Subsequent to the previous Instructables - Display Colorful Message In Limited Resources,

this Instructables show how to use ATtiny13A, NeoPixel strip and reuse a plastic bottle to build a fancy bracelet.

Step 1: Preparation

Study and prepare my previous Instructables - Display Colorful Message In Limited Resources :P

4 further things and some tools you need to prepare:

A plastic bottle

The bottle size depend on your wrist size, my bottle size is 78 mm in diameter.

Card Board

It help to shape the bottle, no specialty requirement, just find some near you. My card board come from the supporting of the A4 photo paper.

Lipo battery

The NeoPixel strip and the bottle wall both are very thin, so the bracelet can be very thin, around 3 mm thick. So please choose a thin Lipo battery, I am using 302030.

Switch

Any switch can work, luckily I have a mercury switch, so I can switch on the light by rising my hand and switch off by dropping my hand.

Tools

A hair dry for shaping the bottle, cutter, scissors, soldering iron and some wire...

Step 2: Cut the Bottle

Masking tape can help you cut a smooth edge.

Step 3: Shape the Bracelet

Cut the card board into 4.2 mm width, a A4 card board can cut into 5 strips. Stick 5 strips into a long strip, then roll the strips inside the bottle. Roll it tight to support the bottle and fix it with masking tape.

Use a hair dry blow the bracelet both edges, the plastic will sightly contract around the card board roll edge.

Cut the extra plastic to make the bracelet around 3 mm thick.

At last remove the card board roll, you can reuse the card board to make many bracelet!

P.S. I remember I have seem someone use iron shape the bottle to bracelet in Instructables, but I cannot find it again by searching keyword "bracelet". If someone know it, please leave a link in comments.

Step 4: Solder Work

Connect summary:

ATtiny13A pin 4 -> NeoPixel strip +ve -> Lipo +ve

ATtiny13A pin 2 -> NeoPixel strip data pin

ATtiny13A pin 8 -> NeoPixel strip GND -> switch -> Lipo -ve

Step 5: Assembly

Put the circuit inside the bracelet, use a transparent tape to connect 2 endpoint. You may try to use some semi-transparent material like butter paper between the NeoPixel and Bracelet for better diffusion.

Switch on to test the effect.

Step 6: Happy Night Party!

The Lipo should have around 140 mAh and the default program settings consume around 60 mA. Since the light not always on, a fully charged battery is good enough a night party.

Step 7: What's Next?

Water proof, it made from plastic bottle, so it can be water proof if sealing well
Remote charge the battery, because after sealing, you cannot take out the battery easily
Remote customize the pattern, replace ATtiny13A with ESP8266 or BLE board