Interface PSoC Analog Coprocessor with an Accelerometer

The project shows how to interface PSoC Analog Coprocessor with an accelerometer (Model 3038 Accelerometer) to measure the Z-Axis acceleration.

The TE Model 3038 Accelerometer is a Z axis accelerometer. The differential analog output from this device varies with Z axis acceleration. This device is rated to detect upto ±200g acceleration with 0.4 mV/g sensitivity.

The 3038 Accelerometer has an inbuilt resistive bridge as shown below.

The differential voltage from the accelerometer is amplified using a two Opamp instrumentation amplifier built using the internal Opamps of PSoC Analog Coprocessor. The output of amplifier is digitized using an ADC as shown below.

The offset error caused by the instrumentation amplifier and the ADC is cancelled out in the Firmware by swapping the differential inputs of AMux_1 Component as shown in the above figure. The ADC data is sent over I2C to Bridge Control Panel software that is running on PC. If the Z- Axis acceleration goes above the threshold value, the Red LED on CY8CKIT-048 turns ON.

The accelerometer is soldered on an Arduino proto shield with CY8CKIT-048 PSoC Analog Coprocessor Kit as base board as shown below.

The following figure shows the connections between the accelerometer and the PSoC Analog Coprocessor.

Testing the project

Follow the steps below to test the project.

1. Make the Hardware connections as shown in the above figure (Note that R131 and R161 on CY8CKIT-048 need to be removed as these resistors are connecting the P2_1 and P2_5 pins to the on-board sensors).

2. Program the PSoC Analog Coprocessor.

3. Shake the board in the Z direction and observe that the on-board Red LED turns On and the sensor data can be observed on Bridge Control Panel software.

The video attached with this project demonstrates the testing procedure of this project.