Hi, my current project is now delayed, because of waiting for others to be finished.
My next project is a versatile IR Sender / receiver for a mobile Intrusion Detection.
As Hardware Receiver I want use industrial receiver modules (sharp GP1Uxxx), because of absolutly low costs.
Now, they do have a band-pass filter frequenzy of 36.7 kHz, 38Khz or 56.8 Khz
the Prize is not the Problem, I tend to 36.7 because of not being the mainstream IR-Remote Control Frequency of 38KHz.
I want to build a system which is not so easy to fool with a usual Remote Control.
I did find in the Help, that 38KHz is the default for PWM_FIX, so why I am asking?
Ok, the Backgroud is, I want to build Bursts from 1% to 5% Peak pulses. My IR Led will be LD 274-3 from Osram, this device take 100mA continously, but can take 3A for 10µs. I will drive it with Bursts of 10 Peaks of 1A with somewhat longer pulses, say 10 x 1ms.
So the question is: What method would fit my needs?
HPWM CCP ?
PWM FIX?
Software PWM?
And most important which Frequency is best?
The lower the more time is for the Programm to construct the PWM Signal...?
The Sender is a standalone Module.
The Receiver will be a standalone module while shall receiver 2-3- sender and give alert when one of them is triggered, or better to say is missing
Last edit: bed 2017-11-13
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Most of my experience is with Vishay as I found them to be generally superior to any others I tested. And there is a module available for just about any specific application or protocol.
I do not imagine that frequency is exttremely critical unless the receiver is located where it could be subjected to modulated infrared from an unintended source.
What is kind of disturbing is that Sharp does not provide specification in regards to spectral sensitivity vs wavelength. Or at least I coud not find it, so I can only guess that their receivers are matched to their emitters at ~940 - 960nm.
What I would recommend in regards to driving the Sender depends upon what your actual application is.
What data protocol?
What data is being sent?
How often is data sent ?
How much data is sent at one time?
What kind of range do you expect?
Perhaps describe how you want the mobile intrusion system to work ie ...what triggers the system, what happens after it is triggered? And so on ..
Last edit: William Roth 2017-11-13
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
One enhancement to my first posting:
When using 36.7 KHz it is going to be 27.248µs Cycle.
So a Burst of 10 will be lasts 277µs right?
in opposite to 38KHz. which is 263µs.
I wonder if it is possible with an 16 MHz PIC, so 4 MHz real, to generate such exact PWM Pulse?
The spectral curve is in the datasheet, 950nm as of the IR LED is quite good in the 90% maximum.
I do not want transmit data, only all 500ms a 10 peaks burst.
The receiver controlls only the persistance of the signal.
If the Burst has not been received say "If a person goes to the path", an alert will be fired, the alert can be sound or optional Light.
The whole thing is for LARP in old industrial facilities. Imagine a sniper is positiong himself in a room with only one door an some windows.
The door is in his back and he can not watch the door while snipping, so he should be alarmed when somebody went thru.
And I will prevent faking the system with a simple Remote control,
Range should be 6m at least the more the better.
The interesting point is in step two overwatch more than one sensors in one receiver, but step after step.
The reason for the receiver Parts are simply the costs, I can get them 10 peaces for less than 1 €
Last edit: bed 2017-11-14
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
I bought some 3 pin vishay sensors for obstacle detection but ordered the wrong ones. The ones I got needed a coded 38KHz to work or they just timed out.
Chose our device carefully for your needs.
I was posting to say that the receivers are not suited to your application, sounds like you need a Photodiode or Transistor rather than a decoder.
The Decoders are designed to ignore everything but a modulated frequency whose Q they are tuned. That way they can ignore Fluorescent lights, Passive InfraRed security devices, sunlight etc.
You can try and use them, but send valid codes and ensure that they are directional with some kind of shielding, as the decoders are omnidirectional by design.
Cheers
Chris
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
While I making some progress, I ordered 10 times the wanted amount IR-Receiver Modules.
(Because I to dumb to read the shopping cart correctly) ;-)
If anyone want some for 0$ , I could sent him, only postage should taken over
Last edit: bed 2017-11-21
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hi, my current project is now delayed, because of waiting for others to be finished.
My next project is a versatile IR Sender / receiver for a mobile Intrusion Detection.
As Hardware Receiver I want use industrial receiver modules (sharp GP1Uxxx), because of absolutly low costs.
Now, they do have a band-pass filter frequenzy of 36.7 kHz, 38Khz or 56.8 Khz
the Prize is not the Problem, I tend to 36.7 because of not being the mainstream IR-Remote Control Frequency of 38KHz.
I want to build a system which is not so easy to fool with a usual Remote Control.
I did find in the Help, that 38KHz is the default for PWM_FIX, so why I am asking?
Ok, the Backgroud is, I want to build Bursts from 1% to 5% Peak pulses. My IR Led will be LD 274-3 from Osram, this device take 100mA continously, but can take 3A for 10µs. I will drive it with Bursts of 10 Peaks of 1A with somewhat longer pulses, say 10 x 1ms.
So the question is: What method would fit my needs?
HPWM CCP ?
PWM FIX?
Software PWM?
And most important which Frequency is best?
The lower the more time is for the Programm to construct the PWM Signal...?
The Sender is a standalone Module.
The Receiver will be a standalone module while shall receiver 2-3- sender and give alert when one of them is triggered, or better to say is missing
Last edit: bed 2017-11-13
Most of my experience is with Vishay as I found them to be generally superior to any others I tested. And there is a module available for just about any specific application or protocol.
I do not imagine that frequency is exttremely critical unless the receiver is located where it could be subjected to modulated infrared from an unintended source.
What is kind of disturbing is that Sharp does not provide specification in regards to spectral sensitivity vs wavelength. Or at least I coud not find it, so I can only guess that their receivers are matched to their emitters at ~940 - 960nm.
What I would recommend in regards to driving the Sender depends upon what your actual application is.
What data protocol?
What data is being sent?
How often is data sent ?
How much data is sent at one time?
What kind of range do you expect?
Perhaps describe how you want the mobile intrusion system to work ie ...what triggers the system, what happens after it is triggered? And so on ..
Last edit: William Roth 2017-11-13
One enhancement to my first posting:
When using 36.7 KHz it is going to be 27.248µs Cycle.
So a Burst of 10 will be lasts 277µs right?
in opposite to 38KHz. which is 263µs.
I wonder if it is possible with an 16 MHz PIC, so 4 MHz real, to generate such exact PWM Pulse?
The spectral curve is in the datasheet, 950nm as of the IR LED is quite good in the 90% maximum.
I do not want transmit data, only all 500ms a 10 peaks burst.
The receiver controlls only the persistance of the signal.
If the Burst has not been received say "If a person goes to the path", an alert will be fired, the alert can be sound or optional Light.
The whole thing is for LARP in old industrial facilities. Imagine a sniper is positiong himself in a room with only one door an some windows.
The door is in his back and he can not watch the door while snipping, so he should be alarmed when somebody went thru.
And I will prevent faking the system with a simple Remote control,
Range should be 6m at least the more the better.
The interesting point is in step two overwatch more than one sensors in one receiver, but step after step.
The reason for the receiver Parts are simply the costs, I can get them 10 peaces for less than 1 €
Last edit: bed 2017-11-14
I bought some 3 pin vishay sensors for obstacle detection but ordered the wrong ones. The ones I got needed a coded 38KHz to work or they just timed out.
Chose our device carefully for your needs.
Stan just beat me to the punch there.
I was posting to say that the receivers are not suited to your application, sounds like you need a Photodiode or Transistor rather than a decoder.
The Decoders are designed to ignore everything but a modulated frequency whose Q they are tuned. That way they can ignore Fluorescent lights, Passive InfraRed security devices, sunlight etc.
You can try and use them, but send valid codes and ensure that they are directional with some kind of shielding, as the decoders are omnidirectional by design.
Cheers
Chris
Chris, I have some 15+ year old 3 pin with ir only case that the pin goes high when only near 38KHz sensed and they're nice to use and changing the 38Khz a few 100 Hz changes the sensitivity. I tried that for obstacle sensing. I got some off these for <£1. Apparently rubbish but I found ok https://www.ebay.co.uk/i/112467561869?chn=ps&dispctrl=1&adgroupid=13585920426&rlsatarget=pla-142405609026&abcId=&adtype=pla&merchantid=6995734&poi=&googleloc=1007416&device=c&campaignid=207297426&crdt=0
While I making some progress, I ordered 10 times the wanted amount IR-Receiver Modules.
(Because I to dumb to read the shopping cart correctly) ;-)
If anyone want some for 0$ , I could sent him, only postage should taken over
Last edit: bed 2017-11-21