Swimming pool

Last Friday we went back to the swimming pool to test our test setup. We taped the mediator on a stick, which Dennis holds up above the swimming pool.


We made Frank our test subject. We taped the zwemsor on his back and threw him in the water.

A little video of some swimming action:


The data was streaming nicely until we needed to stop because of the tape was letting loos. See the pictures below.




After we taped the zwemsor back on Frank we had problems with the communication. After a lot of stress we found it was the battery of the zwemsor that was giving us problems. The battery power level was way to low to operate normaly.

Update

As stated in the previous post, Dennis and Frank had a stand on the nITe last week. They showed the zwemsor, current activities and further development.



We finished up the programming for the communication this week. The zwemsor now sends a 433 MHz signal to our mediator. The mediator sends the data using a 2.4GHz signal to the base station.

We started working on a little GUI to read the data directly from the zwemsor.

On this little GUI we can read the axes variables. The sliders below move left/right responding to the value of the axes.

We also started making a graph. In this graph we can read the data coming from the zwemsor. The graph streams live!
Screenshot:

Tomorrow we are going to the swimming pool to test our test setup.

A new design of the zwemsor is on his way!

Edit: Added some pictures

Update

A little late on the update but we made a lot of progress the last few weeks.

We had a problem with our sender.
The past week we were trying to get the two way communication between the spots to work.
What we encountered was that when both transmitters were active, the entire signal went haywire. To solve this problem we lead the 5v power through the High Voltage driver of the spot.

After doing this, the communication went down en we could not get it up again.

This created a lot of headaches for us, until today we discovered that the extra electronics from paralax on the transmitter created the problems.
So we bypassed the electronics en put the UART bus directly on to the LINX chip on the PCB.

And now everything works perfectly

The day after we tested it inside the aquarium we went into the swimming pool.

The range in the swimming pool wasn't as good as we had hoped. We had a range of 40 cm. However since the swimmer isn't that deep in the water, this should be more then enough. This still needs to be tested with a actual swimmer.

On the programming side Frank and Dennis made a sequence diagram.


You can find Frank and Dennis tomorrow and the day after tomorrow (15-16 October) ad nITe (stand 33b). Located ad the Martiniplaza in Groningen. For more information visit this website.

Download

We made some changes to our plan of action. Also the minutes of our meeting is available for download.

Underwater communication

We got the underwater communication working today. We placed the sunspot inside a box and dumped it in a aquarium. As shown above the sunspot sends a signal through the water to our receiver placed near the computer.

The next step is to test it inside the swimming pool.