Build Log: TOS Intercom Wall Unit


Agreed Will, the accuracy of switches is critical for the look. The Honeywell’s and the replica Herthington’s will set you back though so many people use cheaper switches to mimic the look of what many think is a cheap simple prop. In my photo above I’m using the exact same switches you are showing.

It’s great to see this thread shaking out to cover this prop in detail because it is not a cheap simple prop! Found parts are expensive and adding micro controller kinda eliminates simple from the equation.


It certainly isn’t cheap, that’s for sure. I was thinking that while compiling the parts list. Of course, the more “do it yourself” members of the board have the skills to create their own alert beacons and intercom speaker replicas. If I can buy a part such as those ready to go, I prefer to go that route since I don’t have the time or skills to make everything from scratch.


In for a penny, in for a dollar. If a job is worth doing it’s worth doing right or in my case, over doing.


How about using “lesser” alternatives and upgrading later when budget and interest allow? I guess it would boil down to the diameter of the hole…


Step 2: Prepping the MP3 Player Shield

The “Music Maker” MP3 Shield component arrives from Adafruit with some assembly required before it can be used. Here is what you get. Please refer to the picture below for identication and where the parts are to be soldered.


  1. The shield itself.
  2. A 2x3 female header. When this part is soldered on as indicated in the picture, it will plug into a corresponding 2x3 male header on the Arduino Mega. Note: in this picture, we are looking at the TOP of the MP3 shield. This part should be soldered on UNDERNEATH.
  3. 2-pin terminal blocks x2. These two parts are soldered on TOP of the shield and give us terminal blocks to insert the speaker wires and secure them with the screws built into them.
  4. A stick of male header pins. These pins can be broken into separate segments using a pair of needle nose pliers. We need a 10-pin segment, two 8-pin segments, and a 6-pin segment. These segments are soldered on the shield UNDERNEATH where indicated by the orange boxes.

We are almost there. Please refer to the picture below for the next steps. The jumpers in the red box (labeled 12, 13, and 11) need to be disconnected. You can do this by using a hobby knife and knocking out the small connectors between each side of the jumpers. Then, the jumpers in the green box (labeled MISO, SCK, and MOSI) need to be soldered closed.


For more information about these steps and the MP3 shield itself, please refer to Adafruit documentation and tutorials here:

Now we can plug the MP3 shield into the Mega and it’s ready to go, like what is pictured below. Note that you will see some extra header pins on top the shield. I didn’t cover soldering these pins as they are not necessary for this project.


In the next post, we’ll build a circuit to test the shield with the intercom whistle sound effect and a momentary switch.


^ Is this what the Arduino Kids are calling [Shields] or [HATS]? Hope I’m wrong on that because I dislike when these type of hobbyist platforms come up with their own cutesy little lingo. But hey, let’s use the build thread as a tutorial to learn the platform and silly lingo at the same time.

I believe code is referred to as [SKETCHES] or [SCRIPTS] too but again let’s learn the quirks and idiosyncrasies in the process so these terms are clear.


Great job so far Jeff.
Thanks for taking the time to show us your tutorial.


A board which plugs into the Arduino is called a “shield”, which is why I referred to the MP3 player board as a shield. Sorry if I didn’t make that clear in my earlier posts. I’m not familiar with the “hats” term.

The code one writes for an Arduino is called a “sketch”. It could also be called a “script” I suppose since that is a generic term for program code (I’m a software developer in real life LOL).


Thanks for clearing up what shield means.


^ Thanks, so a board that sits atop an Arduino is called a “shield” but a board that sits atop a Raspberry Pi is called a “hat”.

See what I mean by quirks and idiosyncrasies concerning cutesy platform specific terminology. Other platforms like Beaglebone uses “cape” for a board that sits atop a Beaglebone board etc all have their own terms for the same things.

Attn: Manufacturing and Development: Get a clue, Enough of that silliness already it is completely unnecessary! :woman_facepalming:


I’m thinking about a modification to my goals for this build. How about a remote control instead of the three momentary switches and volume rocker switch? I was just doing some research on RF receivers and remotes and it appears to be super easy to integrate those into an Arduino project. Thoughts?


I think a remote would be way cooler.


I don’t recall them ever being used without walking up to them and pushing the big button, however, why not a remote as well? Maybe you could get Kermit to stand next to it and remote control a conversation…


Just teasing. :flying_saucer:


LOL. If Kermit has Starfleet access he is more than welcome to use it. :slight_smile:

The remote is to make the comm whistle sound effect, change how the big red button works, toggle a continuous audio mode with dialog from TOS episodes, and adjust the volume. I was planning on having switches on the side of the prop to do these things.


The remote would certainly make for a cleaner build by eliminating those switches, and is still way cool.


I’ll second Joe’s thoughts on a clean build.

When I built my TOS Desktop Monitor/Computer I used wireless keyboard, mouse and speaker for this very reason. Didn’t add any external cables, switches or ports that weren’t on the original Desktop Monitors. One power cable going in was all, just like originals.


I’m not sure how much more difficult this would be, but it could be cool to add Google Assistant or Siri support to the wall comm, too. I use Google Assistant, so you could then use the wall comm to make actual phone calls, talk to the “ships computer,” and control other smart home devices.

Maybe an easier way of doing the same thing would be to add a Bluetooth module and pairing with you phone à la The Wand Company communicator.


I love the idea of a remote to be able to interact with the Wallcomm.
I can’t wait to see what you come up with.


I think I mentioned this in the past… but a lot of the digital assistants have developer tools that let you access their speech recognition functions for custom programs. I thought it’d be cool if someone worked up a Star Trek program that could interpret what you’re saying, so if you ask for “Engineering” or “Mr. Scott”, it would parse your question and provide an appropriate sound file of Scotty replying, as an example.


Adding Siri support or some type of bluetooth functionality would be cool, but I think I want to keep this build as simple as possible. The remote control/keyfab is probably where I am going to draw the line. LOL.