on 9 LED's. It's a pretty fun project of 3D modelling, PCB design and programming, and looks pretty awesome in the dark :D

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Really quite difficult to get a clear picture of, though. Either overexposed or underexposed :(

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Just something to look at :)

andrew
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Re: Addressable LED Collar

Post by andrew » Tue Jun 16, 2015 7:51 am

That's really neat, thank you for sharing with us. Does the wearer find it irrating at all, or do they not take any notice of it?

Things
Posts: 36
Joined: Mon Aug 26, 2013 3:47 pm
Location: Cairns, Australia
Contact:

Re: Addressable LED Collar

Post by Things » Wed Jun 17, 2015 9:04 am

Doesn't know the difference between it and his normal collar at all. It's quite lightweight and small :)

Not really limited to just collars though, you could program it to drive any kind of self-clocked strip/LED's you want. The boost converter should be able to handle up to 1.5-2A, however battery life will be extremely limited on a 400mAh LiPo. However I've extended the pads right to the edge of the PCB, so you should be able to easily fit say a 1000mAh cell on it without any changes.

It works with these LED pixels I have with no code modifications at all, although I think green and red channels are reversed:

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It's been a real challenge fitting all the functionality I wanted on the ATTiny85 though. Got it pretty much where I wanted, using 6,470bytes of the available 6,522bytes. I had to switch to the micronucleus bootloader, however I've written a "wrapper" that basically pretends it's avrdude to the IDE, so I can program it transparently from the IDE through the inbuilt USB port - which the end user can do too if they want to modify it for their own use.

I also logged the battery voltage with my DMM and measured how long it would function on various pattern/brightness settings. I think with 9 LED's (number on the actual collar), it lasted about 4 hours on a rainbow scroll at the "max" brightness (it's soft limited to about 80/255, which is still insanely bright). Definitely fits the spec I was hoping for when I designed it :)

Just wish there was a chip identical to the Tiny85 that had 16KB flash instead of 8 8-)

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