“Greetings Treasure Hunters!
Another in the series of tools that I use to create treasure hunts, this is a gadget cashe made from a PVC tube. What is a gadget cashe? The word comes from our friends in the geo-cashing world to describe a place to hide something in plain sight that has a mechanical or electrical “gadgety” air about it. In this case a Arduino with servo, LED lights and keypad to in essence make a safe. Because this is for a treasure hunt I haven’t gone super hard charger on making it bullet proof, bomb proof, or force-ably open-able. It is PVC and wood after all.
The supplies that I used for this project were mostly recycled. Being a ninja level dumpster diver has its distinct advantages. Feel free to modify, change or overall redesign the entire thing to suit what your needs are. Thats why we come to Instructables right? Ideas!
List of materials for this build:
(1) PVC pipe, 4 inch diameter, about 2 feet - this can also be ABS sewer pipe or if you are feeling inspired steel. The pipe needs to be as smooth on the inside as possible as the insert needs to slide within the pipe without a lot of drag. You can lengthen or shorten this to a point but you will need at least a foot to cram all the workings inside the pipe. make it work and still have room for anything else you wish to contain within it. You can go larger with the pipe if you want but it gets expensive really fast for fittings and the pipe itself.
(1) Arduino - I used a mega which is way overkill. An uno, micro or any of the mid sized units will work. You will need 8 pins for the keypad, 2 pins for the two color LED light, and 1 pin for the servo. 11 pins in all. I would suggest using one of the units that can be directly powered with a 9 volt battery without an external power regulator to keep the footprint smaller
(1) 4x4 keypad - available on ebay, amazon, and included in almost every beginners kit for Arduino. You can also use a 3x4 without having to massage the code but you will need to make sure the pins are connected correctly. More on how this is done later.
(1) servo - I used a micro servo from the beginners kit that I had but also they are available from Amazon, Ebay and any decent hobby shop or hobby web site.
(1) two color LED, red/green - I used a two color LED just to keep the foot print small. If you want you can use two LEDs the code will stay the same
Scrap pieces of wood flooring, plexiglas or aluminum - I made this version out of leftover hard wood flooring because, of course, I dumpster dove for it. If I had to do it again I would probably use pleiglas. The wood flooring swells depending on how much moisture there is in the air. If it expands to much then the insert will get stuck inside the tube. The aluminum option takes a bit more specialized equipment to shape.
Springs, wire, header connectors, nuts and bolts, screws and other assorted hardware.”