In support of the Arizona Near Space Research group, I have agreed to set up a new ground station for tracking the balloon flights. We do this in order to point directional antennas at the balloons as they float across the state on their missions. I had done this about 10 – 12 years ago with a PIC processor programmed to read the telemetry from the balloon beacons and calculate the azimuth and elevation to point the directional antennas at the balloon for optimum reception of live video feeds.
As mentioned in my prior post, I found that the elevation rotator for my Kenpro-5400 set had corroded internally to the point where it was no longer working. It had been sitting outside in the weather for over 10 years, with no maintenance or activity, and the seals had allowed water to leak into the rotator, resulting in the corrosion. The Azimuth rotator just needed a bit of fresh grease on the bearings to work smoothly. This post will show some pictures of the cleaning/rebuilding process for the elevation rotator.
After having taken a break for a few years, I have renewed my membership in the Arizona Near Space Research group. This is a club that specializes in high-altitude balloon launches that carry payloads typically designed and built by students ranging from Jr. High to Post Graduate levels. I was involved in the club shortly after it was formed in the early 2000s, then found myself juggling for time to work on our cabin in Northern Arizona, Golf and family matters.
When I was involved years ago, I created an automated balloon tracking/antenna pointing system to keep our antennas pointed at the balloon as it floated downrange from the launch site. These antennas were high-gain 430 Mhz or 2 Ghz directional arrays on which we captured live video feeds from the balloons. My original incarnation was controlled by a PIC Microprocessor and a few I/O devices, driving my Kenpro KR-5400 Azitmuth-Elevation antenna rotator. It would listen to the GPS position info on the balloon’s radio link, and based on the ground station location, would calculate the correct azimuth and elevation to point the antenna at the balloon. It then sent appropriate signals to the antenna control box to steer the array.
In Part 1 of this project, we covered the general design of the battery charger. Part 2 described the physical construction of the charger. In Part 3, we will cover the calibration and operation of the charger, and present the Arduino Nano source code for the project.
Once the board was populated, I isolated the output from the voltage sense resistors by removing the Jumper J3. Then I fed a voltage into the sensors which was adjustable, and substituted for a real battery. I set it up so that 30 volts resulted in 5 volts at the sense point, with 0 volts being zero at the sense point. This gave me a linear range to work with. Jumper J3 is shown below in the operating position.
In Part 1, we went over the design of the 24 volt charger. In this Part 2, we will describe the physical build.
At this point, I developed a PC board to hold all of the components in a solid manner.