Did some ground tests for the APRS tracker we are planning to launch at Field Day this year. Man these capacitors took forever to charge using a USB power bank! Thought I would document what I’ve done so far if anyone cares to follow or wishes to use this to build your own.
The one picture is the APRS packet. Notice at the top I’m transmitting telemetry from the tracker including temperature, pressure (for altitude reference), and voltage (for battery monitoring). Also doing a plug for the club website.
Other picture is of the tracker. Some stats:
Output varies from 0.5-1.0 watt depending on the charge level of the capacitors.
The capacitors are 3.0 volt 3.3 farad. There are 4 in series-parallel to give 6.0 volts and 3.3 farad.
CAPACITOR 3.3F 0% +100% 3V T/H
The antenna is 26ga enameled wire at 50cm. It’s a monopole antenna which is fine since the tracker is meant to be up in the air.
Solar is pending arrival from DigiKey. I’ll be using 2×2.76 volt 55.1 mA monocrystalline solar panels in series. This will give me 5.52 volts at peak sun which is near perfect for my capacitors.
MONOCRYST SOLAR CELL 123MW 2.76V
I’ve got plenty of both Mylar and CyMylar balloons, but this tracker is likely to be a bit on the heavy side. I’m at 15.1 grams so far and im not sure yet what the solar package will weigh. To be safe I’ll use the 60” CyMylar balloon.
60Inch Jumbo Large 4D Clear Sphere Balloons/Transparent Foil Balloons
Next step is to wait on the solar panels and figure out how I want to arrange/attach them.