Author: Jamie

Kiteboat Logger Power Control

5/2/11

We can now start and stop the kiteboat logger and verify that it is powered on without opening its protective waterproof case or connecting from a remote device. This has involved running the power switch and LED from the internal PC to a waterproof switch on the outside of the case, a job which was made trickier by the miniaturization of the PC. This operation also opens the way to making an external supervisory circuit that can control the PC power and monitor the battery state on longer excursions.

Other recent improvements to the logger include auto-detection of removable media, software to assist with calibration of the wind sensor while we are on the water, and an independent charging port. […more]

KAIView Map Update

5/2/11

KAIView 0.2.6 contains several improvements from the last few weeks, particularly in the mapping component and its integration with the other data displays. The overall goal has been to make the mapping window more useful as a primary interface to the data, instead of just a supplement to the graph display. By default the map window is now larger, the data that it already displayed is easier to read, and a legend shows the geographic scale and the meaning of the color-coded data.

In addition to these visual changes, there is now better correspondence between selections made in the graph window and those made in the map. Right-clicking and dragging in either view will create a selection that is shown […more]

Android + Bluetooth Servo Controller

2/11/11

We are exploring the use of our new Nexus S Android phone as a kite-based programmable wireless camera and pan/tilt controller. The first step in making this happen was to make a bluetooth connection to an RC servo controller and control it from the phone.
For extra fun, we mapped the phone’s orientation to its commands so that the pan/tilt unit tracks the phone’s rotations.

Next we will improve the app so that a user interface on a second phone or a remote computer can control the phone remotely over a socket connection. The final step will be to transmit both low-resolution, low-latency “preview” images and full-resolution images from the phone back to its client.

Kitefoiler Tow Test Two

1/25/11

Today we performed a second tow test of the new kitefoiler. Some minor repairs had been made since the last test, the sensors and foils were adjusted, and the tiller was strengthened. The boat now weighs in at 390 lbs, which is a larger increase than expected. It is possible that we under-measured the kitefoiler weight before the first test.

This time Don manned the helm. We were able to get the boat more stably onto its foils, especially after Dudu and Joe began to adjust the foil angles manually. We found that there was interference from the bottom of the cassette fairing. We will make a mod in the morning and be back out there tow testing first thing.

[…more]

Kitefoiler Tow Test

1/21/11

Today the kitefoiler was put into the water for the first time. It floated well and we were able to get a sense for its handling while recording load and speed data. The boat got up onto its front foils at around 16 knots, which required approximately 150 kgf of tension on the line. As the boat came out of the water, the force required to pull it diminished. Once up on the foils there were a few problems, so each towing run ended quickly.

The boat’s weight, measured just before launch, was 355 lbs.

The first graph shows the line tension and boat speed vs. time. There are 8 distinct episodes in which the boat is towed, and as […more]