Uh, oh! When I tried to dry my hair this morning I discovered I’d left my drier on "shrinkwrap". Still, it’ll grow out…

Have been super-gluing, shrinking and even some hot-gluing things together to get this Talrik Jr up.

The IR emitters were added last night, and with my tendency to fiddle around to get things jest right, this was not a trivial matter.

The emitters (3) are just the appropriate LED clipped inside an eyelet laser cut from plastic. The eyelet is superglued into the top plate of the bot. To eliminate as much spurious scattering and reflection between the emitters and the IR receivers, they are mounted on opposite sides of the top plate.

But to eliminate any propagation from the backside of the LED and "internal reflections" inside the bot upto the detectors, a 1 cm length of heatshrink tube is mounted on the back of the LED. To prevent the 2 leads shorting a couple of bits of small diam macaroni is shrunk inside the tube, and to absolutely make sure a bit of dark-coloured hot glue is drizzled on the back as well.

I’ve departed from the "guide" that comes with the kit. It shows the front IR emitters on the top of the plate, with detectors underneath. But I decided I’d like to be able to send IR data from various places in the room — not just from the front of the robot. So that means IR detectors on top, and therefore emitters underneath. Fortunately, there’s enough room.

Similarly, I want to be able to get IR data to various places in the room — not just from the rear end (where #3 emitter is located). So I mounted the rear emitter on top of the plate. Hopefully, there won’t be any back-scatter from this LED to the detectors that face front.

Pix:

The final pix show the 2 front IR emitters all glued into place. The wires are cut to about 5 mm to allow for a home-made connector. To be done later…

The next little task was assembling those nasty wheels. I have some vid of how well (or not!) that worked out, but it appears too big to upload to Youtube.

Anyway, I decided not to screw (see pix) the silly things together, but to hot glue them (since I had the gun all warmed up, anyway .

The 2 different plastics glued together OK, but it isn’t a super-strong bond. Maybe that’s a good thing.

When I dropped my first attempt one of the wheels came right off.

I think if anything falls off again, I’ll be doing the old plastic-to-metal  and metal-to-plastic lamination via a large-sized washer that just happens to fit snugly into both the wheel and the servo horn.

Pix:

And here are the results:

I hooked the servos (already hacked into continuous motion and zeroed out so they don’t power-up running!) upto a couple of controllers that came with my Viper kits, and — hey presto — at least the wheels turned OK.

But there was a 5 deg wobble. It’s quite noticable at full revs (about 30 rpm  and with the bot upside down. Maybe it’ll be OK on the night?

The next steps on Talrik are to hack the digital IR sensors into analog versions via some internal re-wiring. Obviously, this is also a bit of a fiddle. But that’s the middle name of this project.