Arduino Driver guide
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Using existing Device Classes
Already existing Arduino Device Classes, e.g. implemented as Logger or Switch, can be used after configuring the Arduino.
- Install the ArduinoIDE
- For every Device Class, there exists one ".ino" file which can be found in the corresponding Device Class folder
- Double-click the ".ino" file and the ArduinoIDE will open
- Configure your ArduinoIDE by setting the Arduino type (e.g. nano, uno, or mega) and the COM port
- Upload the ".ino" file to the Arduino
- Now your Arduino knows how to handle the commands send by the SweepMe! Device Class
Creating an own Device Class for Arduino
Arduino can easily be combined with SweepMe! However, there are some guidelines which make the implementation much easier:
- Try to sends a text during the setup() routine of the Arduino, so that SweepMe! knows that sending commands can be done from now on.
- The Arduino can send text via its function println() which uses a LineFeed character as terminator ("\n"). Thus, the Arduino should also expect to receive messages ending with a LineFeed ("\n") so that the write and read terminators are identical. The standard terminator of SweepMe! is a LineFeed ("\n") so that you do not have to set it.
- If the Arduino sends a message back after receiving a command, do not send more than one line. Otherwise, one has to read out the COM port multiple times in the SweepMe! Device Class
- Try to have a constant length or format of the return message, so that reading out the string is less errorneous
- Try to make every parameter adjustable by a single command, e.g. "Pixel = 03", "Voltage = 0.05", or "Frequency = 400". That way, multiple items of the sequencer can communicate with the Arduino and multiple parameters can be swept.
- Use the standard baudrate of 9600 so that other Arduino Device Classes can easily be copied and modified.
- After finishing your Device Class, put your ino file as uploaded to the Arduino into the folder of the Device Class. Give the ino file exactly the same name as used for the folder to allow for easy manipulation using the Arduino IDE.
Example Device Class
Arduinos are typically implemented as Switch if you rather set some values or as Logger if your rather read some value. The following code shows a Device Class which can set and read a value.
from EmptyDeviceClass import EmptyDevice # Loading the EmptyDevice Class
class Device(EmptyDevice): # Creating a new Device Class by inheriting from EmptyDevice
def __init__(self): # The python class object need to be initialized
EmptyDevice.__init__(self) # Finally, the initialization of EmptyDevice has to be done
self.variables = ["A variable to read out"]
self.units = ["The unit of the variable"]
self.plottype = [True] # set to False if the variable is a string and cannot be plotted
self.savetype = [True] # set to False if there is no need to save the variable to the data file
self.port_manager = True # using the port manager works seamlessly
self.port_types = ["COM"] # Arduinos are always listed as COM ports
self.port.properties = {
"timeout" : 2, # set timeout of the COM port to 2 seconds, which is necessary to prevent timeout error during initialization
}
def initialize(self):
self.port.read() # readout the COM port to know that the Arduino is ready to receive commands
def apply(self):
print self.value # self.value is always the actual value to be set, print to see exact format
self.port.write("Pixel = " + str(self.value)) # here we send the new command to the Arduino
self.port.read() # read out the COM port to know that the Arduino has finished setting the parameter. Only use it if the Arduino sends a response.
def measure(self):
self.port.write("Read?") # send some command to request a reading of parameters, for example "Read?" or any other command. Only use it if the Arduino can read parameters
def call(self)
self.answer = self.port.read() # read out the COM port
return [float(self.answer)] # return the answer to SweepMe!. Do not forget to transform the string to any format as needed e.g. float or integer
Example Arduino .ino file
The following code shows you an example how to implement the above guidelines into an Arduino ino file. It has to be adapted to your needs.
// define some variables
unsigned int variable1;
unsigned char variable2 = 2;
unsigned long variable3;
String variable4;
// define functions which you need later
void myFunction()
{
variable1++;
}
//
void setup()
{
// configure your pins here
Serial.begin(9600); // set Arduino to baudrate 9600
Serial.setTimeout(50); //change timeout for fast readout
Serial.println("Arduino initialized"); // send some text to let SweepMe! know that the Arduino has finished the setup() function
}
void loop ()
{
// check whether some command has been received at the COM port
if (Serial.available()) {
command = Serial.readString();
if (command == "Read?\n") {
// sending back the answer.
Serial.print("some text");
Serial.print("some further text");
Serial.println(""); // you can send multiple times using print, but only send one time using println to reply with a single message after each command
}
// if the command starts with some special text you can
if (command.startsWith("Voltage=")) {
// split the value from the command here and change the parameter accordingly
myFunction() // do something
Serial.println("Voltage=..."); // reply to let SweepMe! know that the parameter is changed
}
if (command.startsWith("Frequency=")) {
// split the value from the command here and change the parameter accordingly
// ...
Serial.println("Frequency=..."); // reply to let SweepMe! know that the parameter is changed
}
}
}