One of the limitations of the Tello is the fixed position of its camera. The camera points forward with a slight down angle which is great for FPV and taking pictures of what is directly in front of the drone. Some other inexpensive drones that are used for photography have a single axis gimbal that allows you to change the pitch of the camera through about 90 degrees downward. One application that I have for my Tello is to do inspection of my gutters and solar panels. For those purposes it would be nice to have a downward looking camera. I've seen articles on the Internet about adding a downward facing mirror in front of the camera so I thought I would give that a try.
Tello forward facing camera
I found a 3D print design on Thingiverse https://www.thingiverse.com/thing:2911427, but it didn't work well for me and also he had cut an 18mm square from a plastic mirror sheet and I am using a pre-cut 20mm square.
The design is fairly straightforward, so I just came up with a modified design in OpenSCAD.
OpenSCAD design file:
3D Printed Mirror Mount with Mirror
Mounted on Tello
So, I was all set to go out and take a look at my gutters...... charged my drone batteries, but forgot to charge the controller. I didn't want to fly near the roof without without real joysticks (a bit of wind today), but I did take it for a quick spin using the virtual controls in the iPhone app and discovered that I have to tweak the design a bit. The picture below shows that I've mounted the mirror too far forward (you can see around the edges of the mirror).
I do get a nice down looking picture (the steps going up to my backyard deck). Oh well, back to adjust the design and charge the controller. Guess that's why we need 3D printers.
Another thing that is obvious but I hadn't thought about - the image in the mirror is reversed. Not a big deal for my purposes.
