This project was my first introduction to the world of 3D printing. I wanted to choose a project that I knew would require me to print a lot of parts lots of times so that I could get used to the maintenance of the device. I also wanted something cool to show off at the end of it all and I think it worked out.
The printer I was using had a massive 400x400x800 mm print volume, so that wasn’t an issue. I did run into some weather issues, as the printer was inside a warehouse workshop, and winter was quickly approaching. Other than that, this project had no real limits on it.
This project was a fun one, because it’s one of the most visually pleasing final products I’ve come away with. I wanted it to be a talking point for future references and be able to point to it as something I have completed on my own with no direction at all. So, here’s what I did.
I was searching sparkfun to look at different electronic parts that were available to me to start my next project, and I stumbled on the flex sensor. I then had two thought very quickly in succession to each other. First, I think I could probably map someone’s hand using these parts. Second, I bet someone has already done this. So, I googled around really quickly and found someone who had done this type of project before, that is, mapping a glove to a robot hand. But I took a look at the code they uploaded, and thought I could improve greatly on the project they had made. After this, I quickly set out to follow their instructables tutorial.
As I said before, I also wanted to learn about 3D printing, and my goodness, did I ever. In total, there are 18 files to print, but most of the files consist of multiple parts for the fingers. The robot hand itself is actually part of a much larger robot project called InMoov. The project is a fully 3D printable robot, head to toe. I just needed the forearm and hand, so that’s all I printed.
I watched many different youtube videos about 3D printer maintenance and other tutorials trying to learn along the way. If you want my recommendation, Maker’s Muse is one of my favorites, partly because I would find myself exploring other videos on his channel that were not necessarily about 3D printer maintenance just because I enjoyed them. After a while (and a lot of failed prints) I finally got the hand of it and set out to print all the different parts to my hand. It took maybe 20+ hours to get everything printed and re-printed when needed, but a lot of that time was me resetting prints and figuring out what to do when I got stuck.
After printing, I gave each of the parts a nice coat of ABS cement to make sure the part were strong and also had a neat glossy finish. I put all the parts together and strung it up as per the instructions, and then I was only left to begin tuning the strings. It took some time, but hot glue was my best friend when tightening or loosening strings because it was easily re-heatable and I could pull the strings through it.
After the hand itself was build, then began work on improving the code. This was where I really started to add to this project. I created an open-source library to use with the flex sensors that allow you to attach meta-data to the sensors themselves. Things like what you want their hard maximum and minimums to be, as well as the ability to calibrate them easily. I also added smoothing algorithms in the library if you want to use them, and I allowed a boolean method to return if the sensor is currently bent or not. You can see the github repo here!
AUVSI Twitter – https://twitter.com/AUVSI/status/996073977650049024
DigiKey Blog – https://www.digikey.com/en/blog/student-uses-3d-printed-parts-to-create-robotic-arm
Online Article – https://interestingengineering.com/13-of-the-most-forward-thinking-pioneering-engineering-students-to-watch
KSU Newspaper – http://ksusentinel.com/2018/02/05/honors-student-creates-3-d-printed-robotic-hand/