Test four ultrasonic sensors

[ZidongGuo]

• [x] Set up the voltage divider and verify that the voltage is safe (no more than 3.3v)
• [x] Connect one HC-SR04 ultrasonic sensor to Raspberry Pi with the voltage divider and use the hc-sr04.py script available in DP1 in combination with the Piscope and check if there is a pulse in the Piscope.
• [x] Mofidy hc-sr04.py and add it to Read_Ultrasonic_Distance()
• [x] Using Read_Ultrasonic_Distance() to see if the sensor can return the correct distance to the object in the front.
• [x] Check to see if the ultrasonic sensor can return the distance beyond 2cm.
• [x] Repeat the above process for all four ultrasonic sensors

[ZidongGuo]

Set up the voltage divider

Pick one 1k ohms resistor +one 4.7k ohms resistor as the top half of the voltage divider and one 10k ohms resistor as the bottom half of the voltage divider.

[ZidongGuo]

Connect one HC-SR04 sensor to Raspberry Pi

Connect Vcc from the sensor to the 5v power from the Pi, GND from the sensor to GND from the Pi, Trig from the sensor to GPIO5. Connect the Echo from the sensor in series with one leg of the 1k ohms resistor Run in VNC session

sudo piscope

and then run the python script with

python3 hc-sr04.py

Expected result: Show a correct distance between the object in front of the sensor in the command window and see a right pulse in the piscope

[ZidongGuo]

Modify the Read_Ultrasonic_Distance() into four different functions to monitor distances in four directions (Left Right Front Back)