We see a lot of clocks here at Hackaday. Digital clocks, retro clocks, lots of Nixie clocks, binary clocks, and clocks that appear to be designed specifically to be unreadable. But this dual-servo kinematic clock is something we haven’t seen yet, and it’s certainly worth a mention.
[mircemk]’s idea is simple and hearkens back to grammar school days when [Teacher] put a large cardboard clock dial on the blackboard and went through the “big hand, little hand” drill. In this case, the static cardboard clock has been replaced by a 3D-printed dial and hands, while a pair of servos linked together by two arms takes the place of the teacher. The video below shows it in action; the joint in the linkage between the two servos has a screw sticking out that can be maneuvered across the clock face to reposition the hands. It’s a little jittery, though; [mircemk] might want to tune the servo loops up a bit or tighten the linkage joints to make things a little smoother.
Even with the shakes, we find it wonderfully weird and hard to stop watching. It reminds us a bit of this luminous plotting clock from a while back – same linkage, different display.
[Mark Rehorst] has been busy designing and building 3D printers, and Son of Megamax — one of his earlier builds — needed a bed heater replacement. He took the opportunity to add a Kelvin-type kinematic mount as well. The kinematic mount and base efficiently constrain the bed in a controlled way while allowing for thermal expansion, providing a stable platform that also allows for removal and repeatable re-positioning.
After a short discussion regarding the heater replacement, [Mark] explains the design and manufacture of his kinematic mount. Of particular note are the practical considerations of the design; [Mark] aimed to use square aluminum tubing as much as possible, with machining requirements that were easily done with the equipment he had available. Time is a resource after all, and design decisions that help one get something working quickly have a value all their own.
If you’re still a bit foggy on kinematic mounts and how they work, you’re not alone. Check out our coverage of this 3D-printed kinematic camera mount which should make the concept a bit clearer.
The guys over at Rusty Nail Workshop have put up an Internet controlled robotic arm for your amusement. While you’re waiting for the turkey to be done (or, you know, working), try your hand at moving some LEGO pieces around with a remote-controlled robotic arm.
The build log goes through the parts needed for the build. The arm itself is a Lynxmotion AL-5D, a heavy-duty device that’s far more capable and looks a lot better than our old Armatron.
The arm is controlled by an Arduino Uno. The Arduino is connected to the arm’s servo controller. Movement commands are received by an Ethernet shield and translated into servo commands. The entire build runs independently of a computer just like this project’s inspiration, the Orbduino.
Of course you can imagine the mayhem that would ensue if multiple people tried to take control of the robot simultaneously. A bit of code on the project’s website makes sure only one person has control of the robot at any given time. Check out what somebody else is building out of LEGO blocks with a Waldo. If you’re lucky, you’ll be able to knock that work down.