Smart programmable LCD display can wirelessly monitor and control Bluetooth Low Energy devices in small production run, hobbyist, or educational applications

espruino, pixl

The ‘Pixl.js’ from Espruino employs Nordic’s nRF52832 SoC to provide wireless connectivity to Bluetooth-enabled PCs and MacOS platforms enabling rapid prototyping using JavaScript

Nordic Semiconductor today announces that UK-based Espruino has selected Nordic’s nRF52832 Bluetooth® Low Energy (Bluetooth LE) System-on-Chip (SoC) to provide the Bluetooth LE wireless connectivity for its ‘Pixl.js’ smart LCD display.

The Pixl.js can be used to monitor and control other Bluetooth LE devices, or act as a wireless display, to facilitate fast prototyping of wireless products for small production runs, hobbyist, or educational purposes. The device includes pre-installed Espruino JavaScript firmware, a Raytac MDBT42 module featuring the nRF52832 SoC for Bluetooth LE wireless connectivity, and a low power sunlight-readable LCD screen. It also provides Arduino headers, allowing the user to plug in Arduino shields to add features such as SD cards, or Internet connectivity via Wi-Fi, Ethernet, GSM, or LTE.

The Pixl.js display can be powered via micro USB connection or a CR2032 lithium coin cell battery. The battery provides up to 20 days usage with light JavaScript use before replacement, thanks in part to the ultra low power characteristics of the Nordic SoC. The nRF52832 has been engineered to minimize power consumption with features such as the 2.4GHz radio’s 5.5mA peak RX/TX currents and a fully-automatic power management system that reduces power consumption by up to 80 percent compared with Nordic’s nRF51 Series SoCs.

Once powered, the device can be paired to Bluetooth 4.0 (and later)-enabled PCs and MacOS platforms, Bluetooth LE connectivity allows the developer to use Espruino Integrated Development Environment (IDE) or command-line tools to port their code to the Pixl.js. The wireless connectivity allows the developer to communicate with the Espruino JavaScript interpreter from the desktop computer to upload code, change and inspect functions and variables, and perform line-by-line debugs. In addition, the user can send individual JavaScript commands to the device without the need to program it. Any errors encountered while running uploaded code can be displayed on the LCD, enabling quicker debugging and faster prototype iterations.
Nordic's SoftDevice fits in with the Espruino firmware beautifully
Gordon Williams, Espruino

According to Espruino, the use of JavaScript makes writing code much faster and less prone to error than other C-based languages. JavaScript also provides native support for JSON, a common data interchange format for Internet of Things (IoT) devices.

Nordic’s nRF52832 multiprotocol SoC combines an 64MHz, 32-bit Arm® Cortex® M4F processor with a 2.4GHz multiprotocol radio (supporting Bluetooth 5, ANT™, and proprietary 2.4GHz RF protocol software) featuring -96dB RX sensitivity, with 512kB Flash memory and 64kB RAM. The nRF52832 SoC is supplied with Nordic’s S132 SoftDevice, a Bluetooth 5-certifed RF software protocol stack for building advanced Bluetooth LE applications.

“We selected the Nordic nRF52832 SoC-based module because of the SoC’s Bluetooth Low Energy connectivity, low power consumption, large memory, and affordability,” says Gordon Williams, Espruino Director and Lead Engineer.

“And Nordic's SoftDevice fits in with the Espruino firmware beautifully. The SoftDevice doesn't try to take over the microcontroller, instead it uses interrupts to execute code only when it needs to. This fits in very well with JavaScript’s event-based architecture and makes it simple to write code that draws minimal power.

“The support on the DevZone and from Nordic engineers has been great. The level of communication has meant designing Nordic solutions into new products has been very simple.”