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As we enter the final hours, I have completed what I thought would be impossible. The Tipping Tophat finally tips, bringing my kooky idea to reality.

When I first began work on the hat, I had a rough idea of how it was going to work, except that I had no idea of the challenges I would encounter as it all came together.

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The biggest issue here was space. It turns out dolls aren't as small as you would think and getting half of one inside a hat, with room to spare, is quite a squeeze. Luckily I had almost exactly the right amount of space. Occasionally on the way up, he catches on the lid slightly but I can avoid that by being gentle.

My second crisis issue was that the servos I used didn't have quite enough power when running off the rechargeable battery provided in the kit. Fortunately, the kit also included a second connector and I had a spare 3xAA battery holder lying around, which was just enough to get it working reliably.

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One thing that I hadn't thought much about in the beginning was a mechanism to open the hat. Working with a limit of only 3 data pins, one of which I reserved for the triggering button, meant I had to work with only 2 servos. This limitation force me to look into a pushrod system, where the raising of the main arm pushes a rod towards a hinged arm at the back, which in turn pushes up and opens the lid.

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Getting the arm to move turned out to be a lot easier than I had imagined. The doll itself already had a simple shoulder that rotated, so with just a dab of oil, the tip of a servo horn and another push rod, I had my own little roboman. The servo for his arm is mounted into the main hinged lifting arm, so it comes up when he pops out of the hat.

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Internally, this hat is far from glamourous. It's a mess of wires taped to the edges, with enough room to move as needed. While it doesn't look great, it gets the job done.

 

This was a fun competition, albeit stressful and frustrating, but ultimately I'm glad to have been part of it. I plan to release the 3d models for this build soon, but I think I'll finalise a few parts first.