Category Archives: Tutorials
Virtuoso is a program that plays different sequences of pre-defined notes. There are seven push buttons which(each) add one note to the sequence. You can choose between two different octaves bye pressing and releasing each button. Also there are two potentiometers for changing “Tempo” and adding “Tremolo” effect.
Below is the schematics for the circuit which works with the Virtuoso program:
Here is a simple guide to music and music alphabets. Here you can read about mapping of frequency to notes.
This video does a good job explaining PWM.
Accelerometers can measure acceleration and tilt (angle). They are used in many devices nowadays such as Mobile phones (iPhone), Gaming consoles and gadgets (Nintendo Wii), Navigation (GPS navigators, Airplanes), and etc. In physical computing accelerometers are used to measure device’s position relative to the ground. A simple Accelerometers can measure acceleration along one axis. Here, a simple program is presented that interfaces a 3-axis MMA7260Q accelerometer from Sparkfun to an Arduino board.
Be careful while making connections to your Arduino, not to misconnect the Negative and Positive supply.
Download the code for Processing and Arduino in a zip package here*. Unzip and upload the code provided for the Arduino to your Arduino board. Then run the code provided for Processing. Press ‘X’, ‘Y’, ‘Z’ key on your keyboard to see the real time graph for the corresponding axis on your screen.
The Arduino code sends three consecutive bytes by serial baudrate of 9600. On the computer side the processing program gets the data and translates the bytes (each byte for one axis[X,Y,Z]) into a graph representation.
*.The code is taken from here(Thanks to Daniel Goncalves)
One of the cool things you can do with Arduino is interfacing with RF modules.There are different types of RF boards available in the market. We are going to work with “nrf24L01+”Transceiver chip from NordicSemiconductor
Mounted on a breakout board from Sparkfun.
Before you start
For this project you need two Arduino boards and two RF modules. Download and install this library for Arduino program(Mirf). Extract the files and put (the folder) in the Library folder in the Arduino installation path:
OS X: “/Applications/Arduino.app/Contents/Resources/Java/libraries”
You must restart Arduino Program after installing above libraries.
The project consists of a sender and a receiver . The connections for the nrf 24L01+ for the sender and receiver is as picture below
In the sender circuit you also need to connect a potentiometer to pin A0 as shown here:
On the receiver side add a LED as shown below:
Now download the code for the sender and receiver below and upload it to the Arduinos:
By changing the potentiometer on the sender side you see the LED on the receiver side changes intensity.
The code used in this post is slightly changed version of the code from http://www.bajdi.com/playing-with-nrf24l01-modules/
There are different approaches to driving a motor when it comes to driving a motor with Arduino. If a simple relay is used to drive a motor it can only turn the motor on and off. In case a single transistor like TIP120 (BJT) or IRF510 (MOSFE ) is used, it is possible to control the speed of the rotation. There exist smarter DC motor drivers (so called H-bridge) that can control the direction of rotation and even brake.
Seed Studio L298 Motor Driver
MC33887 Motor Driver
An example of such a driver is Plolu’s MC33887 Motor Driver which is affordable and versatile. This driver can control a single DC motor with maximum consumption of 2.5A and peaks of 5A. Motor voltage can range from 5-28V which makes it an excellent general purpose motor driver.
Table below describes the marking of the pins on the back side of the MC33887 driver board from Pololu:
Interfacing MC33887 Motor Driver with Arduino
In order to drive a motor with Arduino you will need the components below:
- A DC motor (5-12V)
- A Breadboard
- A Pololu MC338870 driver board
- An Arduino with a USB cable
- Some wires
- A DC Jack connector
- An adapter matching the voltage of your motor (less than 5-12V)
- 10-50KΩ Potentiometer
Make the circuit shows below:
Your circuit should look like this:
The circuit suggested above is the simplest form of using an MC338870 to drive a motor. By using D1 and D2, Disable1 and Disable2, one can leave the motor pins in tri-state. FS, Fault Signal, pin can be used to determine malfunction of the driver. FB, Feed Back, can aslo be read with the analog inputs to determine the amount of current being consumed by the motors.