Good Morning from my Robotics Lab! This is Shadow_8472, and today, I have shelved the boat race port pending review and started on a new project. Let’s get started.
My next goal is a project to keep the cat off the counter. After some early research, I came across OpenCV, an open source computer vision library. Some people have even already gotten it to identify cat faces. Keeping my long-term goal of a social robot in mind, this sounds like the direction to go, rather than a motion detector attached to a deterrent.
Now, to chose the hardware. I don’t know what the system requirements my program will need, so I decided to overshoot and make a “lab assistant” computer to help me with future small projects. A day or so of research later, taking into account Linux as a platform, system specs, community size, and likeliness of support form said community. Of note, I did try to include Fair Trade or equivalent as a criteria, but with electronics, it’s almost impossible to find a supplier who’s sure their product doesn’t include slave labor in their supply chain. In the end I narrowed it down to the Raspberry Pi 3 model B+. Also of note, the Pi is made in the UK (or China in peak times), so my guess is that at least some of the workers were more likely paid a fair living.
The assortment of starter packages is abundant. You can get the Pi alone for about $35, but starter packages tend to include other necessary things like a power cord and case. This led me to look into them and along the way, I learned that the Pi needs a micro SD card to run.
Before I even picked out the Pi for sure, I found a case to 3D print for it. In this case, it’s a Pac Man Ghost by Darren Furniss on MyMiniFactory.com. I started printing one up, but accidentally interrupted it about 10 out of 28 hours into printing the first part. No more heavy objects in front of a pressure based touch screen for me. While the second attempt was underway, the Pi itself arrived, and I set it up. A camera arrived with it, and I even managed to get a picture, though one test picture crashed the system. I haven’t gone to investigate yet.
The upper part of the case is the ghost’s head. Since I’m mounting a camera as part of the setup, I want to have the Pi look out one of its eyes (I’d need a second board to use a second camera). My first thought was to drill a hole but when I saw the narrow walls in the base with infill, I figured pulling the file into Blender and digitally drilling would be more effective. Before I do that, I need measurements so I drill the right hole and can actually mount the Pi camera correctly.
I started encountering small problems when I realized the Pi was mounted upside down in the ghost’s lower half, extending the distance the already short camera’s ribbon cable has to cover. After sundown Saturday, (I let my family have a day of peace from the printer’s constant whining during Sabbath hours) I started up a fast quality of the top. The file online said both parts were supposed to print without a support structure, but as I suspected, a short, long gap didn’t form correctly. I canceled the print, but learned a lot from the partial print.
Pulling the Pi from it’s kit case and putting it in the printed base, I discovered three things: The screw holes don’t quite line up (The case is meant for a Pi B and I have a Pi B+), and the gap in the top is necessary for port access for the power, if not the HDMI, and finally, by comparing the partial print to the 3d model, I discovered the eye does not line up at all with where the camera cable wraps around.
None of the challenges I’ve encountered so far are insurmountable. My only big concern is that the Pi will melt though the PLA case I have for it. Next week, I’m going to come up with a good 3d model for the ghost’s top where I can mount the camera.
Final Question: There is a real possibility I will need to switch to ABS for computer casings. What colors should I start with?