Help with using a PIR to trigger a NE555

Thread Starter

AllisonAmg

Joined May 18, 2020
71
Hi I am looking for help with a circuit design. I wish to trigger a NE555 with a PIR so that it lights a LED for either a predeterimend time (say 10 seconds) or is reset using a second PIR.

I have a circuit that uses 2 'push to make' switches, but i would like to use PIR's instead.
1591130045516.png
I would appreciate any help.

kindest
Allison
 

KeithWalker

Joined Jul 10, 2017
895
It will probably work but be aware that the module you show has very short range (1-6 cm ). It does not detect dark or rough surfaces well and is very sensitive to changes in ambient light. It all depends on what you plan on using it for.
Regards,
Keith
 

Bernard

Joined Aug 7, 2008
5,524
Do you know output polarity when PIR is activated ? If activated output is low then connect to pin 4, other PIR output needs to be inverted to be connected to pin 2. A logic inverter or NPN transistor
 

Bernard

Joined Aug 7, 2008
5,524
Object shown is 555 with 2 LEDs red & green , but looks like a reflective photo detector.
I misspoke, the picture is a IR reflective detector.
 
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ericgibbs

Joined Jan 29, 2010
10,040
hi Allison,
Are you sure that the module you posted is a PIR, it appears to have a IR Emitter and Detector Diode.
A PIR works on Passive Infra Red, ie; Warm body IR radiation, no active IR Emitter.
Post a link or datasheet for module so that we can check.
E
 

Thread Starter

AllisonAmg

Joined May 18, 2020
71
hi Allison,
Are you sure that the module you posted is a PIR, it appears to have a IR Emitter and Detector Diode.
A PIR works on Passive Infra Red, ie; Warm body IR radiation, no active IR Emitter.
Post a link or datasheet for module so that we can check.
E
Overview:
The sensor module has strong adaptability to ambient light, and has a pair of infrared emitting and receiving tubes. The transmitting tube emits infrared rays of a certain frequency. When the detecting direction encounters an obstacle (reflecting surface), the infrared rays are reflected and received by the receiving tube. After the comparator circuit processing, the green indicator light will be on, and the signal output interface will output a digital signal (a low level signal). The detection distance can be adjusted by the potentiometer knob. The effective distance range is 2~30cm, and the working voltage is 3.3V- 5V. The detection range of the sensor can be adjusted by potentiometer, with small interference, easy assembly, convenient use, etc. It can be widely used in many situations such as robot obstacle avoidance, obstacle avoidance trolley, pipeline counting and black and white line tracking.

Parameter:
1. When the module detects the obstacle signal in front, the green indicator on the board lights up, and the OUT port continuously outputs a low level signal. The detection distance of the module is 2~30cm, the detection angle is 35°, and the detection distance can pass. The potentiometer is adjusted, the potentiometer is adjusted clockwise, the detection distance is increased, and the potentiometer is adjusted counterclockwise to reduce the detection distance.
2. The sensor active infrared reflection detection, so the target's reflectivity and shape is the key to the detection distance. Among them, the black detection distance is the smallest and the white is the largest; the small area object has a small distance and the large area distance is large.
3. The sensor module output port OUT can be directly connected to the MCU IO port, or it can directly drive a 5V relay; connection mode: VCC-VCC; GND-GND; OUT-IO
4. The comparator uses LM393, the work is stable;
5. The module can be powered by a 3-5V DC power supply. When the power is turned on, the red power indicator lights up;
6. With 3mm screw holes for easy fixing and installation;
7. Circuit board size: 3.2CM * 1.4CM
8. Each module has adjusted the threshold voltage to the potentiometer through the potentiometer. For non-special cases, do not adjust the potentiometer at will.

Interface Description:
1. VCC external 3.3V-5V voltage (can be directly connected to 5v microcontroller and 3.3v microcontroller)
2. GND external GND
3. OUT small board digital output interface (0 and 1)

Package Includes:
1 × Obstacle Avoidance Sensor
 

ericgibbs

Joined Jan 29, 2010
10,040
hi Allison,
Your description shows that is is not a PIR, but a IR Emitter and Detector.
Are you able to add a couple of transistors the Signal output of the Detector, in order to drive the 555.?
E
 

ericgibbs

Joined Jan 29, 2010
10,040
hi A,
This is a Monostable example circuit, it shows RESET as a push button.
E

BTW: The components inside the dashed box are your IR module.
I have not shown the LED's,

Updated;
Complete circuit.
Note: The Reset pulse is shown for reference only, If you want to Reset before the 10Sec Time out, either Press the Manual Reset P/B or use the Second IR module output signal.
Ask if you have a query.
 

Attachments

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KeithWalker

Joined Jul 10, 2017
895
hi Allison,
Your description shows that is is not a PIR, but a IR Emitter and Detector.
Are you able to add a couple of transistors the Signal output of the Detector, in order to drive the 555.?
E
If you read the data that Allison posted you will see that the output of the module is capable of directly driving a relay. It does not need amplification to drive the inputs of a 555.
Keith
 

ericgibbs

Joined Jan 29, 2010
10,040
hi Keith,
My circuit does not have any amplification.?
Its a direct drive from his IR module, Low going.
E

Vset and Vreset Low on Active.
 

ericgibbs

Joined Jan 29, 2010
10,040
What does ????? mean, please be more explicit... ;)


Update:
If you do not understand the posted circuit, this is a simplified version.
AAA 375 10.26.gif
 
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