Build Log 7 - More Work on the Quadrocopter

In this video, I install the landing skids (or rings) and the camera. I also show some of the software in action.

I haven't been doing a whole lot of work on the quadrocopter, except for redesigning all the software to use Processing (except for the video). The Processing application handles display of UAV data, joystick input, UDP networking, and piping of GPS data to a virtual COM port. Video is handled by FFmpeg. The Linux side is running a Python script that takes the data from the serial port and sends it over the network via UDP and vice versa.

The servos that I am using for the camera are a bit weak but they seem to work. They are very jittery in the video, but that's partly because the power from the USB port is barely enough to move the servos. When it's plugged into the battery, they are more stable. Also, the camera doesn't have true pan and tilt control with the way it is mounted but it will work for now.

Also, I discovered a major error in my servo control code. As long as one servo was set to 0, it would work fine. But when they were all set, they were not outputting the correct signals. This was because I was resetting the servo timer on the lowest servo value. That is why if a servo was set to zero, it would be okay because it's supposed to reset the timer at zero. But, it was resetting at whatever the lowest servo value was, which may not be zero.

I know you guys want to see the quadrocopter fly, but it's simply not ready yet. I'm having a hard time tuning the PID controller and I'm probably doing something wrong. But, it sort of works and maybe good enough for some very unstable flight. Stay tuned.

Category:

Science & Technology

Tags:

• UAV
• quadrocopter
• quadcopter
• quadrotor
• homemade
• homebrew
• tutorial
• aluminum
• frame
• wi-fi
• 802.11
• Processing
• FFmpeg
• Logitech
• HD
• webcam
• C260
• servo
• servos
• hobbyking
• hobby
• RC
• WIP
• Work In Progress
• landing
• skid

[PatheticComputing]

@saginata I ran the motors at low speed and the camera image appeared to be stable, although I haven't tried it with the motors cranked up. The frame does resonate at a certain motor speed, but its below the speed needed to hover.

[rfsdalotto]

awesome!

[epatto]

Also, when hot gluing plastic surfaces, it helps to roughen them with a sand paper. That provides a lot better surface for the glue to stick to.

[epatto]

Bubble level is actually called a spirit level. :)