For this chapter, I will be using an accelerometer breakout board based on the ADXL335 chip. You can basically use any accelerometer you find for this project. If you already have gone through this chapter, you might have the combined accelerometer/compass/gyro from earlier, which will also work. The reason for using the ADXL335 in this chapter is that it has a different form factor, which fits this project better. This accelerometer also makes readout on analog pins, so there is no need for I2C as presented in Chapter 3, Bike Gloves. Accelerometers are suited for measuring acceleration of gravity or as a result of motion of chocks, however, they are known to be very noisy sensors, which means that their readouts are not always exact. The following sketch demonstrates how to "smoothen" the readouts and how to display the information in degrees, as well as indicate which direction the accelerometer is moving.

First, we need to connect our accelerometer to the Blend Micro board...