Prototype V1

We used an Atom-based single board computer for our V1 prototype. However, this board turned out to be too slow for streaming raw video frames and on-board image processing.

Our first on-board computer. It was a modified version of Advantech MIO-2260. We removed the heatsink with a fan for more efficient and lightweight cooling. WiFi was also attached at the customly machined aluminium plate.
Bottom view.
To make some rooms for electronics and camera, I extended the length of landing gear with DIY acrylic legs. However, the legs were not strong enough to sustain the impact on landing. They broke when the quadcopter touched the ground. Later we sticked to carbon fiber materials.
Crashed due to bad battery. The low-voltage detection system did not work properly so the quadcopter dropped suddenly from the air. Later we added extra battery alarms.

Prototype V2

We tested a high-end WebCam (Logitech C920) and found that it produces terrible images under high vibration, due to lens being attached to a flexible voice coil (for focusing). The voice coil is not strong enough to hold the lens under high vibration.

Logitech C920 with enclosure removed.
Logitech C920 attached at the bottom.
Crashed due to abnormal behavior in the flight controller under high vibration. Later we stopped using this frame completely.

Prototype V3

After previous failures, we decided to choose a new frame for our quadcopters with new single board computer and cameras.

New frame.
Another view.
Testing GPS clock synchronization.
Integration testing. In order to synchronize all cameras, we need to perform a handshake procedure among the flight controller, the GPS and the on-board computer.

Prototype V4

Having gone through three prototypes, we had a much better understanding of the system and came up with the final version. The final prototype has a longer landing gear to accommodate the WiFi antennas. We chose PointGrey cameras because they allow exchangable lens and shutter synchronizatin.

You probably noticed some parts in green color. They were 3D-printed!

The on-board computer together with the camera and WiFi antennas.
We still had another horrible crash caused by bad parameter tuning. It was very hard to notice because it only caused trouble under very windy condition.