sensor_hub

Dynamically configure ultrasonic range sensors on an Arduino running the sensor_hub firmware

sensor_hub firmware

The sensor_hub firmware implements ROS Service Calls that configure the various sensors and other parameters for the publication of data.

sensor_hub_node driver

The sensor_hub_node acts as a driver, initializing and configuring the sensors by calling the services exposed by the counterpart firmware.

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Installation

Firmware

1. Open the sensor_hub.ino sketch in the Arduino IDE
2. Install the required dependencies:

• Rosserial
• Ultrasonic <- Modified!

3. Select the platform and amend the SENSOR_MAX variable
4. Upload the firmware

ROS Node

1. Change directory your catkin workspace cd ~/catkin_ws/src
2. Clone the sensor_hub repository into your catkin workspace git clone https://github.com/eliotlim/sensor_hub
3. Build the package from source by performing catkin_make

ROS dependencies

• rosserial_client
• rosserial_python

Configuration

Shared sensorConfig.yaml with sensor_pointcloud

Add a <sensorName>/device key to each sensor_hub sensor, and specify the

• type:
  • SRF05 # For SRF05/HY-SRF05/Ping)))
  • SRF10 # For SRF08/10
• connection point:
  • pin: 14 # For SRF05 use a pin number
  • addr: 0xE0 # For SRF08/10 use an 8-bit I2C address (as per datasheet)
• timeout:
  • timeout: 60000 # Wait 60 ms for ping return

sensor0:
    topic: ultrasound/range
    device:
        type: SRF05
        pin: 14
        timeout: 60000
    transform:
        frame: sensor0
...
sensor1:
    topic: sensor_hub/range
    device:
        type: SRF10
        addr: 0xE2
        timeout: 60000
    transform:
        frame: sensor1

See the sensorConfig.yaml guide for more details

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Usage

Option 1: Using roslaunch

1. Run the sensor_hub/sensor_hub.launch file after loading the sensorConfig.yaml into node namespace using rosparam or sensor_pointcloud

roslaunch sensor_hub sensor_hub.launch device:=/dev/ttyACM0

Option 2: Manually starting each node

1. Connect the device and run: rosrun rosserial_python serial_node.py <device>

For Example:

rosrun rosserial_python serial_node.py /dev/ttyACM0

2. Run the sensor_hub_node rosrun sensor_hub sensor_hub_node to load the sensor configuration onto the Arduino

Possible Errors

Unable to find Service Provider

When sensor_hub is not connected by rosserial, the service call cannot be resolved and will fail. By default, sensor_hub_node will block and wait for the SetupSensorHub service to become available. Check the power, data cable, serial port, and any collision with other sensor_hub_node / Arduino IDE instances.

Initialization Failure

If the sensor_hub has run out of slots (exceeding SENSOR_MAX), any sensor attachment service call will fail.

Invalid Sensor Data

The sensor_hub_node will monitor initialized sensors and highlight signs of sensor errors:

• Measured value exceeds defined range
• Timeout resulting in no reading

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Miscellaneous

License

This library is licensed under the MIT License.