Friday, 13 October 2017

Eyes on the prize: Raspberry Pi robot gets a camera

Cheap Mobile Camera: MoboCam

As a mobile camera, the smartphone is hard to beat: it has two cameras, autofocus, front light, backup battery and best of all, virtually no additional interfacing 'glue' hardware. I used my old Samsung Nexus 1, and set it up to log into my WiFi.

To stream video back to my laptop, I used the App IP Phone Camera by Deskshare. To link to it I simply point my browser to the Nexus 1's WiFi IP address and port 8080:

Camera and platform is controlled from a laptop
 Typical front camera view:

Let sleeping dogs lie: will they be replaced by AI?
Rear-facing camera view:
MoboCam looks back ...
The nice thing about this is I get to postpone putting in encoders (and the attendant interfacing circuits), motor drives, control software and jump straight to the fun stuff.

The control commands are much the same (see previous blog post):

Command line interface: a proper GUI has yet to be done

 As usual, the smartphone is attached to the platform with a small cardboard box (the same one the Arduino parts came in), duct tape and scotch tape. The smartphone needs to be easily removed and mounted in order to start the app.

It needs to be reasonably rigid: positional accuracy is important to navigate the house. Barely one hour later, assembly was complete and MoboCam made its first remotely-controlled sortie from its birthplace: the study.

First sortie: MoboCam needs to traverse a corridor
It went down a 1m wide by 5m long corridor with no difficulty, mainly because it could center on the bright window at the end. Turn to the left and MoboCam sees its first light of day.

Light of day. Notice Mark I mobile alarm system on front guard duty.
The platform sorely needs two more wheels. It gets stuck very easily: even the thinnest doormats gets stuck on the front and back supports. And it would be nice to be able to reverse.

A dedicated program needs to be done to issue Piface commands on pressing the keyboard arrow keys. A surprising amount of turning was required to orientate myself.

The wheels needs encoders or tachometers to measure distance traversed. This makes it able to be programmed to travel to specific waypoints.

There you have it: the cheap Raspberry Pi robot platform becomes a camera carrier. Possibly applications are a telepresence robot, a mobile house alarm platform and best of all, a fun toy.

In case you are wondering, here is what a cheap Raspberry Pi robot looks like when it is not made from cardboard and duct tape: the Dexter Industries GoPiGo (USD200 or RM840):


Happy trails.

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