Safety fireworks launcher

Safety fireworks launcher, a set on Flickr.

It is obviously considered un safe to hold lit rockets and roman candles by hand. we (me and my son) thought we would not miss the fun of waving lit fireworks around so we constructed this remotely operated rig that allows one to safely light and manipulate fireworks.
The jig uses standard RC-servos that are hacked for continous operation. The servos internal potentiometers are removed and replaced with external ones. The external potentiometers acts as bearings for the pan/tilt axes. The axes are driven by laser-cut nylon gears mounted on the servos and the motion is fed back to the servo electronics by the potentiometers effectively making each axis a giant RC-servo.
This is our first prototype but we plan to expand the concept with several launchers, targets and some sort of battle scenario.

NEW: video of launcher in action

Link to raw design in various formats

Measuring temperature using thermistors

When building my laser chiller I needed to measure the coolant temperature. All I could find in my lab was a couple of 10k thermistors.
Using a look-up table of the thermal characteristics for thermistors I was able to get accurate readings.
I thought it may be usefull for other projects. This arduino code has a function for measureing the resistance in ohms of the thermistor and another function to convert this to centigrade.

More Quad2 build pictures

More Quad2, a set on Flickr.

Made some adjustments to the video pod. The camera now have a fixing brace so that it is now held in place by more than two tiny screws.
Installed camera, transmitter, sensors and OSD.
Here is the frame and camera pod in .hpgl format. If you don't have a laser cutter there are plenty of online services that cut for you.
If you make one please send a picture :)

Quad2 video version

Quad2 video version, a set on Flickr.

Decided to extend the arms of Quad2 for better stability and add video transmitter for FPV operation.
This will be the first prototype in a series of FPV attempts.