Jordi and I have been hard at work on the Minimum Blimp UAV and things are coming together nicely. Here are some videos:
First, a test of the Ping))) sensor that we're using for altitude hold. Don't you love the tray-table simulation platform? ;-) The Ping))) sensors are strapped to the far end of the table.
Next, a test of the location-spotting IR tranceivers. In this test we've done a few interesting things. First, you'll note the LEDs turn off for part of the trial. That's because the onboard IR tranceiver doesn't need to have its LEDs on (which consume a lot of power) because it's only receiving data on the position of the beacon transceiver. (The ground-based beacon doesn't need to know where the blimp is) So we take a reading every second, then disable the board for the rest of the second--it's easy to do in software and the board comes back in 75ms each time. Like this:
-Set the Enable pin to High (turn on the beacon)
-Wait 75 milli seconds to give time for wake up
-Read and store the 4 inputs (depending on how noisy the data is in the real world, we make take a dozen readings at 200Hz here and average them to create a direction vector)
-Turn off the beacon (Enable pin low)
-Process the data, and return the result for navigation...
The second thing we've done is boost the voltage going into the ground-based transceiver to extend its range. We got 10 feet at 5v, but the boards can take up to 16v. We'll do a proper test over the next few days, but I'm hoping to get at least 20ft with higher voltage. And since that's 20ft in each direction, it potentially gives us a working blimp range of 40ft, centered around the beacon.
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