Long-Distance Text Communication With LoRa

May 25, 2022 by Bryan Cockfield 50 Comments

Affordable and reliable cell phones have revolutionized the way we communicate over the last two decades or so, and this change was only accelerated by the adoption of the smartphone. This is all well and good if you’re living in a place with cellular infrastructure, but if you’re in more remote areas you’ll have to be a little more inventive. This text-based communications device, for example, lets you send text messages without all of that cumbersome infrastructure.

While [Arthur] didn’t create this project specifically for off-grid use, it’s an interesting project nonetheless. The devices use a physical QWERTY keyboard and a small screen, reminiscent of BlackBerry devices from the late 2000s (partially because they are actually using BlackBerry keyboards). One of the other goals for this project was low power consumption, and between polling the keyboard, the memory LCDs, and receiving and transmitting messages using LoRa, [Arthur] was able to get the current draw down to 12 mA.

Between the relatively common nRF52840 and SX1262 chips, plus the fact that [Arthur] made the schematics available, this makes for an excellent off-grid device for anyone who likes to drive off into the wilderness or lives far enough outside of town that cell phone reception is a concern.

Looking for something a little easier to put together before your upcoming camping trip? This similarly styled LoRa communicator from [MSG] uses off-the-shelf modules to greatly reduce the part count. Another option for off-grid communications is to use existing smartphones paired with a LoRa network like we saw in this project.

How Low Can An ESP32 Go?

January 7, 2020 by Jenny List 17 Comments

Many of us have experimented with the ESP32 microcontroller, attracted by its combination of WiFi and a powerful processor core, but how many of us will have explored all of its many on-board features? One of the more interesting capabilities of this chip comes in the form of its ultra-low-power (ULP) co-processor, an extra core that allows an ESP32 to function while sipping tiny quantities of power with the ever-hungry main cores turned off.

It’s a feature that [Max Kern] has used to great effect in his low power ESP32 handheld computer, where he’s paired the chip with a low-power Sharp Memory LCD and used the ESP32’s ULP core to keep the display alive while the ESP cores are sleeping. Software wise the device sports basic PDA and clock functionality including an RSS parser, all of which can be seen in the video below the break. Its inspiration came from Panic’s crank-equipped Playdate console, with which it shares the Sharp display.

Seeing this device reminds us of some of the badges featuring ESP32 power that we’ve seen over the last few years. An event badge creator has a constant battle to give the device enough battery life to last the distance. It’s a problem the designers of the SHA 2017 badge solved with an e-ink unit, but perhaps the Sharp display could offer a cost-effective alternative for new designs.

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Working With Very Cool LCD Modules From Sharp

July 1, 2013 by Brian Benchoff 11 Comments

LCD

Here’s some interesting hardware for you: Sharp came out with a very cool series of LCD displays, gong by the name Sharp Memory LCD. Not only are these displays very low power – on the order of about 5 microAmps to keep the display alive – but some of the smaller displays are reflective, making them eminently readable even in daylight. [Mike] decided he’d take a look at these displays and liked what he found.

While these displays are still pretty new, there are a few breakout boards available to make them accessible to desktop tinkerers. The folks at MakerDyne have a breakout board available and there’s one by kuzyatech over on Tindie.

While these displays are readable in daylight and are extremely low power, don’t expect to display LCD video on them anytime soon. The refresh rate is still fairly slow, but you might be able to get away with simple animations with interlacing and so forth. Still, outside of eink, you’re not going to find a better display in terms of power consumption and daylight readability.

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