Papyr - Nordic nRF52840 epaper display
What is Papyr?
With the exploding number of connected devices being deployed, power consumption is a major concern. Technologies like BLE (Bluetooth Low Energy) are built from the ground up with low power consumption in mind. Another technology which is extremely low power is the e-paper display, which was made famous by its adoption by Amazon for the Kindle devices. Papyr from Electronut labs combines these two core ideas - a low power wireless technology combined with a low power display system. By choosing the Nordic nRF52840 SoC, Papyr is able to support not only BLE but mesh networking protocols like Thread, BLE Mesh, and Zigbee. Papyr has many extras too - like build in NFC antenna for BLE pairing or Thread commisioning, CR2477 battery holder, micro USB port, extra GPIOs, RGB LED, etc. There are a lot of applications possible with Papyr - dynamic price tags, for example, or sensor data display in a mesh network. Papyr can be used anywhere you need a low power, connected display.
Getting Started
Thank you for purchasing Papyr, the compact Nordic nRF52840 based epaper display developed by Electronut Labs.
Here's how you can get started with Papyr.
Hardware Setup
Insert a CR2477 coin cell into the holder, or connect power via the micro USB connector. Make sure S2 is set to the correct position - USB or BATT.
!!!WARNING!!!
Ensure correct coin cell polarity before inserting it. Papyr does not have reverse polarity protection, and will get damaged if battery is inserted reversed.
On start, the LED will blink GREEN twice and turn off. At this point, Papyr is advertising as a BLE peripheral and you can connect to it from the Electronut Labs mobile app.
Using the Mobile App
Download the Electronut Labs mobile app from the Android Play store. (The iOS version will be released soon.)
Click on Papyr, and you will should find your Papyr device in the list of scanned BLE peripherals. Click on the Papyr entry and you will see the following dialog.
There are three options on application - Draw, Select image, Trasnfer data over MQTT. For details on app usage, please see our documentation page.
Factory Reset
When running the default firmware, once you transfer an image to Papyr, it will remain there across power resets. This is by design. If you want to go back to the original image (papyr + Electronut Labs logo), there's a little trick - connect GPIO P0.08 to VDD and press S1 (reset), and boom - the original image is restored.
Programming Papyr
Papyr can be reprogrammed using SWD header. You can use our inexpensive Bumpy SWD debugger and PogoProg Model B adapter for that purpose.
Information regarding programming Papyr can be found here.
You can find several interesting applications of Papyr in the code directory.
If you need to revert to the default firmware, you can find the hex files under the top level firmware folder in this repository.
Hardware Specifications
- Raytac MDBT50 module with Nordic nRF52840 BLE/802.15.4 SoC
- 1.54 inch 200x200 pixel red/black/white epaper display
- CR2477 coin cell holder
- Micro USB (device)
- RGB LED
- NFC (PCB) antenna
- Push button
- USB/Battery power switch
- Extra GPIOs
- SWD Programming header
- Mounting holes
Datasheet and Schematic
You can find the schematic and data sheet in the links below.
Papyr Dimensions
Dimensions for Papyr v0.3 board can be downloaded here.
Current Consumption
Papyr is designed for very low power applications. For the default fimrware that ships with Papyr, when the device is advertising (not connected), the current draw is about 22 uA.
Code Repository
You can find all code and design files related to Papyr at the link below:
https://gitlab.com/electronutlabs-public/papyr/
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