Changes between Initial Version and Version 1 of IR_Proximity_Sensor


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Timestamp:
Nov 8, 2013, 10:17:53 AM (6 years ago)
Author:
hazen
Comment:

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  • IR_Proximity_Sensor

    v1 v1  
     1This page describes ideas for an IR proximity sensor.
     2
     3For a simple proximity sensor, one can drive an IR LED with a modulated
     4signal which matches the subcarrier frequency of an inexpensive reciever
     5designed for IR remote control applications.
     6
     7For example, the Sharp GP1UW70QS (stock at Digi-Key) works at a subcarrier
     8frequency of 40kHz.  If an LED is driven with an on/off modulated
     9square wave of this frequency, the same on/off pattern should be output
     10by the reciever when light is reflected into the receivers photo-detector.
     11
     12For the proposed application (low-power proximity-controlled LED light)
     13the best solution would probably be a microcontroller with a wake-up
     14interrupt which would power the proximity sensor briefly at a rate
     15of a few Hz, and illuminate the LED lamp when a signal is seen.
     16
     17=== PCB Design ===
     18
     19==== Rev 3 ====
     20
     21Notes:  The IR sensor is obsolete.  Switch to the GP1UW701QS0F (lead free)
     22which is stocked now but is a 38kHz part.  ''''NOTE:  Needs updated firmware'''
     23
     24* [http://joule.bu.edu/~hazen/GaitTimer/IR_Sensor_Rev3.sch IR_Sensor_Rev3.sch]
     25
     26==== Rev 2 PCB ====
     27
     28* [http://joule.bu.edu/~hazen/IRdet/IR_Sensor_Rev2.sch IR_Sensor_Rev2.sch]
     29
     30==== Rev 1 PCB ====
     31
     32 * [http://joule.bu.edu/~hazen/IRdet/ir_sensor_sch.pdf Schematic]
     33 * [http://joule.bu.edu/~hazen/IRdet/ir_sensor_pcb_legend.pdf Layout]
     34
     35* GP1UW70QS IR Detector [http://joule.bu.edu/~hazen/IRdet/GP1UW70QS.pdf Data Sheet]
     36 - [http://www.sharpsma.com/part.php?PartID=722 Sharp Web Page]
     37
     38* LNA2802L IR LED [http://joule.bu.edu/~hazen/IRdet/LAN2802L_IR_LED.pdf Data Sheet]
     39* ATTiny45 microcontroller [http://joule.bu.edu/~hazen/IRdet/attiny45.pdf Data Sheet]
     40