Output Devices - Assignment 11

Discovering Output Devices


So the objective of this week is to get introduced to using output devices. Output devices could be anything that converts a signal recieved from a microcontroller into something sensible, such as a light, motion, representing something on an LCD and many more.

There are many output devices in the market that could be used to connect the microcontroller to the outside world. Those output devices could be an LED, a voltage relay,an LCD, a Stepper or Servo motor and many more. Technically everything that allows you to know what is happening inside the circuit or what provides motion to a system.

In this section, we will learn on how to use and connect an output device to a microcontroller, and how to use it to produce motion and save data that is collected using sensors from its surrounding.



Assignment

We had a Group Assignment and an Individual Assignment this week.
  1. Group Assignment
    2. Measure the power consumption of an output device.
    You can check the Group Assignment on the following link: Group Assignment
  2. Individual Assignment
    3. The individual assignment was mainly to add an output device to a microcontroller board I've designed, and program it to do something.

    Machines Used

    The main machines and equipment used in this week's assignment are machines that are usually used to produce any PCB. The list of machines we used are the following:
    1. Roland MDX-40 is the Desktop CNC machine used to mill copper boards.
    2. Tektonix TBS 1052B is the oscilloscope used to observe the operation of the microcontroller circuit board.
    3. FLUKE 179 was the multimeter used throughout all the process.
    4. ProsKit SS 207 was the soldering iron used for welding the components.


    Software Used

    The following software were used in this week's assignment:
    1. Eagle
      2. was used to design the PCB.
    2. GIMP
      3. was used to extract and enhance the image of the PCB design.
    3. Fab Module
      4. was the main online platform used to produce the g-code used by the CNC machine.
    4. Arduino IDE
      5. was used to write the code and upload the code.


1- Group Assignment - Measuring the power consumption of an output device



Testing

The assignment this week was to measure the power consumption of an output device.

So what i did was connect a multimeter to measure the power consumption the stepper motor is consuming while in motion.

Testing the Power Consumtion of a Stepper Motor

The stepper motor was set on contineous motion, and the power consumption was measure. The power consumption was equal: 0.247A


2- Individual Assignment - Measure Something



Hello Board

In the individual assignment, we had to output something using a board we have designed.

So as a first step, i already built my Hello Board in the past weeks having a built in LDR sensor on it. The board has 2 LEDs of different colors, one Red and one Green, in addition to a Photoresistor (LDR) and a Button.
In this example, the LED is considered to be the output device.

You can check the full details of the Hello Board by visiting the following link My Hello Board

Controlling an Output Device

The objective of the board is to measure the light intensity and based on that, the LEDs will turn on. The Green LED will turn ON when there is light and the Red LED will turn on when there is darkness. Note that the frequency of the LEDs flash depends on the intensity of Light or Darkness measured by the LDR. The more the light or darkness, the faster the blink of the LED.

Due to my limitation, the only way to represent the values read was by using the on board LEDs. Thus the board reads an Analog Value from the LDR, and converts it into a frequency for th LEDs blinks.

So i gave the board an extenal power using an FTDI Basic Breakout - 5V and checked if it works all by itself. And it did work :D. The video represents the functionality of My Hello Board.


3- Individual Assignment - Building My New PCB and Programming it



My Board Design

As a second step in this week's individual assignment, I wanted to start designing a new board that will be used on board of the Pipe Surveying Robot i am planning to build in my Final Project.

Thus to do that, some research was done to check the available outputs that i will be using to control the robot. The main mission of my Robot is to survey existing pipes, gather data related to its path underground, mainly anglural data, and save this data on a memory stick. So the set of outputs needed that i could be using on my robot are mainly the following:

  1. Stepper Motors used to put the robot into controlled motion
  2. Servo Motor could be used to set the angles of the wheels with the pipe walls
  3. Micro SD module used to save the collected data to be studied later.


The next step after chosing the outputs i want to use is to test those outputs. I did my testing using Arduino Uno, because i am planning to use the ATmega328/p as the main microcontroller on my board, which is the same microcontroller used on the Arduino, thus both board will have almost the same capabilities and limitation.

1 - Preparing the Board Design

Next i need to design the control board of my pipe surveying robot i am building. Many points had to be taken into consideration while designing the board, mainly the Architecture of the Microcontroller i am using, the pin connection to the sensors and outputs i am using.

When i first designed my board, the idea was to have 6 wheels drived by 6 small stepper motors. However, because i could not find the stepper motors i want in the market, i decide to change my design to have 4 NEMA 17 stepper motors. Those motors will drive 4 Mecanum Wheels that will achieve front motion and linear motion when needed, to correct the angle of the robot inside the pipe.

In addition to that, a servo motor will be used to control the angle of contact between the wheels and the inner survace of the pipe. Another servo could be used to push to the top side of the pipe to prevent slipage while motion.

My Board

2 - Outputs Pins

Based on the new design, some edits were made on the board design, to achieve what i want. Two stepper motor output pins were deleted, and 2 Servo motor output pins were added.

  1. Stepper Motor:I will be using a DRV8825 Stepper Motor driver to control the Stepper motors in my system. So a 6-pin header was designed on the board that whould supply the motor driver with 12V power supply for the motors, a 5V power supply for the board, 2 GND pins, and 2 Digital Pins.
  2. Servo Motor: The Servo Motor needs 3 pins. So i will prepare a pin header that has 3 pins, one connect to 5V power supply.
  3. SparkFun microSD Transflash Breakout: The SparkFun microSD Transflash Breakout has 7 pins. So i will prepare a pin header that has 7pins, that will be mainly used to support the breakout flat paraller to the board. The 7 pins will be connected to the microcontroller as described above.


Board Schematic

3 - Finalizing Board Design using Eagle

After connecting all the components on the board, the next step is to organize the schematic of the components. This schematic represents the location of the components on the board and the path of the connection in between the components. This step takes time and requires some art and concentration. During this level, the following points must be taken into consideration:

  • The connecting lines have to be more than 12 in width
  • Different connecting lines must not overlap, otherwise a short circuit will occur
After finalizing the design and location of all components, using the "Line" function, draw the external parameter of the Board that will be used to mill the external traces of the board.

You can download the original Eagle design from the following links: My Board



Board Design

4 - Preparing Images Used for Machining Coper Board

After finalizing the layout of the PCB on Eagle, we want to extract the image that represents the PCB design. To do so we need to follow the following steps.

  1. First we turn off all layers by following the following path "view" > "layer settings" > "select none"
  2. Next we turn on only the layers we want to appear, mainly the ones we need to stay on the copper board during the milling process
  3. Extract the image in a monocrome form
You can download the extracted images for My Hello Board from the following links:
So the next step after extracting the image from Eagle is to produce the images we need to use on Fab Modules to generate the g-code later.

So first we open the original image from Eagle and "extract as" a new copy that you can edit.

Using GIMP is easy, just fill the area you dont want with black and that's it. I produced 3 images to be used in fab modules. The images are the following: Please note that in my board, 2 different images needed to be extracted, and the same process had to be done 2 times. One image represents all the paths of the connections between the components, and the other represents the position of the drilling positions.

You can download the extracted images for My Board from the following links:


My board

5 - Preparing G-Code using Fab Modules

After extracting all images that represent the internal and external paths of the milling bit, it's time now to produce the g-code. I used Fab Modules to produce the g-code for PCB milling on the Roland MDX-40.
The following steps were followed on Fab Modules to generate the g-code:

  1. Choose input format and select image (png) that the g-code is going to be generated from
  2. Then select the file from the specific folder
  3. Then go on to Output format and select the format that applies to the CNC machine you are using, in our case it was Roland mill (.rml)
  4. Then select Process and choose PCB traces (1/64) for internal paths and drilling and PCB Outline (1/32) for the external parameter
  5. Then under Output, select the CNC machine you are using, it was a Roland MDX-40. Change the X0, Y0 and Z0 to save space on copper board used. Then check the Feed Speed. I was using 4mm/sec for the Internal Traces and 0.5mm/sec to the External Parameter and Drilling
  6. Then Under Process, adjust the cut depth which should be 0.0 mm for the internal tracing, and 1.7mm for the external parameter and drilling. The tool diameter (milling bit) which was 0.1 mm for the internal traces, 1 mm for the external parameter, and 0.8 mm for drilling.
    The Number of offsets used was 4. The offset overlap used was 70%
    No other adjustments were be made.
  7. Once the Input, Output, and Process tabs are double have been adjusted and double checked. Go ahead and press the Calculate button
  8. Then finally click the Save button and save it to the designated folder. It would be saved as an .rml file
You can download the g-codes for My Board from the following links:

Fab Modules

6 - Machining Copper Board

After preparing the G-code, the following steps were taken to mill the layout onto the copper board:

  1. First I needed a software that would send the g-code directly to the Roland MDX-40. In my case I used the Drop-Out software to send the .rml file to the CNC machine
  2. On the Drop-Out application press the add button and choose the .rml file you created and press open
  3. Then go to File and select Print Setup
  4. On the Print setup first choose the name of your printer, in my case it was the Roland TS-30
  5. Then go to Properties and press the Tool tab, the only thing that should be adjusted are the Z down position and Z engraving pitch both should be at 0.00 mm. During the milling the RPM used was 10,000 for all jobs
  6. Then go on to the Options tab and select Operation Panel
  7. Set the X and Y-axis on the position where you want your PCB to be engraved on the copper board inside the CNC, then press the XY axis SET button
  8. As for the Z-axis, we needed to zero the tool at the top surface of the copper board. In order to do this delicate process we need to gradually bring it down onto the board, with the help of a multimeter with the beep mode on and have one of the cables on the copper board and the other on the drilling bit. In this case as soon as the drill-bit touches the copper board the multimeter would beep. Make sure to go extremely slow at the end so you dont risk breaking your drill-bit
  9. Once the beep is heard, you know that the drilling bit is right at the surface and you can go back to the operational panel (on Drop-out), select the Z-axis from the dropdown menu and set the Z-axis.
  10. Once everything is set press OK until you reach the first page of drop-out and press theOutputbutton. Your CNC machine should now start the process of milling/engraving the copper plate set inside. watch the process until its done
  11. Check the final result, using a multimeter with the beep setting to make sure components are isolated and all conductivity channels are connected
.


Machining

7 - Welding All Components

Now that we have the PCB layout cut-out, the next step is to start soldering. In order to do so we first need certain tools to proceed, find the list with specs below:

  • Soldering Iron: set at 320 degrees celcius
  • Solder wire: 0.5 mm
  • Tweezers
  • Desoldering copper
  • Vacuum
  • Tack-it
Use a fine tip for the soldering Iron as the components are small, and a magnifying glass would be more than just helpful.
The following list represents the list of components used in My Board:
  • ATmega328/P
  • 1 x 16 MHz Crystal
  • 2 x 22pF Capacitor
  • 2 x 10uF Capacitor
  • 1 x 1uF Capacitor
  • 2 x 100pF Capacitor
  • 3 x 10 Kohm Resistor
  • 2 x 499 ohm Resistor
  • 1 x White LED
  • 1 x Green LED
  • 1 x 4-pin push button
  • 1 x 6-pin FTDI pin headers
  • 1 x 6-pin ISP pin headers
  • 4 x 6-pin headers
  • 1 x 6-pin headers
  • 2 x 3-pin headers
  • 1 x 4-pin headers
Now for the actual soldering, I used schematic produce by Eagle.
Now for the final step in this process, make sure all connections are ok using the multimeter on the beep option. And you should be set to move on to the next step.

Welding

8 - Downloading Firmware

After finalizing the code, the next step is to upload the code to the newly constructed Board. To do that, we have to set first the Arduino Board as an ISP. To do so, the following steps are followed.

  1. Choose the Board as "Arduino/Genuino Uno" by going to "tools" > "board" > "Arduino/Genuino Uno"
  2. Next choose the port where the Arduino is connected
  3. Then follow the following "file" > "exaples" > "ArduinoISP" to open the Arduino ISP code
  4. Next upload the code to the Arduino Board

After setting the Arduino board as an ISP, the next step is to push the code to My Board

Connect the Arduino Board to the new Board following those connections:
  • 5V to Vcc
  • GND to GND
  • 10 to Reset
  • 11 to MOSI
  • 12 to MISO
  • 13 to SCK
To do so, the following steps were followed:
  1. Choose the Arduino/Genuino UNO board
  2. Choose the terminal that the Arduino is connected to, usually a COM and a Number
  3. Burn Bootloader by pressing "tools" > "Burn Bootloader"
Now the Board is able to be programmed using the FTDI cable.


Programming

9 - Problems Faced

Because nothing works correctly for the first time, i had a problem in my board. Downloading the code was working correctly, but the code wasn't launching on the baord unless i pressed the Reset button. So i was sure that there is something wrong in the Reset Button Design.

After checking all connections, i noticed that the +5V and GND were switched in the design, so tynically the system was always on reset mode, and presseing the button would allow the microcontroller to start the code.

Some minor changes were done on the board, mainly remaping the +5V and the GND, which fixed the problem, and the design was then edited.

Welding

4- Individual Assignment - Testing My Board with Inputs and Outputs



Pinout Diagram

After burning the bootloader, the next step is to test the various inputs and outputs using the newly constructed board.
But first, i wanted to make sure that my board really works before testing the inputs and outputs.
So in the beginning, I performed various test to check if my board is working, and then to check if i can successfully recieve data from my inputs and issue and save data on my outputs.

You can download the test file from the following link: Serial Test This code tests if the board works and sends data to the serial monitor
Next i tested the board using the very famous Blink code.
After that, i tested all the previously used codes that are used during my test with the Arduino board. All codes are linked above and in the previous week. The codes were edited based on the pins that are used to connect to the inputs and outputs. The image represents the relative Arduino pins that i will be using during coding, with respect to the ATMEga 328/p Microcontroller

To program the board, I used an FTDI cable through the FTDI pin found on my board. As shown in the image above, the Ground pin is the one near the Crystal. The following process is usually followed to upload the code on the Board.

  1. Compile the code and check for any bugs
  2. Choose the baord as Arduino/Genuino Board from the "tools" drop down menue
  3. Choose the Port related to the board
  4. Upload the code to the baord using the "Upload" button

1 - Stepper Motor

In order to control a stepper motor, a Stepper Motor Driver is required which will recieve two signals from the microcontroller in addition to two power supplies, one coming from the Control Board and the other is the Voltage Needed to power the Stepper Motors.
The stepper motor driver has the the following pins

  1. Reset pin which is connected to the 5V power source, either from the Arduino Board, or any other board
  2. Sleep pin which is also connected to the 5V power source, either from the Arduino Board, or any other board
  3. Step pin which is connected to a digital pin which will be set as an output pin and control the direction of the rotation
  4. Dir pin which is connected to a digital pin that is set to be an output and control the steps of the motor
  5. GND pin which is connected to the GND of the power source or board you are using
  6. VMOT pin that is connected to the positiove poleof the motor power supply
  7. GND that is connected to the GND of the motor power supply
  8. B2, B1, A1, and A2, that are the output pins going towards the stepper motor.
So a Four-Pin connection will be needed on My Board for the DRV8825 stepper motor driver. You can check the full details of the DRV8825 stepper motor driver by visiting the following link DRV8825 Stepper Motor

Below is the code used to read data from the Ultrasonic Sensor
/* Simple Stepper Motor Control Exaple Code */ // defines pins numbers const int stepPin = 8; const int dirPin = 9; void setup() { // Sets the two pins as Outputs pinMode(stepPin,OUTPUT); pinMode(dirPin,OUTPUT); } void loop() { digitalWrite(dirPin,HIGH); // Enables the motor to move in a particular direction // Makes 200 pulses for making one full cycle rotation for(int x = 0; x < 200; x++) { digitalWrite(stepPin,HIGH); delayMicroseconds(500); digitalWrite(stepPin,LOW); delayMicroseconds(500); } delay(1000); // One second delay digitalWrite(dirPin,LOW); //Changes the rotations direction // Makes 400 pulses for making two full cycle rotation for(int x = 0; x < 400; x++) { digitalWrite(stepPin,HIGH); delayMicroseconds(500); digitalWrite(stepPin,LOW); delayMicroseconds(500); } delay(1000); } Testing was done using My Board after it was constructed. The Video shows the test done.
You can download the original Arduino Code Used from the following Link
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2 - Servo Motor

The Servo motor is maily used to produce a controlled angular motion. The servo motor is connected to the control board using 3 pins:

  1. Vcc which is connected to the 5V power supply from the board
  2. GND which is connected to the GND pin on the control board
  3. Signal pin which is the output pin that controls the motion of the servo
Saying that, The Stepper Motor requires a 3-pin connector at the control board.

To test the servo motor, i used the example code found in the Arduin IDE.
Below is the code used to control a servo motor
Servo myservo; // create servo object to control a servo // twelve servo objects can be created on most boards int pos = 0; // variable to store the servo position void setup() { myservo.attach(9); // attaches the servo on pin 9 to the servo object } void loop() { for (pos = 0; pos = 180; pos += 1) { // goes from 0 degrees to 180 degrees // in steps of 1 degree myservo.write(pos); // tell servo to go to position in variable 'pos' delay(15); // waits 15ms for the servo to reach the position } for (pos = 180; pos >= 0; pos -= 1) { // goes from 180 degrees to 0 degrees myservo.write(pos); // tell servo to go to position in variable 'pos' delay(15); // waits 15ms for the servo to reach the position } } Testing was done using My Board after it was constructed. The Video shows the test done.
You can download the original Arduino Code Used from the following Link



3 - microSD Transflash Breakout

The main tool i will be using to save the data collected by the robot is the microSD Transflash Breakout.
Breakout board for the microSD socket that is not much bigger than your fingernail. Compatible with the SPI interface found on any SD card, this tiny form factor was created for cell phone storage and is perfect for your next MP3 project! Board comes fully assembled and tested.

The microSD Transflash Breakout has 7 pins:

  1. Vcc that could be connected to a 5V or 3.3V power suply.
  2. GNG pin which is connected to the GND of the control board
  3. SCK which has to be connected to SCK pin of the micro controller, known by the Analog 5 pin on the Arduino Board
  4. D0 pin which has to be connected to the MISO pin of the microcontroller.
  5. DI pin which has to be connected to the MOSI pin of the microcontroller.
  6. CS pin which is connected to a digital pin.
  7. CD pin which is connected to a digital pin.


You can check the full details of the SparkFun microSD Transflash Breakout by visiting the following link SparkFun microSD Transflash Breakout

Below is the code used to save data on the micro sd
/* SD card read/write This example shows how to read and write data to and from an SD card file The circuit: * SD card attached to SPI bus as follows: ** MOSI - pin 11 ** MISO - pin 12 ** CLK - pin 13 ** CS - pin 4 (for MKRZero SD: SDCARD_SS_PIN) created Nov 2010 by David A. Mellis modified 9 Apr 2012 by Tom Igoe This example code is in the public domain. */ #include <SPI.h> #include <SD.h> File myFile; void setup() { // Open serial communications and wait for port to open: Serial.begin(9600); while (!Serial) { ; // wait for serial port to connect. Needed for native USB port only } Serial.print("Initializing SD card..."); if (!SD.begin(10)) { Serial.println("initialization failed!"); while (1); } Serial.println("initialization done."); // open the file. note that only one file can be open at a time, // so you have to close this one before opening another. myFile = SD.open("test.txt", FILE_WRITE); // if the file opened okay, write to it: if (myFile) { Serial.print("Writing to test.txt..."); myFile.println("testing 1, 2, 3."); // close the file: myFile.close(); Serial.println("done."); } else { // if the file didn't open, print an error: Serial.println("error opening test.txt"); } // re-open the file for reading: myFile = SD.open("test.txt"); if (myFile) { Serial.println("test.txt:"); // read from the file until there's nothing else in it: while (myFile.available()) { Serial.write(myFile.read()); } // close the file: myFile.close(); } else { // if the file didn't open, print an error: Serial.println("error opening test.txt"); } } void loop() { // nothing happens after setup } Testing was done using My Board after it was constructed. The Video shows the test done.
You can download the original Arduino Code Used from the following Link

4 - Ultrasonic Distance Sensor

As mentioned previously, the Ultrasonic Distance Sensor is a Digital Sensor. The HC-SR04 Ultrasonic Sensor Module has four pins:

  1. Vcc which is connected to the 5V power source, either from the Arduino Board, or any other board
  2. Trigger pin which is connected to a digital pin which will be set as an output pin
  3. ECHO pin which is connected to a digital pin that is set to be an Input
  4. GND which is connected to the GND of the power source or board you are using


You can download the data sheet for the Ultrasonic Ranging Module HC-SR04 from the following
  • link

    • Below is the code used to read data from the Ultrasonic Sensor
    // defines pins numbers const int trigPin = A0; const int echoPin = A3; // defines variables long duration; int distance; void setup() { pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output pinMode(echoPin, INPUT); // Sets the echoPin as an Input Serial.begin(9600); // Starts the serial communication } void loop() { // Clears the trigPin digitalWrite(trigPin, LOW); delayMicroseconds(2); // Sets the trigPin on HIGH state for 10 micro seconds digitalWrite(trigPin, HIGH); delayMicroseconds(10); digitalWrite(trigPin, LOW); // Reads the echoPin, returns the sound wave travel time in microseconds duration = pulseIn(echoPin, HIGH); // Calculating the distance distance= duration*0.034/2; // Prints the distance on the Serial Monitor Serial.print("Distance: "); Serial.println(distance); }
    You can download the original Arduino Code Used from the following Link


    5 - Accelerometer and Gyro (MPU-6050)

    The main sesnor i will be using in my Pipe Surveying Robot is the the MPU-6050.
    The InvenSense MPU-6050 sensor contains a MEMS accelerometer and a MEMS gyro in a single chip. It is very accurate, as it contains 16-bits analog to digital conversion hardware for each channel. Therefor it captures the x, y, and z channel at the same time. The sensor uses the I2C-bus to interface with the Arduino.
    The MPU-6050 is not expensive, especially given the fact that it combines both an accelerometer and a gyro. Also note that Invensense has combined the MPU-6050 with a magnetometer (compass) in a single chip called MPU-9150.

    The accelerometer measures the acceleration along one direction, while the gyroscope measures the angular acceleration on one axis. The module has 8 pins:

    1. Vcc that could be connected to a 5V or 3.3V power suply. The MPU-6050 module has a voltage regulator on board
    2. GNG pin which is connected to the GND of the control board
    3. SCL which has to be connected to SCL pin of the micro controller, known by the Analog 5 pin on the Arduino Board
    4. SDA pin which has to be connected to the SDA pin of the microcontroller, known by the ANalog 4 pin on the Arduino board.
    5. XDA pin
    6. SCL pin
    7. AD0 pin
    8. INT pin
    The analogic pins are not set on INPUT because it's their default setting. The values read by the analogic pins will be sent to the serial port.

    Open the Serial Monitor, move the sensor and try to see how the values change.

    You can download the data sheet for the Accelerometer and Gyro (MPU-6050) from the following link

    Below is the code used to read data from the Ultrasonic Sensor
    #include<Wire.h> const int MPU=0x68; int16_t AcX,AcY,AcZ,Tmp,GyX,GyY,GyZ; void setup(){ Wire.begin(); Wire.beginTransmission(MPU); Wire.write(0x6B); Wire.write(0); Wire.endTransmission(true); Serial.begin(9600); } void loop(){ Wire.beginTransmission(MPU); Wire.write(0x3B); Wire.endTransmission(false); Wire.requestFrom(MPU,12,true); AcX=Wire.read()<<8|Wire.read(); AcY=Wire.read()<<8|Wire.read(); AcZ=Wire.read()<<8|Wire.read(); GyX=Wire.read()<<8|Wire.read(); GyY=Wire.read()<<8|Wire.read(); GyZ=Wire.read()<<8|Wire.read(); Serial.print("Accelerometer: "); Serial.print("X = "); Serial.print(AcX); Serial.print(" | Y = "); Serial.print(AcY); Serial.print(" | Z = "); Serial.println(AcZ); Serial.print("Gyroscope: "); Serial.print("X = "); Serial.print(GyX); Serial.print(" | Y = "); Serial.print(GyY); Serial.print(" | Z = "); Serial.println(GyZ); Serial.println(" "); delay(333); }
    You can download the original Arduino Code Used from the following Link
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    Copyright © 2017 Wael Khalil - Design: Tooplate