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I have just bought a KC7783 PIR sensor and I am trying to connect it to my BX-24. I actually thought it would just give a logic high when movement is detected. But it has a TTL output - how do I syncronize this with the BX? The datasheet can be found on http://www.electronics123.com/amazon/datasheet/kc7783.pdf |
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KC7783 PIR sensor and BasicX
Started by ●June 15, 2004
Reply by ●June 15, 20042004-06-15
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By looking at the schematic at:
http://electronics123.com/amazon/datasheet/k76_spec.jpeg it looks like the signal is a logic "high" when the KC7783 sees IR. "TTL" stands for transistor-transistor-logic and the specifications for that logic family is compatible with a BX-24 I/O pin when configured as "input". To see how the PIR actually performs, I would wire up the module to a 5 VDC power source and measure the voltage at the output relative to ground with a voltmeter. Depending on the IR in view and how you want to use the sensor will suggest how you will want to write the code. Depending on your application, it may be as simple as "polling" the input pin and taking some action as a result of the "poll". There are various techniques like "doing something on the leading edge of IR signal", "doing something when the signal ends" or "doing something if the IR signal is longer than X seconds" etc. These are easily accomplished in a subroutine that reads the input pin (the IR signal) and compares it to a stored variable of the last read "IRsignalWAS" and sees if the signal has changed. If it has, the "IRsignalWAS" variable is updated and the appropriate action taken. The BX-24 is very, very fast and if your control algorithm is relatively simple, a DO LOOP using "polling" might be all you need. Eric ----- Original Message ----- From: larzyharzy To: Sent: Tuesday, June 15, 2004 11:29 AM Subject: [BasicX] KC7783 PIR sensor and BasicX I have just bought a KC7783 PIR sensor and I am trying to connect it to my BX-24. I actually thought it would just give a logic high when movement is detected. But it has a TTL output - how do I syncronize this with the BX? |
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Reply by ●June 15, 20042004-06-15
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You would use Pulsein to measure the sensors output. Something like this: Call PuseIn(12, Data, 1) or Call PuseIn(12, Data, 0) depending on if the data is on the high or low pulse. Pin 12 is the assumed i/o pin in the above examples. Chris ----- Original Message ----- From: "larzyharzy" <> To: <> Sent: Tuesday, June 15, 2004 11:29 AM Subject: [BasicX] KC7783 PIR sensor and BasicX > I have just bought a KC7783 PIR sensor and I am trying to connect it > to my BX-24. I actually thought it would just give a logic high when > movement is detected. But it has a TTL output - how do I syncronize > this with the BX? > > The datasheet can be found on > http://www.electronics123.com/amazon/datasheet/kc7783.pdf > Yahoo! Groups Links > > |
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Reply by ●June 16, 20042004-06-16
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I have tried with the code below. But the PulseWidth is always 0 both when there is motion in front of the sensor and no motion. What can the problem be Public Sub Main() dim PulseWidth as Single ' PIR sensor Do Call PulseIn(20, 1, PulseWidth) debug.print cstr(PulseWidth) call delay(0.01) Loop End Sub --- In , "Chris" <chrish@n...> wrote: > You would use Pulsein to measure the sensors output. > > Something like this: Call PuseIn(12, Data, 1) > or Call PuseIn(12, Data, 0) depending on if the data > is on the high or low pulse. Pin 12 is the assumed i/o pin > in the above examples. > Chris > ----- Original Message ----- > From: "larzyharzy" <larzjessen@h...> > To: <> > Sent: Tuesday, June 15, 2004 11:29 AM > Subject: [BasicX] KC7783 PIR sensor and BasicX > > I have just bought a KC7783 PIR sensor and I am trying to connect it > > to my BX-24. I actually thought it would just give a logic high when > > movement is detected. But it has a TTL output - how do I syncronize > > this with the BX? > > > > The datasheet can be found on > > http://www.electronics123.com/amazon/datasheet/kc7783.pdf > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > |
Reply by ●June 16, 20042004-06-16
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I just read the spec sheet on this device and found that the minimum pulsewidth is 1/2 second, that is way to slow for Pulsein to see. I also noted that it requires a 25 second power up delay. Maybe for it to temperature stabilize? I would recommend making a do loop to increment a counter and "roll your own" long pulse counter. Once you get it working properly you can turn it into a task and let it run in the background. Quick example: Dim IR_Raw As Long Dim IR_Data As Long Dim New_IR_Data As Boolean Const IR_Pin As Byte = 20 Sub Main() New_IR_Data = False IR_Raw = 0 Do DoWhile GetPin(IR_Pin) = 0 Call Sleep(5) Loop If GetPin(IR_Pin) = 1 Then IR_Raw = IR_Raw + 1 Else IR_Data = IR_Raw New_IR_Data = True IR_Raw = 0 Call Sleep(5) Loop End Sub You may need to switch around the code to look for data on 0 instead of 1, the docs really don't say if the data pulse is high or low, I'm just assuming it's on the high pulse. Chris ----- Original Message ----- From: "larzyharzy" <> To: <> Sent: Wednesday, June 16, 2004 2:52 AM Subject: [BasicX] Re: KC7783 PIR sensor and BasicX > I have tried with the code below. But the PulseWidth is always 0 > both when there is motion in front of the sensor and no motion. > > What can the problem be > Public Sub Main() > dim PulseWidth as Single > > ' PIR sensor > Do > Call PulseIn(20, 1, PulseWidth) > debug.print cstr(PulseWidth) > call delay(0.01) > Loop > > End Sub > > --- In , "Chris" <chrish@n...> wrote: > > You would use Pulsein to measure the sensors output. > > > > Something like this: Call PuseIn(12, Data, 1) > > or Call PuseIn(12, Data, 0) depending on if the data > > is on the high or low pulse. Pin 12 is the assumed i/o pin > > in the above examples. > > > > > > Chris > > > > > > ----- Original Message ----- > > From: "larzyharzy" <larzjessen@h...> > > To: <> > > Sent: Tuesday, June 15, 2004 11:29 AM > > Subject: [BasicX] KC7783 PIR sensor and BasicX > > > > > > > I have just bought a KC7783 PIR sensor and I am trying to > connect it > > > to my BX-24. I actually thought it would just give a logic high > when > > > movement is detected. But it has a TTL output - how do I > syncronize > > > this with the BX? > > > > > > The datasheet can be found on > > > http://www.electronics123.com/amazon/datasheet/kc7783.pdf > > > > > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > > > > > > > Yahoo! Groups Links > > |
Reply by ●June 17, 20042004-06-17
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thanks chris and eserdahl I tried hooking the PIR up to a voltmeter and I never get a high (regardless of movement), so I guess it is broken. Also the values I get using getADC are always very low between 0 and 20. I will get hold of another module to test. /lars --- In , "eserdahl@" <eserdahl@p...> wrote: > By looking at the schematic at: http://electronics123.com/amazon/datasheet/ k76_spec.jpeg > it looks like the signal is a logic "high" when the KC7783 sees IR. > > "TTL" stands for transistor-transistor-logic and the specifications > for that logic family is compatible with a BX-24 I/O pin when configured > as "input". > > To see how the PIR actually performs, I would wire up the module to a > 5 VDC power source and measure the voltage at the output relative to > ground with a voltmeter. Depending on the IR in view and how you want > to use the sensor will suggest how you will want to write the code. > > Depending on your application, it may be as simple as "polling" the > input pin and taking some action as a result of the "poll". There are > various techniques like "doing something on the leading edge of IR signal", > "doing something when the signal ends" or "doing something if the IR signal > is longer than X seconds" etc. These are easily accomplished in a subroutine > that reads the input pin (the IR signal) and compares it to a stored variable > of the last read "IRsignalWAS" and sees if the signal has changed. If it has, > the "IRsignalWAS" variable is updated and the appropriate action taken. > The BX-24 is very, very fast and if your control algorithm is relatively > simple, a DO LOOP using "polling" might be all you need. > > Eric > > ----- Original Message ----- > From: larzyharzy > To: > Sent: Tuesday, June 15, 2004 11:29 AM > Subject: [BasicX] KC7783 PIR sensor and BasicX > I have just bought a KC7783 PIR sensor and I am trying to connect it > to my BX-24. I actually thought it would just give a logic high when > movement is detected. But it has a TTL output - how do I syncronize > this with the BX? > |
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Reply by ●June 17, 20042004-06-17
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--- In , "larzyharzy" <larzjessen@h...> wrote: > thanks chris and eserdahl > > I tried hooking the PIR up to a voltmeter and I never get a high (regardless of > movement), so I guess it is broken. Also the values I get using getADC are always very > low between 0 and 20. I will get hold of another module to test. > > /lars > Lars, I have a PIR myself, and to my knowledge they do not implement that logic you are checking for. Mine is a switch basically..NC contact when movement is detected it opens, OHM it with your meter for connectivity, usually the sensors are fed into an and gate..If one is low=alarm.. Hope it helps daniel |
Reply by ●June 17, 20042004-06-17
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> > > > > > I have just bought a KC7783 PIR sensor and I am trying to connect it > > to my BX-24. I actually thought it would just give a logic high when > > movement is detected. But it has a TTL output - how do I syncronize > > this with the BX? > > lars, just saw your data sheets maybe it is broke...I would ohm it just to be sure.. :) Daniel |
