It all started with the ‘Leave Me Alone Box‘, built by Michael Seedman. He made a fairly complex design, with servo motors and electronic control. Brett Coulthard saw this design, and made a simpler version he called ‘The Most Useless Machine‘, and put a video of it on YouTube. This video went viral with more than 5 million views. You can now buy a kit to build you own machine.
To build this model you need the parts listed in the table below, plus 2 switches: Sw1 is a double pole, double throw toggle switch, and Sw2 is a single pole normally closed push-button switch. I didn’t want to mutilate Meccano parts, so I made two 3 x 3 hole plates from unused PCB material, with a larger hole for the switches. In the building instructions below, all numbers in bold are Meccano part numbers. I used the numbers as listed on the excellent Meccano site of Oscar Felgueiras. In a few photos you see 2 red 74, they are later removed to make way for 2 46 holding the battery enclosure 710. The parts-list may not be completely correct, I didn’t disassemble the model to count every last part. 37 and 38 should be added as needed.
The wiring of the switches is shown below, you should experiment with the position of Sw1 and the polarity of the battery and motor to get the correct functionality of the model. In the bottom-most position of the arm, the 111 bolt on the 27d pushes the push-button Sw2 to the ‘on’ position, stopping the motor.
The front and back of the machine consist of a 52a and 2 2, bolted together with 10 48a, 2 47 and a 235h. The lid is built with a 48a, 9f, 5 and 72. The arm consists of 6 90a, 2 111, 4 111a, a 38, 4 38a and a 27d. The motor is bolted to the rear, in the left-most position. The gear-train is as follows: the motor holds a worm 32, that drives a 27a; a 25 engages a 27, and a 26c engages the 27d of the arm.
With these instructions and the photos below you should be able to build the model. If you click a photo, you get a high-resolution version which may be helpful. If you have a question or another remark, please leave a comment.