Others Extensions
From GCtronic Wiki
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Range and bearing
You can find more information about this board in the following link http://www.e-puck.org/index.php?option=com_content&view=article&id=35&Itemid=23.
A simple MPLAB project was created to let start using these modules. With the selector it's possible to choose whether the robot is an emitter (selector in position 0) or a receiver (selector in position 1). The receiver will send the information (data, bearing, distance, sensor) through Bluetooth.
Ground sensors
You can find more information about the ground sensors extension module in the following link http://www.e-puck.org/index.php?option=com_content&view=article&id=17&Itemid=18.
The main demo was extended to handle the ground sensors extension for the e-puck, this demo can be found in this link http://projects.gctronic.com/E-Puck/DemoGCtronic-complete-groundsensor/DemoGCtronic-complete-groundsensor.hex. In order to get the values from the sensors you must put the selector in position 3 and then issue the command m that will return three values, one for each sensor.
If you are interested in the sources you can refer to the section http://www.gctronic.com/doc/index.php/E-Puck#Standard_firmware in which there is a link to the MPLAB project and some information on how to build it; to enable the ground sensors you need to uncomment the definition at the top of the Asercom.c file before building.
If you couple the e-puck extension for Gumstix Overo with the ground sensor refer to the section http://www.gctronic.com/doc/index.php/Overo_Extension#Ground_sensor to have an example on how to read the sensor values.
Cliff sensor
Software
E-puck
The standard asercom demo (selector 3) released with the epuck robot is extended in order to request and visualize 5 sensors values instead of 3 when issueing the m command; the sequence is:
- ground left, ground center, ground right, cliff right, cliff left
Extension firmware
The ground sensor fimrware developed at EPFL (can be downloaded at the http://www.e-puck.org site from this page) was extended to interact with the additional two sensors. The source code can be downloaded from cliff-firmware; it is an MPLAB project and the MPLAB C Compiler for PIC18 MCUs is needed to build the project.
The communication between the e-puck and the module is handled through I2C (address 0xC0) and the following registers are defined:
- 0x00: reflected light, left IR sensor - high byte
- 0x01: reflected light, left IR sensor - low byte
- 0x02: reflected light, center IR sensor - high byte
- 0x03: reflected light, center IR sensor - low byte
- 0x04: reflected light, right IR sensor - high byte
- 0x05: reflected light, right IR sensor - low byte
- 0x06: ambient light, left IR sensor - high byte
- 0x07: ambient light, left IR sensor - low byte
- 0x08: ambient light, center IR sensor - high byte
- 0x09: ambient light, center IR sensor - low byte
- 0x0A: ambient light, right IR sensor - high byte
- 0x0B: ambient light, right IR sensor - low byte
- 0x0C: software revision number
- 0x0D: reflected light, right cliff sensor - high byte
- 0x0E: reflected light, right cliff sensor - low byte
- 0x0F: reflected light, left cliff sensor - high byte
- 0x10: reflected light, left cliff sensor - low byte
- 0x11: ambient light, right cliff sensor - high byte
- 0x12: ambient light, right cliff sensor - low byte
- 0x13: ambient light, left cliff sensor - high byte
- 0x14: ambient light, left cliff sensor - low byte
Images
Robot equipped with the cliff sensor:
The robot can be easily moved to the charging station as shown in the following figure:
The following figure shows the two additional sensors (near the wheels) mounted on the cliff module and the three frontal sensors of the ground module:
