I know I said my last post was the final one, but I decided to write one more summarizing some of the decisions I made, and what makes the Real Time Coach Athlete Monitoring System so great.
The first critical decision that I made was to make this work with a large number of athletes rather than just one. This was largely due to the fact that while some sports are individual, many of them consist of a team with a number of athletes that each need to be monitored. This was something that I kept in mind throughout the competition and it inspired my next decision.
The second critical decision I made was not to use bluetooth as the direct communication to the device. Bluetooth is limited in it's range which means that the entire system is only functional if you are close enough. I knew that I would have to use bluetooth to some extent as I wanted the front end to run on an android phone, but since bluetooth connects in a one-to-one manner (one device can be connected to one other device. This meant that I would have to have some sort of router that the phone communicates to with bluetooth, and then that device can communicate with all of the individual RTC units. I did this using a serial bluetooth monitor hooked up to an arduino board with a wireless shield, which brings me to my next decision.
Xbees were the logical choice in wireless communication. They have very good range, are not very expensive, and require minimal skill to implement. This means that in order to put this together, there is not much skill required meaning that it could potentially be reproduced very easily. Also, there are many different models of xbees, some of which have an effective range of greater than 10 miles, effectively allowing you to use this device in activities with very large ranges such as marathons.
I was going to make my own heart rate monitor, but after acquiring all of the materials, I realized that there was not enough time to finish, test, and perfect it before the competition was done. This lead to a major spike in price, but could be reduced to $30 or less per HRM with more time.
All in all, my goal with this was to make something that is affordable, easy to manufacture, and easy to use. I feel that I accomplished each of these fairly well.
In total, the costs come out as follows:
|Item name||Cost (USD)|
|Chest and Shoulder Strap||~10.00|
|Assorted Wires and Connectors||~5.00|
|Heart Rate Monitor||50.32|
|Bracket and bolts||~2.00|
|Serial Bluetooth Module||11.99|