Getting more throttle resolution from an old RC Controller.

I have been flying my tricopter around lately, and have been getting a bit better at not running it into things. However, one thing in particular has been bugging me about the my controller for the tricopter. The throttle stick resolution has felt really low, especially when compared to a friend's newer and nicer controller. When flying it around at the Makery there was about one notch of difference between it barely skidding around the floor, and heading straight to the ceiling.

So, tonight I took it apart to see what I could do about getting finer control out of it.  It turns out there is just a small spring arm with a bump at the end riding on notches molded on the back of the joystick. I believe this is pretty standard from what I’ve seen online.

This is one of the times where having a 3D printer, and knowing how it works pays off. I needed a very specialized piece with several notches running up a curved surface. This immediately reminded me of the surface that 3D printers make as they lay down each layer of an object. So I took a few measurements, fired up the 3D modeling software and made a “cap” that will sit on top the current notches, so that the spring rides on it instead. You will notice that the 3D model has a perfectly smooth surface, but we get the ridges that it needs by setting the layer height for the printer.  I measured the old notches at .5mm on center, so I set the layer height to .3mm for the first try.

After trying to print one by itself, and having it end up all blobby and malformed, I remembered to turn the “cool” setting on in Slic3r,  and put five of them on a plate to make sure they have time to cool between layers. I also turned the fan on, which I believe is why they all came detached from the build platform halfway through the print. After turning that off and trying it again, 3 out of the 5 finished properly, and I was able to test it out. It worked great! The new piece fit right over the top of the old piece and the spring lined up perfectly on top.

It turned out to be a great improvement over the original. The ridges were smaller and more rounded, which gave it a lighter feel, but the spring was compressed more, so it still felt like it was strong enough to hold position. And most importantly, it had better resolution, and I can fly it around without worrying so much about it running into the ceiling while indoors.

All in all it took about an hour from idea to completion. I would say it’s definitely worth trying this if your controller is like mine.

 

Egg Drop Contest – Results

Last Sunday (April 1st) was the first Omaha Maker Group Egg Drop.  The competition was much in the same style as the Nerf Gun Mod Contest run last fall; This competition had a lower entry barrier, and thus far greater turnout, with 10 total entries (Eric entered twice).  All the eggs survived the drop, but Stephanie was the big winner, with a score that bested the next entrant by a factor of 4. Click through for full results, and a little high-speed video, thanks to Ben. Continue reading

Microscope Photography – Integrated Circuits

On Tuesday night, we were disassembling some old printers, and salvaged some large ROM chips. Patrick got the idea to use the mill to remove the top layer of the case, and expose the IC inside.  Here are some photos we took of the chip’s insides with a microscope. Magnifications range between 4x and 40x, thought the 40x were pretty difficult to illuminate properly, because the lens obscures most of the light. As for the cameras, we  used a little point and shoot and a cell phone camera, both just held up to the microscope’s eyepiece.

Contacting the International Space Station

Last Wednesday, OMG member Pat Joseph (KØCTU) stopped by the Makery to see if we could make contact with the International Space Station, as it passed overhead.

The Space Station has a few amateur radio operations on board, and the one we were making contacts with was an automatic mode known as APRS. The automated station heard my transmission and sent back an acknowledgement three times during the pass.

About a  half-dozen people took part in the attempt.  James and Rick manned the antenna, while Pat ran the radio.  The rest of us provided moral support :)

The antenna that Pat brought down was pretty innovative. The main body was made from plastic conduit, and the elements were built from bits of metal tape measure.  The result is a quick-setting antenna that is difficult to damage, yet easy to fold up and store.

 

Web-attached pan tilt camera

With some help from Brandon and Ben I got the mechanics for the pan tilt camera rig going. The servos attach to an Arduino which is connected to a computer running a Windows web service that provides access to the camera.

I had an issue with the movement speed initially, and had to update the Arduino code with some position speed ramping. That went well and it is moving more smoothly. It flops around a bit, but I think that is mostly the slop in the mechanism.

The web service supports tagging of positions so that interesting views can be labeled. Once labeled a single button press takes the camera back to the associated position.

I will post some video of it in action soon.

Tippy forge

Here are a couple of videos of the tippy forge I've been working on for the Omaha maker Group. At this point it just needs the frame to hold it and a handle to make it easy to tip. There is a little leakage from the input that we need to get sealed up, but it works quite well so far.


Motor demonstration rig

One of the interesting projects from the Omaha Maker Group meeting on Jan 10. Ben put together this little motor demonstration rig with a couple of magnets, a 3D printed frame, and the armature from a commercial motor. Here he is just holding a couple of wires against the commutator as brushes. It's interesting to see the effect of adjusting the brush positions relative to the magnets.


OMG’s Patrick Pecoraro to present Contrast, a custom pinhole camera inspired exhibition

From Patrick’s website:

“In order to assemble this series, I faced a specific problem: most pinhole cameras have only one shot. You expose film or paper and have to go back and develop it in the lab before loading the next shot. When there is more than one opportunity for a great photograph, the only option is to carry more than one camera. I came up with a solution. I designed and built a pinhole camera that uses regular 35mm film, but in a larger format. Three rolls are combined, equally spaced, giving a triptych like image. The resulting triptych blends together by persistance of vision. No longer limited to the short distances from the photo lab; I can take this camera hiking and get four to six exposures per set of film. Exposures only limited by the number of canisters on hand and the available light.

This new camera enhances the subject matter. For the last few years I captured images of nature reclaiming the fruits of man, photographing anything from abandoned buildings on the verge of collapse to old tires dumped in a field. Fascinated by the rusting, disintegrating, forgotten objects reclaimed by nature. I believe that capturing these scenes this way helps one understand that, over time, all man-made things will disappear, nature reclaims all.”

You can see Contrast beginning the 13th of January at:

The Tea Smith

1118 Howard St
Omaha, NE 68102
(402) 932 3933