cd4017 misfire periodically (remote control switch)

[khluise]

I have made a simple circuit to turn on a light switch using a ir receiver. Here i have used cd4017 decade counter and the clk pulse comes from the output of the ir receiver. When i press any button on the remote the state of the relay changes and the light turns on and off. But it does not stay at that state. After some times (5-10min some times 1-2 minutes) it automatically changes the state. I mean if it turned on the light pressing a button, it turned off after some times and then turn on after some times without pressing any button. I have tired to connect pin 13 with ground with a 560k resistor and a 100nf capacitor to stop the miss fire but it doesn't work. What can i do to solve this problem?

 

[KlausST]

Hi,

* no powers upply decoupling capacitor
* I expect the IR receiver to have GND, VCC and Signal_out ... seems not to be the case with your circuit.

***
Missing part values of R5 and IR_receiver makes detailed assistance impossible.

Klaus

 

[khluise]

Hi,

* no powers upply decoupling capacitor
* I expect the IR receiver to have GND, VCC and Signal_out ... seems not to be the case with your circuit.

***
Missing part values of R5 and IR_receiver makes detailed assistance impossible.

Klaus

value of R5 is 1k ohm. and the ir_receiver is a generic one i bought from the store i don't know the specifics where the pin_1 data, pin_2 is GND and pin_3 is vcc. Can you tell me more about the power supply decoupling capacitor?

 

[danadakk]

You should use a 1 - 10 uF electrolytic and a .1 uF ceramic disk right
at the power pins of the CD4017 for starters. How much current does
relay coil draw when on ?

 

[khluise]

You should use a 1 - 10 uF electrolytic and a .1 uF ceramic disk right
at the power pins of the CD4017 for starters. How much current does
relay coil draw when on ?

i have tried to add the decoupling capacitors but it didn't worked. by current you mean between the ac pin?

 

[barry]

value of R5 is 1k ohm. and the ir_receiver is a generic one i bought from the store i don't know the specifics where the pin_1 data, pin_2 is GND and pin_3 is vcc. Can you tell me more about the power supply decoupling capacitor?

Well, you've got two of the three pins shorted together.

How can you design a circuit for a sensor when you don't know anything about that sensor????

I don't know what a 'generic' IR receiver is. There are generic resistors, and generic capacitors, but a generic IR receiver?

 

[danadakk]

i have tried to add the decoupling capacitors but it didn't worked. by current you mean between the ac pin?

View attachment 193958

The caps to the Vdd and Vss pin. the electrolytic is polarity sensitive, + to Vdd, - to Vss, the ceramic
has no polarity limitations, just connect it between the same two pins.

I would recommend you do some youtube videos on construction, especially grounding. And mix signal
grounding techniques.

 

[khluise]

Well, you've got two of the three pins shorted together.

How can you design a circuit for a sensor when you don't know anything about that sensor????

I don't know what a 'generic' IR receiver is. There are generic resistors, and generic capacitors, but a generic IR receiver?

sorry i made a mistake while drawing the circuit diagram. Actually the middle pin of the ir receiver is connected to the negative of 5v dc.(picture added). And about ir sensor the seller couldn't tell me the model so i couldn't find the datasheet. i have tried it with a arduino, the (from the left) the 1st pin is for data when a button is pressed the received frequency is sent throught the 1st pin, and the 2nd is for ground and 3rd is for positive thats all i know

 

[khluise]

The caps to the Vdd and Vss pin. the electrolytic is polarity sensitive, + to Vdd, - to Vss, the ceramic
has no polarity limitations, just connect it between the same two pins.

I would recommend you do some youtube videos on construction, especially grounding. And mix signal
grounding techniques.

i have attached it with the right polarity in mind.


okay i will look more into it

 

[dick_freebird]

The 10uF B-E shunt cap is presumably for HF rejection,
but electrolytics (as shown) have lousy HF ESR (ESL
mostly, even worse). You'd be better off with some series
R and a better quality ceramic cap, for a RF filter.

If you set up a 'scope triggered off spurious output change,
single shot, while capturing the Q1 base signal, maybe you
can catch the spurious trigger pulse and do a job of tuning
the trap cutoff freq.

Similarly with the second filter stage, try series R addition
and may as well lose the 560K shunt resistor which helps
nothing.

 

[danadakk]

The caps to the Vdd and Vss pin. the electrolytic is polarity sensitive, + to Vdd, - to Vss, the ceramic
has no polarity limitations, just connect it between the same two pins.

I would recommend you do some youtube videos on construction, especially grounding. And mix signal
grounding techniques.

As you can see when current is first applied the cap has 0V across it, looks like
a dead short. But as it accumulates charge the V rises and the current starts dropping,
making its effective resistance/impedance rise.

Capacitive ESR versus types, the lower the ESR the more effective it is.

POSCAP is polymer electrolytic type....

 

[betwixt]

I see the operation of this schematic differently to other posters. I think it relies on the burst of IR pulses from the transmitter making C3 charge and discharge, seeing the envelope of the pulses rather than the data they carry. This clocks the counter via Q1. Q2 just provides a reset pulse to the counter as the power is applied.

If I am right, it will never be reliable for many reasons, the main one being C3 being connected directly across a digital output. Yes, it forms a low pass filter but at the expense of almost certainly overloading the IR sensor output. Similarly, the B-E of Q1 probably sinks more current than the sensor is designed to provide. Those sensors are not just photodiodes, they contain a carrier filter and pulse shaping circuit, providing a TTL level output corresponding to the data bits sent from the remote. It is also puzzling that it doesn't work on alternate pulses but every fourth one, otherwise the Q0 output of the counter would be used. It seems to rely on the remote repeating its code burst to produce more than one clock to the counter. It will always be prone to mis-triggering, that's why in a real IR remote control circuit there are protection bits in the data so it can't respond to random pick-up from the sensor.

Brian.