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Q1: Is SU04 compatile with ARUDUINO?

A:  No. ARUDUINO is different from PIXHAWK, which is the FC that SU04 works with.


Q2: When connect open-sourced PIXHAWK with Radiolink ultrasensor module SU04, the module functions well at Alt-Hold Mode. But the aircraft flies to left when toggle the joystick forward at Loiter Mode. Why is that?

A: This is the firmware problem and it can be solved by flashing firmware of V3.6 or above.


Q3: Why my SU04 dosen't function after connecting to RadioLink Mission Planner via RadioLink PIX controller?

A: When connecting SU04,  the flight controller should be powered by battery instead of by USB to connect with RadioLink Mission Planner.


Q4: How to turn on/off the obstacle avoidance function?

A: This function can be turned on/off by setting the value of  AVOID_ENABLE in RadioLink Mission Planner.

CONFIG/TUNING- Full Parameter List- AVOID_ENABLE, the value 2 is to turn on while 0 is to turn off.


Q5: How to set avoidance distance of SU04?

A: The distance can be set by modifying the values of AVOID_DIST_MAX and AVOID_MARGIN.

CONFIG/TUNING sheet- ALL PARAMETERS- AVOID_DIST_MAX:  The maximum distance(meter) with Alt-Hold Mode

CONFIG/TUNING sheet- ALL PARAMETERS- AVOID_MARGIN:  The maximum distance(meter) with Loiter Mode


Q6: Why there's no obstacle avoidance displays in the PIXHAWK Mission Planner?

A:  Data displays in the latest PIXHAWK official Mission Planner may be unusual. Please click below link to download the RadioLink Mission Planner specially for RadioLink Pix.

When finish downloading, disconnect PIXHAWK and restart  then all module data is available.

Note  When connecting the RadioLink Mission Planner, there's a new interface automatically popping out where module data displayed. If it doesn't show, please click the icon at the taskbar to activate it.


Q7: Do I need to set an individual channel to control the obstacle avoidance function of SU04?

A: YES. Setting steps as below

1 )Flight Controller (CH7_OPT Parameters)

 CONFIG/TUNNING - Full Parameter List- Input CH7_OPT in search column at the lower right corner and press Enter.  As the searched CH7_OPT shown in RadioLink Mission Planner, change the value to 40(Object Avoidance) then click Write Params on the right to save.



2) Transmitter setting steps

 Choose a 2-way switch to control CH7 and click INITIAL SETUP- FailSafe, then the PWM value of CH7 is shown. When toggle the switch, if the PWM value of  CH7 is more than 1800, it means the avoidance function is enabled . If the PWM value of CH7 is less than 1200, it means the avoidance function is disabled.



Q8: How many SU04 at most can be installed?

A: There are maximum 3 to install at the same time.  Two arbitrary directions (forward/backward/left/right/upward/alt-hold downward) of obstacle avoidance can be realized simutaneously. Every press on the button, the avoidance direction changes once clockwise and the flashing frequency of  led indicator changes accordingly, showing current direction and can be saved as preferred. The default direction is forward. It can be also checked in RadioLink Mission Planner.


Q9:How to connect SU04 to realize ailttude holding downward?

A: With PIXHAWK- A 4 pin wire is needed with one end to connect the I2C port of PIXHAWK and the other to SU04 module

With MINIPIX- A 4 pin to 6 pin wire is needed with the 4 pin end to the SU04 and the 6 pin end to the GPS port of MINIPIX

Mission Planner setup: INITIALSETUP - Optional Hardware- Range Finder- Click the pull down menu and choose MAXBOTIX12C or LIGHTWAREI2C

No need to save. When you repower on the flight controller and revisit this interface, if there's displayed module distance, it means setting is done with success. 


RNGFND_MAX_CM and RNGFND_MIN_CM represent the detectable max imun and minimun distance(cm) of flight controller at Alt-Hold Mode.

Set RNGFND_MAX_CM as 450 and RNGFND_MIN_CM as 43, meaning the flight controller cannot identify the distance when the detective distance of SU04 module is less than 43cm or more than 450cm. And the alttitude holding by the height of the barometer will be activated by  default.


Q10: Is there directional difference of the obstacle function?

A: Yes. When the direction is forward, press the button once and the SU04 module will flash with data can be checked in RadioLink Mission Planner as below, meaning the current avoidance direction is upward.



It's only the module of upward avoidance connected. If  another module of forward avoidance needs to be connected at the same time, there would be real-time distance jitter. As the data displays only shows horizontal distance, data of upward avoiidance should be checked via log.