Introduction: Bluetooth Controlled Ouija Board
What goes better with Halloween (other than candy) than talking to the spirit world through a Ouija Board? This is part of a large and growing home built animatronics display set up by my family. Originally conceived by my daughter as an homage to Stephen King, it has grown to include many memorable scenes and references to classic horror and Halloween films. Click here to visit us on the web.
The board can be controlled through the Arduino's USB port with the IDE serial monitor, or bluetooth through the book which It is a separate unit which is not required to run the Ouija. Our goal here was to do something really cool on the cheap. We did not want to spend hundreds of dollars on CNC controllers, linear rods and the like. Ideally we wanted to spend around $80 not including bench stock like wire etc. Trolling the net yielded few options to use as a guide. They were either really expensive, not replicable (custom circuits and hardware), or just randomly moved a planchette around a board. We have a fully controllable, yet moderately budgeted alternative. Other than the obvious electronic parts, a trip to Home Depot will provide just about everything required. That said, the linear motion is delivered through cabinet drawer slides; around five bucks each.
Version 2 will probably upgrade to linear rods and pillow blocks but that will push us over our initial target.
The overall size of the enclosure came about mainly by chance. Scrap plywood measuring just under 24"x18" determined the physical size and the Hasbro Ouija Board Game fit that nicely. We used their board and planchette; make your own, buy a different one or use the Hasbro. Size the enclosure so the mechanicals have room to work outside the working area under the board. Regardless of what you choose, the overall size of the enclosure needs to be larger than the Ouija itself to allow space for the motors and controllers and to allow the planchette to extend beyond the physical size of the board. Materials The BoardOuija Board Game from Hasbro. There are two versions. One uses batteries and has a lighted planchette (the triangle pointer). That's the wrong one. Get the basic version, no batteries. It worked perfectly with Home Depot magnets. The Enclosure Just to reiterate, these are our dimensions. There is nothing magical about them. Use Craigslist and get an old coffee or end table instead of building one. Build the gantry so the top is almost up to the underside of the Ouija. You want it close but not rubbing as it moves. 24"x18"x 1/2" MDF for the bottom.
Its cheaper than most alternatives and is easy to work with. We found 24" square and cut it down. The scraps were used to build the carriage.24"x18"x 1/8" overlayment, plywood, or equivalent. This needs to be rigid enough not to flex but not so thick that the magnets have trouble working.24"x18"x .096" plastic to cover the board. Before we did this, the planchette started to leave marks on the Ouija and it slides better on the plastic anyway.5"x1"x8' for the sides of the enclosure. These dimensions use 7 linear feet of board so there is minimal waste. The 5" board width worked out as the perfect height of the enclosure.#6 or #8 x 1 1/2" wood screws. Use what you have. Its not that important.Whatever you want for legs for freestanding or keep it as a tabletop model. It will be heavier than you think.
We used a 4x4 8' pressure treated post that was in the garage.Corner braces, brackets, and supports. Depending on materials and your skills, these come in handy for joining pieces, tying off the timing belt and supporting the top. I used small 1"x1" brackets as well as 1x3 and 2x2 flat brackets. Most were leftovers from old projects. They all come with small flat head wood screws.The Mechanicals Cabinet drawer slides x3. They are typically sold in pairs so you end up with an extra. 14" to 16" will work depending on how they are made.
Try them in the store. Remember you will be mounting these horizontally (flat) so make sure whatever you pick works when its not vertical. Pick a spot on the slide and make sure it has a range of motion that covers your board. The Y axis is a little shorter than the X so try out both. The easier they slide the less strain on the motors. Alternatively, go for linear rods and pillow blocks. Super precision is not required here. You don't need CNC level accuracy.Magnets. You need 9 total. The six for the planchette need to be ring shaped.
The three on the gantry can be solid.Timing belt. This turned out to be the best solution and was pretty cheap. 8ft 2.5m 2GT GT2 Timing Belt & 2X Pulley, 2X Idler, 4X Tensioner. Included pulleys and tensioners.
Too easy.Felt stick on furniture pads. The planchette has plastic push-on feet. They worked ok but the felt worked better. And they are quick and easy and cheap to replace if they wear. I only found square so punched round ones out of them.The Electronics Arduino UNO R3. We used the Microcenter clone since it was on sale for $5.99.Adafruit Motor/Stepper/Servo Shield for Arduino v2 Kit - v2.3 .
Well worth the 20 bucks. We tried some other stepper drivers but this shield was just too easy to work with, it did everything and really cleaned up the wiring.Stepper motor - NEMA-17 size - 200 steps/rev, 12V 350mA. x2. These are too easy to use regardless of how you drive them. Plenty of power and minimal current draw at 12V.12V 2A power supply. Power the motor shield and set the jumper for the Uno to draw power from it. No need for a second power supply. FYI we power the book with a separate 9V supply.Limit switches x2. You can manually zero the planchette each time you start but why bother. We used NTE 54-403 switches but use whatever fits your model. We mounted the X switch to the base and attached the Y to the moving carriage for no particular reason.