Thread: Need help with 555 timer.

Tweet

Need help building and connecting a 555 timer chip. I think I have everything except the relay. Also saw this in another thread will this work for rapid fire?


Adjustable Timer With Relays Output

What kind of help are you looking for?

Is this all I need or is there more? I have a bread board, 100k 1/2 watt risistors,8 pin 555cn chip,100uf electrlytic capacitor and wire. Also not sure what kind of relay and how to connect it. Thanks

Relay Timer Circuit

The following circuit is a simple timer circuit for operating a 12V relay. With the parts specified it will have an on time duration of 0 to about 60 seconds. Using a different capacitor for C1 will change the maximum on time. The timer can be triggered by a simple switch across the trigger points or connect an NPN transistor to the trigger points to allow a motion detector or logic voltage or another circuit to trigger the timer (see Fig.1 for an example of a motion detector trigger).

The link you posted is a timer board that constantly cycles. That is fine if you want a prop that you plug in and it runs all night.

As far as your 555 circuit, you need to decide if you want astable or monostable.

Astable as in the link cycles repeatedly.

Monostable can be triggered and then outputs a pulse (one-shot).

See the following site for more information:

555 timer

the relay connects to the board? then the Solenoid Valve connects to the relay? Is that right?

Actually, I think this is a monostable circuit. There might be a problem with using a 470uF cap at C1 - it may not allow the 555 to reset, especially with pin 4 connected to Vcc. I'd change that cap to a 220uF and up the value of VR1. Also, pin 5 needs to have a 0.1uF cap connected to ground.

Thanks otaku where does the output connect?like my solenoid

The solenoid would be connected to the Normally Open and Common pins of the relay. The power supply for the solenoid is wired in series with the solenoid. I think I have a wiring diagram for this type of application on my machine at work. Drop me a PM with your email and I'll send it to you.