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Description
To use this sensor:
- Determine the offset by taking an average reading with no current passing through the sensor. This value is usually ~485
- When current is passing through the sensor, take many readings (we use 100) to obtain an average.
- To get current, subtract the offset and then divide by 32.
current = (average – offset) / 32
For example, below, we graphed the current going into a motor controller against the power being sent to the motor.
Another application would be to know when a motor is stalled. When a motor stalls, the current spikes to multiple times the normal operating current. Your program can then turn off power to that motor or try driving the opposite direction.
Sensor Type | Three Wire Analog Sensor |
Dimensions | 32 mm x 32 mm x 5 mm |
Mounting Holes | 24 mm x 24 mm, 4mm ⌀ |
Power | 3 V or 5 V DC, 5 mA |
Signal Logic Levels | Analog 0 V – (3 or 5) V |
Additional information
| Weight | .0120 lbs |
|---|---|
| Dimensions | 3 × 4 × .5 in |
FTC SDK
Android Studio Example Program
Download the below program for an example of how to read this Analog sensor. The FTC SDK will supply a value from 0-5 representing a voltage.
In your configuration file, name an Analog Input “light” and name a Core Device Interface Module “Device Interface Module 1”
/*
Modern Robotics Analog Example
Created 7/25/2017 by Colton Mehlhoff of Modern Robotics using FTC SDK 3.10
Reuse permitted with credit where credit is due
The Modern Robotics Core Device Interface reads analog input
using a 10 bit value meaning the Android Phone reads a value from 0 to 1023.
The FTC SDK supplies a "voltage". The SDK is scaling this value of 0-1023 to 1-5 with decimal places.
Configuration:
Analog Input on Core Device Interface "light"
Core Device Interface named "Device Interface Module 1"
Support is available by emailing support@modernroboticsinc.com
*/
package org.firstinspires.ftc.teamcode;
import com.qualcomm.robotcore.eventloop.opmode.LinearOpMode;
import com.qualcomm.robotcore.eventloop.opmode.TeleOp;
import com.qualcomm.robotcore.hardware.AnalogInput;
import com.qualcomm.robotcore.hardware.DeviceInterfaceModule;
@TeleOp(name = "Analog Example", group = "MRI")
//@Disabled
public class MRI_Analog_Example extends LinearOpMode {
//An Analog Input. In this example, we used a Light Sensor although it could be any analog sensor.
AnalogInput MRLightSensor;
//CDI. Using this, we can read any analog sensor on this CDI without creating an instance for each sensor.
DeviceInterfaceModule cdi;
@Override
public void runOpMode() {
telemetry.addData("Status", "Initialized");
telemetry.update();
//Link objects to configuration file
MRLightSensor = hardwareMap.analogInput.get("light");
cdi = hardwareMap.deviceInterfaceModule.get("Device Interface Module 1");
waitForStart();
while (opModeIsActive()) {
//Read the light sensor using the Analog Input object
telemetry.addData("light", MRLightSensor.getVoltage());
//Read each Analog Port of the CDI. 0-7
for (int i = 0; i < 8; i++) {
telemetry.addData("Analog " + i, cdi.getAnalogInputVoltage(i));
}
telemetry.update();
}
}
}
