zoobot / robot-block-lib

robot-block-lib

robot block is a hardware abstraction layer for ROS that automatically creates ROS communication channels for supported sensors actuators and interfaces. This aims to replace low-level code and firmware, with an experience that's more similar to defining docker containers.

This is a core repository of supported devices. We encourage everyone to submit a PR and add your own.

supported devices

Name	Type.	Desc.
ADS1015	Interface	4-channel 12-bit I2C ADC
pi-gpio	Interface	Raspberry Pi GPIO Wrapper
VL53L1	Range Sensor	ToF Sensor
VL53L1_Array	Range Sensor	Configurable array of ToF Sensors
ICM20948	Motion Sensor	9-Axis MEMS IMU
LSM9DS1	Motion Sensor	6-Axis MEMS IMU
SparkfunTwist	Sensor	Sparkfun Dual Encoder Reader
INA219	Power Sensor	Voltage/Current/Power Sensor
4245-PSOC	Motor Driver	Serial/I2C Motor Driver found in Sparkfun Auto pHat
pi-cam	Camera	Official Raspberry Pi Camera (V4L2)

Planned

LIBRARY	Type.	Desc.
PCA9685	Interface	16-channel 12-bit I2C PWM
SRF04/05	Range Sensor	Affordable Hobby Ultrasound Sensor
pi-motor	Motor Driver	Direction + PWM Motor Driver for Raspberry PI
steering	Motor Driver	DC Power Motor + Steering Servo
arduino-firmata	Interface	Arduino Support in Firmata Mode
arduino-ros	Interface	Native ROS support for Arduino

How to write your own

You can basically write any valid python code as long as some conventions are followed. Let's take ADS1015, a 4-channel Analog-Digital Converter as an example.

1. Package folder must contain a JSON configuration file that defines it's properties, dependencies, ros message types and callback functions. All fields in this example are mandatory. We also take care of dependencies for your as long as you add them to your config. (currently only pip packages are supported)

{
	"name":  "ADS1115",
	"info":  "4-channel 12-bit I2C ADC",
	"dependencies":  [

		{
		"type":  "pip3",
		"package":"adafruit-circuitpython-ads1x15"
		}

	],
	"callback":  ["read0","read1","read2","read3"],
	"ros_message":  ["std_msgs.msg",  "Int32"]
}

2. For the dynamic imports to work, folder name, config file, python file and class constructor must all share the same name: ADS1015, ADS1015.json, ADS1015.py, ADS1015(args)

3. devices with multiple channels must expose read and update callbacks for each channel: ["read0","read1","read2","read3"]

4. You can make use of the utility functions in robot-block as they get imported at runtime. Take a look at utils.py

compatibility

Due to particularities on how low level interfaces (I2C/CSI/etc) work in different SBCs, robot-block and it's packages are limited to the following boards

• Raspberry Pi 3/4/Zero2
• Jetson Nano
• x86 (with USB-to-I2C Bridge)