Wireless Image Transfer with Circuit Playground Bluefruit and E-Ink Gizmo

Send Images over the air for display on Circuit Playground Bluefruit + E-ink Gizmo!

by Collin Cunningham

published February 06, 2020, last edited March 08, 2024

posted in LCDs & Displays/ eInk / ePaper Internet of Things - IOT/ Bluefruit / BLE Circuit Playground/ Bluefruit

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Beginner

Skill guide

Overview

The Tri-Color E-Ink Gizmo gives Circuit Playground Bluefruit the ability to display images on a bold black, white, & red e-ink screen. And since it's e-ink, the image can still be seen even after power has been turned off. Even better – you can now display images on E-Ink Gizmo by sending them wirelessly from your phone or tablet using the Bluefruit LE Connect app for iOS or Android.

This guide shows you how to:

Assemble your E-Ink Gizmo & Circuit Playground Bluefruit
Install the Bluefruit LE Connect app
Transfer images wirelessly to your E-Ink Gizmo & Circuit Playground Bluefruit

Parts

Hand holding E-Ink gizmo bolted onto PCB, refreshing itself

Circuit Playground 152x152 Tri-Color E-Ink Gizmo

Discontinued - you can grab Circuit Playground 200x200 Tri-Color E-Ink Gizmo instead! Extend and...

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shot of a Black woman's neon-green manicured hand holding up a Circuit Playground Bluefruit glowing rainbow LEDs.

Circuit Playground Bluefruit - Bluetooth® Low Energy

Circuit Playground Bluefruit is our third board in the Circuit Playground series, another step towards a perfect introduction to electronics and programming. We've...

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USB cable - USB A to Micro-B

This here is your standard A to micro-B USB cable, for USB 1.1 or 2.0. Perfect for connecting a PC to your Metro, Feather, Raspberry Pi or other dev-board or...

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Lithium Ion Polymer Battery 3.7v 350mAh with JST 2-PH connector and short cable

Lithium Ion Polymer Battery with Short Cable - 3.7V 350mAh

Lithium-ion polymer (also known as 'lipo' or 'lipoly') batteries are thin, light, and powerful. The output ranges from 4.2V when completely charged to 3.7V. This...

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iOS or Android device

You'll also need a device to run the Bluefruit LE Connect app, which we'll use to send images over the air:

Bluefruit LE Connect for iOS works with iPhones or iPads running iOS 11.3 or later
Bluefruit LE Connect Android works with most Bluetooth LE capable Android devices

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Assembly

This page shows assembling the Circuit Playground TFT Gizmo, but the process is identical for the E-Ink Gizmo.

Placing the Circuit Playground TFT Gizmo on the Circuit Playground Express or Circuit Playground Bluefruit is pretty straightforward. All you need is a #2 Phillips screwdriver.

There may be plastic covers over the screw holes on the TFT Gizmo, which you will need to remove before assembly.

The amber colored Kapton tape dots must be removed from each of the twelve standoffs before assembling the boards. These are electrically insulating and will prevent the Gizmo from working properly if left in place.

You can use your fingernails or some tweezers or a pin to poke and lift each dot as shown here.

Start by aligning the two boards side by side like in the photo with the black plastic speaker connector and battery connectors pointing in the same direction.

Place the Circuit Playground board on top of the Gizmo being sure that the connectors mentioned in the previous step are still aligned.

Install a few screws loosely, so that all of the holes are still aligned, before tightening them down.

Finish installing the remaining screws. After that, you're done!

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Bluefruit LE Connect

The Bluefruit LE Connect app provides iOS devices with a variety of tools to communicate with Bluefruit LE devices, such as the Circuit Playground Bluefruit! These tools cover basic communication and info reporting as well as more project specific uses such as remote button control and a NeoPixel color picker.

The iOS app is a free download from Apple's App Store. As of this writing, it requires iOS 11.3 or later and works on the iPhone, iPad, and iPod Touch.

Install Bluefruit LE

The first step is to install the app on your device.

Enable Bluetooth

If Bluetooth is disabled on your device, enable it by going to Setting > Bluetooth on your iOS device and then turning it on.

Enable Location Services

If you plan to use the app to send location/GPS data to Bluefruit LE, enable Location Services. Enable it on iOS using Settings->Privacy->Location Services.

Scan for Devices

Launch the app now -- it will automatically begin to scan the airwaves for Bluetooth LE devices. These are presented in a list at the bottom of the page.

Notice, you can use the Must have UART Service filter to prevent BLE devices from showing up that can't work with the app.

To refresh the list and start a new scan, simply swipe down on the current list.
Each device's signal strength is displayed in the left side of its row.

If you tap on the device entry (not on Connect), you'll see more detail about a particular device:

Connect

Tap the Connect button on the UART capable device you wish to use. The app will connect to the Circuit Playground Bluefruit! Now, you'll be presented with the Device name and signal strength, and a number of different Modules you can use.

Controller Module

Click on the Controller module. You'll see a number of different sensor data streaming options. Enabling these will allow you to send data from your phone, such as the Accelerometer data or Location data, directly to your Circuit Playground Bluefruit!

The two modules on this page that can send data to the Circuit Playground Bluefruit are the Control Pad and Color Picker.

Color Picker

Click on the Color Picker. Now, you can dial in the hue, saturation, and value of a color using the color wheel and value slider.

Follow this page for setting up the CPB with the color picker code.

Press the Send selected color button and your color values will be sent to the Circuit Playground Bluefruit to adjust its NeoPixels!

The app provides many other features with the additional modules. Have a look at the Bluefruit LE Connect for iOS and Android standalone guide for an explanation of each feature.

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Transfer Images

Setting up Circuit Playground Bluefruit (aka CPB) + E-Ink Gizmo for use with Bluefruit LE Connect is simple & only requires loading one new firmware file.

Load Firmware

Click the button below to download the UF2 firmware file.

eink_upload_v3.uf2

Connect your CPB + E-Ink Gizmo to your computer using a micro USB cable.

Double click the Reset button at the center of the CPB. You should see the CPB's NeoPixels turn green, then a new drive named CPLAYBTBOOT appear on your computer.

Drag the image_eink_upload_V3.uf2 file onto the CPLAYBTBOOT drive. When the file is finished copying, the CPB will reboot and its NeoPixels will turn off.

Connect App to CPB

Make sure your iOS or Android device has Bluetooth enabled, then open the Bluefruit LE Connect app.

On startup, the app will begin scanning for nearby Bluetooth LE enabled devices.

When the app detects the CPB, it will be displayed in the list of detected devices as Bluefruit52. Tap the Connect button to the right of the Bluefruit52 label.

Send a Test Image

After connecting, the app will display a list of modules to choose from.

Tap the row labelled Image Transfer.

The Image Transfer module starts with the Adafruit logo as a default image. Above the logo, you'll see a list of controls for formatting image data. The most important control is Resolution – it should be set to E-Ink: 152 x 152. If it's not, tap the resolution button to change it.

Tap the Send button at the bottom of the screen to transfer the image to your CPB + E-Ink Gizmo.

After the transfer has completed, the E-Ink Gizmo's display will blink several times and the image will fade into view as the e-ink renders.

Send Your Own Image

Next, try sending one of your own images:

Tap the Choose Image button
Select a picture from your device's photo library
Use a pinch gesture to resize the image as needed
Tap Done
Tap the Send button at the bottom to transfer your image.

The app converts your photo to red, white, & black pixels suitable for tricolor e-ink displays. This super simple palette and dithering give all the images a clean & very novel look – it's e-ink chic ✨

Learn More

If you're interested in customizing the e-ink upload firmware, you can find the Arduino source code here
To learn more about the Bluefruit Connect app's Image Transfer feature and the format it uses for image data, check out Image Transfer section of the Bluefruit LE Connect guide.
To learn all about the E-Ink Gizmo, check out the full Adafruit Circuit Playground Tri-Color E-Ink Gizmo guide.