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FantomXR

Adafruit Trelli

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Posted (edited)

Hey people,

I was looking for cheap buttons that have an integrated RGB-LED. I was searching the internet but couldn't find anything affordable. So I looked for alternatives. I found Sparklefuns Button-Pads. They look great, but for me they are too big (15x15mm). So Adafruit has similar soft-buttons called "Trellis". They are smaller (10x10mm). 

I downloaded their eagle-library and adapted it to my needs. The layout was made for 3mm single-color LEDs. You can find videos of it. They look already great. But wouldn't it be even more fun if we could add RGB LED? So I did.

I  added WS2812 LEDs underneath each button in 3535 footprint. I needed to change the pad-layout a bit to make them fit. 

To make it short: I made a layout, that has a HC165 on Board. The PCB is made for 4x4 Adafruit Elastomer but you could split it to get two single Boards with 4x2 each. You'd just have to set the correct solder-jumpers to make it work.

Here is a picture of the layout:

Trellis.thumb.png.6d310cbae007348b21e3c8

So if you want to use the upper 8 and the lower eight you have to bridge J1A and J2A and leave J1B and J2B open. If you want to break it and connect another of those boards to the right, you have to bridge J1B and J2B and leave the other two open.  I just noticed it misses one jumper. If you want to add a board to the right, you now need to manually solder a wire from the input of J1B at the top to the output of J1B at the bottom. This needs to be changed in the next revision.

It was necessary to use SMD parts for the whole design to make it fit. The connection of the boards is made through edge-SMD-pads like in the original design. To make it more stable there are not only connectors for the digital signals on the bottom, but also some bigger pads on the top. This should give it enough strength. 

I also made a adapter board, to connect to my core.

Trellis-Adapter.png.0b18ba174eb20c60099a

Of course I could design another adapter board to fit the midibox connector-pinout.

So I've just ordered that. I hope to received it in two weeks or so.

SMT placement of the LEDs is done by the factory. The SMD parts on the back have to be placed by oneself. It's not a big deal since I used 0805 parts which can be perfectly soldered by hand. Also the HC165 is SOIC-16, which is also not that hard to solder with a good soldering iron.

In case everything is working well I'd set up a bulk order if you are interested in those boards. 

So, if you are in, just let me know. I'll keep you posted.

Stay healthy!

Best,
Chris

 

Edited by FantomXR
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