Tom the Tortoise Thief
This four-legged walker “belly flops” to obtain items on the ground.
Slow and steady wins the race, or so they say, but you still don’t expect a slowly moving turtle to make off with your cash or credit card. That’s the idea behind Tom the Tortoise Thief by Bill Bob.
This 3D-printed tortoise model leisurely walks up to its target, then belly flops onto its stomach to pick things up using a piece of tape affixed to its underside. It’s quite a clever arrangement. Given its speed, one might actually forget that there was previously something on the ground by the time it walks off.
The device was made as a weekend project with parts on hand, including eight 2014-vintage TGY-90 servos, along with an ESP32 development board that was already attached to stripboard. The body is 3D-printed, with space for five servos – four for the legs and another on the front that wasn’t implemented. Each servo connects to a second servo in order to create a two-axis shoulder mechanism, which combine to push the robot forward in a quadruped gait.
The plan was to incorporate a 3.7V Li-ion batter for power with a boost converter. However, this converter wasn’t operational, so is now used while tethered to wall power. Control is via a Python script running on a PC, which connects to the slow-and-steady terrapin via WiFi.
The build is finished off with a paper head and "shell," which makes it cute enough to avert suspicion of its potentially nefarious intent. It's quite the clever use of parts on-hand, and a good reminder to keep unused electronics organized and ready to go for whenever inspiration strikes!