Arduino comms (#31)

* init commit: raspberry to arduino communication added

* added baud rate and simplified names

* added orientationMsg.proto and start with $

* added in functionality to read in from Arduino

* fixed missing message

* fixed import error

* fixed more bugs and added $ check to stringToMessage

* fixes

* added message

Author: Timothy Tamm

arduinoCommunicationModule.py

@@ -0,0 +1,74 @@
+#!/usr/bin/env python3
+
+import os
+import robomodules as rm
+import serial
+from messages import *
+
+ADDRESS = os.environ.get("BIND_ADDRESS","localhost")
+PORT = os.environ.get("BIND_PORT", 11297)
+
+FREQUENCY = 10
+
+class ArduinoCommsModule(rm.ProtoModule):
+    def __init__(self, addr, port):
+        self.subscriptions = [MsgType.CTRL_MSG]
+        super().__init__(addr, port, message_buffers, MsgType, FREQUENCY, self.subscriptions)
+        try:
+            self.serialConnection = serial.Serial('/dev/ttyUSB0', 9600)
+        except Exception:
+            raise RuntimeError("serial connection to Arduino failed")
+
+    def msg_received(self, msg, msg_type):
+        # This gets called whenever any message is received
+        if msg_type == MsgType.CTRL_MSG:
+            # turn it into a string
+            # turn the string into binary
+            # send the binary
+            self.serialConnection.write(self._stringToBinary(self._messageToString(msg)))
+
+    def tick(self):
+        # this function will get called in a loop with FREQUENCY frequency
+        # from https://www.raspberrypi.org/forums/viewtopic.php?f=32&t=54182
+        msg = self._stringToMessage(self._binaryToString(self.serialConnection.readline()))
+        if msg:
+            self.write(msg, MsgType.ORIENTATION_MSG)
+
+    def _messageToString(self, m):
+        ans = "$"
+        # go through each of the properties in the message
+        for prop in ["x", "y", "z", "roll", "pitch", "yaw"]:
+            # convert the number into a string
+            # separate the properties with a semicolon
+            ans += (str(getattr(m, prop)) + ";")
+        return ans
+        
+    def _stringToBinary(self, s):
+        return bytes(s, "ascii")
+        
+    def _binaryToString(self, b):
+        return b.decode('ascii')
+        
+    def _stringToMessage(self, s):
+        ans = OrientationMsg()
+        # take off leading '$'
+        s = s[1:] if s[0] == "$"
+        # get all of the values in the string
+        # need to take off the last empty string that split will leave
+        numbers = (s.split(";"))[0:-1]
+        # didn't get a good input
+        if len(numbers) != 3:
+            return None
+        # assumes the values are coming in in that order
+        for (number, name) in zip(numbers, ["roll", "pitch", "yaw"]):
+            setattr(ans, name, number)
+        
+        return ans
+            
+
+def main():
+    module = ArduinoCommsModule(ADDRESS, PORT)
+    module.run()
+
+if __name__ == "__main__":
+    main()

messages/Makefile

@@ -1,5 +1,6 @@
-protobuf: mockMsg.proto cameraFrameMsg.proto ctrlMsg.proto humidityMsg.proto
+protobuf: mockMsg.proto cameraFrameMsg.proto ctrlMsg.proto humidityMsg.proto orientationMsg.proto
 	protoc -I=./ --python_out=./ ./mockMsg.proto
 	protoc -I=./ --python_out=./ ./cameraFrameMsg.proto
 	protoc -I=./ --python_out=./ ./ctrlMsg.proto
 	protoc -I=./ --python_out=./ ./humidityMsg.proto
+	protoc -I=./ --python_out=./ ./orientationMsg.proto

messages/orientationMsg.proto

@@ -0,0 +1,9 @@
+syntax = "proto2";
+
+package mateROV;
+
+message OrientationMsg {
+  required float roll = 1;
+  required float pitch = 2;
+  required float yaw = 3;
+}