It's already the end of August and the nights are getting cooler. Luckily, my latest robotics project is keeping me busy during these shortening evenings. I ordered a couple assembled uArm kits from UFactory a few months ago with their latest manufacturing run ready in time for the summer. To my surprise, I received an email from one of the sales reps who offered to send me four unassembled kits instead of the the two assembled arms. I figured that this is a great opportunity to learn about the engineering of the arms and decided to jump right in.
uArm was the result of a very successful Kickstarter funding campaign. Similar to the Makeblock team, it looks like the Chinese company was founded with the approach of using Kickstarter to fund their initial product line. A uArm is an fully open source hardware and software platform that brings robotics to the masses. I had been looking for a good robotic arm for experiments and found that arms with comparable robustness, precision and accuracy tend to run a couple hundred dollars more per unit so this $299, it's not a bad deal.
The unboxing was pretty straightforward which was to be expected. The acrylic parts were easy to remove from their sheets and the hardware (screws, bolts, etc.), were usually well labelled. The pdf instructions were also easy to follow. I have to admit, it was a little frustrating screwing in the tapping screws from the servo horns to the acrylic. Metal horns would be a better fit with the metal gear and precision cut acrylic. This isn't enough for me to say that the kits aren't great. Although it took me a few hours to assemble my first arm, the second one was much easier as I knew what to expect with each step. I ended up building one arm with the vacuum pump end effector and one with a claw.
Turning on the connected uArm Arduino board for the first time, there was a large consistent tone from the buzzer. This is normal. It stopped once my initial program was loaded. Using Ubuntu, it was pretty easy to get the uArm libraries installed and get the initial calibration software installed. Unfortunately, one of my arms had defective software but after calling customer support, they assured me that they would send replacement servos. After building the second arm, it wasn't too difficult to find out how to swap the main servos out. The servos have the potentiometer wire already integrated, so feedback is possible to be read from the board. This is quite important for more advanced uses.
True to their open source hardware and software company policy, UFactory publishes all of their schematics and code. This helps cultivate the community and some people have improved upon the initial code,. For example, for the calibration step, Scott Grey has thankfully release his version that helps prevent the arm from damaging the servos during the initial setup.
Scott Grey's calibration:
Other useful test utility:
I hope the software continues to improve, especially from uFactory's branch. The arms have a lot of untapped potential which makes them great for robotics, to support those who enjoy the weekend hobby to university/research alike.
Tuesday, August 26, 2014
Sunday, August 10, 2014
It's summer time and the living's easy. When I'm not trying a new IPA or attending wedding/pool activities, I'm spending my leisure time on my post-Spartacus era robotics project. Being a strong supporter of open source software and hardware, my research on finding the right prototyping hardware for my ambitious new project led me to Makeblock.cc. They ran a successful Kickstarter campaign back in January 2013 and from what I could tell, it looked like the industrious entrepreneurs had designed a high quality product. I decided to order their Lab and Robotics electronic kits to get a full sense of the capability of this open source construction platform.
It's difficult for me to review a construction set without comparing them to LEGO blocks. I've used LEGO Mindstorm products for hobby projects, engineering studies and even in the design of work training programs. I love this product series. The Makeblock platform takes a similar approach, but with high quality aluminium parts instead of plastic and electronics that are Arduino based or compatible. All of the common robotics sensors and motors are there, from ultrasonic sensors to stepper motor control. They also all connect quite nicely with RJ25 wires - no soldering required. This makes for a very versatile kit that is useful for beginners and for professionals. It's a real pleasure to work with the parts and the quality feel of the anodized aluminium is impressive. Of course, this comes at a price of overall expensive parts in large robotic prototypes. For my application, it is well worth the premium.
From a software point of view, after I imported the Arduino scratch library, it was a breeze to test out running some motor controls. All of the code is available on github being true to the open source nature of this platform. For a couple $100s it's possible to have a small robot roaming in your home in a matter of hours.
The folks at Makeblock have the right concepts in place for customer service from forums and wikis. Email wise, I also had some good back and forth with a sales rep (thanks Tony). The Leave a Message feature on their site didn't yield a reply to my initial questions but hopefully this was a unique instance and others have used the form with more success.
I'm looking forward to seeing what the robotics or maker community dreams up. I'm quite satisfied with the parts and my project is coming along quite nicely. Good job Makeblock, now if you could just get prices down a bit...
|Solid robot base that is fully customizable|