4.0 IRPD

Infrared Proximity detection (IRPD)

The IRCF360^TM offers non-contact distance measurements from about 0.5cm (0.25") to about 30cms (1ft), by sending short bursts of infrared pulses from either all 8 infrared transmitters or in any one direction. The sensing distance can be increased or decreased for different applications by the following methods:

• Changing the carrier frequency configuration value (see command 030 description)

• Adding a 'hat' on top of the controller to reflect more stray IR beams towards the sensor

• Adding heatshrink sleeve shield over the Infrared LED's to channel the IR beams. Some experimentation will be necessary to achieve the optimum IRPD range for you own project.

• Changing the value of the resistors connecting to the Infrared transmitters which produces more power and/or

The IRCF360^TM interprets the distance of an obstacle by measure the number of reflected ‘hits’ detected by the IR sensor. For most Infrared Proximity Detection (IRPD) applications the IRCF360^TM has been tuned to an optimal range of about 0.5cm - 200cm, which has proven suitable for most swarm, competition and ‘desktop’ style robot projects. The is because normally objects within a short range are of immediate interest to the robot. Object further away can normally be ignored.

Infrared Proximity Sensing Envelope

The 8x Infrared proximity transmitters provide 360 degrees of proximity detection. The IRCF360^TM can interpret in which direction an obstacle is located and also an approximate distance. The IRCF360^TM covers the full 360 degrees, but there may be some small blind-spots between the infrared transmitters. See diagram below.

The combined directional and distance sensing data provides an excellent autonomous control through narrow passages or mazes.

Infrared Proximity detection - Directional Indication

The circular ‘compass’ style LED-display, ‘points’ in the direction of the nearest obstacle (within a 180 degree arc) during the ‘Infrared Proximity Detection’ (IRPD) routine.

Directional information of localised obstacles offers instant decision making during obstacle avoidance, maze running and robot gaming. For example, objects that are not directly ahead are ignored or using your own fuzzy logic routines, you can track an object and determine whether it is getting closer or further away.

Visual Feedback, based on Mode of operations

The circular display is also useful for providing visual feedback on the state of the program being executed. Each command will display a different display pattern so you can quickly debug your program by seeing the current routine being executed. Details of the display patterns for each command are provided in the command overview section.

Fuzzy Logic

The pre-programmed Fuzzy Logic proximity detection algorithms enable instant object avoidance decision. This frees-up a lot of processing power that your main robot controller would normally need to do.

If you don't want to use the pre-programmed logic, you can also experiment and design your own Fuzzy Logic algorithms, based on the six bytes of 'raw' proximity detection data.

By interpreting the data from each of the sensors over a period of time, it is possible to determine whether an object is moving towards / away from the robot. Further details of how to create your own Fuzzy Logic routines are detailed on Appendix C – Overview of Fuzzy Logic.

Infrared Remote Control

For remote control of robots and electronic projects using a standard TV remote control, the IRCF360 is equipped with an onboard Infrared remote controlled receiver and transmitter.

The protocol used with IRCF-L is the Sony format known as Sony SIRC Protocol. See Appendix B – Overview of Principal of Infrared Remote Control for more details of the various device and button commands available to be used.

Inter-Robot communications

By using simple coded IR messages, it is possible to transmit signals to other robots. For example, it is possible to determine whether an opponent robot is a friend or foe. You could also configure a unique ID for each robot and robot team, allowing your robot to communicate between team members and sending a 'tag' or ‘zap’ code to the other opponent team. For example, ten ‘zaps’ of device code/button code 10,10 to the centre sensor could mean, ‘your it!’ (e.g. in a game of tag) or “your dead!” (e.g. in robot battle game)

Modifications for increased sensing range.

The standard IRCF360^TM has been designed to provide optimum sensor distance for most robot projects. However, in a very few circumstances, an increased sensing range may be required for certain experiments.

The sensing range can be increased to a range of about 1 meter (1yard) by modifying the IRCF360^TM. This modification is only recommended for students with a basic electronics understanding and some experience with soldering. See APPENDIX J Modification for increase range

Calibration of the Infrared Control Freak

As the infrared emitters and sensors position is fixed by the PCB the positions cannot easily be moved out of position. Limited calibration is required. Some of the Infrared Tranmitting LED's may need to be adjusted downwards or upwards to reduce 'ground noise'. See Appendix C on details of how best to calibrate the module.

Customise an Infrared Control Freak - LIGHT

If you require special functionality, special protocols or other special control characters for your robot project, just send an email to [support@robotmaker.eu]. A quotation for the custom design will be issued on request.