How to Make Climbing Holds?

*Note: you will also need a 3/8" bolt and wall with corresponding T-nut to bolt to.
- 1x climbing hold to cast. You can make your own out of foam (not covered in this Instructable, but others exist), or use an existing one (but be aware of copyrights!)
- rubber cement and spare cardboard box to glue the hold to
- silicone for mold making. I used both Oomoo 25 and Rebound 25 for this project. I'll explain pros and cons of both in the next steps.
- polyurethane (or polyester) 2-part resins. I used Smooth-Cast 325/326 (main difference is pot life, which I'll explain shortly).
- 1x circuit board with LEDs to cast in the hold. See below for board BOM.
- 1x 3/8" washer

When mixing the silicone and plastic (polyurethane / polyester) compounds, please do this in a well-ventilated area and wear gloves to protect your skin. Take time to read the MSDS and Technical Bulletins for any product you use, so you understand any additional risks and understand what to do if you accidentally splash something on you. Polyurethane or polyester compounds can have some nasty long-term health effects associated with either breathing them in or having skin contact, so additional personal protective equipment may be necessary depending on exactly what you're using.

Bill of Materials (Holds Electronics):
*Note #1: The github contains files for regular RGB LEDs and controllable WS2812 RGB LEDs. The holds for our Burning Man project will use the WS2812 boards, but I also have controller boards ready to go for the other two options as well.
*Note #2: I used 0603 packaged passives, but you can modify the board in Eagle to use different sized resistors/caps if you're more comfortable with other sizes. The LEDs are also SMD components; both are 5050 packaged.
- 2x LEDs (RGB or WS2812)
- 4x 28 AWG wires, different colors preferred. Pick your length depending on your wall height (taller wall = longer length).
- 1x 2x2 0.1" pitch Quickie connector (what I used)
- (for WS2812 holds) 2x 150 ohm resistors (what I used)
- (for WS2812 holds) 2x 0.1uF capacitors (what I used)
- (for WS2812 holds) 1x 22 ohm resistor (what I used)
- (optional) a 2-56 machine screw and corresponding nut, at least 3/4" long, to help prevent holds from spinning

Bill of Materials (Controller):
*Check github for BOMs. Controller BOM varies greatly depending on if you're driving regular RGB boards or WS2812 RGB boards.