After migrating from an Arduino to a Raspberry Pi, Maker Jonathan Peace discovered that there were still some things that he just couldn’t do with a barebones Unix platform. In search of a way to help alleviate this problem, Ardhat was born
Billed as the “missing link that connects the Raspberry Pi with the real world,” Ardhat embeds an Arduino-compatible MCU (ATmega328P) in a Raspberry Pi-compatible HAT, which responds quickly to real-time events while letting the Pi do all of the heavy lifting.
For those unfamiliar with HATs, or Hardware Attached on Top, the Raspberry Pi B+ had been designed specifically with add-on boards in mind that conform to a specific set of rules that make life easier for users. A significant feature of HATs is the inclusion of a system that allows the ARM Cortex-A7-based Pi to identify a connected HAT and automatically configure the GPIOs and drivers for the board.
“Ardhat adds the environmental protection and awareness, real-time performance, and low-power operation that a real world system needs. In a super-compact Raspberry Pi compatible HAT, Ardhat protects and enhances the Raspberry Pi for real applications, and is accessible to everyone that has used an Arduino,” Peace writes.
The Ardhat comes in four different models — two equipped with long-range radio modules, the other two without. Each unit is packed with analog sensors, a real-time clock, user interface controls, supply monitoring, 5V Arduino shield capability, a wide operating voltage range (including automotive), high-current outputs for driving peripherals and full power/sleep management — all of which are accessible from either the Raspberry Pi or the Ardhat’s on-board chip. Makers looking for a little more oomph can also choose between the Ardhat-I and Ardhat-W. The first adds a 10-DOF inertial measurement unit, while the latter boasts a long-range ISM wireless node (with up to 15km range) to make it IoT ready right out of the box.
Not only does it accept most Arduino shields, the Ardhat sports a ‘FlatTop’ design which leaves plenty of space for any battery or a prototyping board. It even comes with an optional tailored high-capacity 1800mAh battery that plugs directly into the standard JST connector and fits snugly between the shield headers of the flattop board design.
Ardhat’s smart power management features a power switch and charge control, and enables a Raspberry Pi to run on real world power supplies, ranging from automotive to LiPo batteries, for months. This allows the HAT to connect to and drive 5V systems like servos, quadcopters and smart LEDs.
The Ardhat doesn’t just protect the Raspberry Pi from external voltage spikes and power outages, an optional laser-cut perspex ‘TopHat’ enclosure can physically safeguard it as well. However, Makers can still gain access to the Arduino shield pins for experimenting and teaching purposes, without the danger of damaging the delicate circuitry of the Raspberry Pi circuit board.
In true Maker fashion, Ardhat’s scheduler and applications are entirely open-source. Though its real-time software is supplied as a preloaded sketch, Makers can modify and update it as they wish using the Arduino IDE.
So whatever you’re building, whether it’s a self-balancing robot, an IoT gateway or a mind-blowing light show, Ardhat has you covered. Those wishing to learn more can head over to its official Kickstarter page, where the ubIQio team is currently seeking £25,000. Shipment is expected to begin in August 2015.