Timeline for IR Sensor Replacement
Current License: CC BY-SA 4.0
8 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Nov 28, 2019 at 7:23 | vote | accept | lucenzo97 | ||
| Jul 4, 2019 at 16:44 | comment | added | D.A.S. | This is far more reliable but slightly more complex than a simple pot adjusted DC threshold to Ambient+ IR light. but can be made to work with high current and <1 degree apertures on both sides. the pulsed fake data makes it immune to beamwidth and can measure any multipath interruption or modulation reduction of light | |
| Jul 4, 2019 at 16:43 | comment | added | D.A.S. | the Sharp/Vishal IR receiver chips use this AGC to get 1000x times the ambient light rejection or 60dB SNR improvement and sensitivity for Remote controls to go 30m with 100mA LED peaks. You don’t need this range so current is significant reduced to maybe 5mA or less. thus AGC detects the carrier and a dropout looks like a momentary data pulse. But a better more reliable solution is to send a data pulse e.g. 0001 and detect this pattern with dual one shots and absence of data pattern means light deflection (i.e.= data error) | |
| Jul 4, 2019 at 16:03 | comment | added | lucenzo97 | Well, I just quickly learned few important stuff about what is the point of such modulation - to avoid interference with ambient visible light. However, I still didn't quite understand what you meant with ACG thing. | |
| Jul 4, 2019 at 15:38 | comment | added | lucenzo97 | However, looks like you know what you are talking about and how to solve this problem, but I don't understand it yet. Thank you anyway. | |
| Jul 4, 2019 at 15:36 | comment | added | lucenzo97 | At first I understood some words, then you lost me somewhere in the middle.. Why would I use modulation at frequency 26 kHz? I don't intend to transmit data or something alike. I want to make sure that as IR beam is interrupted, sensor reacts to that and that only. | |
| Jul 3, 2019 at 21:46 | comment | added | DKNguyen | A photodiode or phototransistor with a daylight blocking filter will look like a chunk of black plastic (opaque to visible, but not to IR) rather than clear. | |
| Jul 3, 2019 at 21:11 | history | answered | D.A.S. | CC BY-SA 4.0 |