Impact Sensor

Introduction
My project is to build an impact sensor using the IMU of the max32630fthr. Basically I wanted to be able to attach the sensor to an object so it could measure the impact force when the object is moved and store the readings to an sd card.

The difficulty level for this project is easy.

BOM
MAX32630FTHR
Battery or usb cable if running tethered to a pc
Micro SDCard

Schematics
All the required hardware is already on the board.

Instructions
To build the project all I had to do was load my code to the board , add a sd card and battery if you want to by itself or using the usb cable so you could watch the console output.

After doing research for the project, I found out that a couple of the sample projects for the board contain the majority of the code required. I decided to use the MAX32630FTH_IMU_Hello_World source code as my starting point. It contains all I needed to read the IMU values. I then added code to be able to enable different modes using the on board button. When the button is pressed, it executes an interrupt which will increment a variable that is used to enable and disable various functions, this also enable or disables the on board leds so you can tell which mode your in. The last step was to add code to write to a sd card.

Here is a couple of screen shots of the console. In the second image, the data is down further on the screen because I was playing around with positioning text on the screen.


Here is a sample of the output on the sd card:
Fields are as follows Time Temp xAcc yAcc zAcc xGyr yGyr zGyr
The data can be easily plotted using excel or a similar program. My intent was to use processing to create an app that would be able to continuously scroll as the data came in. The app would also let you set thresholds to highlight when the force exceed the set point, but I was unable to get the serial connection to work properly which was odd because terminal programs would connect without issue.

I would of like to get bluetooth working, but I didn't find any examples until an email came out a couple of days before the due date. Since processing apps can run on a phone or tablet, bluetooth would of been the best choice to get working as I wouldn't need the usb connection to monitor the output. This setup would also be ideal for one of my test which was to mount it on the back of my sons sparing gear, so I could see how hard he was actually getting hit.

After playing around with this board, I think adding a LoRa transceiver would be a great idea too. The sensor could then be mounted in remote locations and the data could be monitored very easily. I did see someone else has already added to a board like this which looks very interesting. I think when my transceivers come in that I order, I may try to add one to see if it works.

Conclusion
I found this board rather easy to get started with. The fact it works with the mbed compiler makes great development platform. The price for the board is pretty good especially for what you get built onto the board. If I had give a con for the board, I would have to say that there isn't very many examples out there for it, but I suspect that will change as people use it


Source Code