Interfacing with Arduino
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This document summarizes various computer interfaces including wired interfaces like USB, serial ports, and parallel ports as well as wireless interfaces like WiFi and Bluetooth. It also discusses 'embedded' interfaces like SPI, I2C, and 1-Wire. The document then focuses on the RS232 serial port protocol and issues like voltage levels. It provides an example project of an Arduino thermometer and includes the Arduino and PC code used. It concludes with mentioning an example OrangeMessenger project.
Interfacing with Arduino
- 1. Omer Kilic | omer@tinkersoc.org
- 3. Standard Computer InterfacesWiredUSBSerial PortParallel PortFirewireEthernetAnd others…Wireless
- 4. WiFi
- 5. Bluetooth
- 7. RS232 – The Serial PortAsynchronous serial communications protocolNo clock is sent - the receiver must provide the clock signalData rate must be known by transmitter and receiverArduino implements a ‘virtual’ serial port via USBhttp://arduino.cc/en/Reference/Serial
- 8. Voltage LevelsDifferent devices may have different voltage levelsExample: RS232Voltage levels specified as +12/-12 volts in the standardHooking these levels up to the micro will FRY it!Solution: Use a level converter
- 10. Virtual COM PortsSerial port via USBApplications think they are talking to a serial port, which is emulated by the driversNo need to have a physical serial port!Most new machines don’t have them anywayA LogicalChoice(tm) !
- 11. Example Project: ThermometerA temperature sensor is connected to an analog input on the ArduinoArduino periodically reports the temperature back to PCPC uses this data to plot graphs etc.
- 12. It’s an analog world…Digital – only has two values: on/offAnalog – has many (infinite) valuesComputers don’t really do analogSo they fake it, with quantizationFrom Tod E. Kurt’s ‘Spooky Projects’ notes - http://todbot.com/blog/spookyarduino/
- 13. Thermometer: Arduino CodeintsensorPin = 0; // the analog pin that the sensor is connected tovoid setup(){Serial.begin(9600);}void loop(){//getting the voltage reading from the temperature sensorint reading = analogRead(sensorPin); // converting that reading to voltage, for 3.3v arduino use 3.3float voltage = reading * 5.0 / 1024; // print out the voltageSerial.print(voltage); Serial.println(" volts");// now print out the temperaturefloattemperatureC = (voltage - 0.5) * 100; // converting from 10 mV per degree with 500 mV offset // to degrees ((voltage - 500mV) times 100)Serial.print(temperatureC); Serial.println(" degress C");delay(1000); // wait a second}From Ladyada’s TMP36 Tutorial - http://www.ladyada.net/learn/sensors/tmp36.html
- 14. Thermometer: PC SideRead the incoming data every X seconds (cron)Collect and plot temperature graphs (rrdtool)Example: thermostat-graphhttp://www.anders.com/projects/thermostat-graph/Not an Arduino project but easily hackable!
- 16. Thank you for listening Any questions?Further questions/comments to omer@tinkersoc.org please…