Monday, May 2, 2011

Antenna Launcher Digital Scope Part 2

These are the final touches to the Digital Scope System and the Antenna Launcher.

I made a hood out of a sheet soft closed-cell foam and attached it to the aluminum frame of the scope with Velcro for easy and quick installation/removal - takes 5 seconds to install it. This picture also shows the trigger support bracket and the safety strap for the trigger.

This hood works very well - it reduces dramatically the glare and improves the display contrast on a bright sunny day.

What's better way to calibrate the accelerometer sensor than Mother Earth's gravitational force? I glued a small Spirit Level to the frame to aid the GeoCam software calibration. After the scope is installed and level (according to the Spirit Level), the GeoCam calibration routine is executed to establish 0 degree pitch reference point.

Update on performance: The antenna launcher and the scope system work fantastic and I couldn't be happier! At 40 psi (less than half of the maximum 100 psi pressure), shooting at a very steep angle (75 degrees) and towing a line, I was able to go over a 110 ft tree with huge reserve in the trajectory. The scope allows for repeatable and well controlled launches - I was able to produce a nice group - 3 consecutive launches where the ball falls within 2-3 yards area every time with peak height of the trajectory of over 150 ft (4 oz ball, no wind, no line). Spray of silicon lubricant on the ball, lubricates the inside of the barrel too and makes for easy loading and probably decreases the friction during launch - with Schedule 40 2.5" barrel the tennis ball is a tight fit - SDR-21 type pipe is recommended for better fit and weights less but it is also less sturdy.