(Complete list of all blog entries in this series)
Wohoo! When November was coming up, I was looking forward to a nice, peaceful and relaxing winter time. Participating in two contests in a row can be really stressful, and coordinating with all the other activities (spending time with the family, even more with my son and the caring about house and garden) got difficult at times. But then when this challenge came along, I could not resist. I fought until the last day and finally submitted my application.
Many thanks to Leeds Beckett University and Element14 for finding my proposal interesting enough to allow me participating in this challenge. Also, many thanks to Analog Devices, Electrolube, Tektronix and Farnell for sponsoring the contest - the provided tools and kits will be very useful.
Last but not least I shall thank my son for being not only the final user, but also the guinea pig for this project, and helping me with some of the experiments on the way.
The project
When I read the challenge description, I immediately thought of our skiing vacations. Last season our son started downhill skiing too, and will continue his skiing lessons this time. As we know from our own skiing history, this will not come without tumbles and drops. So my idea was to monitor any acceleration of the head and report any abnormal values.
At about the same time Cypress introduced their new range of PSoC4 BLE chips. So not only did I had a project, I even have the main component that looks like a perfect fit for the job. Especially since Cypress was so kind to send me one right after Electronica, which should arrive any time (it pays off being a regular Cypress user and being active in the development forums 
Since the monitor needs to be snow-proof, I will enclose with the provided resin. The user interface (when needed) will be provided by CapSense buttons and LEDs. Battery charging should be done wireless (which I know a little bit about thanks to the Beyond the phone challenge...)
A project needs a plan...
No, I won't do Gantt charts or even a MS project, but nonetheless there should some planning ahead. Especially since the next skiing trip is scheduled for next February, which leaves me less than two months for a first prototype.
First task is to evaluate the accelerometers. Probably I will use either the ADXL377 or ADXL375, since they can handle higher g-values. I will also need to find out how high g-values can get when the helmet drops to the floor.
Also, I need to test whether I can communicate with the PSoC4 via BLE from my Android phone. Thats probably the main challenge. But OTOH, the PSoC should provide an easy-to-use CapSense solution, and also make other functions easier to use (due to its advanced component system).
For the wireless charger I want to use an off-the-shelf solution to save some time.
When the prototype (hopefully) works, will have nearly two months left to improve on the solution. Probably the Android app will need some overhaul, and I want to experiment with adding a Gyroscope. That should allow to recognize not only frontal acceleration, but also torsion forces on the head (which are much more dangerous). Biggest challenge here is that they are mounted in the wrong place (they should be in the center of the rotation which is a little bit difficult). Also, they do not really come in hobbyist-friendly LGA or even BGA packages (would be nice if one of them would have been part of the provided kits), so mounting it will be interesting...
Next steps
Hopefully a PSoC4 BLE board arrives so I can start working with the BLE connection. Until then I will work on a preliminary outline of how the hardware and the software should work. That will also be the topic of the next blog entry.
