ePaper Badge

The ePaper Badge is an Open Source JavaScript-powered ePaper Display

Features
Errors
Uploading Apps
Power Consumption
Information

Variables
API Calls
Qwiic Connector

Notes on making apps
Firmware Updates
Troubleshooting
Other Official Espruino Boards

Features

ESP32C3 with 320MHz RISC-V processor, Bluetooth LE and 2.4GHz WiFi
900kB available flash storage
3.97 inch 800x480 4 color (black/white/red/yellow) ePaper display
3 Axis Accelerometer
Temperature and Humidity sensor ()
250mAh battery
110 x 65 x 10 mm case
On-board Qwiic connector for adding Qwiic I2C devices
Can be disassembled with just 1 screw

Errors

If you got your badge at a Conference, it may ship with a firmware designed for that conference, which will look for certain WiFi access points and/or servers. After the conference, it may show an error message, which will point back to https://espruino.com/Badge

There's nothing to worry about though - you can easily boot up the badge and connect with the IDE to program it. Just remember that the pre-loaded firmwares often put the badge to deep sleep very soon after power on - so you must power on, connect with the IDE and then type reset() as soon as possible to avoid the badge disconnecting itself.

Uploading Apps

The badge can be programmed directly using the Espruino Web IDE at https://www.espruino.com/ide/

However there are a bunch of pre-made apps available at https://espruino.github.io/BadgeApps/

Simply go to the website, connect with the Badge turned on, and upload the app of your choice!

Power Consumption

Idle - 44mA
Light Sleep (ESP32.lightSleep) - 0.5mA
Deep Sleep (ESP32.deepSleep) - 0.1mA

Information

Variables

Badge.i2c is the I2C instance used for the accelerometer and humidity sensor, but also the Qwiic connector

Badge.spi is the SPI instance used for ePaper

Badge.led_rgb is a Uint8Array(30) with RGB for the 10 LEDs

Badge.epaperBusy is try when the ePaper is currently busy writing something

Badge.rev shows the badge revision - 1.2 in production badges

API Calls

Badge.showTestScreen() shows a simple test screen

Badge.showError(e) shows a screen displaying the error given - can be a string or an Error object

Badge.getTemperature() => Promise({temperature,humidity}) gets temperature and humidity

Badge.getAccel() => Promise([x,y,z]) gets current acceleration on the Badge

Badge.setLEDs(r,g,b) can be used with rgb values, or Badge.setLEDs("#0f0")

Badge.setLEDArray([r,g,b,r,g,b,....]) Set LEDs individually. Supply 30-element RGB array, or 'undefined' uses Badge.led_rgb

Badge.i2c is the I2C object used for the accelerometer/temp sensor, but also the on-board Qwiic connector

Badge.epaperBusy is true if the ePaper is being written to

Badge.getGraphics() returns a 400x240 2bpp graphics instance with .flip() method that will write the output to the display

Badge.showRendering(gfxCallback) calls gfxCallback(gfx) repeatedly in order to render multiple slices of the ePaper display (as it won't all fit into RAM). It returns a Promise.

Badge.dumpRendering(gfxCallback) works as Badge.showRendering, but dumps the image to the console as a URLencoded BMP file, which the Web IDE can interpret. You can do Badge.showRendering = Badge.dumpRendering and then run showRendering code in order to get a screenshot.

Badge.showImageFile(fn) load a raw 800x480x2 image file from storage, return a Promise

Badge.showImageFileRendering(fn, sliceHeight, gfxCallback) load a raw 800x480x2 image file from storage, but call gfxCallback(gfx) with a Graphics instance on the first 800 x sliceHeight slice, return a Promise

Badge.showRaw(rawCallback) show raw image data on the ePaper. rawCallback(data,done) is called. data should be called with 8004802bpp = 96000bytes (over multiple calls) and finally done is called at the end.

Badge.sleep() puts the badge to sleep, waiting to restart on a button press. The button can be read with ESP32.getWakeupPin()

Badge.connectWiFi() Connect to wifi using details in wifi.json ({"ssid":"--","options":{"password":"---"}},"backup_ssid":..,"backup_options":{}). Returns a promise which only completes on success (on failure an error screen is displayed)

Qwiic Connector

The badge contains a Qwiic connector on the PCB. It is 3.3v, with I2C pins which can be accessed using the Badge.i2c interface.

Note these pins are shared with the Accelerometer/Humidity sensor so must be used for 3.3v I2C and not as Generic IO pins.

Notes on making apps

The badge doesn't have enough memory to store the full-resolution picture in RAM, so you have two options:
- Use Badge.getGraphics() returns a 400x240 2bpp graphics instance with .flip() method that will write the output to the display
- USe Badge.showRendering(gfxCallback) which calls gfxCallback(gfx) repeatedly in order to render multiple slices of the ePaper display. It returns a Promise.
The ePaper screen is paletted such that 0=black, 1=white, 2=yellow, 3=red
Espruino's Images only support a maximum width and height of 255px in binary mode. When using https://www.espruino.com/Image+Converter for images bigger than this, you'll need to export as Image Object which allows arbitrary width and height.
It's recommended to use https://www.espruino.com/Image+Converter with Colours: ePaper: 2 bit (4 color) BWYR and Diffusion: Atkinson for the best result

Firmware Updates

Firmware updates on the badge can be done by USB. Right now firmwares are not being built automatically, but when they are they can be flashed from the https://www.espruino.com/Espressif+Flash webpage.

Troubleshooting

I can't connect - the pre-loaded firmwares often put the badge to deep sleep very soon after power on - so you must power on, connect with the IDE and then type reset() as soon as possible to avoid the badge disconnecting itself.