We prefer development boards with a screen because it makes products much easier for customers to operate. A screen is also invaluable during development, as it can show far more debugging information than the usual blinking LED. Unfortunately, we couldn't find a small off-the-shelf nRF52 development board that incorporates an ultra-low power screen. So, we created Moddable Four.
The hardware components in Moddable Four have been carefully selected to support a wide range of uses while keeping power consumption to an absolute minimum.
Moddable Four contains a Sharp memory display. It requires very little energy to display an image (about 1 µA), but unlike ePaper displays, the Moddable Four display can animate at up to 60 FPS to support smoothly animated, highly responsive user interfaces.
For user interactions, Moddable Four incorporates a classic Jog Dial, once widely used by Sony. This compact user input device supports fast one-handed operation and uses almost no energy. While a touchscreen would be nice, the power consumption is generally prohibitive for an ultra-low power product.
Moddable Four includes an accelerometer, not primarily to determine the display's orientation, but for sophisticated power management. Because the accelerometer detects motion, it can tell whether Moddable Four is being held or is resting idle on a surface. Projects can use this information to automatically enter and exit energy saving modes.
For expandability, Moddable Four has 12 IO pins along the right side. Use these to connect sensors, displays, real-time clocks, buttons, LEDs, and other peripherals.
The display in Moddable Four motivated major updates. Our Sharp display driver takes advantage of the generous memory of the nRF52, to support the optional frame buffer mode for faster, more energy efficient rendering. It also implements optional real-time dithering to allow grayscale images to be displayed using only black and white pixels. The display driver integrates with Piu, our powerful user interface framework. Piu has been optimized to reduce energy use with improvements to the animation scheduler.
Creating fonts that look readable and smooth on a monochrome display is difficult. A unique feature of the Moddable SDK's tools is the ability to optimize any OpenType or TrueType font for the Moddable Four's display. This is done automatically when building a project and supports most languages including Japanese, Chinese, and Korean.
Putting It All Together
Compelling IoT products are more than simply the combination of hardware components and software modules. Thoughtful design and careful engineering allow hardware and software to seamlessly work together to achieve the user's goals.
We created Moddable Four's First Run application to show just how much is possible when design brings together the hardware and software. First Run has an animated user experience built using dozens of software modules that exercises all the major hardware components on Moddable Four.
The complete source code of First Run app is included in the Moddable SDK for you to learn from, enhance, and even use in your own projects.
Get Your Moddable Four!
When you receive your Moddable Four, you'll have immediate access to many resources to support you. You can use xs-dev to easily install the development tools, try out the many examples in the Moddable SDK, ask questions on our GitHub repository, refer to our extensive documentation, and learn from our book.