I love animatronics but apart from Peter the Pumpkin (part 5 - final thoughts) I haven't actually made anything credible so when Element14 Community Project14 themed along these lines I just could not resist starting, even though I had two other tasks on at the time BASYS MX3 Trainer Board - Review and iBox: #4 Summary of Project; the latter project suffering from lack of time unfortunately. At this stage I'm still not going to say what I'm trying to make as it will be less embarrassing if it fails completely but instead want to share some of the bits I've been designing and printing over the last 2-3 weeks.
So this blog hopefully gives some peeks of the construction without actually revealing too much yet by showing you the current build state .
My animatronic hopefully will be cute (depending upon the final paint job I achieve) and will have most body parts and I'm going to try and move it about using some servos. The initial four servos that I bought were miniature 90gram variety and they seemed a bit weak so I purchased four more with metal gearing and I hope those have enough torque to make the animatronic move properly. Any tips on painting PLA would be appreciated - I was thinking about using acrylics.
The animatronic does have a head which I have already 3D printed - it took many hours and is a bit of a lump adding to the problem of servo mobility....we'll see when we get that far if I made a big mistake.
I made a cradle for two of the servos and I am yet to print another, it was meant to be a bank of four but the Lulzbot Mini bed is too small - not a huge issue as I just split the design down into two separate units:
My initial pulley design in OpenSCAD was like this shown below. Each groove has a hole that the filament can be fed into, out of the pulley's side and then fixed with a knot or fishing tackle crimp sleeve. Once printed I realised it would be hard to adjust the line tension when one side was against the servo body. I therefore changed to the single disc design as in the above photo and I also added some posts to help secure the filament as that stuff is super slippery.
This is another dual servo mount I came up with - it is also much quicker to print but I realised the control lines would start to tangle.
These are some of the other components at the moment...more are planned.
Once working I have a few ideas how to give the animatronic an outer covering/skin and I have to buy a few things in to realise that, including some paint and latex glue. I've a worrying feeling it will either not flex and the servos will stall or it will look ghastly. Only one way to find out.
4. Control Electronics
I've bought a simple 16-channel Servo breadout board and plan to use that with an Arduino to control the servos, add some movement and choreograph the output. The Arduino I plan to use is the MKR1010.