Hi all,

I'm new to the site and am aware there are altready other threads on Traffic Lights - but I'm looking to make mine a little different!

As part of my course, I am required to create and adapt a circuit. I have chosen to create a traffic light circuit, and adapt it by adding buzzers, so that when each light is illuminated, a separate buzzer also sounds. Also, if anyone else has any other ideas as to what I could add then I am open to new ideas!

Basically, I have the circuit, and can upload an image if required. It is pretty much the same as the Circuit Wizard sample circuit (if anyone is familiar with it).

All I would like to know is, how can I add the buzzers to it, and also any other component ideas if anyoen has them.

Thanks

 

could you not just wire a buzzer in parallel with the bulb so when the bulb is on the buzzer buzzes until the light goes off.

What kind of voltages are you working with?

 

Okay so here is what I have so far (the input voltage should be 9V):

(Alternate link: http://tinypic.com/r/28khjyc/6)

No matter what I do, the buzzer does not function in parallel or series. Any ideas>

 

What voltage are the LEDs running at, and what voltage are the buzzers your using?

 

I'm not sure what voltage the LED's are at, but the buzzers are 3V, but can be either 6V or 12V. I've been told I may need to include an operational amplifier?

 

LEDs should be 3V. I don't think you need an op-amp, but where were they suggesting you use it?

The buzzers should buzz if you connect the positive lead "above" the resistor and the negative lead "below" the LED, as shown on the diagram.

 

I'm not too sure, above the resistor I think.
I've just tried that, the simulation still doesn't work. The LED doesn't power on either when it is supposed to, which suggests that it is a power issue?

 

an op-amp for each LED?? if that's the case then the voltage from the IC probably isn't enough to light the LED.

I haven't built this circuit, so I just figured adding the buzzer in should work, but it's hard to figure out what to do when you don't know the voltages.

where did you get the diagram?

 

I got the diagram from the sample circuits on circuit wizard and recreated it myself. Would it be possible for me to send it you?

 

I use multisim, but I'll see if I can simulate there in about 30 mins.

I'm curious myself now.

 

Thanks very much - your help is much appreciated!

It's bugging me too!

 

Anyway to show the 74LS190 pin numbers?

 

I just noticed that you don't seem to have power going to the VCC pin on the 74LS190...perhaps thats the problem.

 

I can't get it to simulate in multisim either, but I could have the pins connected wrong. I need to know which pins on the 74LS190 are which number....the labels are different in multisim.

 

I'm not 100% sure either. What do you need me to provide?

Thanks

 

I guess I could check the datasheet....*facepalm*

But as it turns out there seems to be 5V at each of the LEDs, and it does seem to be triggering them correctly, but the LEDs just aren't coming on.

 

Yeah you appear to be getting the same result as me. I just can't understand why though...

 

I was mistaken, I used the wrong LED, it works fine.
I used a basic 555 in my circuit, with a 1Hz frequency, and the lights are working ok.

I would say the reason it isn't simulating for you is because there is no power or ground connected to your 74LS190.

 

L1 - L2 - L4 - L8 are tied to ground( 0V)

How are Q1 - Q2 - Q4 - Q8 supposed to change?

Edit: Never mind I didn't catch that it was a 'counter'

 

Ok thanks for the help. So where do you recommend I amend the circuit?

(Sorry I'm a little new to this)

Or if you could provide me with an image, that would be helpful, thanks!