Arms are a favorite with robotic enthusiasts. The number of joints in an arm ensures this. For instance, an arm can be made to rotate a full circle, and bend to almost at right angles. Each finger on an arm can be manipulated independently, and each finger can have at least three joints. Therefore, an arm with even two fingers and an opposing thumb can pick up objects—with pressure sensing. A simple project such as an arm can become as complicated as one can make it.
The above reasons made the original MeARM kit a veritable success. It was a pocket sized robot arm and budding Raspberry Pi (RBPi) enthusiasts quickly latched on to it. The design was simple, an open-source. It needed only three parts, the servomotors, screws, and the laser-cut parts. This simplicity spread the design round the world, making it massively successful. Although parents were skeptical of its complexity, children loved it. Its makers, the Bens, are now back with a new project, the MeARM Pi.
The workings of the MeARM Pi are straightforward and simple. The GPIO pins on the RBPi drive the servos directly. The RBPi communicates directly with the joysticks using an I2C ADC. Even the on-board RGB LED gets its power directly from the GPIO pins, so playing around with colors is simplified. Although the regular 2 Amp RBPi power supply delivers all this power without any issues, you may consider using an upgraded power supply rated at 2.5 Amps, if you are planning to plug in some more devices.
The HAT with the kit has its own power supply, which will comfortably power both the arm and the RBPi. As the HAT follows the reference design for all RBPi HAT designs, the accompanying open-source Node.js app performs a few key tasks that include controlling the servos in the arm via the GPIO pins. It also reads the state of the joysticks via the ADC.
This great kit is just right for any budding programmer stepping into the world of digital electronics. The kit contains everything needed (except the RBPi): all plastic parts, Allen key screws and Allen key, four metal-gear servos, RBPi HAT with two on-board joysticks.
To improve the quality, the kit comes with metal gear servos rather than the usual plastic ones. Moreover, small fingers of children aren’t well equipped to handle screwdrivers. That is the reason for including the Allen key parts—more reliable.
Depending on preference, you can go for either the blue color kit or the orange one. The programming languages are already available on the RBPi, so as soon as you have assembled the arm, it is ready to pick up things.