examples: added battery simulator

examples/sim_battery.py

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+#!/usr/bin/env python3
+
+import dronecan, time, math
+
+# get command line arguments
+from argparse import ArgumentParser
+parser = ArgumentParser(description='simulate DroneCAN battery')
+parser.add_argument("--node-id", default=100, type=int, help="CAN node ID")
+parser.add_argument("--debug", action='store_true', help="enable debug")
+parser.add_argument("--balance", action='store_true', help="simulate cell balance node")
+parser.add_argument("--battery-id", type=int, default=1, help="battery ID")
+parser.add_argument("--rate", type=float, default=10, help="broadcast rate Hz")
+parser.add_argument("--voltage", type=float, default=24.6, help="voltage")
+parser.add_argument("--num-cells", type=int, default=6, help="number of cells")
+parser.add_argument("uri", default=None, type=str, help="CAN URI")
+args = parser.parse_args()
+
+C_TO_KELVIN = 273.15
+
+def publish_BatteryInfo():
+    '''send BatteryInfo message'''
+    msg = dronecan.uavcan.equipment.power.BatteryInfo()
+    msg.battery_id = args.battery_id
+    msg.voltage = args.voltage
+    msg.current = 0.3
+    msg.temperature = 17+C_TO_KELVIN
+    msg.state_of_charge_pct = 0
+    msg.remaining_capacity_wh = 0
+    msg.full_charge_capacity_wh = 0
+    node.broadcast(msg)
+    if args.debug:
+        # display the message on the console in human readable format
+        print(dronecan.to_yaml(msg))
+
+def publish_BatteryInfoAux():
+    '''send BatteryInfoAux message'''
+    msg = dronecan.ardupilot.equipment.power.BatteryInfoAux()
+    msg.battery_id = args.battery_id
+    msg.voltage_cell = [0.0]*args.num_cells
+    for i in range(args.num_cells):
+        msg.voltage_cell[i] = args.voltage / args.num_cells
+    node.broadcast(msg)
+    if args.debug:
+        # display the message on the console in human readable format
+        print(dronecan.to_yaml(msg))
+
+# Initializing a DroneCAN node instance.
+node = dronecan.make_node(args.uri, node_id=args.node_id, bitrate=1000000)
+
+# Initializing a node monitor, so we can see what nodes are online
+node_monitor = dronecan.app.node_monitor.NodeMonitor(node)
+
+# setup to publish battery info
+if args.balance:
+    node.periodic(1.0/args.rate, publish_BatteryInfoAux)
+else:
+    node.periodic(1.0/args.rate, publish_BatteryInfo)
+
+# Running the node until the application is terminated or until first error.
+try:
+    node.spin()
+except KeyboardInterrupt:
+    pass