Create a personal blacklight spotlight under this UV parasol.

Most parasols are designed to keep UV light out. This one is designed to bathe you and your snazzy outfit in ALL the UV light, and make you glow like the Rockstar Candy Raver you are. 

This guide details how to work with UV NeoPixels and make a very sturdy and festival-proof prop. It will still keep the harsh rays of the sun away during the day, but flick the switch at night and let the UV pixels underneath light up and put you in the spotlight.

There is a good bit of soldering and wiring required for this project, so be sure you're comfy with a soldering iron. The code, however, is incredibly simple - we'll just turn the pixels on as bright as they'll go! Using the Circuit Playground Express gives you lots of options to add sound or motion sensitivity with no additional wiring or add-on sensors. Make your UV umbrella react to your environment in a way that suits your style.

Parts

Here's another option for the on/off switch and extension cable. You don't have quite as much control over where the switch will end up, but it does save you a lot of soldering -- this switch is great because it's just plug & play!

Also Needed

• Umbrella or Parasol - I used this one
• Devcon Silicone Glue
• Hot Glue Gun
• Heat gun
• Soldering iron & accessories
• Needle & thread or sewing machine

You'll also need a fabulous black light reactive costume -- but if you're making this project, you've probably already got that in the bag!  The brighter your fluorescence, the better this project will work. The fluorescent pigments linked above work great to enhance your favorite accessories.

Since we want these lights as bright as possible, it's best to connect the battery in the middle of the circuit instead of powering from one end. Power flows both ways, but degrades if it has to travel a long way, so hooking up the battery halfway through the strips will give you the most bang for your buck in terms of brightness. 

The Circuit Playground Express needs to be connected at the IN end of the strips, since, unlike power, data can only flow one way. So we'll put it at the beginning of the very first strip.

• CPX VOUT --> NeoPixel +5V
• CPX G --> NeoPixel G
• CPX A1 --> NeoPixel IN

Then, we'll connect each of the strips' OUT end to the IN end on the next strip: 5V to 5V, G to G, and OUT to IN.

The on/off switch will be put inline with the red wire (5V) halfway through the run of strips.

The easiest way to get the lights on bright is using Microsoft's MakeCode editor. It just takes a few minutes to drag and drop code blocks to get your Circuit Playground Express up and running.

Head to https://makecode.adafruit.com/ to get started.

The code we're writing is simple: we'll tell our Circuit Playground that we have a strip soldered to pin A1, with (in my case) 112 pixels. We'll set it to full brightness, then set all the lights to bright white.

Note: making your pixels full brightness will suck your battery dry really quickly. I've recommended a pretty beefy battery, but if you're planning to take this out for more than an hour, you might want to get two batteries so you can keep your glow at maximum brightness.

Here's the finished code in case you want to just download and go!

1. From LOOPS: drag an instance of on start into your workspace.
2. From NEOPIXEL (click LIGHT tab to make this appear): drag set strip to create strip on A1 with 30 pixels. Change the 30 to reflect the total number of pixels you have.
3. From NEOPIXEL: drag set strip brightness and change to 255 for full brightness.
4. From NEOPIXEL: drag set strip all pixels to red and change red to white

That's it! Click the "Download" button to download the code. Plug your Circuit Playground Express into your computer via the USB port, and a drive will appear called CPLAYBOOT. (If you don't see it, try clicking or double-clicking the onboard reset button.) Drag the file you just downloaded onto this drive to program the board.

If you're having trouble, head over to this MakeCode tutorial for some troubleshooting tips.

More Ideas

MakeCode has lots of easy to use options to spice up your project. Play around with using the onboard sensors (accessed under the INPUT tab) or create light animations (from the NEOPIXEL tab) to see what kind of fun things you can make your parasol do.

Here's how the strips will be laid out on the parasol. My parasol has 16 spokes, so I'm using 8 strips that are slightly shorter than the spokes (so they're not too crowded in the center). There will be a strip along every other spoke. The Circuit Playground Express will be attached near the outside edge, and the battery will live up in the center, out of the way. The on/off switch will be placed close to the outer edge as well.

On/Off Switch Assembly

This shows how to assemble the on/off switch using the clicky tactile switch and extension cable. Another way to do this is to simply use this JST cable with switch already included. You don't have quite as much control over where the button ends up, but it can save you several steps and some soldering! 

If you've got the tactile switch and extension cable, here's how to set up the switch.

Prepare UV NeoPixel Strips

It may save you time if you trim the strips from the middle instead of from the ends. It can be tricky to solder wires securely to these strips, and there are already wires soldered to both ends! You can take advantage of this and use those wires. Just trim out the middle few pixels instead of chopping off the ends of the strips if they're slightly too long for your parasol.

Grab your 4 strand ribbon cable and find the wire with the white stripe on it. This will always be our 5V wire (so imagine it's red!). Remember: striped wire = red (5v) power wire. Be consistent with this or you'll end up with a world of hurt.

Grab the fourth wire (the one on the opposite side from the striped wire). Pull it off the ribbon cable entirely, so that you now have a 3-wire ribbon cable and a spare black wire. Save the spare wire for another project.

Plug your battery into the Circuit Playground's battery port and test to be sure your strips light up. Test each strip as you go to make sure all your solder connections are good and solid. One bad connection will cause all the lights downstream to fail.

Unplug your battery before making any more solder connections. The fastest way to fry your Circuit Playground is to solder on strips while the power is on.

Notice how the first strip only needs a few inches of wire at the end to connect to the next strip since they'll be close together near the center of the parasol. The second strip will need a longer run of wire since it will be going along the outside edge of the parasol. You want to get as close as possible to the right amount of wire, so you don't end up with a lot of extra wire flopping around.. but you also don't want the wire pulling taut when you open the umbrella. 

Solder on your fourth strip with a shorter piece of ribbon cable. Then solder your longer ribbon cable to the far end, in preparation for going to the fifth strip. At this point, STOP and take a break! We're halfway through the strips, and it's time to add the battery and switch connections.

Splice the wires from the battery cable as shown: the striped wire will get twisted with the red wire, and then both striped wires get soldered back together with the red wire incorporated. The black wire will get incorporated in the same way into the third wire from the ribbon cable.

Plug your battery into the other end of the battery extension cable and flick the switch. The lights should turn on and off. If they don't, check your wiring again!

Start with your Circuit Playground Express along the outside edge of the parasol, then lay out the strips where you want them. You'll need to do some threading in and between the spokes of the parasol. I found it worked best to place the 8th strip first, then the 7th, and so on, threading the wire all the way around and through the spokes so it all ends up inside the head of the parasol.

Once you're happy with strip placement, glue the strips to the parasol using copious amounts of silicone glue. Don't skimp on the glue. You may need a couple tubes of it, but if you don't apply it thick enough the strips will peel off.

Now, take your fluorescent pigments and go crazy with your outfit! These are not meant to go on skin, but they work great on fabric. Just mix a bunch of water with a paintbrush and brush it on. You can also add these pigments to dyes or resin to create fancy glow effects.

For skin, there are some really great black light reactive body paints available. My favorite brand is Kryolan - these pigments really pop!