captain_spalding said:

Easy

You want content with that?

Could someone please look at this simple circuit, and tell me what i’m doing wrong that causes the flashing LED to glow continuously?

http://arduinobasics.blogspot.com.au/2013/12/pir-sensor-part-1.html

Skeptic Pete said:

captain_spalding said:

Easy

Back off, Peter, this is my area!

Captain, I really can’t see a problem with your circuit.

sibeen said:

Skeptic Pete said:

captain_spalding said:

Easy

Back off, Peter, this is my area!

Captain, I really can’t see a problem with your circuit.

Nor can i. The circuit is so very simple. Yest, when i assemble it as depicted, the LED begins to glow continuously, even though it’s a flashing LED.

captain_spalding said:

You want content with that?

Could someone please look at this simple circuit, and tell me what i’m doing wrong that causes the flashing LED to glow continuously?

http://arduinobasics.blogspot.com.au/2013/12/pir-sensor-part-1.html

without looking

an led will flash if the delay() is slow enough for the eye to see

an led flashing with a delay of delay (1) will be too fast for the eye to see when its on or off

have you tried using the “blink” programme first that uses pin 13 and the associated tiny LED on the board?

captain_spalding said:

sibeen said:

Skeptic Pete said:

Easy

Back off, Peter, this is my area!

Captain, I really can’t see a problem with your circuit.

Nor can i. The circuit is so very simple. Yest, when i assemble it as depicted, the LED begins to glow continuously, even though it’s a flashing LED.

Maybe it’s flashing so quick you can’t tell and it looks like it’s glowing.

download the blink programme first that uses the LED on the board

does the LED on the board glow continuously?

poikilotherm said:

the LED begins to glow continuously, even though it’s a flashing LED.

OK, can you please explain what you mean by a flashing LED.

Are you using a standard LED or not?

the “blink” programme uses the LED on the board

if you hook up an LED correctly to the actual pin 13 itself you should also see a blink that matches the LED on the board

it is safe in this case just using LEDs to simply wire an LED from pin 13 to ground

as you might know an LED is normally accompanied by a small resistor in line with the LED

LEDs normally require the current passing through them to be controlled and the resistor reduces the current flowing

with the arduino it is unnecessary for the resistor to be used if the arduino is providing power to the LED

the “blink” programme uses the LED on the board

if you hook up an LED correctly to the actual pin 13 itself you should also see a blink that matches the LED on the board

it is safe in this case just using LEDs to simply wire an LED from pin 13 to ground

as you might know an LED is normally accompanied by a small resistor in line with the LED

LEDs normally require the current passing through them to be controlled and the resistor reduces the current flowing

with the arduino it is unnecessary for the resistor to be used if the arduino is providing power to the LED

sibeen said:

poikilotherm said:

the LED begins to glow continuously, even though it’s a flashing LED.

OK, can you please explain what you mean by a flashing LED.

Are you using a standard LED or not?

You’re as bad as buffy with the quoting…

OK, i can dig that it may be flashing so rapidly as to appear constant.

I think i should clarify that i’m not using and Arduino – just trying to create the elementary circuit with PIR, LED, resistor.

sibeen said:

Back off, Peter, this is my area!

backs away also….

sibeen said:

poikilotherm said:

the LED begins to glow continuously, even though it’s a flashing LED.

OK, can you please explain what you mean by a flashing LED.

Are you using a standard LED or not?

the arduino has a programme that causes the LED to flash on and off

you set up a pin output to provide power at set time periods

sibeen said:

poikilotherm said:

the LED begins to glow continuously, even though it’s a flashing LED.

OK, can you please explain what you mean by a flashing LED.

Are you using a standard LED or not?

No, i’m using these/similar:

http://www.ebay.com.au/itm/like/321267772316?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=107

captain_spalding said:

OK, i can dig that it may be flashing so rapidly as to appear constant.

I think i should clarify that i’m not using and Arduino – just trying to create the elementary circuit with PIR, LED, resistor.

just seen

the circuit is either wired wrongly or the PIR is boned

captain_spalding said:

OK, i can dig that it may be flashing so rapidly as to appear constant.

I think i should clarify that i’m not using and Arduino – just trying to create the elementary circuit with PIR, LED, resistor.

just seen

the circuit is either wired wrongly or the PIR is boned

wookiemeister said:

captain_spalding said:

OK, i can dig that it may be flashing so rapidly as to appear constant.

I think i should clarify that i’m not using and Arduino – just trying to create the elementary circuit with PIR, LED, resistor.

just seen

the circuit is either wired wrongly or the PIR is boned

Yes, i suspected the PIR, too.

So, i swapped it for another identical one i have.

Same result.

captain_spalding said:

sibeen said:

poikilotherm said:

the LED begins to glow continuously, even though it’s a flashing LED.

OK, can you please explain what you mean by a flashing LED.

Are you using a standard LED or not?

No, i’m using these/similar:

http://www.ebay.com.au/itm/like/321267772316?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=107

And I suspect that is your problem. The flashing LED has inbuilt circuitry.

Get a standard LED and try it again.

the forum seems to be seizing up on my computer

just looked at circuit
have you checked that the connection on the bread board is good (are you using a bread board?)

I find that bread boards can create high resistance joints or open circuits

the forum seems to be seizing up on my computer

just looked at circuit
have you checked that the connection on the bread board is good (are you using a bread board?)

I find that bread boards can create high resistance joints or open circuits

sibeen said:

And I suspect that is your problem. The flashing LED has inbuilt circuitry.

Get a standard LED and try it again.

Ok, sounds like a good idea

I’ll have another go at it.

I would have liked a m ore conventional circuit diagram.

Can anyone confirm my understanding that the wire from the negative pin on the PIR, and the wire linking the resistor to that negative pin share a common joint to the battery’s negative terminal?

sibeen said:

captain_spalding said:

sibeen said:

OK, can you please explain what you mean by a flashing LED.

Are you using a standard LED or not?

No, i’m using these/similar:

http://www.ebay.com.au/itm/like/321267772316?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=107

And I suspect that is your problem. The flashing LED has inbuilt circuitry.

Get a standard LED and try it again.

What he said.

Those flashing LEDs contain a circuit like this which may do weird things when it’s embedded into anything but a simple circuit that supplies clean power to it.

IOW, the electrical characteristics of your PIR are (probably) screwing with the timing of the built-in flashing circuit of your LED.

it shouldn’t make any difference as long as the right Voltage is being used

he wants the led to flash when a voltage is being introduced to the LED

as I see it the PIR is powered by the 9V battery, the PIR consumes power itself (return to negative) and also provides a signal voltage to the flashing LED

I would just see what voltage is on the signal wire coming out of the PIR to the LED if its on continuously it shouldn’t make any difference about what LED is being used

captain_spalding said:

I’ll have another go at it.

I would have liked a m ore conventional circuit diagram.

Can anyone confirm my understanding that the wire from the negative pin on the PIR, and the wire linking the resistor to that negative pin share a common joint to the battery’s negative terminal?

the PIR provides current to the LED then flows to the resistor which them shares a common negative with the PIR

captain_spalding said:

I’ll have another go at it.

I would have liked a m ore conventional circuit diagram.

Can anyone confirm my understanding that the wire from the negative pin on the PIR, and the wire linking the resistor to that negative pin share a common joint to the battery’s negative terminal?

A big +1 on having a conventional circuit.

Yes to your question, the battery neg feeds the PIR and one side of the resistor.

if you provided voltage to the LED – the right voltage by using a resistor to the LED does the LED actually flash?

ie does the LED flash or remain on when fed with a constant power source ?

ok different approach

remove the LED and replace it with a multimeter

does the PIR provide constant power?

if it does then its the LED causing problems

personally I never use strange types of LEDs to build circuits

the circuit shown uses a bog standard LED

I wonder if you put a diode in series between the PIR output to the LED if its causing problems?

wookiemeister said:

ok different approach

remove the LED and replace it with a multimeter

does the PIR provide constant power?

if it does then its the LED causing problems

That’s a good idea, too.

Tried them both.

Replaced the yellow flashing LED with a standard red LED. Same result – LED came on, and stayed on.

Replaced the LED with the multimeter. Steady 8.37 volts.

captain_spalding said:

wookiemeister said:

ok different approach

remove the LED and replace it with a multimeter

does the PIR provide constant power?

if it does then its the LED causing problems

That’s a good idea, too.

Tried them both.

Replaced the yellow flashing LED with a standard red LED. Same result – LED came on, and stayed on.

Replaced the LED with the multimeter. Steady 8.37 volts.

is this PIR meant to react to IR? so if you covered it, it should shut down voltage to the signal cable to the LED? by covering the PIR with a cloth the signal to the LED / multimeter should drop to zero?

you could always take a 1.5 cell (“battery”) put the resistor in series and see if the flashing LED works then

wookiemeister said:

it shouldn’t make any difference as long as the right Voltage is being used

he wants the led to flash when a voltage is being introduced to the LED

as I see it the PIR is powered by the 9V battery, the PIR consumes power itself (return to negative) and also provides a signal voltage to the flashing LED

I would just see what voltage is on the signal wire coming out of the PIR to the LED if its on continuously it shouldn’t make any difference about what LED is being used

Fair points. I’ve never played with PIRs. Does the output signal just look like a simple voltage source?

As you & Sibeen might guess I’m speculating that some capacitive effect of the PIR is screwing up the frequency of the astable flip-flop in the flashing LED.

As an alternative hypothesis: how long does the output signal last for when the PIR is triggered & how long does it take to recover, or can that stuff be adjusted?

So, it has to be the PIR, does it not.

In the absence of detectable movement, should it not cease supplying volts to the LED? Yet, it does so continuously.

hang on

this is a motion detector

isn’t it just detecting your movement all the time?

if you cover with a cloth the sensor should stop seeing movement and the voltage to the LED should drop to zero

captain_spalding said:

Replaced the yellow flashing LED with a standard red LED. Same result – LED came on, and stayed on.

Replaced the LED with the multimeter. Steady 8.37 volts.

Ok. But in that case it’s a bit weird that the flashing LED didn’t want to flash.

Have you tried Wookie’s suggestion to check that the flashing LED works in a simple series circuit with the resistor. It’ll probably need more than 1.5v to run it, though.

Get rid of the LED and just feed the resistor. Measure the voltage across the resistor and see whether there is a change.

wookiemeister said:

hang on

this is a motion detector

isn’t it just detecting your movement all the time?

if you cover with a cloth the sensor should stop seeing movement and the voltage to the LED should drop to zero

I wish it would.

I now have covered by a black nylon bag, immobile on the table, with a piece of cardboard on top of the bag.

But, the LED glows as brightly as ever.

captain_spalding said:

So, it has to be the PIR, does it not.

In the absence of detectable movement, should it not cease supplying volts to the LED? Yet, it does so continuously.

I would say yes but there could be a small delay time perhaps

with no movement you’d expect the voltage to the LEd to cease

•Output: Digital pulse high (3V) when triggered (motion detected) digital low when idle (no motion detected). Pulse lengths are determined by resistors and capacitors on the PCB and differ from sensor to sensor.
•Sensitivity range: up to 20 feet (6 meters) 110° x 70° detection range
•Power supply: 3V-9V input voltage, but 5V is ideal.

you are feeding 9V

by the looks of it the PIR is meant to pulse the voltage to the LED as well (Output: Digital pulse high (3V) when triggered (motion detected) digital low when idle (no motion detected). Pulse lengths are determined by resistors and capacitors on the PCB and differ from sensor to sensor.)

I would see what happens when you feed continuous power to the LED you’ve got (does it flash?)

sibeen said:

Get rid of the LED and just feed the resistor. Measure the voltage across the resistor and see whether there is a change.

Well, i did substitute the multimeter in place of the LED. Is that what you mean?

captain_spalding said:

So, it has to be the PIR, does it not.

In the absence of detectable movement, should it not cease supplying volts to the LED? Yet, it does so continuously.

I would say yes but there could be a small delay time perhaps

with no movement you’d expect the voltage to the LEd to cease

•Output: Digital pulse high (3V) when triggered (motion detected) digital low when idle (no motion detected). Pulse lengths are determined by resistors and capacitors on the PCB and differ from sensor to sensor.
•Sensitivity range: up to 20 feet (6 meters) 110° x 70° detection range
•Power supply: 3V-9V input voltage, but 5V is ideal.

you are feeding 9V

by the looks of it the PIR is meant to pulse the voltage to the LED as well (Output: Digital pulse high (3V) when triggered (motion detected) digital low when idle (no motion detected). Pulse lengths are determined by resistors and capacitors on the PCB and differ from sensor to sensor.)

I would see what happens when you feed continuous power to the LED you’ve got (does it flash?)

preview alters the code and can actually break it

captain_spalding said:

wookiemeister said:

hang on

this is a motion detector

isn’t it just detecting your movement all the time?

if you cover with a cloth the sensor should stop seeing movement and the voltage to the LED should drop to zero

I wish it would.

I now have covered by a black nylon bag, immobile on the table, with a piece of cardboard on top of the bag.

But, the LED glows as brightly as ever.

you might have two problems

boned LED and boned PIR

captain_spalding said:

sibeen said:

Get rid of the LED and just feed the resistor. Measure the voltage across the resistor and see whether there is a change.

Well, i did substitute the multimeter in place of the LED. Is that what you mean?

No. Feed the resistor directly with the output of the PID, basically the LED is shorted out. Then measure across the resistor.

SCIENCE said:

preview alters the code and can actually break it

o rly

captain_spalding said:

sibeen said:

Get rid of the LED and just feed the resistor. Measure the voltage across the resistor and see whether there is a change.

Well, i did substitute the multimeter in place of the LED. Is that what you mean?

sort of

by measuring voltage across the resistor you are seeing if the PIR can provide power (current to actually flow), measuring just voltage doesn’t check if power can be provided by the PIR when it has a load 9the led) though you’d assume it as the load is tiny

Tested the flashing LED with power passed through the resistor. It flashes beuatifully.

take the LED and the resistor and provide them with 3VDC (two 1.5 cells in series)

if the LED does not flash then its boned

sibeen said:

captain_spalding said:

sibeen said:

Get rid of the LED and just feed the resistor. Measure the voltage across the resistor and see whether there is a change.

Well, i did substitute the multimeter in place of the LED. Is that what you mean?

No. Feed the resistor directly with the output of the PID, basically the LED is shorted out. Then measure across the resistor.

OK, i think i did it. Got 2.28 v across the resistor.

wookiemeister said:

take the LED and the resistor and provide them with 3VDC (two 1.5 cells in series)

if the LED does not flash then its boned

The LED is good! The LED is sound! :)

captain_spalding said:

Tested the flashing LED with power passed through the resistor. It flashes beuatifully.

ok LED works then it might mean that the PIR is boned or as suggested the circuit of the LED is playing havoc with the PIR or the PIR is boned and can’t provide power.

put the circuit together and remove the LED so that the PIR is providing power to the resistor only

put a multimter across the resistor and see if voltage is across the resistor

you might be able to see what current is actually flowing through the resistor by using the amp measurement (put it on the smaller amp measurement ) to measure current put the multimeter into the larger measurement scale and connect it so that all current flowing to the resistor must pass through the multimeter 9you might need to change terminals on your multimeter)

captain_spalding said:

sibeen said:

captain_spalding said:

Well, i did substitute the multimeter in place of the LED. Is that what you mean?

No. Feed the resistor directly with the output of the PID, basically the LED is shorted out. Then measure across the resistor.

OK, i think i did it. Got 2.28 v across the resistor.

OK, therein lies the problem, if the sensor is covered up there shouldn’t be any voltage.

Internal circuit of PIR

might help. maybe.

captain_spalding said:

OK, i can dig that it may be flashing so rapidly as to appear constant.

I think i should clarify that i’m not using and Arduino – just trying to create the elementary circuit with PIR, LED, resistor.

just seen

the circuit is either wired wrongly or the PIR is boned

I wonder

I wonder

if the PIR is actually providing an ultra fast pulse rather than a clean continuous source of current like a battery then this might affect the flashing LED

you’ve got two problems

1 wrong LED to use with PIR

2 boned PIR (its always on regardless)

the ultrafast pulse from the PIR wouldn’t be noticed by the human eye but renders the flashing circuit in the LED useless and it remains ON

sibeen said:

captain_spalding said:

sibeen said:

No. Feed the resistor directly with the output of the PID, basically the LED is shorted out. Then measure across the resistor.

OK, i think i did it. Got 2.28 v across the resistor.

OK, therein lies the problem, if the sensor is covered up there shouldn’t be any voltage.

Yeah, looks like it.

I’ve got two more PIRs somewhere around. Hope one of them works. I’ll try on the weekend – too late now.

Thanks to everyone for suggestions and assistance.

captain_spalding said:

Tested the flashing LED with power passed through the resistor. It flashes beuatifully.

Ta, captain.

My guess is that the internal settings of your PIR are such that once it’s triggered it stays on for a long time, possibly as long as it has a steady input voltage. But it may be possible to adjust it so that it behaves the way you want it to.

wookiemeister said:

I wonder

I wonder

if the PIR is actually providing an ultra fast pulse rather than a clean continuous source of current like a battery then this might affect the flashing LED

you’ve got two problems

1 wrong LED to use with PIR

2 boned PIR (its always on regardless)

the ultrafast pulse from the PIR wouldn’t be noticed by the human eye but renders the flashing circuit in the LED useless and it remains ON

to bring back the flashing of the LED you might need to have a capacitor in the circuit between the PIR and the LED

you need the capacitor to smooth the output of the pulse from the PIR???????????????

wookiemeister said:

I wonder

I wonder

if the PIR is actually providing an ultra fast pulse rather than a clean continuous source of current like a battery then this might affect the flashing LED

you’ve got two problems

1 wrong LED to use with PIR

2 boned PIR (its always on regardless)

the ultrafast pulse from the PIR wouldn’t be noticed by the human eye but renders the flashing circuit in the LED useless and it remains ON

to bring back the flashing of the LED you might need to have a capacitor in the circuit between the PIR and the LED

you need the capacitor to smooth the output of the pulse from the PIR???????????????

the fact that the LED flashes when attached to a plain old voltage and then stops working when connected to a PIR might mean that the voltage from the PIR is fed via a series of pulses to create 3 VDC

the pulse output from the PIR plays merry havoc with the special LED

wookiemeister said:

the fact that the LED flashes when attached to a plain old voltage and then stops working when connected to a PIR might mean that the voltage from the PIR is fed via a series of pulses to create 3 VDC

the pulse output from the PIR plays merry havoc with the special LED

But, it does the same thing with the standard red (non-flashing) LED.

wookiemeister said:

ok LED works then it might mean that the PIR is boned or as suggested the circuit of the LED is playing havoc with the PIR or the PIR is boned and can’t provide power.

Please try to keep up, Wookie. :) As captain_spalding said a little earlier:

captain_spalding said:

Replaced the yellow flashing LED with a standard red LED. Same result – LED came on, and stayed on.

So my theory re the flashing LED circuit may still be relevant, but it looks like the PIR itself is the primary culprit.

PM 2Ring said:

wookiemeister said:

ok LED works then it might mean that the PIR is boned or as suggested the circuit of the LED is playing havoc with the PIR or the PIR is boned and can’t provide power.

Please try to keep up, Wookie. :) As captain_spalding said a little earlier:

captain_spalding said:

Replaced the yellow flashing LED with a standard red LED. Same result – LED came on, and stayed on.

So my theory re the flashing LED circuit may still be relevant, but it looks like the PIR itself is the primary culprit.

I do tend to agree, PM. Just shorted the PIR out of the circuit (by bridging between the posittve and centre pins on the PIR), and the flashing LED works fine with that. So, all my solder joints etc must be OK – It has to be the PIR.

If the PIR is like the one on this page it shouldn’t be too hard to adjust.

captain_spalding said:

wookiemeister said:

the fact that the LED flashes when attached to a plain old voltage and then stops working when connected to a PIR might mean that the voltage from the PIR is fed via a series of pulses to create 3 VDC

the pulse output from the PIR plays merry havoc with the special LED

But, it does the same thing with the standard red (non-flashing) LED.

a standard LED won’t flash

the PIR doesn’t flash the LED it just provides a pulsed current to the LED so that 3VDC is fed to it (the resistor then drops the voltage)

if the LED is always on then the PIR is boned

the flashing LED works when fed with a clean source of voltage and when fed with a pulsed voltage from the PIR stops working (it must confuse the LED circuit)

PM 2Ring said:

wookiemeister said:

ok LED works then it might mean that the PIR is boned or as suggested the circuit of the LED is playing havoc with the PIR or the PIR is boned and can’t provide power.

Please try to keep up, Wookie. :) As captain_spalding said a little earlier:

captain_spalding said:

Replaced the yellow flashing LED with a standard red LED. Same result – LED came on, and stayed on.

So my theory re the flashing LED circuit may still be relevant, but it looks like the PIR itself is the primary culprit.

hmmm I thought he said the flashing LED worked with a clean source

the PIR source (always on because its broken) is not a clean source it must be pulsed from 9VDC (the original source). the “dirty” voltage from the PIR plays havoc with the LED circuit s it remains ON

captain_spalding said:

PM 2Ring said:

wookiemeister said:

ok LED works then it might mean that the PIR is boned or as suggested the circuit of the LED is playing havoc with the PIR or the PIR is boned and can’t provide power.

Please try to keep up, Wookie. :) As captain_spalding said a little earlier:

captain_spalding said:

Replaced the yellow flashing LED with a standard red LED. Same result – LED came on, and stayed on.

So my theory re the flashing LED circuit may still be relevant, but it looks like the PIR itself is the primary culprit.

I do tend to agree, PM. Just shorted the PIR out of the circuit (by bridging between the posittve and centre pins on the PIR), and the flashing LED works fine with that. So, all my solder joints etc must be OK – It has to be the PIR.

PM 2Ring said:

If the PIR is like the one on this page it shouldn’t be too hard to adjust.

It’s just like the last images on the page, with the delay and sensitivity adjustments. But, tweaking those adjustments seems to have no effect on the situation.

I’ll start from scratch on the weekend, and see how it goes.

Thanks again, everyone

wookiemeister said:

captain_spalding said:

PM 2Ring said:

So my theory re the flashing LED circuit may still be relevant, but it looks like the PIR itself is the primary culprit.

I do tend to agree, PM. Just shorted the PIR out of the circuit (by bridging between the posittve and centre pins on the PIR), and the flashing LED works fine with that. So, all my solder joints etc must be OK – It has to be the PIR.

if you short the positive and the centre pin supplying the LED you then provide a clean source of voltage to the LED meaning that it suddenly starts flashing – as soon as the PIR source is used the flashing stops and it remains on

you’d think the PIR would smooth its output so it isn’t “dirty”

Great. I’m starting to program an Arduino myself, so now I know to come here for help.

Sure your sensor is not wired around backward.

mollwollfumble said:

Great. I’m starting to program an Arduino myself, so now I know to come here for help.

turns out he wasn’t using arduino just components you’d normally attach to it

>turns out he wasn’t using arduino just components you’d normally attach to it

so maybe needs a buffer/switching transistor and pull up or pull down resistors.

transition said:

>turns out he wasn’t using arduino just components you’d normally attach to it

so maybe needs a buffer/switching transistor and pull up or pull down resistors.

I was unable to find the circuit diagram of the entire pir, but IF the BISS0001 pir chip is unbuffered (ie its output is directly driving the `S’ pin on the connection pins)
then it may be that it is incapable of outputing enough current to drive the led flasher circuit inside the led (most require 50ma or more)

Absolute max. ratings
Description
Condition
Range
Unit
Supply voltage
—
3 ~ 5V
Input voltage
—
Vss-0.3~ Vdd+0.3V
Output current
Vdd=5V
10mA

Altho the link you gave to the pir board doesnt agree with the 10ma max either (if the led output from the pir on the breadboard is 5v, then a 330 ohm resister would allow 15mA to flow and if its 9v then its 27mA- both of which are above the 10mA limit of an unbuffered 0001 chip’s spec according to that page)

one way to tell for sure if its unbuffered is to measure from pin S on the 3 pin plug to pin 2 on the BISS0001 IC- 0 ohms is unbuffered, hi megaohms is buffered (this is with the pcb unpowered of course)