Introduction: Acceleration Measuring Helmet
Recently, there's been a lot of discussion in the sports community about the effects of concussions that can be commonplace during an athletic season. Research is still being done to find a link between the development of CTE, chronic traumatic encephalopathy, later in an athlete's life due to previous concussions.
This device is an accelerometer that's been programmed to find the change in acceleration and stores data in a microSD card. Data is collected every tenth of a second and the information can be used for a sports medicine physician to determine whether an athlete is at risk of a concussion. There is no definite amount of change in acceleration that will result in a concussion as every person is different but the device can provide more insight for a medical professional.
Step 1: Gather Parts
For this project you will need
- Arduino Nano
- Triple Axis Accelerometer- LSM303DLHC
- MicroSD card breakout board+
- Battery Pack
Step 2: Coding
First, you must download the Arduino IDE. The file given has code that should get raw data from the accelerometer, the acceleration in the x, y, and z directions. It then takes these components to find the magnitude of acceleration. That is found by squaring each component, adding them together and taking the square root of it. The code is also able to calculate the change in acceleration from the previous data point to the next. The change in acceleration is called the Jerk. The code finds the jerk in the x, y, and z components and finds the magnitude of the jerk as well. Using the serial monitor on the Arduino program, you can see all data points collected. The code prints the jerk for x, y, and z components as well as the magnitude to the SD card for data collection.
If the code is erroring, make sure to download all coding libraries needed. Check Tools -> and the board is Arduino Nano and the Port is the right one.
Step 3: 3-D Print Cases
The next step is to custom make cases to attach onto the helmet and hold all necessary parts.
Here are some examples for custom cases
The first file is a case for the nano, second one for the microSD card and the third is for the battery pack.
The cases shown in the files are fit for the hockey helmet that we used in the project. The cases can be made differently to suit different types of helmets.
Step 4: Wiring
Wiring from accelerometer to Nano
- VIN->5v (It will also work on 3.3v)
- SDA->SDA (A4 on 'classic' Arduinos)
- SCL->SCL (A5 on 'classic' Arduinos)
Wiring from microSD card to Nano
- 5V pin -> 5V
- GND -> GND
- CLK -> pin 13
- DO -> pin 12
- DI -> pin 11
- CS -> pin 10
Since the Nano has limited space, you may have to combine two of the GND wires together. In our prototype, we combined the GND wire from the SD card and the battery pack together.
Step 5: Final Details
The accelerometer was placed between the inside of the helmet and the padding but the placement can be changed to fit different helmets.
If you run into issues with getting code onto the nano, check this instructable: https://www.instructables.com/id/FT232R-USB-UART-Ar...
The text file made in the SD card can be opened in an excel doc and you can plot the time in tenths of a second and the magnitude of the jerk. The file attached is an example of how data can look like when it's recording for more than a minute. You may have to delete the contents of the data file every time you do test runs because the code will keep adding to the text file. If you don't want any previous data points you have to erase the text file for each run.