AP_Scripting: added a frsky battery example

libraries/AP_Scripting/examples/frsky_battery.lua

@@ -0,0 +1,63 @@
+--[[
+  Simple example that sends battery info down the frsky link
+  it works with SPort using SERIAL_PROTOCOL=4,10 and with
+  FPort using SERIAL_PROTOCOL=23.
+  
+  We'll be using OpenTX genuine data IDs (https://github.com/opentx/opentx/blob/2.3/radio/src/telemetry/frsky.h)
+  
+  CURR_FIRST_ID  0x0200
+  VFAS_FIRST_ID  0x0210
+  
+  and we'll be responding to unused sensor IDs.
+  This is a list of IDs we can't use:
+  - serial protocol 4 uses IDs 0,2,3 and 6
+  - serial protocol 10 uses ID 7,13,20,27
+  - serial protocol 23, no IDs used
+  
+  For this test we'll use sensor ID 4 (0xE4), 
+  Note: 4 is the index, 0xE4 is the actual ID
+--]]
+
+local loop_time = 500 -- number of ms between runs
+local sport_data_frame = 0x10
+local sensor_id = 0xE4
+
+-- battery 1->instance 0, battery 2->instance 1, etc
+local batt_instance = 0
+
+local curr_id = 0x020E
+local vfas_id = 0x021E
+
+local function send_voltage(instance)
+  local volts = battery:voltage(instance)
+  gcs:send_text(7,string.format("FRSKY: batt %d, %.01fV", instance, volts))
+  if volts ~= nil then
+    frsky_sport:sport_telemetry_push(sensor_id, sport_data_frame, vfas_id, math.floor(volts*100+0.5)) -- centivolts
+  end
+end
+
+local function send_current(instance)
+  local amps = battery:current_amps(instance)
+  gcs:send_text(7,string.format("FRSKY: batt %d, %.01fA", instance, amps))
+  if amps ~= nil then
+    frsky_sport:sport_telemetry_push(sensor_id, sport_data_frame, curr_id, math.floor(amps*10+0.5)) -- deciamps
+  end
+end
+
+local alternate = 0
+
+function update()
+  if batt_instance > battery:num_instances() then
+    error("Battery " .. batt_instance .. " does not exist")
+  end
+  
+  if alternate % 2 == 0 then
+    send_voltage(batt_instance)
+  else
+    send_current(batt_instance)
+  end
+  alternate = (alternate+1)%2
+  return update, loop_time
+end
+
+return update() -- run immediately before starting to reschedule