I need to design a as simple as I can Multiple delay on circuit.

[toxsick]

Hi.

Been a while since ive been here, hehehe

I hope I can get a little help.

I wish to create a circuit which will turn a few outputs.. (these outputs will be safety items like overheat circuits and light detection circuits)

I am going to want to have it turn on solenoids right away, via direct feed to the input voltage. Then Some outputs will be on delay via relays.
(these delayed circuits dont want to be on as the start as it will force a shutdown of the solenoid)

12v will be the input voltage.

I assume a simple way would be to use capacitors, transistors and resistors.
I wouldnt know where to start with what transistor model to buy..
I have a kit of capacitors so I can trial and error delay times via try nd replace model Ive adopted to.. Hhahah

I am very unfamiliar with the method of how the capacitors delay a transistor while charging the capacitor.

If you can help me to design a simple diagram of how to accomplish this, id really appreciate the help!

Ty,
Shaun.

 

[JimB]

Hello Shaun,

It would be useful if you could give us an idea about how long a delay you need, less than 1 second, between 1 and 10 seconds, a minute or more.

Also, rather that just using resitor/capacitor/transistor, it may be better and more repeatable if you used a timer such as a 555.
The 555 and a few resistors and capacitors will allow you to define the timing quite well.

JimB

 

[alec_t]

Will the same delay apply to all delayed switch-on relays, or will they have individual delays?
Does the/each delay need to be adjustable?
How accurate/repeatable does the delay need to be?
How will the relays be switched off after their delayed switch-on?
Have you considered using semiconductor switches instead of relays?

 

[toxsick]

The delay needs to be between 10 and 20 seconds

Would be nice to have maybe 2 to 3 relay delays which do operate at different times..

Accuracy is not important.. 2-4 seconds of accuracy is not a concern

The 555 might be an issue due to pcb creation.. Id rather stick to easy as possible and least components to be used.

No need for adjustable delay

Switch off will be via input power being cut.

Im also considering a autostarting system. Like a high voltage spark to ignate the gas. Like a cheap coilpack and a sparkplug for example.
So would need to have a circuit which sparks maybe every 0.5sec for upto 5 seconds...
This is something I am thinking of...

 

[Nigel Goodwin]

The delay needs to be between 10 and 20 seconds

Would be nice to have maybe 2 to 3 relay delays which do operate at different times..

Accuracy is not important.. 2-4 seconds of accuracy is not a concern

The 555 might be an issue due to pcb creation.. Id rather stick to easy as possible and least components to be used.

Simplest, cheapest, and most effective method would be to use a PIC - you just need a minimum of programming to do what you looking for.

An extra advantage is that it's easily changeable (in a matter of seconds) to alter the way it works.

 

[JimB]

Simplest, cheapest, and most effective method would be to use a PIC - you just need a minimum of programming to do what you looking for.

True...

BUT...

The OP lacks experience in very basic electronics, never mind PICs and programming.

All depends if he wants to just make a delay, or wants to embark on an adventure learning PIC programming.

JimB

 

[toxsick]

Pic program would seem very cool but would venture into it later if want advance my project.

Trying to keep costs low..

 

[alec_t]

The 555 might be an issue due to pcb creation.

You don't have to make a pcb. You could use Veroboard (strip-board) for the project.

a high voltage spark to ignate the gas

Now I'm worried . There are safety issues involving gas. If you don't have the knowledge to design and build your circuit, how will you ensure the circuit remains reliable?

 

[Nigel Goodwin]

Pic program would seem very cool but would venture into it later if want advance my project.

Trying to keep costs low..

And a PIC would be VERY low cost

You could even avoid the (fairly low) cost of a PIC programmer by using a PICAXE - which is an easy to use PIC preprogrammed with a BASIC interpreter, often used in schools as they are so easy to use.

 

[AnalogKid]

What is this for??? Your descriptions are incomplete, confusing, and keep changing. Please make a sketch of a block diagram showing the time delay stages, solenoids, and any control signals to give us an idea of the overall plan. What power is available for the timing circuit? What is the power source for the solenoids? What is the current in each solenoid?

ak