11. Input devices - David Vaughn and Angelina Yang¶
Assignment¶
- Probe an input device’s analog levels and digital signals.
Probing a Phototransistor¶
To begin, we decided to probe analog levels on an IR phototransistor using both an oscilloscope and a multimeter.
After callibrating the oscilloscope by plugging in the probes and selecting auto-setup, we placed one probe on the signal pin, and the other on GND. We shined a light on the sensor to see if we could detect changes in voltage, but it remained constant at 5V the entire time. We similarly tested it with a multimeter (attempting with current and voltage settings), but it returned the same result. After much trial and error, we could not find any indication of the data sent from the phototransistor to the microcontroller in the oscilliscope readings.
Unsure of whether the circuit configuration was correct or if the sensor is always supplied power, we looked towards the internet. This source indicated that voltage was supposed to rise and drop as more light entered the sensor, so we ultimately concluded that there was an issue with the circuit itself.
Probing a BNO-055 9-axis DOF¶
I2C Signals¶
Thankfully, Landon Broadwell allowed us to use his input, which was a BNO-055 9-axis DOF. We hooked the probes of the oscilloscope to the I2C connection signals of the sensor (SDA, SCL).
We also probed the power going to his OLED screen using a multimeter, which displayed the data collected from the 9-axis DOF. We simply put the probes of the multimeter on the VCC and GND pins of the OLED.
