Adding a magnetic switch to a Featherweight GPS tracker

[Adrian A]

For my StratoSpear rocket, I'm making 2 ejectable av-bays for the booster and the 2nd stage that include a Featherweight GPS tracker. I'm adding Featherweight magnetic switches to the trackers, and I'll document the process here since it might be of general interest. This requires beginner-intermediate solder skill.

Step 1: Remove the terminal block. Optional: remove the slide switch. For the terminal block, use a hot iron to melt both terminals at the same time. Hold or mount the tracker with the terminal block on the underside so that it will just fall out once the solder is melted. Add some solder and flux to ensure good heat transfer from the iron and the terminals. The terminal block will just fall out once both pins are fully melted; you don't want to try to force it out.

The trackers with the switch and terminal
block removed:

View attachment 604619

Next, add the battery connection to the switch. It's possible to solder the tracker's battery adapter directly to the board, which is a nice option if you have access to plug in the battery.


In my recent av-bays, I have soldered on a connector on the end of wires for easier access when my very tight av-bays are assembled.



Next, solder the switch output wires onto the tracker. The red + side goes to the hole labeled "+sw" on the underside of the board, and the black ground wire goes to the - hole were the terminal block was. Space the wires out so that they line up with the Out and Gnd terminal holes on the switch, as shown:



Solder the switch onto the wires, and glue the switch down with the adhesive of your choice. I used hot glue for this installation. Bonus feature of this installation and glue choice is that the tracker's red LED is still visible through the magentic switch mounting hole:



For me this tracker will go into my av-bay with 29mm Blue Ravens like this (a previous version where the tracker was getting its power from one of the Blue Ravens:

 

[Dave S.]

In that 2nd to last photo it looks like one of the mounting holes for the GPS is blocked by the magnetic switch.

When you, solder the switch output wires onto the tracker, couldn't the red and black wires be an inch or so longer so the switch gets mounted near to the edge of the sled. [that way the switch would be near the outside of the coupler and within the range of the magnet.] The GPS's mounting holes would then be free and clear to use as intended.

 

[Adrian A]

In that 2nd to last photo it looks like one of the mounting holes for the GPS is blocked by the magnetic switch.

When you, solder the switch output wires onto the tracker, couldn't the red and black wires be an inch or so longer so the switch gets mounted near to the edge of the sled. [that way the switch would be near the outside of the coupler and within the range of the magnet.] The GPS's mounting holes would then be free and clear to use as intended.

Yes that’s true, but it all depends on installation you’re using. The one in this example did not use the mounting holes, and needed the switch to be centered to fit between the threaded rods of the av-bay.