This is a 3D printed PKE METER with custom electronics inside similar to the one in the movie; Ghost Busters. Print this and use it to complete your ghost busters prop set or costume. Being a designer, I've improved the design a bit, so this PKE meter is not %100 same with the one in the movie, a bit smaller to fit smaller printers, better buttons and minor changes at the details. Internals should be quite different as i've never seen the inside of the original. :D
the antennas are linked to each other by two gears attached to them internally and move symmetrically by the push of a microservo.
Step 1: 3D Printing the Parts
I've cut the big body parts in two to fit in smaller printers. Also added internal details to screw them back to each other after printing. A bit of epoxy glue should also be fine. I managed to print this on my UP printer and glued them with epoxy. I've used the internal screws to secure parts together while glue sets, later removed them.
Step 2: The Circuitry and Code for the Microcontroller
The circuitry is designed from scratch around a PIC 16F88 and mainly drives the RC servo to move the antennas, powers the leds, checks for button presses and generates some sound effects as you can see at the video below.
I've added the circuit schematic and the hex file for programming the microcontroller.
Also added the Proteus simulation file, if you have the proteus software you can simulate and see how the thing works, press the buttons, hear the sounds etc.
you can increase & decrease the scanning frequency of the leds by pressing inc / dec buttons or preset buttons as you can see in the video. There is also a potentiometer hidden at the handle of the pke meter for you to operate secretly with your index finger while searching for ghosts. The sound frequency also changes together with the led flowing speed.
A distance sensor can also be used for the pke meter to operate its antennas and change the led/sound frequencies in the next version. I've added the necessary holes to the 3d model for the IR led and receiver for the distance sensor. This sensor is not implemented in the code yet.
there is a sensor suitable for the job here. The seller had kindly provided the circuit schematic for the sensor, if you'd like to build it yourself.
Step 3: Assembling the Antennas
Assembling the antennas is a bit tough as there is a very limited amount of space inside. Still it is quite adequate and I've managed to fit the necessary wiring to lit up all 7 leds. I've used multi threaded and very flexible ribbon cables taken out of old printers. If you can not find wires thin and fiexible enough for the job, you might install wiring for 3 leds on each side and light them up by soldering two in parallel. The original pke meter antenna leds also work in parallel.
Step 4: Preparing the Prototype Boards
I've cut one sided multi hole prototype circuit boards to use in my pke meter. I've arranged the board dimensions enabling the onboard micro buttons to be direcltly below the 3d printed button parts. First cut the board into the required dimensions, drill holes for the screws, screw the board onto the body part, mark the locations of the micro buttons then place them and solder. now you might proceed to actual circuit assembly on the same boards.
Step 5: Assembling the Display Board
This is quite a tough job as the display board is very small and I'm using 5mm thru hole LEDS, which are a bit big. If you use smaller LEDS, your job definitely will become much easier. you might use double copper sided prototype board and smd LEDS as well. it is up to your decision. If somebody designs a PCB for this project, I'd happily add it to the instructable.
Step 6: Assembling the Main Board
The circuit assembly is again quite tough as it was done on a multi holed prototype board bu using large thru hole components. It might be a good idea to draw a pcb with smd components. But i've managed to fit everything on to the mainboard.
Step 7: Painting the Body
After checking and adjusting everything to fit in properly, I've painted the body parts with matte black spray paint. you can also create scratch marks etc if you like. I've left it to time.
Step 8: Final Assembly
I reinstalled all parts which I've disassembled for painting. Straightforward job as I've already done it multiple times while preparing them. As I've lost the printed buttons in the workshop, I've left their space empty. I'll either reprint them or use them when i find them :D. They can't be too far.
Step 9: Lets Go Hunt Ghosts
Ghosts are everywhere. :D