We return with a post about the M5Stack family (which we saw in this post) to see a relatively recent member, the M5Paper. A device that stands out for its e-ink touchscreen.
The M5Paper mounts an ESP32-D0WDQ6-V3 processor with 16MB Flash and 8MB of PSRAm. The rest of the characteristics are those that we already know of the ESP32, which we summarize in a 2-core processor of up to 240Mhz, with WiFi and BT connectivity.
But the most remarkable feature is to incorporate a 960x540 pixel e-ink screen, with 16 levels of gray, and multi-touch (2 points) capacitive GT911. This supports partial update and a refresh rate of up to 200ms.
The electronic ink provides improvements in visibility and consumption. However, the manufacturer recommends not using the screen for prolonged periods under UV sources (i.e. it is not suitable for outdoor use).
The set is completed with a 1150mAh battery, RTC BM8563, temperature and humidity sensor SHT30, magnets to fix the M5Paper on a metallic surface, and a side button in the shape of a “scroll wheel” that allows action in two directions + pressing.
As we can see, it is a very interesting device. To mention some ‘buts’, the side button sometimes has a somewhat erratic behavior and on (few) occasions does not correctly detect the press.
Another small inconvenience is that there is no easy way to know if the device is turned on. Due to its way of working, an e-ink screen retains the last view shown. You cannot imagine how annoying it is not to know in what energy state it is. A small LED connected to a GPIO would solve this problem.
Apart from these small opportunities for improvement (and to ask for it, a 9-axis IMU), the M5Paper is a very interesting device with many possibilities. Besides, because let’s not deny it, electronic ink screens have something special.
The number of possible applications is enormous, from a remote control for home automation applications, remote signage, applications in IoT and industry 4.0. In short, a little toy worth taking a look at.