This tiny FPV Quad Tank uses Lego tracks driven by servos. It turns via skid steer. The tracks can articulate 30 degrees up and down for going over obstacles.
See the third design - a turret tank - here: https://www.thingiverse.com/thing:3481012
To build you need the following:
-Four Lego tracks (Lego Part: x939 or 43903 - www.bricklink.com for best prices)
-Four servos (continuous [FS90R] or modify a regular one – Search "FliteTest 360 Degree Servo Mod" on YouTube)
-Receiver of your choice (the smaller the better)
-Mini FPV camera AIO (I used this one: AKK BA2 5.8Ghz 200mW FPV Transmitter Raceband 600TVL 1/4 Cmos Mini FPV Micro AIO Camera (https://www.akktek.com/akk-ba2.html)
-5v pololu step up/down regulator
-1s batteries (I used tattu 800mah); There is space enough inside for a 2s Battery if you so desired.
-Twelve M3-0.5 x 14mm socket cap screws/bolts (or similar) – you could use M3x12mm, but the 14mm are better.
-Twelve M3-0.5 Nylon lock nuts
Quick Test video: https://www.youtube.com/watch?v=pfvYdi5RJv0
This is my second designed Tiny Trak (See the original at https://www.thingiverse.com/thing:2977620)
A Note on Printing: All parts can be printed WITHOUT SUPPORTS. These files were designed with integrated supports. There may be some tabs to cut out (See Assembly Instructions).
-One Body (has integrated supports)
-One Body Tail (Optional)
-Four Lower Suspensions (has integrated supports)
-Four Transverse Levers
-Four driven wheels (four of both Driven Wheel A & B)
-Sixteen Bogey Wheels (Non-drive)
- Print all required parts. (Figure 1)
- Cut/remove the print tabs from the “Body” and “Lower Suspension” prints. (Figures 2 & 3)
- Ensure the “Body” and “Chassis” click together and have a good fit. parts should go together and come apart without much effort. (Figure 4) If you desire to have the “Body Tail” (Curved tailpiece) attached, glue that up now.
- Install continuous servos into “Chassis.” Consider cutting down the wires and soldering the leads together to save on space. Make sure to connect the left side signal wires together and then the right side signal wires together (either direct soldering or using a Y-harness). Then connect all of the positive and negative leads together respectively for all four servos. Connect the power leads to to a 5V regulator/Pololu. Attach power and signal wires to the receiver of your choice. (Figure 5)
- Prepare the drive and lower assembly parts (Figure 6)
- Super Glue (CA Glue) the “Driven Wheel A & B” Parts together. Once dry, glue in the included servo arm in the driven wheel slot. ensure the hole in the servo arm is centered. (Figure 7). Give this ample time to completely dry and set up. Then cut the servo arm tab hanging off the wheel. (Left side of Figure 9) You can also detach the center print support of the driven wheel if desired (See images from https://www.thingiverse.com/thing:3481012 ro see how that looks. The circle was left on in the images for this print.
- Install the driven wheels onto the servos (Refer back to Figure 5)
- Install the “Transverse Lever” onto the “Lower Suspension.” Ensure the flat or smooth part of the lever - typically the part that printed down on the print bed - is facing the “lower suspension.” This will help reduce friction. Install the four “bogey Wheels” onto the lever. again, ensure the smooth face of the bogey wheels face the lever to reduce any friction. (Figure 8 & 9)
- With the Chassis flipped over, glue the lower suspension assembly (four) to the chassis. BE SURE TO LINE UP THE TRANSVERSE LEVER AND THE DRIVEN WHEEL in the same plane. also make sure the center bolt of the lever is in line with the center of the driven wheel. (Figure 10)
- Attach the Body onto the Chassis. (Figure 11)
- Install LEGO Tracks (Figure 12)
- Bind your radio and get moving. Experiment with different track configurations (Figure 13)
- If using FPV, you can print the Camera Pod if you wish or just use foam to prop it up in the cavity. The camera pod file is designed for the specific camera I used, so print if you desire. (Figure 14 & 15)