[nilu_2005]

i am building this project which i found from poptronicx.

Pdf file attach with this topic. I found error on main ultrasonic motion detector pcb.
The error is like this. When i give supply to circuit with 9 volt battery, LED will start glowing indefinitely. At first i think it was motion detected by ultrasonic thats why led is glowing. I first remove ultrasonic TX and RX from pcb and try again. Same error. Led still glowing without ultrasonic TX and RX. Actually LED should only glow when there is motion oocur. But without ultrasonic pair it is still glowing. I tried out everything i could to overcome this problem but unable to resolve problem.

If you found answer for this technical problem, please let me know.

Note: There is only one LED in this circuit. Actually i am trying to create project which will automatically switch on power supply when motion is detected and vice versa. I will add movie file as soon possible for better demostration of error.

 

[audioguru2]

Hi Nilu,
Welcome to our forum. ;D
Pin 8 of the LM324 is supposed to be near 0V without a signal. Measure it.
The value of R14 is pretty high at 1M. If the bias current of your LM324 is at its max limit of 0.5uA then it will cause the output pin 14 of the LM324 to go high which will turn on the LED.
Replace the LM324 and hope you get one with a lower input bias current.

 

[nilu_2005]

thx for reply.There is no problem with LM324 IC.  I just used multicim software to simulate as per your given digram. and it simulate this time properly. When i removed C8,D4,R18 from circuit and run simulation again. LED blink only this time when there is clock  i/p signal at R3.

I do have question though ask, in multicim i used clock i/p at R3 in the place of BZ1 receiver. Actually i wanna know what is the signal available at Receiver (Ultrasonic Rx)
Whether it is amplitude vtg variation because of motion detection (Sine wave or square wave)? So i can decide what i/p simulation i enter in my circuit in multicim, because multicim don't have sensor component available. And i allready designed the pcb and soldered it also. So, will circuit work when i actually place again ultrasonic Tx & Rx without damaging much to the PCB.

 

[audioguru2]

If your LM324 has a low input bias current and the sensors are close enough together then the receiving sensor will pick up amplitude variations of the reflected ultrasonic signal from something that is moving.

I think a PIR infrared motion sensor will be much more sensitive and therefore will have a farther range.

 

[nilu_2005]

I tried out the pcb with ultrasonic sonic Tx and Rx. This time LED doesn't glow when there is motion in front of ultrasonic pair. How do i check whether the ultrasonic sensor pair  is working correctly?

Actually due to part unavailability i used 32 Khz crystal instead of 40 Khz. Is because of this i got error again.

I think whole circuit is faulty. Do you know circuit for ultrasonic motion detector which is error free and can be build quikly? Please if you know let me know.
And Very thanks for your previous reply.

Note: Attachment contain image of 40 Khz matched ultrasonic sensor that i used in my circuit.

 

[audioguru2]

You used the wrong crystal frequency.
Does the 40kHz ultrasonic transmitter have any output at only 32kHz?
Does the 40kHz ultrasonic receiver receive anything at only 32kHz?

Do you use water instead of gasoline to power your car?
Do you add gasoline instead of water to a car's battery?

Maybe the ultrasonic circuit is faulty. I have seen many infrared PIR motion detectors that work very well.

 

[nilu_2005]

Ok, i will change crystal and install 40khz crystal and run the circuit again.
One think to ask i check the pcb layout. I found that Transistor (Q1) BC639 are not layout properlly on pcb because when i saw the component side, it connect base to led and collector to pin 14 of Lm324. which is actually wrong. (Attachment included) this should in vice versa.

 

[audioguru2]

If you showed the component side of the pcb then the BC639 is correct.

 

[nilu_2005]

I didn't get 40 khz crystal from our local electronics store. They said that i should use
4 Mhz crystal with divide by ten counter to reduce it's frequency to 40 Khz. I ask them how to do it but they don't know how to do it. So if you know how divide by ten counter (IC) is used to down the frequency of crystal from 4 Mhz to 40 khz please post it here so i will use it in my circuit.

Thanks in advance !

 

[audioguru2]

Use a CD4060oscillator/divider IC. It can't oscillate as high as 4MHz and it divides the frequency in binary instead of by 10, but if you can get a crystal frequency of 2.56MHz,or 1.28MHz it will produce 40kHz.

 

[nilu_2005]

Thx, first i have to find 2.56mhz or 1.28mhz crystal. If it is available i will give it try and see what frequency i got at output. Currentally i found method to down frequency from 4 Mhz to 40 Khz using two 7490  (divide by10*10) ic. I made simulation in multisim to check whether i am right or not. It gave 40 Khz output at o/p of ic2 when i applied 4 Mhz input to first ic. What do you think about this circuit ? Whether this will work practically.  Because my project partner just bought these circuit parts from our local electronic store. Please reply, your opinion always great help to me.

I just attach simulation image please check it.

 

[nilu_2005]

Please "audioguru", I need answer from you. Waiting for yor answer. and also please check my post at "Inventive/New Ideas" . If you know anything please do reply !

 

[audioguru2]

Sorry, I haven't used old 74xx TTL logic ICs for many years. I used to have a TTL Cookbook that was very useful for connecting those very old ICs.
The 7490 is probably explained on the internet.

I have used CD4000 series Cmos and 74HCxx high speed Cmos ever since. They have dual divide by 10 IC (CD4518) that divides by 100 in a single IC.

 

[nilu_2005]

can you show the circuit(CD4000) to divide 2.56 Mhz or 1.28 frequency to get 40 Khz frequency at o/p?
Beacause i don't have application circuit for CD4000.

And thx reply ! 

Note: Please read my topic at Inventive Ideas about designing motion capture system.

 

[audioguru2]

Go to www.datasheetarchive.com and get the datasheet for the CD4060 oscillator/counter.
Connect a 2.56MHz crystal in its oscillator and take 40kHz from its divide by 64 output.
Or use a 1.28MHz crystal and get 40kHz from its divide by 32 output.

The CD4000 is a series of hundreds of Cmos logic ICs. CD4000, CD4001, CD4002 etc. They use a supply voltage from 3V to 18V that doen't need to be regulated at 5V like old TTL ICs. Cmos logic ICs use an extremely low supply current.

 

[nilu_2005]

I just used 7490 to down the frequency from  4 mhz to 40 khz and gave it to trasmitter
transmitter section. When i give battery supply of 9 volt to circuit it again always on the LED. Giving an o/p of 7.7 volt continuously. Make some motion in front of sensor and still it shows o/p of 7.7 volt at signal out. Because this voltage is not sufficient to drive 9 volt relay thats why i can't able run external circuit when motion is detected.

Conclusion: 1) Circuit is faulty or 2) May be I did some mistake again.

Hello "audioguru", if you know any PIR motion circuit which is 100% working, please post the circuit diagram of that PIR motion detector circuit with parts list. I just have 20 more days to submit my project to my college. If you find anything useful for me please let me know.

 

[audioguru2]

I don't know if the pins on the BD639 transistor are connected backwards.
I don't know if your old 7490 counters have a supply bypass capacitor and a regulated 5V supply.

The circuit doesn't have enough power to drive a relay unless the transistor has very high gain, but most don't. Change the value of the 10k base resistor R19 to 330 ohms then the transistor will be able to turn on a pretty big relay.
Here is the voltage measurement when the circuit detects motion and the transistor turns on:

 

[nilu_2005]

i try that also, same problem, LED still glowing with 7.7 volt signal o/p even without sensor or with sensor.

Please suggest any PIR motion detector circuit(100% working) with parts list.

 

[audioguru2]

The output must be low for the LED to light. Your output is not low, it is high so something is wired wrong.

The collector of the transistor must go down to 1.8V less than the 9V supply for the LED to be very dim. The collector must go down to 0.2V for the LED to be bright and for the relay to be active. It should be connected like this.

I have never looked for a PIR motion detector circuit. Google probably has lots of them.