Thursday, April 2, 2015

Day at the Beach

School got out early today so we went to the beach.  Set the boat in with instructions to go out 600 feet, come back, toot the horn, send some Morse code with the light (can do horn but it is so loud) and then loop and do it again.  Things went perfect for about a half hour then it acted up.   Only then we remembered that there is a problem where the phone powers down the screen and the bluetooth after a half hour.  We could not see any way to set it longer.  Once it does this, even though our software is running it can no longer talk to the relay controller.  So we touched the screen and sent it out again but took it in about a half hour later.

The current software only bothers to turn if it is aimed more than 15 degrees off target.  So it can be far off the centerline in the middle.  We could use more than 2 waypoints to make it stay closer to a fixed path.

We ended up using different types of couplers between the motor and the driveshaft on the left and right.  One seems to lose a lot of power.  So the other side has to be off much of the time to keep going straight.   Will get more of the good couplings in the next 2 weeks.  Once this problem is fixed it should go a bit faster.
Boat is in far right near the top

Someone had to go check it out

Boat right is green, here boat left red is on. Shows that side motor is on.  The new purple foam on the front is in case we run into something.  Did not have any such trouble today.

We will still be at Roys for awhile longer.   If you get here before we leave we can give you a demo.

Data and Results

The data from this run that is logged to Google in real time is available here and the map with data in clickable points is here.  Note there were a couple bad tracks after the tracks at the top were posted.  One time when it was far out it kept going.  It seems the wind out there was strong enough it was having trouble turning.   There was one track near shore where it went under the dock.  This was when the phone went to sleep.

Note clock ticks are 100 ms, so 10 ticks per second.   Status reports are 20 seconds apart, so there should be 200 clock ticks between reports.

There is some more stuff logged to the phone but mostly to help figure out what went wrong if something goes wrong.  Also have more detailed GPS data logged to the phone.

If I look at the data from clock 9678 to 12278, which is 260 seconds I calculate it covered 0.12 miles.  This is 1.66 MPH.   That was coming into the wind.

If I look at the data from clock 14478 to 16278 I calculate 506 feet in 180 seconds or 1.9 MPH.  That is going downwind.

These were good parts (no turns or stopping to send Morse code).  So an average of about 1.8 MPH in good parts.  Not bad.

From clock 12478 to 13278 it was not using the motors.  During this 80 seconds it drifted 50 feet.  This is 0.4 MPH with waterbreak on.  There are other times it moved much less while the motors were off, though there might have been a human holding it for a bit.

So if it can go 1.8 MPH during the day and only drift 0.4 MPH at night, it can make progress even into the wind.  :-)  At least on days like this were it was not too windy.

Fix to 30 minute sleep problem

Update:   There is an Android developer option to "Stay Awake" while charging.   We have now set this option and will connect the phone to the USB power before launching again.  This should fix our 30 minute limit problem.   

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