This Instructable details how to build a holiday dreidel display for your roof. It uses coat hanger wire, rope light, and an Arduino controller to control a fading demo mode and a “spin” mode. In the demo mode, the symbols fade in and out, going from one to another. In “spin” mode, the symbols flash in sequence with an increasing delay between symbols until the dreidel “stops” on one and flashes. The spin function is activated by a remote push button.
NOTE: This project involves the use of 120V AC line voltage outside and in possibly bad weather. THERE IS A DANGER OF ELECTROCUTION AND DEATH if you are not careful. If you are not comfortable with this, either do not attempt this or seek professional advice from an electrician or other adequately trained person. I expressly disavow any guarantees, promises, warranties, or claims regarding the safety of this project. You undertake it at your own risk.
If you’ve decided to continue on, great! This project can be adapted to something besides a dreidel; it could be any interactive light display you want.
The project consists of the following major steps:
1) Constructing the symbols from coat hanger wire and attaching rope lights.
2) Constructing the Arduino controller box along with wiring for the lights.
3) Programming the Arduino.
4) Putting it all together.
This Instructable includes the schematics (Eagle files) and code for this project. I assume that you have the ability/knowledge/comfort to do the following:
1) Etch your own circuit board and solder components.
2) Conduct basic wiring (connect an extension cord cable to a plug, strip wire, etc.)
3) Work with basic hand tools.
If you’re new to working with circuit boards, there are numerous tutorials out there on Instructables and at places like YouTube.
Check out the video below to see it in action. (And, yes, I know, shin means put one in the pot, not lose
Step 1: Construct the Symbols with Rope Lights
First, you’ll need to obtain some coat hangers and electrical tape and some dreidel symbols. You’ll also need a way to size/image the symbols.
Obtain some extra coat hangers. If you have your clothes dry cleaned with any regular frequency, you probably have about 7 million of them hanging around. You’ll need about 4-5 per symbol. Cut the hook off the top so that you have a majority of the hanger below.
While you can use wire cutters, I find that tin snips or other heavy duty cutters work best. Hold the wire because it will fly away when you cut it. Wear safety glasses and use gloves to protect yourself.
Note: Use the “full” coat hangers that typically hold shirts. The ones for pants with the cardboard roll to avoid lines in your pants do not have a wire that runs through the cardboard. This will work, but you’ll be piecing together lots of little wires.
Next, straighten out the hangers. I use a vice which works great for both straightening and putting bends in the wire. You don’t need to be super straight. You just want a somewhat straight piece to start from.
Make the Symbols
To make the symbols, I used some graph paper to layout things. Design the outer symbol first, since it involves mostly straight lines. You can adjust the inner symbols (nun, gimmel, etc.) to fit.
Take some straight wire and start bending it at the proper angles and lengths to make the shape. When you run out of wire, tape another to it using electrical tape. Overlap about 4-5 inches. Start at one end, wrap to the other, and then wrap back. It’ll make a strong joint.
Obtain Rope Wire and Attach
You’ll need to buy 120V rope light. There are many vendors. I got mine from http://www.noveltylights.com because they will sell 120V rope light by the foot with a plug at a decent price. To determine your required length, use a string to trace out the symbol. Add 5-10% to be safe. (Though this was more than enough for me.) Keep in mind that rope light can only be cut in 1 – 2′ sections, so you can’t plan on something like 10.5′.
If you can, get 3/8″ 2 wire rope light. It’s easier to bend and shape. If you can’t, 1/2″ 2 wire will do but you’ll have to use more zip ties. My symbols are 1/2″ and the green dreidel shapes are 3/8″. (I had a good portion of a spool left over from another project.)
Attach your rope light to your symbols with zip ties. Put a zip tie immediately before and after each turn to closely follow the wire. Use electrical tape to cover up any transitions, as with “hay”.
Congratulations! You’ve made dreidel symbols. If you just want to put them on your roof, you can stop here. But why stop here when we can make this thing interactive and all flashy-fady-neato to make people ooh and aah?
Step 2: Arduino Controller
This circuit does two things. First, it isolates the Arduino and the push button from line voltage with some optoisolaters and triacs. Second, it permits whatever control functions we want to use.
The input for the push button is on digital input #4 (pin 6). It’s held high until pulled low with a push button. I used a simple momentary button connected to this pin via some speaker cable.
The board has 6 pins for a FTDI connection for programming.
Note: In the board file, you will notice a “top” trace. This was required to be able to fit everything on the board. You can use jumper wires, as I did, instead of a double sided circuit board. I made a mistake, however. I use common holes for some resistors and the jumper wire. This required me to drill larger holes to accommodate both the jumper wires and things like resistors. Make a separate hole so you don’t have to do this.