Meet the maker of the MeArm robot arm

Figure 2: The trusty yet inexpensive MeArm is a perfect counterpart for the Raspberry Pi.

To Arms

MeArm is a rising star in the Raspberry Pi community. We talk with Phenoptix owner Ben Gray about what inspired him to build this fiendishly clever (and open source) pocket-sized robot arm.

When it comes to building Raspberry Pis and components for makers and hackers, Ben Gray at Phenoptix [1] is a real rising star (Figure 1). We recently caught up with Ben to find out how he got started in electronics, how he came to design an open hardware robot arm, and why the popular MeArm holds great promise as an educational tool.

Figure 1: MeArm's co-creator Ben Grey.

Before Ben Gray became a "purveyor of cool things" at Phenoptix, he was a chemistry student. "I went into chemistry straight from school and studied it for my Masters. I was fortunate enough to be selected for a PHD in theoretical chemistry. I moved away from the wet labs and went on to using large computer clusters."

This, says Ben, was where he got his first introduction to Linux: "We were calculating accurate potential energy profiles for diatomic systems and running big computation jobs on huge Linux clusters, trying to find out how two atoms interact as they move closer together. I had my own small cluster too, so I could do jobs on my own." These early experiences with telnetting into PCs were his first introduction to the world of the command line.

£20 and 100 LEDs

Just as Ben started his Masters, he also launched Phenoptix as a pocket-money project with just £20 and 100 LEDs. Remarkably, Ben credits the power of Linux as a driving force in helping him get his online store off the ground: "As my proficiency with scripting improved, I was able to run more jobs on more clusters with increasingly less interaction. This allowed me to put more time into the business."

You'd be forgiven for thinking this background in chemistry and theoretical physics would not have led him to build the MeArm, but Ben played the field a little before settling down in the maker community. "After university, I decided to become a chef. I'd always fancied it so I gave that a go for six months," he explained. "In the end it was the complete lack of seeing my friends for six months that was the death knell. I'm glad I tried it." After trying recruitment for a short time after that ("it was just horrible"), Ben decided to go full-time with Phenoptix and start building the kinds of cool gadgets and technology that he'd like to buy.

"I stumbled further into electronics with the help of websites like Instructables, which has lots of cool things on it – that's what I became more interested in. It really inspired me to start creating my own cool projects."

The Power of Open Hardware

Ben's love of cool projects is more than skin deep. Open source and open hardware are key components of all his projects. As he explained, "if it weren't for open hardware, there's no way I'd be working in electronics today: The sharing of knowledge that open source has given us is fantastic. Actually, being able to not just see a product, but take a look at the PCB and take a look at the software – literally pull it apart and see how it works. In the best examples of open hardware projects, the makers explain why they've made each design decision too. It's how I learned my trade."

The freedom of open hardware also rather neatly accounts for how the MeArm came into being. "A lot of the products I sell are remixes of other things. The MeArm (Figure 2) is essentially a remix of an item called the Plotclock." The Plotclock [2] was uploaded to Thingiverse earlier this year and is a brilliant project designed to put an interesting twist on telling the time. It's comprised of a robot arm powered by two servos that holds a dry-wipe pen (Figure 3). The Plotclock writes out the time before periodically reaching over to an eraser so it can scrub it out and start again.

Figure 2: The trusty yet inexpensive MeArm is a perfect counterpart for the Raspberry Pi.
Figure 3: The Plot Clock reports the time by writing it on a dry erase board.

The MeARM is a similarly tiny robot arm made of acrylic and was designed in partnership with Jack Howard. "It originally started out as a personal project," recalls Ben. "But as it grew, we built a plan around it. We stared it in February this year… It's been a quick development process, and I think that's all down to it being open."

The MeArm itself has four degrees of freedom. It can move left and right, up and down, round and round, and of course it has a claw. The project manages to come full circle – back to its roots – as Ben explains that the pincer at the MeArm's extremity might eventually have an attachment designed to hold pens, meaning a user could turn the MeArm back into a Plotclock.

Despite a very short development time, the MeArm has been iterated on several times over. The very first MeArm, for example, was actually made out of cardboard. "I went out to buy little brass split-pins from Ryman (a UK stationer)," recalled Ben. "I laser-cut cardboard and put it together so I could work out how all the levers worked and how to control it."

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