I've recently been doing quite a bit of programming for my co-op, developing software tools to control hardware for experiments in lab environments. I started with LabWindows/CVI, but after discovering ANSI-C interfaces from National Instruments to the libraries I need (notably VISA & DAQmx) I've been migrating to using QT/C++.

This first program of mine doesn't use anything from National Instruments - it's more of a post-process tool that translates data files into nice pictures. There were a few headaches interpreting the documentation, but with just a week of development while learning QT I've come up with a nice solution that is nearly complete and self-contained.

Most of my code was straight QT, but I did create my own class to do the processing, and I had it inherit the signal/slot behavior of QObjects. Coming from micro-controller C programming, I really appreciated how easily C++ made keeping track of things - and the QT documentation was sufficient though I spent a lot of time reading forums and mailing lists for actual examples of code because I'm not used to C++/QT methodologies.

With this project nearly complete, I'm preparing to get into a much more ambitious series of projects. I have much to learn yet, but with what I have learned so far I think I can overcome many of the challenges I'll see along the way. It should be fun.

My new Himoto Racing MXB-3 buggy had a throttle/brake servo binding issue that prevented use of the brakes. Inspection of the area showed that the binding was caused by a slider installed on the portion of the servo that has a linkage connecting to the carburetor. From the illustrations provided by Himoto, this slider is installed on the top of the servo - as mine was.

Unfortunately due to the geometry involved with the servo and motor/carburetor mounts, this is incorrect and leads to binding. The problem is that the slider can only rotate in the horizontal plane through the screw that connects it to the servo arm - but it can not be aligned vertically with the carburetor linkage. This constraint leads to binding when the brake is applied, and as a result no braking force is produced.

The fix is simple - reinstall the linkage under the servo. Now it can be aligned vertically with the linkage end at the carburetor, and is free to rotate horizontally as intended. When the brake is applied, it slides freely and allows the brake to engage. Please reference the image below if you are having binding issues with your RC car.

Last night I had a chance to head out to Wallops Island to watch a sounding rocket experiment. I think that this one was designed to create a high altitude cloud of particles for VHF radio experiments. Here are a couple of pictures from the night.

Sounding rocket on the rail early in the evening.

Lift off!