Pickleball Machine

Description

This pickleball machine can hurl balls at you at upwards of 60 MPH! It features adjustable speed, top/back spin and feed rate, a 100 ball hopper and a remote control. Weighing in at only about 7 lbs (without the battery), you can mount it to a standard tripod, or you can print the mini-tripod shown. It runs for several hours on a 9ah, 12v battery. And for all those loose balls, try my Ball Scoop: https://www.thingiverse.com/thing:3813749 Watch it go at: https://youtu.be/mo0VZ6vfwUY UPDATE: I've posted STEP format CAD files for an updated version of this thing that uses direct-drive DC motors rather than the belt drive system used here. **Part List:** 2x 8mm rod x 2.625", v-groove in end for retaining ring (wheel axle) 2x 8mm retaining ring (wheel axle) 2x 8mm x 0.020" thick shim washers 1x 8mm rod x 1" (roto axle) 3x 608 ball bearing 3x 8-32 x 0.375" screw (rod set screw, shield) 6x 8-32 x 1.125" screw (arm plate) 4x M3 x 6mm screw (RS550 motor) 2x RS550 motor (flywheels) 1x Maxon 2140-937-58.236-050 motor (rotor) 12x 8-32 x 1.5" (wheels) 12x 8-32 nylock nuts 4x 8-32 x 0.75" screw (coupler) 3x 10-32 x 0.75 FH screw (hopper plate) 8x 8-32 x 0.75" FH screw (hopper plate, tripod plate) 4x 10-32 x 0.75" screw (tripod plate) 8x 4-40 x 0.375" screw (hopper motor, controller cover) 3x 0.75" x 14" aluminum tube 1x 0.75" x 7.688" aluminum tube 1x 10-32 x 8" threaded rod 2x 10-32 coupler nuts 1x 1/4-20 x 3.5 bolt (tripod lock) 1x 1/4-20 nut 2x 120MXL025 belt (150t) 4mm corrugated sign board (approx 6 sq ft) Hopper plate Tripod plate 3/4" thick EVA foam (2lb/ft^3 density) Gaffer's tape **Wheel Assembly** The wheels are 6" dia. discs cut from lightweight EVA foam. (I used a Fiskar's kneeling pad from Home Depot.) Use a hole saw to cut out a 1" diameter center hole, and then rough cut with a knife, jig saw or bandsaw an oversized 6" diameter. Press the disc over the pulley90_back piece and use the hole pattern in the back piece to drill out the six holes in the perimeter of the foam disc. Press the 608 bearings into the pulley90 and pulley90_back pieces. These two pieces will be clamped together over the foam disc to form the flywheels. Before assembling, apply a thin bead of superglue to the inside edge of each of these pieces to that the inside edge will be glued to the foam. Assemble the flywheels with the 6 8-32x1.5" screws and the 8-32 nylock nuts. It is important that that the wheels run perfectly true. To finish the outer edge of the foam, I made a jig with a piece of 8mm rod so that I could spin the wheel by hand a fixed distance over a belt sander. (Basically, I drilled a hole in a board, stuck the piece of rod in, and then clamped the board to the fence on my belt sander.) This will give you a perfectly concentric foam tire. The foam edge, by itself, would get torn up quickly by the pickleballs. To reinforce it, wrap the edge with exactly 3 layers of gaffer's tape, trimmed to the 3/4" width of the wheel. Try to have the end of the tape just line up wiht the starting point of the tape. Use a small bead of superglue on the end edge of the tape to keep it from flying loose. At this point, the wheels will work, but it will leave black smudges on your pickleballs, as a final step, I coated the top of the tape with a very thin layer of Aquaseal repair adhesive to form a very tough, flexible urethane coating. **Controller** I pieced together the controller from surplus PIC-SERVO, PIC-I/O and SSA-485 controller boards. These are too obscure (and probably expensive) to recommend for anyone else to use. Instead, I would recommend an Arduino board driving two MOSFET transistors for the flywheels, and a Pololu JRK G2 controllwer for the rotor's servo motor. Alternately, you could instead use a NEMA 17 stepper for the rotor and use a Pololu TicStep controller board. Please post questions in the comments if you need help figuring out a controller.

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