Simple Private Off-Grid Local Texting & Tracking Devices: Touchscreen, Encrypted, Mesh-Enabled - No Grid / No Phone

Build a set of mobile touchscreen off-grid local communication & tracking devices by following these instructions. You'll need at least 2 to be able to communicate, but you can have up to 90 in a private group. They use mesh techniques to communicate, so the more you have, the farther your signal can go. Check out the attached video and main project website for details of how the mesh system works.

If you build these devices, they'll be compatible with Lilygo T-Deck+, Lilygo Pager, and any other Blackout Comms devices you have now or build/buy later.

Required

T-Deck

Battery - 3000 mAh fits nicely

Realtime Clock - DS3231 from Adafruit (with stemma connections)

Antenna & Connector - Need both the antenna and the pigtail connector. Other antennas can work too.

Micro SD Card - The linked one works well, but it's picky. Here's a compatible list.

Grove Stemma to Qwiic - Connects the T-Deck to RTC

M3 Heat Inset Nuts

M3 Screws - For securing the case closed

Optional

Qwiic Connector - If adding GPS or vibrate

GNSS/GPS - DFRobot TEL0157. 1103 works if you can't find 0157.

Qwiic Gravity Cable (if adding GPS)

Vibrate (Haptic) - Sparkfun 17590

Watch the video here as I build one from start to finish.

There is a base set of components required (see the components list), but you have a few options.

1. GPS? It uses more battery power, but definitely good to have for many reasons (tracking, etc).
2. Realtime Clock? You must have GPS, a realtime clock, or both. The realtime clock is necessary in my opinion, because it completely takes away the need to have a GPS signal to startup, communicate, and maintain accurate time (vital for secure communication). But, if you have GPS, you can get by without the RTC.
3. Vibrate Alerts? This is nice because obviously then you dont need to have sound enabled to know if you've got a message. It's not required though.
4. Antenna Selection - The antenna linked in the parts list is excellent, but you'll find many options on Amazon and others. Just be sure to get one tuned for the frequency band you're using (915 in the US, might be 915, 868, or 433 outside the US).

You'll need a case front, back, reset button, and power button. You can also find the print files on Printables.

Materials

I have used PETG, PLA, and ABS with good success.

Personally, I prefer PETG-HF from Bambu Lab

This enclosure was designed by Alley Cat with very minimal modifications by me.

Use a soldering iron tip or other heating method to heat sink the nuts into the locations on the case. The nuts shown here are M3s.

The power and reset switches will need to just rest in place until the T-Deck is inserted. The T-Deck will hold them in place after that.

Notice the power switch has a notch for the T-Deck's power switch. When pressing the T-Deck into place later, make sure they line up so you don't bend the T-Deck's power switch.

The T-Deck’s reset button is too long for the enclosure. If you don’t clip it to be flush with the side of the T-Deck, the case will hold the reset button down, and the T-Deck will appear to be dead.

Remember, if you go to turn on the T-Deck in the final steps and nothing happens - see if your case is holding this reset button constantly.

Connect Adapter to T-Deck

1. Attach Grove / Qwiic Connector to T-Deck
2. Attach pigtail antenna connector
3. Move T-Deck speaker out of the way (pry it up carefully with a small flathead screwdriver)
4. If you need a battery adapter, install it now. The 3000 mAh battery linked in the parts does not need a battery adapter.

Insert T-Deck into the Enclosure

1. Remove the screen protective film
2. CAREFULLY press the T-Deck into the case, USB port end first

You’ll need to spread the case open a little and gently work the T-Deck into place.

As your placing the T-Deck (before applying pressure), make sure the USB port is lined up and on the other side, the keyboard is not outside the enclosure. It's easy to accidentally wedge the keyboard outside the enclosure, and if you press the T-Deck into place while the keyboard is incorrectly wedged, you may pop a key or bend something.

Move the DFR’s switch to IIC, and then use a wire cutter/clipper to clip the long plastic switch much shorter. It will just be in the way later on if you don’t.

Also, attach the GPS antenna, as well as the Gravity/Qwiic adapter cable.

1. GPS and DS3231 clock are plugged together and to the T-Deck via the Grove/Qwiic connector as shown.
2. Add the RTC battery (CR1220)
3. If you're adding vibrate/haptic, that should go between the RTC and GPS using a standard Qwiic cable.
4. Insulate metal surfaces of both components with electrical tape so they don’t create a short when we mash it all together.

Plug the battery into the T-Deck when you’re sure the polarity is correct. The T-Deck and amp should both be able to take a charge and power on at this point, verifiable by on-board LEDs.

Component Arrangement

Arrange the components in such a way they fit into the enclosure. This isn’t as easy as it would seem, as it’s a very tight fit. You may even want to consider getting smaller than a 3000 mAh battery. You could easily get by with a 2000 or 2500 mAh battery.

Battery Polarity

** Double-check polarity - yours may be different! ** DO NOT BLINDLY FOLLOW THIS IMAGE! Check your own battery and board polarity.

However you connect the battery, be sure the polarity is correct. I test the T-Deck’s polarity by checking for continuity between each battery plug pin and the T-Deck’s ground. If you don’t understand this statement, do not attempt to build this! If you turn on the power and nothing happens, quickly turn it off and double-check that your polarity is correct.

1. Attach the enclosure’s back using a couple of M3 screws.
2. Insert a compatible SD card.
3. Now you are ready to flash the firmware.
4. The USB-C port on the bottom is for both charging and flashing the firmware.

Flashing The Device

The Blackout Comms firmware needs to be "flashed" (installed) onto the T-Deck. The basic steps are...

1. Connect the device to your computer using a high quality USB data cable.
2. Power on the T-Deck
3. Hold the boot button of the T-Deck (trackball), tap the reset button (closest to the edge), and then release the boot button.
4. Using Chrome or Brave (other browsers may work), go to the Lilygo T-Deck firmware page.
5. Click the install button

Configuring Blackout Comms

1. Choose a device name. I use a person's first name typically. This is always encrypted on the device and when transmitted, so it doesn't need to be cryptic to you.
2. Choose a Private Cluster unless you really want to use public channels for some reason (not recommended in most cases).
3. Is this the First Device? If so, go ahead and make it root. If not, just choose "standard"
4. If this is the first device, you'll want to set up a new cluster, which is easy. Typically you just choose a name for your cluster (your last name, etc), and click through all the defaults. Subsequent devices should all be "standard" and they'll copy settings form the root.

Creating a Cluster (Only the First Device)

If this is your first Blackout Comms device, you'll need to create a new cluster while intializing it (it's just a few steps on the device). It's only a one-time step, and all other devices you add to the cluster can skip this step.

How to create a Blackout Comms Private Mesh Cluster

Onboarding a New Device (All Extra Devices)

If you already have a cluster, you'll need to onboard any new devices you make (or buy) to it.

How to Onboard a New Device to Blackout Comms

Blackout Comms has many capabilities for messaging, tracking, and even remote controlling circuits, all while having no reliance on cell service, internet, or grid.

The Blackout Comms firmware (and diy guides) are basically just a building block, upon which you can create elaborate secure mesh networks that can do a variety of things.

To Learn More:

Main Website

Blackout Comms YouTube Channel

Other Blackout Comms DIY Guides