“Have you ever been at work and suddenly remembered something you really need to do at home (or vice versa), but you’re worried that you won’t remember to do it when you finally get there? You might phone or text to ask someone to put a sticky note up as a reminder, but that won’t work if no one is there. This Instructable offers an alternative approach that allows you to upload text to a cloud service that will send your text to an inexpensive (< $20 in parts) Desktop Scrolling LED Display that is much more likely to grab your attention than a paper sticky note. Of course, an electronic sticky-note is is just one of several ways to use this device. For example, it can be also used as a clock/calendar, a desk nameplate, a customer counter display, a message receiver, and much more).
The scrolling display uses a small (32 x 132 mm) 8 x 32 LED matrix module connected to an ESP8266 development board. The LED matrix and ESP board are powered by a rechargeable 3.7 V Li-ion battery (18650) attached to a battery charging module (TP4056). Everything is contained in a 3-D printed enclosure that makes it completely portable within range of your Wi-Fi signal.
The ESP8266 code takes advantage of the Adafruit IO (AIO) cloud service, which is available free for the small number of data feeds (<10) used here. Users with AIO accounts can upload 3 different text messages to the cloud via phone, tablet or computer. Users can also select which text message is displayed, the time of day it will be displayed, and the rate at which the message scrolls across the LED matrix. If no message is selected, the default display will scroll the time of day, day of the week and date.
This project requires access to a 3D printer, some soldering, and general familiarity using Arduino IDE 2.1 to edit and upload program sketches to microcontroller boards.
The following items are needed for this project:
- MAX7219 Dot Matrix Module 4-in-1 LED Display Module ($2.99)
- D1 Mini ESP8266-12F (~$2.83)
- Toggle switch, ON/OFF (~$1.10)
- 18650 Lithium Battery (~$4.50)
- 18650 Lithium Battery Charging Board TP4056 5V 1A (~$0.78)
- Battery Springs AAA Battery (~$0.35)
- Breadboard jumper wires (~$0.50)
- 1 x 5 male header, 0.1” pitch (~$0.07)
- Two (2) 4/40 x 3/8 machine screws
- 3D printer filament: PLA and TPU (any color)
- Wire, solder, heat shrink, hot glue sticks”