Halloween is great. Lots of candy, cool fall weather, and pumpkins! In this project we will light up a pumpkin with a Tinyduino and some LEDs!
This project is designed as an introduction to working with the Tinyduino and doesn't require much more than the Tinyduino starter kit and some LEDs.
Step 1: Parts!
With this project the only limiting factor is your own imagination! I made a few mistakes along the way, including soldering too much wire to the LEDs and choosing a pumpkin just a little to small for what I had planned. However as an introduction to the ideas of integrating the TinyDuino into a real world project this is a great project. You only need a handful of parts for the most basic version of this project:
- The Tinyduino Starter Kit (https://www.tiny-circuits.com/tiny-duino-starter-k...)
- Paraffin Wax
- LEDs (20mA, 1.2v)
- 220Ω resistors (One for Each LED)
- Solid Core Wire (I used stranded core wire, this was a mistake because it takes up a lot of space)
- A Pumpkin!
Step 2: Carve the Pumpkin!
Time to let your creativity shine! Grab your pumpkin carving kit and give that squash some personality! Make sure to clean out as much of the seeds and pumpkin guts as you can.
Step 3: Melt the Wax
In Order to safely install our Tinyduino inside a pumpkin we have to first make the pumpkin nonconductive. This can be tricky because the fact a pumpkin is organic, and inherently full of water and pumpkin guts. To make the inside of the pumpkin Tinyduino friendly we must coat it in a nonconductive material. Paraffin Wax is the obvious substance for a few reasons:
- It's cheap ($5 for 500g)
- It's easy to find (Check the canning section of your local supermarket)
- It sticks to pumpkin wonderfully
- its nonconductive!
To wax a small pumpkin (mine is a tiny white colored gourd) you must first melt a stick of wax. To do this safely get a pot and fill it with enough water to come halfway up a small pie tin. Put the pot on the stove and heat on medium. At the same Time add about 200g (1 stick, from the package I got) of Paraffin to the pie tin and set it in the water. This will slowly heat the wax without vaporizing it or causing it to get hot enough to burn you. However, as always when using anything hot caution is necessary. An adult should supervise.
Waxing a large pumpkin is much more tricky but follows the same principles. Use a cheap pot rather than a pie tin to melt the full 500g or more depending on the size of your pumpkin. Most of this wax won't stick to the pumpkin and afterwards you can remelt it to coat another.
Step 4: Wax the Pumpkin
To wax the pumpkin I chose to set it in a second pie tin and pour the molten wax over it, It's best to get an even coating over the inside and outside. This step is actually really easy. The wax should only be kept in the hot water long enough to let the whole 200g to melt. The longer it's left on the stove after completely melting the hotter it will get and the more chance it can burn you.
This step should be done by an adult.
Step 5: Prep the LEDs
The first thing we need to do when preparing our LEDs is add our current limiting resistor. Without this component the LEDs will burn out almost instantly!
- Start by cutting down the negative leg of the LED to 2-3mm
- Trim one leg of a resistor to 2-3mm
- Using a set of helping hands or other tool aline the short legs of the LED and resistor
- Carefully solder the two components together
Do this for each LED you plan to use. I used 8.
Step 6: Wire the LEDs to the Tinyduino
The next step is to add wire to the legs of the LEDs and connect them to your Tinyduino. You can do this much the same way as you did the resistors. Be very careful to not short anything out in this step.
- Solder a wire to each LED leg
- Connect the negative wires from each LED into one common ground
- Wire each positive wire from the LEDs to its own point on the Tinyduino ProtoShield (I used points 2 to 10)
- Wire the common ground to the point labeled GND on the ProtoShield
Once the LEDs are wired you can put them into your pumpkin. What I found works best is to put a tiny dob of super adhesive on the lense of the LED and glue it to the wax.
Step 7: Program Your Light Show!
Here is a basic light show program for your pumpkin. Use this code as a launching point to make your own more complex effects.