How To Make Any Land Metal Detector Headphones Wireless - Tutorial, page 5
Modify Your Metal Detector's Armrest
To be able to mount a protective container/case for the transmitter onto the detector's current armrest, you need to make a little modification to it. For this project, I used a strong armrest that was made out of a section of a PVC pipe 12 years ago (when the Minelab armrests used to break apart easily).
This durable homemade armrest had also been used for housing a repositioned headphone jack and its wiring (see the "Replacing an Original Armrest on Minelab E-Trac with a Home-Made One" section of my tutorial on "How To Prevent Breakage of a Headphone Jack on Minelab Explorer, Safari or E-Trac"). After 12 years of continuous use, the 1/4" phone socket did not grip the headphone plug as tight as it used to due to metal fatigue of its 'normally closed' (NC) contact, so I decided to remove the old assembly. Had not the E-Trac become just one of my back-up metal detectors, I would replace the adapter to avoid having a similar problem with the Minelab E-Trac's headphone jack in the future. As my E-Trac took a long vacation last season, I dismounted the old assembly - the main socket/jack adapter, wires and a 1/8" female-male adapter, from the armrest.
Dismounting Assembly of Repositioned Audio Jack from Metal Detector's Armrest
After Adapters and Wires Were Removed
As I had already selected a plastic container for housing the digital transmitter, I had to determine the container's optimal position on the armrest: the container should be compactly placed against both the armrest and the detector's body, and without sticking out too much in any direction. The armrest has a length of 5 inches (12.7cm), so the 4.7-inch long container would nicely fit on the outside and within the armrest's length.
My next step was to mark spots for holes to be made on the armrest. The holes would be used for zip ties that could hold both the container and the connecting cable in place. If you use the detector's original armrest made of thin plastic, the holes should be made away from the armrest's edges and stiffening plates not to weaken them. The closer the hole to the edge, the narrower the space between the hole and the edge. Being tightly put around this narrow "bridge", a closed zip tie can crush it.
Mark Locations for Required Holes on Armrest
After I marked four spots on the armrest, I positioned the plastic container against the armrest again and marked the corresponding spots on the container as was shown on a previous page.
If your metal detector has a metal armrest, you can drill holes for zip ties. Or you can use zip ties of substantial length to affix the container any way possible.
The easiest way to make holes in the plastic armrest is the same as the above-described method of using a soldering iron with a large tip of a Chisel type. The holes should be larger than the holes made on the container so that additional zip ties for affixing the connecting cable's harness could run through them as well.
Use Soldering Iron To Make Holes in PVC Armrest
In five minutes, I had the armrest ready for coupling with a digital wireless module.