When you look for a part, and it doesn’t exist, what do you do? Well, if you’re a hacker, you make it! The Rotary Encoder Display or RoEnDi for short was created by Tindie seller MuTko because they wanted an encoder with a graphical display, and no open-source project existed. The encoder features a circular 1.28″ TFT display in the center, with a 15 pulse per revolution decoder behind it. It also has a 128Mbit NOR flash, which is perfect for a graphical application like this. An STM32L433 microcontroller rounds out the specs: an ultra-low power ARM Cortex-M4 with FPU (again, a great choice for an application like this!) with USB, multiple timers, capacitive touch inputs, and 256k of flash for program storage.
With such a flexible MCU driving the device, it can be used in just about any application. Built-in ADCs and DACs allow usage for both sensors and control applications, and multiple supported serial protocols allow connection to just about any peripheral needed. To top it all off, the CAD drawings and all software are open-source, so you’ve got just about everything you need to start your project.
I can see all sorts of neat applications for this. Obvious ones include a smart thermostat: you can show all the temperature data in the centre, and then change the set temperature with the rotary encoder. Off-grid energy management would also be a great application. The display can show the incoming power from solar, and how much the house is consuming. Then the encoder can be used to set charge states or minimum battery reserve.
If you’ve got an awesome idea for this product, make sure to check out the store listing and the documentation on Hackaday.io!
