TeraBee TOF RangeFinders¶
The TeraBee TeraRanger One and EVO family of rangefinders are lightweight, high-performance distance measurement sensors based on infrared Time-of-Flight (TOF) technology. They are much faster than ultrasound and far smaller and lighter than laser-based systems. Their small size, high performance and low power consumption make it ideal for modern robotic applications, drone operations and automation.
More technical information about these senors can be found below:
These rangefinders are only supported in ArduPilot autopilots via I2C protocol.
Connecting to the TeraRanger/EVO via I2C¶
The TeraRanger One sensor can be easily connected to the Pixhawk or other ArduPilot autopilot with the TeraRanger I2C adapter. Most other versions can be directly connected, see setup table notes in next section.
Solder the connector cable for the TeraRanger I2C adapter:
Connect the I2C adapter to the Pixhawk via a DF13 4S cable to the autopilot and the TeraRanger One to the I2C adapter:
For the other EVO rangefinder versions, just connect the SCL/SDA lines from the rangefinder to the autopilot’s I2C signals of the same name.
some of these rangefinders consume over 100ma of current and should NOT be powered from the autopliots’s I2C port, but from an external 5V regulated supply source.
Setup in Mission Planner¶
To use the TeraRanger One/EVO sensor as rangefinder, connect with Mission Planner and open the CONFIG/Full Parameter List menu and set:
RNGFNDx_MAX_CM: This parameter sets the maximum distance that the rangefinder is used by the autopilot.
RNGFNDx_MIN_CM: This parameter set the minimum distance that the rangefinder is used by the autopilot.
RNGFNDx_ADDR: 48 (for TeraRanger One) or 49 (for EVO series), 0 will disable the rangefinder setup.
RNGFNDx_ORIENT: 25 (for downward facing). If used for Object Avoidance or ceiling distancing, instead of altitude ranging, mount and chose the appropriate orientatioin.
Values for the rangefinders are shown below:
- Do not power from autopilot port, unless port is known to have sufficient current capability.
- Requires 3.3V to 5V level shifting to connect to autopilots I2C signals. Use TeraRanger I2C adapter
Testing the sensor¶
The distances read by the TeraRanger One sensor can be displayed on the Mission Planner Flight Data menu. The Status button the left will show status values. Then choose “sonarrange”.
When the autopilot boots, the rangefinder needs to already be powered on, or at least be powered on at the same time as the autopilot. If you power the rangefinder after the autopilots has booted, it will not be recognized since the autopilot will have already scanned its I2C bus for devices!