Motion Sensor Interfacing for Panda Board based Dash Board System
Contents
Panda Board and System Integration
Panda Boards are computers based on arm v 7 processor. One of the main advantage of using panda boards in different projects is there ease of integration in existing system. We have variety of different interfaces on these boards to connect to different systems using network connectivity or local I/O. One of those interfaces is General Purpose Input and Output (GPIO) port which we will be using GPIO port to connect a motion sensor to panda board.
GPIO/Expansion Connector on Panda Board
Motion Sensor
Motion Sensor attached with panda board will bring more intelligence to the system by making efficient use of energy. Motion Sensor will detect the motion and tell the panda board operating system to turn on or standby the dash board display system.
Motion Sensor Module
We are using zilog motion detection module as motion sensor. The good thing about this module is that it includes a built in micro controller with application software running on it. This Micro Controller Unit (MCU) along with its application software is not only meant for providing standard interfaces to existing computer system but also gives more control to programmers to control this module from their own program/logic.
Interfacing Sensor with Panda Board
Motion Sensor Module is implemented using Low Voltage TTL (LVTTL) which means the electrical signals on its pins vary between 0V to 3.3V to carry bits over electrical interface while GPIO Module(pin) is based on TTL implementation. TTL voltages vary between 0V to 5V to carry data bits. To connect LVTTL pins(sensor) to TTL pins(GPIO), we will have to use extra circuitry for interfacing which ensures the data sent or received is consistent on both side.
Example of LVTTL to TTL convertor
System
On detecting a motion, motion sensor would send the signal to panda board GPIO pin which we could read as a file in Linux. Based on the file content which is signal received from motion sensor, we can use system calls to turn on the display from standby mode to display mode. We can automate all of these activities in a script which will always be running in back ground. The whole system could be customized for different environments like the range of sensor, response time of display by changing script and customizing application software in sensor's MCU.
Parts List
Supplier: Digikey
| Name | Quantity | Part number | Unit Cost | Extended Cost (CAD. and excl. TAX) | |
|---|---|---|---|---|---|
| IR Sensor | 1 | 269-2513-ND | 5.72 | 5.72 | |
| Diodes | 2 | 1N457CT-ND | 0.39 | 0.78 | |
| LVTTL to TTL Converter | 1 | MAX232CPE+-ND | 4.09 | 4.09 | |
| Male Connectors | 1 | SAM1030-14-ND | 2.43 | 4.86 | |
| Female Socket | 1 | ESQ-114-34-G-D-ND or ESQ-114-13-G-D-ND | 6.39 | 6.39 | |
| Bread Board | 1 | Solderless Breadboard | 9.73 | 9.73 |
