====== PIDflight Lap ======
===== How to setup 3DR Telemetry module for lap timing device =====
This guide describes the process for configuring a 3DR 433/915Mhz telemetry module to use with PIDflight Lap timing devices.

===== Configuration =====
To configure the 3DR telemtry modules you will use the Ground module to configure both it and the Air module. You will need the Air Module to be powered up for this.

By default the Ground module is set to **57600** baud rate. Both the Ground module and Air module need to have the serial speed, and some other settings tweaked before it's ready to use.

  - Open **Serial Monitor**, select 'No line ending' and baud rate '57600'.
  - Type **+++** and press **Send**. The module should respond with ''OK''.
  - Change line ending to 'Both NL & CR', type ''AT'' and press **Send**, the module should respond with another ''OK'' to verify the module is in **command mode**. Proceed to next step.<code>
AT
OK
</code>
  - Type ''ATI5'' to get list of S registers for the ground module to view the current settings.<code>
ATI5
S0:FORMAT=25
S1:SERIAL_SPEED=57
S2:AIR_SPEED=64
S3:NETID=25
S4:TXPOWER=20
S5:ECC=1
S6:MAVLINK=1
S7:OPPRESEND=1
S8:MIN_FREQ=915000
S9:MAX_FREQ=928000
S10:NUM_CHANNELS=50
S11:DUTY_CYCLE=100
S12:LBT_RSSI=0
S13:MANCHESTER=0
S14:RTSCTS=0
S15:MAX_WINDOW=131
</code>
  - Type ''RTI5'' to get list of S registers for the air module.<code>
RTI5
S0:FORMAT=25
S1:SERIAL_SPEED=57
S2:AIR_SPEED=64
S3:NETID=25
S4:TXPOWER=20
S5:ECC=1
S6:MAVLINK=1
S7:OPPRESEND=1
S8:MIN_FREQ=915000
S9:MAX_FREQ=928000
S10:NUM_CHANNELS=50
S11:DUTY_CYCLE=100
S12:LBT_RSSI=0
S13:MANCHESTER=0
S14:RTSCTS=0
S15:MAX_WINDOW=131
</code>
  - Set the **SERIAL_SPEED** register (S1) to 115 for 115200 baud rate on both modules. Type ''ATS1=115'' and ''RTS1=115''.<code>
ATS1=115
OK
RTS1=115
OK
</code>
  - Set the **ECC** register (S5) to off on both modules. Type ''ATS5=0'' and ''RTS5=0''.<code>
ATS5=0
OK
RTS5=0
OK
</code>
  - Set the **MAVLINK** register (S6) to off on both modules to disable Mavlink framing. Type ''ATS6=0'' and ''RTS6=0''.<code>
ATS6=0
OK
RTS6=0
OK
</code>
  - Set the **OPPRESEND** register (S7) to off on both modules. Type ''ATS7=0'' and ''RTS7=0''.<code>
ATS7=0
OK
RTS7=0
OK
</code>
  - The final configuration for both modules should appear as the following.<code>
ATI5
S0:FORMAT=25
S1:SERIAL_SPEED=115
S2:AIR_SPEED=64
S3:NETID=25
S4:TXPOWER=20
S5:ECC=0
S6:MAVLINK=0
S7:OPPRESEND=0
S8:MIN_FREQ=915000
S9:MAX_FREQ=928000
S10:NUM_CHANNELS=50
S11:DUTY_CYCLE=100
S12:LBT_RSSI=0
S13:MANCHESTER=0
S14:RTSCTS=0
S15:MAX_WINDOW=131
RTI5
S0:FORMAT=25
S1:SERIAL_SPEED=115
S2:AIR_SPEED=64
S3:NETID=25
S4:TXPOWER=20
S5:ECC=0
S6:MAVLINK=0
S7:OPPRESEND=0
S8:MIN_FREQ=915000
S9:MAX_FREQ=928000
S10:NUM_CHANNELS=50
S11:DUTY_CYCLE=100
S12:LBT_RSSI=0
S13:MANCHESTER=0
S14:RTSCTS=0
S15:MAX_WINDOW=131
</code>
  - Write the new changes to the EEPROM. Type ''AT&W'' and ''RT&W''.<code>
AT&W
OK
RT&W
OK
</code>
  - Done!

==== Pin-outs ====

^Arduino^3DR Air Module^
|5V|VCC|
|GND|GND|
|RX|TX|
|TX|RX|