Been off the grid for a while but I hope to get back to new projects first of the year or so. In particular I’m looking forward to designing a bluetooth tablet app for controlling my Xbee network and also doing a bit of web work and exploration. I had a bit of surgery a week ago, going to change jobs first of the year and the assorted holiday chaos manifests itself. So I’m pretty much whacked out for a bit.

Finally got my control system tested out in the woods. Very happy with the range. The Xbee will do 300ft and I can’t even see the RS3 if I go that far away. This is my design. All the wireless communications are handled by the Xbee. I can send any sort of data to or from anything with this system in real time. Those are 16 byte data packets that are controlling the throttle and coupler servos.

The RS3 has the throttle, front and rear couplers and single channel sound all hooked up and working. All of it is powered by a 5000mah hour LiPoly battery driving a Pololu 18v7 motor controller. The control widget drives the servos directly. There is also an RFID reader under the fuel tank which works quite well too.


The results of my latest attempt at mold making and resin casting. 3D print original and his clones. Click on the picture above for a more detailed (and sharper) image. These guys are about 2.5 inches tall or 6 ft in 1:29 G Scale.

I’m trying to get these to a point where I can make consistent resin casts from 3D figure models.

Anyhow, this is the sixth or seventh? iteration of mold making and so far the best. I do think I need to explore some of the finer points of this process but for now I’m finally getting decent results.


Well, I got tired of Makerbots at the library that were always busy or broken, and the UPrints in the Engineering Lab were basically junk for printing 1:29 size figures.

So, I uploaded my Fab Four 3D peoples to Shapeways this time and man, I am glad I did. Much better resolution, really nice. Need a bit more facial detail for the two on the left but that’s not something I could even see on the other prints!

As cooler weather approaches, I will be getting back to s/w development on my Xbee control system and doing some more character modeling for 3D printing. The Xbee stuff works quite well, however there are only hooks in for the configurable portions. The Attiny 1634 processor has 256 bytes of eeprom for non-volatile storage, I want to leverage the code into getting the various control limits and settings from this instead of hard-coding everything per device. I will also implement a new network message to program the client devices via a web page interface, this should make setup and tweaking of each device much more user friendly.

As for the 3D character modeling, I have found a potent set of freeware tools that I am currently working through the learning curve on. In particular Blender has a somewhat non-standard interface but once you get the hang of it, not too bad. (see various posts below for more reading on this). It has some really neat options too, including cloth physics (draping clothes over 3D people, etc) and can also load bvh motion capture files to apply animations to your creations. While I don’t specifically use animations for my 3D printing, selecting a single frame as a basis for a pose is quite handy. Make Human is the other freeware package, it’s learning curve is actually quite small. You just move a set of sliders to create human 3D mesh objects, you can select gender, age, weight, height, etc, quite cool.

Another hobby/business that is coming along well is the airplane. One Seven Two Mike Echo now sports a newly overhauled 320-E2D engine with new mags, a startek starter and the 160hp STC upgrade. She really flies great now, MUCH noticed improvement in performance and a few more knots in cruise. Really sweet. I’m looking forward to more adventures.Now she just needs to rent rent rent so I can pay for all that! ha.

I am also trying to finish up the first section of my outdoor train layout, I have the frame built and am currently experimenting with concrete scenery shell techniques (ala Disney magic mountain) and it’s coming along nicely. I don’t have much time left before the cold will become too much to cure the concrete (actually sand/topping finish mix) so I’m putting most of my effort there. My plan is to get the basic scenery shell done and lay the track into the ballast so I can do some research on how the whole thing survives the winter. Ah, engineering, I do love it so!


I realized I didn’t have this posted up- this is the single channel mp3 sound card from combined with a simple audio amp. The amp is quite loud and can be built with parts from Radio Shack. This is what I’m using on my RS3 in the pictures below. I’m using the Attiny 1634 s/w UART to drive this from the client widget. It works quite well, you just send a single byte to the card to set the volume or play one of the sounds. However, you get what you pay for, $10 only gets you one sound at a time.