(Thanks to chemforever, who initiated a group-buying of this on PTT.)
It's a good one, but after carrying them for a few days, I found a little problem that is troubling me. The design of the buttons on both the remote control and the receiver made them easily to be activated unintentionally.
Almost every time I took out the receiver from my bag, it's already powered on.
To prevent batteries from running out unintentionally, I made some modification to them.
Not a sophisticated modification, instead, I just added a sliding switch to them.
Try it yourself if you're bothered by the same problem.
Tools:
Screw driver, box cutter, soldering iron, solder, wire cutter, multimeter and filer.
Electronic parts:
Sliding switch*2, electrical wire, some plastic from a disposable box (for stuffing) and AB Glue.
Remote Control
Remove three screws here (red circle), the blue square is where the switch will be installed.
After the screws are removed, squeeze along the groove on the edge with your fingernails to pry apart the case.
You can decide where to install the switch, and then drill a hole for it.
It will be better to glue the switch next to the screw hole (which can be an extra fulcrum), but the hole I drilled is a little bit deviates from it.
Thus, I stuffed some plastic chips in between.
Here comes the tricky part: where should I put the switch in this circuit?
There is not much space in the remote control, and all the electrical components are installed on the circuit board. So I chose the (positive) battery contact spring.
The spring contact is well soldered, desoldering can be quite challenging. In the end, I cut it off after a few attempts. And replace the contact part with my single strand electrical wire.
I have also glued some plastic chips on the switch to prevent it from stick out too much.
Originally, I planned to solder the wire with the remainder of the battery contact. But it's too thick to tuck it back; the wire substitution thus became an alternative solution. This is how it looks like:
Check for short circuits with a multimeter before reassemble the remote control. Note that the wire should not get in the way of the Mode Selection button.
Receiver
There is much more room in the receiver, no need to worry about the wire anymore.
Remove 3 screws as well; two of them may require a smaller screwdriver.
I took this picture after installing the switch (blue square).
A closer look:
In order to add a switch in the original circuit, I cut the battery contact like what I did to the remote control.
This time, the battery contact here are all springs, can't just replace it with the wire.
So I soldered the spring with a wire to the switch, then glued it in-place.
I made the wire connect to other side of the circuit board. It's mainly because I don't want it too close to the switch, causing short circuit or something else.
Luckily, there is a groove on the edge of the circuit board, which allows the wire to pass through.
This part (yellow square) on the lid needs to be filed a little bit, to make room for the wire through the groove.
Reassembly, and it's ready to go!