remote control operated switch for room light

[amritsen]

The output is not coming from pin no. 2 When pressing the button of the remote... and when pressing .. Red led just blinks once..

 

[Reloadron]

Look at the clock input to the counter (4017). Do you understand the circuits operation? You need to understand how the circuit is supposed to work.

Ron

 

[Les Jones]

First check that the TSOP1738 is recognising the infra red input from the remote control. Connect the positive of your multi meter to the +5 volt rail. Connect the negative lead to pin 3 of the TSOP1738. Without any buttons pressed on the remote control I would expect a reading close to zero volts. Point the remote control at the TSOP1738 and hold any button down. (This unit will not recognise any of the codes from the remote. It only recognises the presence of infra red pulses.) I would expect the meter to now read 0.6 to 0.7 volts. If these results are correct then move the negative meter lead to collector of T1. With no button pressed on the remote I would expect a reading close to 5 volts. with a button pressed I would expect a reading close to zero volts. Do these tests and report the results.

Edit.
I cannot see a link between pins 4 and 15 of the 4017 on your circuit. Also a picture from directly above the board would help.

Les.

 

[cowboybob]

Welcome to ETO, amritsen!

What is the signal on pin 14 (CLK) when you activate the IR remote?

 

[amritsen]

Yup .. tsop is OK .. when not pressing remote it shows 0.05v .. when pressing ..shows 0.5-0.6 V ....


Similarly .. @ t1.. shows 5 v when not pressing button ... and 0 v when pressing ...

But 0v only for a second .. after this again 5v ... that means it is not holding (might be )...

 

[amritsen]

OK cowboypop...
When not pressing - pin 14 shows 4.7 V and when pressing .. showing 0 v .. but only for 1 second .. after this again 5 v

 

[cowboybob]

OK cowboypop...
When not pressing - pin 14 shows 4.7 V and when pressing .. showing 0 v .. but only for 1 second .. after this again 5 v

Exact opposite of that needed.

When "not pressing", pin 14 should be at 0VDC (or very close to it).

 

[alec_t]

Did you have the black probe of your meter connected to ground (battery negative) when making those voltage measurements?

 

[amritsen]

No... positive 5v on red probe .. nd 14 pin .. black probe

 

[Les Jones]

Hi cowboybob and alec_t,
For the tests that I asked armitsen to make I had said to connect the + meter lead to + 5 volts. (This was to see the base emitter voltage of TR1 better.) I think he also took the readings that cowboybob requested with the meter connected that way. (It should still work even if the clock signal was inverted. The state change would then occur when the button was release rather than when it was pressed.) It looks like the remote is sending out the burst of pulses for 1 second but this should not stop it from working. The fact that the red LED blinks off suggests that the 4017 must be clocked out of state zero. I suspect that C1 may not be filtering out the code pulses properly. I do not like the design of the coupling between the IR receiver and T1. From the data sheet for the IR receiver the output is an NPN trnsistor between 0 volts (Emitter) and the output pin (Collector.) With a 80k (From memory ) pull up resistor to pin 2. There is nothing to limit the current when that transistor is turned on. It is trying to apply 5 volts across the base emitter junction of T1. I think a few extra resistors are needed to limit this current and to improve the filtering provided by C1.
armitsen, try pressing the button on the remote for a shorter time to see if it works sometimes. If you removed the link from pin 4 to pin 15 of the 4017 then you may be able to see how many pulses the 4017 is seeing. (Provided it is 9 or less.) With the link removed I would expect the red LED to stay off after most button pressed. when it is off you should be able to check which output from the 4017 is high.

Les.

 

[cowboybob]

... I suspect that C1 may not be filtering out the code pulses properly. I do not like the design of the coupling between the IR receiver and T1. ...

Les has a point. The data pulse stream generated by the remote may very well be over whelmng the 4017.

Do you intend to continue using the TV remote on a TV? If not, go into the remote you're using and disable the coding component of the unit. Basically, use it as a simple IR single pulse transmitter.

That, or wire up a simple, switched IR LED and test the circuit with that.

 

[Dr_Doggy]

HI, please elaborate why you do this, do you want to learn IR? AND do you want your switch to work with specific buttons and remotes, or do you want the lights to flicker every time it detects any signal?

I have heard types of lights themselves that cause false IR triggers.
I would use microcontroller to decode instead of counter. for more accuracy

the counter will work, but you need to tune it to toggle on the right number of counts for said button, ie on pin 2 counts every 3rd pulse, when a single press of button is more like 16 pulses, try a higher "decode output #"

 

[amritsen]

I want to submit a project before 1 Oct. . But .. it isn't working ..Dr.

 

[Dr_Doggy]

try a higher "decode output #", and it will toggle more slowly

 

[ChrisP58]

The output is not coming from pin no. 2 When pressing the button of the remote... and when pressing .. Red led just blinks once..

The red LED should be normally be ON. It should go OFF when the green LED goes ON and the relay trips.

But there is one thing that is missing in the schematic, and therefore, probably missing on you board.

All digital ics, including the CD4017 need a decoupling capacitor across their power supply pins. And it should be as close to the to pins 8 and 16 as possible. Anything from about 0.01u to 0.1u would be fine. Without this capacitor, the logic sequence is subject to false triggering from various noise sources, including self induced. It is quite possible that the spike from engaging the relay may be resetting the the signal that should be keeping it on.

 

[Gannu9]

One should also consider RC circuit at Clock pin of 4017, otherwise one button press of Remote control is counted multiple times and light will be on and off multiple times, this RC circuit remove the TSOP1738 oscillation and noise of circuit. I have faced that problem, then found solution in below articles, consider looking below circuits, they also demonstrated its working:
Remote Controlled Switch
Remote controlled Switch 2

 

[Mikebits]

I would think a 2N3702, 2N3906, BC557 or BC327 should work. While looking at the data on the TSOP1738 I noticed that the maximum output current rating is 5 mA There is nothing in your circuit to limit the output current. I would suggest adding a 1K resistor from pin 3 of the TSOP1738 to the junction of C1+ and the base of T1

Les.

Actually the tsop1738 has a 100k inside the part, I don't think the external resistor on pin 2 is needed.
https://www.google.com/url?sa=t&rct...6pyEnGvh7pIwG_ipw&sig2=VkZ-__1ozODDiAOI1lCwvw

 

[Mikebits]

I'm surprised that thing would work at all. R1 is way big, you will have very little collector current. The CD4013 only sources around 3ma, hardly adequate to drive the LED's.