Category: DIY, Electronics

Sunfounder Quadraped Robot

I’ve been working quite a bit with robotics lately which is a completely new area for me. My Advanced Technology Club are building battle bots this academic year and I’ll be doing a more detailed write up about the project at some point. Needless to say, it’s been eating a tremendous amount of time (and money). It’s also the most fun I’ve had in a while. I tinkered around with electronics as a kid (back in the analogue days) so I’m pretty comfortable with hacking things together but it’s been quite a challenge getting funding for the project and keeping the group on task. We’ll be putting on a tournament later in 2016 where the robots can battle it out (unlike the TV shows, our weapons are more tongue and cheek). It’s an exciting project which really has the potential to inspire students of all ages and certainly pushes the club to live up to the ‘advanced’ part of its name. I say all this as a preface to why I haven’t been updating the journal much lately and why I’m about to do a review on a piece of kit which is not my usual type of overpriced gadget.

I picked up the Sunfounder Quadruped Robot Kit a couple of days ago out of frustration more than anything else. I’ve been hitting a few walls lately with the drive system on my Viking battle robot. The differential track steering has proven to be a real drag (pun intended). I needed a distraction so went for something I could tinker with that 1) didn’t use wheels or tracks and 2) had pictured directions of a working design (it’s exhausting building stuff from scratch). The Sunfounder Quadruped is an open source, Arduino based crawling insect that you assemble and programme yourself. It’s a pretty cool, attention grabbing technology demonstration and I’m always looking for something like this to spark the imagination of students at school.

I have little experience with electronics kits so this review is not based on a comparison with anything else. I’m more accustomed to hacking existing products to workaround design flaws or adding functionality. I have to say, this kit while fun to build, was not without it’s own frustrations. It’s a well packaged kit containing everything but the batteries. Be warned, it takes 4x 18650 3.7v Li-ion batteries so it adds some cost if you don’t already have these laying around. The kit includes 12x micro servos, precise laser cut acrylic plates, array of well labeled screws, nuts and bolts, battery holders, control boards and 2x Sunfounder version of the Arduino Nano. It also comes with a quality, precision screw driver which is nice because you’re going to be spending quite a bit of time with it.

Much of the build process is a tedious exercise. The servos alone are attached with 100 tiny screws. This is the unfun part of the build and highlights the biggest issue with this kit – the quality of screws. I had about 5 screw heads sheer off while attaching the servo arms. These are tiny M1 self tapping screws and it doesn’t take much force. To be fair, the directions do state to clear the acrylic parts of debris caused during the cutting process and those tiny holes do need to be cleared out otherwise they will stress the screws. But even then, I had heads sheer off with little force which was disappointing. It was almost a show stopper when one of the server attachment screws sheered off in the servo! If it hadn’t been for some precise Dremel work, the servo would have been a write off.

But the directions are well written and I had no major issues following them. All the software is available on their website. There are a number of Arduino Sketches provided for testing the robot parts during the build and there is a calibration process which must be performed once the build is complete. I believe this calibration process is what makes the quadruped behave exactly as it does in the demo videos online which is very accurate and polished. It’s a cool, satisfying robot to watch and control and the kit represents fair value for money. I particularly like that it’s open source with code that can be tweaked.

Of course, within about 10 minutes of completing the thing, the compulsion to add an infrared sensor took over. I managed to bolt on a Sharp IR sensor and soldered it to an unused analogue port (A7) under the servo control board. With a bit of modification to the Arduino control loop, I was able to code in some object tracking capability so the quadruped appears to follow your hand. It works in conjunction with the remote control and adds a compelling level of human interaction to the robot.

Update: After contacting Sunfounder about the sheered servo, they have offered to send me a new one.