Lilygo T-Display Touch LoRa Pager

Introduction

This is another in a series of articles for my Ripple LoRa mesh pager devices. Recently, I ported the firmware to the Lilygo T-Deck. Prior to this, are other how-to articles using various LoRa dev boards, like the Heltec and TTGO ones.

Now, I'm pleased to announce the firmware has been ported to a touch device--the LilyGo T-Display S3. This forms quite a nice, neat little device that easily fits in a pocket. The colour screen is very nice and easily readable in all light levels, and the touch interface is quite nice.

The Touch UI

I had to re-think some of the UI concepts and design, to fit the touch paradigm. The same 4-way navigation model has been kept (ie. up, down, back, select), but are now achieved with a single tap in one of the 4 quadrants per this help screen:

the centre tap does nothing at this stage, but might be used for something in the near future. To turn the screen on/off you press the hardware button to the bottom-right.

To access the 'extras/context' menus for each screen, you just do a long-press anywhere on the screen.

Entering Text

For screens which need text to be entered, you will see a small keyboard icon, like the conversation screen:

Just tap on the icon, to go to the full-screen Qwerty keyboard input screen:

Tap in the bottom-right area to do a backspace. Tap on the top-left area (on the back arrow icon) to navigate back to the previous screen. (the text you entered should then be filled in the relevant place). For conversation screen, you then tap on the right-hand quadrant to send the message.

Entering Numbers

A lot of the Setup screens involve entering a single number, like the Radio/Set Frequency screen:

These screens look pretty much the same as in previous models, but tapping on the up/down areas increases/decreases the number. Tap the left quadrant to cancel (go back), or tap the right quadrant to submit.

Flashing the Firmware

You can download the firmware from my BuyMeACoffee page.

Also, I have a general guide for flashing ESP32 devices here.

NEW: 'Ultra' Version

I have released a new 'Ultra' version, which now has much better stand-by power optimisations, and a totally revamped UI. And it now features a map tile renderer! Load up map tiles of your area, and enjoy GPS moving maps! You can download here.

Here is the home screen map tab, for example:

Starting the Build

There is a wiring diagram below. You will need moderately good soldering skills, especially with the LoRa module, which has pretty small contacts. You can either put it all together in some case/enclosure of your own, or 3D print one I have here.

For the case I have designed, you need to do roughly in this order:

• insert the two 3D printed 't-btn' buttons into the underside of the 't-top' piece.
• insert the T-Display via the top of the 't-top' piece, then secure in place with an m2 bolt/screw with a small washer. (see pic below)
• solder wires to the various T-display pins (later to be cut down to better length)
• place the 't-rack' piece over the T-display. Then hot-glue into place the GPS, LoRa module and Polulu.
• Cut the various wires to a better length after testing where each needs to go, then solder onto the other components.

Wiring Diagram

The finished wiring should look something like below. (for reference)

Initial Tests

You should see the 'powered by Ripple' logo on powering the device. Shortly after are two help screens, then a prompt to create the encryption key-pair.

If you encounter any issues, just carefully check your wiring and make sure it matches the diagram above. Before screwing the case together, check that the red LED comes on the GPS when the T-display screen is on. Also, it should turn off, when the screen goes off. (can press the screen on/off button on the front side to test).

Please refer to the prior articles for help on using the Ripple qwerty pagers. (links at top of article).

Future Direction

I haven't got any power consumption/endurance benchmarks yet, but will not be surprised if this is a bit power hungry. (but, prob not as bad a the T-Deck) Some power optimisations are already in this initial version, like turning the GPS on/off along with the screen. However, I will be looking into whether this version can use the ESP32 deep sleep, which I use in most of the other Ripple pager firmwares. That could save a lot of power consumption.

NEW: PCB Version

A custom PCB has now been developed by a colleague, and the finished builds are very nice indeed:

Here is a link to a post showing some details on this custom PCB, and the build.

If you have any suggestions for improvements, please get in touch here, or via my BuyMeACoffee page, and as always any donations you can spare will help support my efforts with the project.

regards,

Scott Powell.