Maker Pro
Maker Pro

Clap switch confusion!

ObviousOllie

Feb 15, 2017
5
Joined
Feb 15, 2017
Messages
5
I have a clap switch project for my college, I have meticulously looked over the diagram and alas nothing has come of it. I shall need some assistance from whomever sees this, I would be grateful. Thanks... DSC_0018.JPG DSC_0017.JPG Clap-Switch-Circuit-Diagram1.jpg
 

duke37

Jan 9, 2011
5,364
Joined
Jan 9, 2011
Messages
5,364
What is wrong?
You need diodes across the relay coils to protect T2, T3 and T4 from induced voltages.

Have you got it wired correctly I do not see R7, R8 and R9. Not that it matters. There seems to be many connections from T2,T3 and T4 to +5V. Are you putting too much current through the transistors?
 

ObviousOllie

Feb 15, 2017
5
Joined
Feb 15, 2017
Messages
5
What is wrong?
You need diodes across the relay coils to protect T2, T3 and T4 from induced voltages.

Have you got it wired correctly I do not see R7, R8 and R9. Not that it matters. There seems to be many connections from T2,T3 and T4 to +5V. Are you putting too much current through the transistors?

I removed r7 r8 and r9 along with the relays because I'm not using mains access and the resistora don't do anything vital.
 

duke37

Jan 9, 2011
5,364
Joined
Jan 9, 2011
Messages
5,364
You have not said what is wrong.:rolleyes:
If nothing works, then split the circuit between the chips and check the stages individually.
Do you have enough voltage? 5V into the 4017 will give less than this out, check the data. There will be 0.6V lost in the transistor, you have not said what voltage the leds need.
 

ObviousOllie

Feb 15, 2017
5
Joined
Feb 15, 2017
Messages
5
You have not said what is wrong.:rolleyes:
If nothing works, then split the circuit between the chips and check the stages individually.
Do you have enough voltage? 5V into the 4017 will give less than this out, check the data. There will be 0.6V lost in the transistor, you have not said what voltage the leds need.
The LEDs need around 5v to function but will still light at less. I don't know what it wrong with it but obviously when I clap, nothing happens
 

AnalogKid

Jun 10, 2015
2,884
Joined
Jun 10, 2015
Messages
2,884
1. There is no decoupling of anything anywhere. Add a 100 uF electrolytic and 0.1 uF ceramic in parallel across the two power rails where the red and black wires enter. Add a 0.1 uF ceramic cap across IC1 pins 1 and 8 and IC2 pins 8 and 16.

2. Disconnect IC1 pin 3 from IC2. Add an LED and 220 ohm resistor in series from IC1 pin 3 to GND. Clap. Observe. Report. If the LED does not flash, the problem is in the 555 circuit. Debug.

3. If the 555 circuit is working, reconnect it to IC2, remove T2, T3, And T4, and connect the cathodes of the three LEDs to GND. This should show if the counter is advancing.

I removed r7 r8 and r9 along with the relays because I'm not using mains access and the resistora don't do anything vital.

Given that the circuit does not work and you can't figure it out, I don't think you are in a position to proclaim what is and is not vital. They prevent IC2 from burning up due to overcurrent stress of the output transistors. What is the forward conduction voltage (Vf) of the LEDs?

ak
 

ObviousOllie

Feb 15, 2017
5
Joined
Feb 15, 2017
Messages
5
1. There is no decoupling of anything anywhere. Add a 100 uF electrolytic and 0.1 uF ceramic in parallel across the two power rails where the red and black wires enter. Add a 0.1 uF ceramic cap across IC1 pins 1 and 8 and IC2 pins 8 and 16.

2. Disconnect IC1 pin 3 from IC2. Add an LED and 220 ohm resistor in series from IC1 pin 3 to GND. Clap. Observe. Report. If the LED does not flash, the problem is in the 555 circuit. Debug.

3. If the 555 circuit is working, reconnect it to IC2, remove T2, T3, And T4, and connect the cathodes of the three LEDs to GND. This should show if the counter is advancing.



Given that the circuit does not work and you can't figure it out, I don't think you are in a position to proclaim what is and is not vital. They prevent IC2 from burning up due to overcurrent stress of the output transistors. What is the forward conduction voltage (Vf) of the LEDs?

ak
I don't know vf of the leds, the box just describes "white LED"
I am extremely new to electronics. The course literally throws us into a project where they haven't taught us timers or counters yet, I've tried my best to find out how to use them but it's very confusing...
 

AnalogKid

Jun 10, 2015
2,884
Joined
Jun 10, 2015
Messages
2,884
In a quiet room, look at the collector of T1 and report its voltage. Hopefully it is sitting near 5 V.

ak
 

davenn

Moderator
Sep 5, 2009
14,254
Joined
Sep 5, 2009
Messages
14,254
The LEDs need around 5v to function but will still light at less. I don't know what it wrong with it but obviously when I clap, nothing happens

The LEDs shouldn't be in the Base cct of the transistors .... they wont work there
 

AnalogKid

Jun 10, 2015
2,884
Joined
Jun 10, 2015
Messages
2,884
A 4017 can make 4 mA, granted at a sagging Vout. That should be enough to see something if the diode Vf isn't too high. I'd change to a standard little green LED and reduce the base resistors.

ak
 
Top