First, I wanted to make sure that we could do something that looks like a wreath - if we got the electronics working, it wouldn't matter if we couldn't actually make it look like an Advent Wreath. 

First, we need a green base. The first set of pipe cleaners we got only had one shade of green, and it was a bright neon green shade, so didn't look great. We later went to get a different packet of pipe cleaners that included more of a pine green.

Next, we needed something that looked like candles. We ended up going with a simple design of twisting a white and colored (either purple or pink) pipe cleaner around a wire, which did a pretty good job of standing up straight.

Finally, to look like a wreath, my daughters were in charge of coming up with some decorations. They used pipe cleaners to make flowers and leaves that would go on the final product (and would cover up some of the electronics.

While the girls were working on decorations, I got out a breadboard, an Arduino Nano and some electronics components and started figuring out the electronics. 

One non-obvious snag with dealing with the Arduino Nano was that it required using Linux - Mac didn't have support for the right drivers to hook it up. So I got out my old Linux laptop.

Obviously, we needed 4 LEDs and resistors. That was an easy part, and mostly followed standard "Hello World" Arduino tutorials.

I also experimented with adding a button for changing the week. Of course, it's not enough to detect when the input pin goes high and hook that up to a counter, for a few reasons. First of all, when the input pin goes high, it may stay high for several cycles, meaning the counter will end up on a random number. Also, some stray current could make the pin high even without the button pressed. These issues can be solved by adding logic to detect that the button was low, stayed high for a certain amount of time, and then the pin went back down to low again. In the end though, since this was a button that we'd press once a week, it didn't seem worth it to add to the final build.

Before building the full, final product, we needed a way to provide power. I didn't want to rely on it being plugged in, so I decided to hook up a 9V battery. You can get a pack of 10 9V clips pretty cheaply off Amazon. I clipped off the plug head (since I wasn't going to plug it in), used a wire stripper to expose a bit of wire, and did a quick sanity check that I could power the wreath circuit prototype with the Arduino hooked up to the 9V battery instead of my laptop power.

The hardest part in this project was soldering the electronics components together - at least for me, since I haven't done many soldering projects before. 

First, I laid out the Arduino Nano on the board to see where it would go. I have a few Nanos around, but I didn't want to permanently attach one to this project, so instead I connected header pins so I could remove the Nano easily later on, but it was still snug enough into the board so that it wouldn't move around. As I had to go to different parts of the house where I keep different things (my laptop upstairs, my tools in the garage...), this made it easier to pop-out the Arduino to tweak code.

Second, I soldered the 9V clip to the board. The ends of the wire on the 9V clip were a little fragile, so I ended up using some tap to keep it in place.

Next, I soldered the resistors in place, followed by a ground rail, the wires (2 for each candle, one connected to the resistor, one to the ground rail), and finally the LEDs. Before I soldered the LEDs in place, I double checked that I had the correct wire in place with a multimeter.

Some things I would do differently next time:

- I should have soldered wires to the board first before wrapping pipe cleaners around them.

- I should have used heat-shrink wrapping around the LED ends

- I only had black wire around. It would have been better to have multiple colors of wires in order to tell more easily which wire was which (for example, which wire was connected to the positive and negative ends).

- I should have installed a power switch. What I ended up with is serviceable, but it would have been easier to not have to take the battery out each time.

The most fun part was taking the circuit and wrapping pipe cleaners around everything. I put the PCB in the middle of the green circle, made sure that the candle pipe cleaners were in place, and used some other pipe cleaners for attaching the PCB to the green circle making up the wreath. 

We then decorated the whole mess with the flowers my daughters had made earlier.