Gemma Cat
Introduction: <PERSON>
This is a cool mood light I made from a repurposed cat deterrent.
A while ago I had a problem with cats pooping on my lawn. So I bought a couple of these. Basically, they are a cat silhouette stamped out of sheet metal.
They didn't work, so I removed them again. I was going to throw them away. But then I decided to make a cool mood light. My idea was to use a microcontroller and some Neopixels. The Neopixels would go on the back, and cat would be placed near a wall. The light would then reflect off the wall to create the mood lighting.
Supplies
Cat deterrent: https://www.ebay.co.uk/itm/3-PACK-GARDEN-SCARE-CA...
https://www.amazon.co.uk/Defenders-Deterrent-Garde...
(I couldn't find the exact one I used, but just search eBay or Amazon or whatever for "Cat deterrent".)
Adafruit GEMMA v2 - Miniature wearable electronic platform: https://www.adafruit.com/product/1222
Adafruit NeoPixel Digital RGBW LED Strip - Black PCB 60 LED/m: https://www.adafruit.com/product/2837?length=1
(I know; this is a bit pricey for this project, but I didn't use the entire strip. I had a bit left over from another project. But you don't have to use this particular product; Adafruit have a number of different Neopixel strips available, and I'm sure there are other suppliers.)
Momentary push button switch: https://www.ebay.co.uk/itm/5-x-Momentary-push-swi...
Hookup wire.
Sundry bits of scrap wood.
Step 1: The Base
Because the cat is just on sheet metal, it doesn't stand up on its own. It's designed to be stuck in the ground. So I needed to make a stand for it. The stand was made from a scrap piece of wood 7" x 1¾" x ¾" (180mm x 45mm x 20mm). The size of this isn't critical. I cut the ends at 45° just to decrease its profile a bit. Again, not critical.
The base was an ideal place to put the microcontroller. 769
The microcontroller in this case is the Adafruit Gemma. This is a very small unit, circular with a 1" (25mm) diameter. It was easy to just drill a 1" dia hole ¼" (6mm) into the base to accommodate the Gemma.
In addition to the Gemma, there is a switch to allow you to change modes. I made covers for the top and bottom from 1/10" (2.5mm) MDF, and the switch was mounted into the top one.
There were holes in the cat's feet; presumably you could nail it to a fence or something. I used these holes to screw the cat to the base.
Step 2: Neopixels
The Neopixel strip comes with a protective silicon sleeve over it. I removed it from this covering as I didn't need it for this project.
I stuck the Neopixel strip to the back of the cat with double-sided tape. Some of these strips come with adhesive already on the back, but this one didn't. Double sided tape did the trick perfectly.
Step 3: The Eyes
These cats have marbles for eyes. I thought it would be cool to put lights behind the eyes in addition to the Neopixel strip. Since every LED in the strip is addressable individually, I could then control the eyes independently.
To mount the Neopixels behind the eyes, I made a tiny box. This was because I wanted to shield the eyes from any light getting in from behind, other than from the Neopixels. I cut two Neopixels from the strip, and they were mounted at the rear of the box. I had to cut them into singles because they needed to be spaced exactly right behind each eye, which they were not. They were close, but it made the cat look crosseyed.
The pieces of wire are to hold the Neopixels at exactly the right distance apart, so that they are exactly behind each eye. They also provide electrical connection between the two, to provide power and data. Once I was happy the Neopixels were in the right place, I fixed them into the box with hot glue.
The last thing was to hot glue the whole box behind the eyes. As you can see from the last photo in this group, I was able to line up the box, and therefore the eyes, by temporarily removing the marbles. 635