Arduino Setup & Flexing the ExBow

Transcription

1 Arduino Setup & Flexing the ExBow

2 What is Arduino? Before we begin, We must first download the Arduino and Ardublock software. For our Set-up we will be using Arduino. Arduino is an electronics platform. This platform is made for anyone making interactive projects. The Board we will be using for this project is the Arduino nano. An Arduino Board receives inputs from many sensors, and affects its surroundings by controlling lights, motors, and other actuators. Using the Arduino software we will be able to communicate with the board by writing code and using the Arduino development environment. What is Ardublock? Source: Ardublock is a programming environment designed for beginner physical computation. It allows you to visually program using code blocks, without the hassle of correct coding syntax or misplacing semicolons. In terms of this project, it will make coding for the elbow much easier to understand.

3 Installing Software (USB Stick) 1. Install Arduino 2. Install Ardublock

4 Getting Started: Blink Program Insert your Arduino Nano into your bread board, and let s run a a simple program. Run the sample program, blink, in Arduino and make sure your board is working. Set up the circuit as shown to the right The positive end (long leg) of the LED must be connected to the resistor The negative end (short leg) of the LED must be connected to ground Digital Pin 13 (D13) LED 100 Ohm Resistor Ground Long leg Short leg The online instructions use the Arduino Uno Board:

5 Before Verifying and Uploading Code Before uploading a code, it is important to make sure you have the right board, processor, and port selected, otherwise, the code will not be uploaded. For this project: the board we are using is the Arduino Nano, the processor is ATmega328, and you should select the port you have plugged your Arduino Nano to. NOTE: If you are using a Macbook, you will most likely notice that your port has not appeared, and may just see bluetooth ports. In this case, you will need to download a driver. A driver will allow Arduino to recognize the port. A driver can be downloaded from this link:

6 Physical Circuit Your circuit should look like this

7 Code Initialize pin 13 as an output pin - we will output a signal to tell the LED what to do For us, wherever it says LED_BUILTIN write 13 Turn the LED on Turn the LED off

8 Completed Code For us, wherever it says LED_BUILTIN write 13

9 Output When you ve uploaded the code, then you should see the small LED light blinking. NOTE: it may be hard to see at first due to the brightness of the Nano s light.

10 Voltage Divider A simple circuit which turns a large voltage into a proportionally smaller one By changing R1 and R2, we can make Vout be a fraction of Vin Try R1=1000 Ohms and R2=1000 Ohms What should you get? What about is R2 is really high? For the Exbow, R2 will be our flex sensor

11 Voltage Divider with Flex Now let s program our flex sensor.

12 Physical Circuit

13 Output To see printed outputs, go to the Arduino Program and click on Tools > Serial Monitor (Text Display) or Serial Plotter (Plot Display) You should see one solid line.

14 Integrating the Flex Sensor Type out this code in Arduino: This is where our Ardublock comes into play. Once you type out this code in Arduino, go to Tools and select Ardublock, and replicate this code. Once complete, Upload it to Arduino. You should see a now changed Arduino code.

15 Output Use Serial Plotter As you move the flex sensor back and forth you should see something to the right

16 Min - Max Function Range of outputs for person using the flex sensor differs Use a formula to find bounds Initiate high minimum and every time the flex sensor has a lower value, the minimum becomes that Initiate low maximum and every time the flex sensor has a higher value, the maximum becomes that

17 Code

18 Output As the flex value grows, so does the maximum As the flex value shrinks, so does the minimum Blue = actual output red=max green = min

19 Finding the angle Now that we have the flex values and the range of values, we can convert them to angles Example: Find the proportional value of the flex from the MAX and MIN and multiply by 180 deg

20 Code The left side of the equation maps the Flex value to a value between a new range of 0 to 1 (min to max) The right side then multiplies that into an angle from 0 to 180

21 Output Use the Serial Monitor: Tools > Serial Monitor As you move the flex sensor back and forth you should see something to the right yellow is the angle now

22 Servo Motor Sweep Image: With-Arduino-Nano/

23 Physical Circuit

24 Code

25 Output Use the Serial Monitor: Tools > Serial Monitor As the servo moves the arm back and forth you should see something to the right Try increasing the Max Angle to see how the arm moves

26 Putting it all together

27 Physical Circuit

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