Arduino Driver guide

Arduino can easily be combined with SweepMe! However, there are some guidelines which make the implementation much easier:

1. 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.
2. The Arduino can send text via its function pringln() 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.
3. 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
4. Try to have a constant length or format of the return message, so that reading out the string is less errorneous
5. 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.
6. Use the standard baudrate of 9600 so that other Arduino Device Classes can easily be copied and modified.

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 formatting

        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("R?")         # send some command to request a reading of parameters, for example "R?" 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