You can easily connect a PTT (Push-To-Talk) button to your TK-Talkie. Connecting a button consists of just two wires, a negative (ground) and a positive (signal.) The great part about it is that it doesn't matter which pin you connect to which between the Teensy and the button itself, so you can't go wrong. This tutorial will show you how to construct a PTT button and connect it to your TK-Talkie.
The software defaults to using pin 2 for the PTT (pins 0 and 1 are used by the BLE), but you can change this in your profile with the setting:
By default, button 2 is used for PTT (Push-To-Talk) and Sleep/Wake functions. The Sleep/Wake functions will only work with digital pins on the Teensy board (well, sleep will wake on analog pins, but the wake function will not...)
The available digital pins (the audio adaptor takes up some pins...) are 2, 4, 16, 21, 26, 30, and 33.
If you decide you don't want to make one, you can always buy one from the TK-Talkie Store.
There are only a few parts needed for the PTT button:
And of course you'll need a soldering supplies (iron, solder, etc.) as well as wire strippers and cutters.
Where to buy:
The heat shrink tube can be found on Amazon, eBay, Radio Shack, Frys, Microcenter, etc.
A Note About Microswitch Buttons:
Microswitch buttons come in a lot of shapes and sizes. After a lot of experimentation, I have found the one linked to in this tutorial has the best overall characteristics:
In addition, I've seen some setups with some larger buttons that go in the palm of your hand or even on the side with the thumb. You can of course use whatever button you like, but I found that using the smaller microswitch button positioned under the pad of a finger inside a glove allows me to trigger it while doing things like holding a blaster and pressing my finger against it, for instance.
Before you begin, it's a good idea to take your male and female jacks and put them together and check your connections. That way, you know which lugs match between the two parts. If you are using mono jacks, it's pretty simple...there's a ground and a signal lug. If you are using stereo jacks (for example you can use a mono male jack with a stereo female jack) you will want to make sure you are connecting the wires to the right lugs. Typically on a stereo jack, the ground is a larger lug with a hole in it and the lug next to that is the right (R) channel and the lug on the opposite side is the left (L) channel. If you are using stereo and mono plugs together, you'll want to use the left channel on any stereo jacks.
Insert the male jack into the female jack, then take a multimeter (and if you don't have one...why not? ;) They are pretty cheap and one of the most useful tools you'll own for electronics work...) and set it to use resistance (it's the symbol that looks like an Omega Ω) of about 200 (or 2000, depending on how your meter is setup.)
Place one of the probes (doesn't matter which) on one of the lugs on the male jack. Next, place the other probe on the lugs of the female jack until you see the numbers on the meter go down to 0 (zero.) This signals continuity of signal (no resistance) between those two points. Be sure to mark these down for later. If you do not see the numbers go down to 0, you may have a faulty male or female jack (or both!)
NOTE: Although in this application it doesn't really matter what connection points (lugs) are used, common practice is to use the GROUND lugs (the long metal piece with a hole on the male jack and (typically) the larger lug with a hole in it on the female jack) for the ground signal.
Strip the wires and remove any extra wires. You only need 2 ;)
Next, take your button and test fit the wire connections so that you can trim to length. With the microswitch button (and most momentary-contact buttons with 4 connectors) you'll need to connect the wires opposite each other diagonally.
Solder the wires in place. For extra protection, you can put some hot glue on the back to cover the wires to help protect against stress on them.
Note: To help keep everything in place, it's helpful to tape it down while soldering.
Once you have soldered the wires to the lugs, trim the unused lugs to make it easier to fit the heat shrink tube.
Place the heat shrink tube over the button and wire. Pull the tube about a 1/2" or so past the button.
Heat the tube so that it shrinks around the wire up to the start of the button. Do the same for the tube that is hanging past the button.
Once done, mark where the button is located with a Sharpie (just to make it easier to know where to press.
Notice how the heat shrink forms a sort of "bubble" around the button. If you shrink the tubing around the button as well, you might end up with the button in the pressed position.
Next, strip the other end of the wire and prepare it to connect to the male jack. Since it's a mono jack, it doesn't REALLY matter which wire goes to which lug on the jack (as long as the wires are connected the same on the female jack to the board.)
BEFORE YOU SOLDER, cut a piece of 1/2" heat shrink tube and slide it over the end of the wires. Then slide the case of the jack over the wires. This piece of heat shrink will be used to hold the jack cover in place as well as protect the inside connections from stress.
Optional (and maybe overkill): Also cut some small heat shrink tubing for the signal wire (not ground) that will be soldered to the jack. Be sure to push the tube as far away from the solder lug as possible. If it heats up it will shrink before you can get it in place. If you have difficulty with this, don't worry...the 1/2" piece that goes around the outside of the cover will provide plenty of stress relief.
Ok, now that the cable is ready, time to solder the female jack to the TK-Talkie!
Next you'll need to connect the female jack to your TK-Talkie.
You'll need a mono or stereo female 3.5mm (1/8") jack and a couple pieces of approximately 3" of wire. As always, you can use heat shrink tubing to protect and strengthen the connections.
Solder the wires to the ground lug (typically a larger lug with a hole in it) and the signal lug. If you are using a stereo jack with a mono male jack, you'll want to use the left channel (L) lug. This is typically the lug on the opposite side of the ground lug (See the "Check Your Connections!" section.) Cover with heat shrink.
Once you have soldered the wires to the jack, it's a good idea to test fit it in your case so you can trim the wires to fit. Place the wires where they will be connected (here the blue signal wire is over pin 2.)
The last step is to solder the wires to the TK-Talkie. You'll need to connect the signal and ground. By default the software is set to use pin 2 (be sure to change the setting in your profile if you use a different pin.)
You'll also need a ground connection. You can use a ground connection on the Audio Adaptor if needed.
Once everything is done, plug your PTT into your TK-Talkie and power it up.
By default, your TK-Talkie starts in Voice Activated mode. To enable PTT mode, simply press the button (you can also talk at this point if you want.)
Then, just press your PTT button each time you want to talk. When you release the button, a sound effect will play.
To disable PTT mode and return to VA mode, hold the button down for 2 seconds without talking. You'll hear some beeps to signal you are back in VA mode.
If you want a sound effect to play when you press the button, simply edit your profile and set the following entry:
OR you can use the mobile app to set the button-press sound effect.
The sound file should exist in the "EFFECTS" folder configured in your profile.