I found it a slow process from design to getting the model for the dog made. There was a lot to think about when it came to the motors and how the legs where going to move. We decided to make a small model to test out how the motors would turn to make the legs move. Below is a model that we made from cardboard and wood.
We found this movement inside was not as good as first anticipated. There was also issues with the movement of the legs as they were not able to freely move as we had glued it into place, making it difficult for it to walk. The idea was only to have the one motor powering the legs, but after this experiment with the mechanics inside we felt that two motors would be conducive.
Also thoughts on using a bluetooth signal for the dog to hone into. From our Arduino workshop we had a pretty good idea of how to programme the motors. It was getting the legs to move that was going to be the hard one.
This is the model that was made to fit the Arduino onto, with the motors slotting inside the case to hold it all in place. After making this model was decided to make the casing bigger to take into account the batteries and switch that was going to be added later on in the process. After we got this point we starting to delve into the ascetics of the actual dog itself.
Aurdino motor programming
We were able to write the coding for the movement of the legs, for Forwards, Backwards, turn left, turn right and stop.
Originally the idea was to 3D print all of the parts of the dog and fit together. We found a file at https://www.thingiverse.com/thing:979218 and had a go at 3D printing it to get an idea of time scale and how t would look for our own robotic dog.
Unfortunately the file that was downloaded from the site was not as good as anticipated. As well as this we found out that 3D printing can be a little temperamental. As you can see below the finish on the dogs head was not as clean as we needed.
Was a good experience using the 3D printer, but we swayed towards the possibility of laser cutting instead, as 3D was a lot more time consuming and we were able to adapt our design more efficiently using the laser cutter.
Laser cutting – casing for the Arduino
This video shows the laser cutter cutting out the box for housing the electronics in the body of the dog. The files for the printer were produced in illustrator. I found it difficult to get the measurements correct, but got there in the end. The rest of the dog including the body, head and legs were all produced with the laser cutter, it was just a matter of fitting them altogether.
This is the head of the dog, taken from d-torso template, which was traced in illustrator so that we could send it to the laser cutter.
Once all was put together we tried to change the power cable to batteries, however once the batteries were fitted there was not enough power to get any movement out of the dog itself. We had to go back to the original power cable for our presentation unfortunately. Probably should have given ourselves more time to tinker around with the electronics, but time was consumed with the ascetics of the Dog head and body, which took longer than expected. However in the time that we had to produce this, I was pleased with the overall look of the robot.