Connecting a timer and a motor

[Justin2398]

can anybody explain to me what I would need to connect I timer to a motor so when the timer goes of to whatever it is set to the motor spins some small plastic gears and how I would go about that

 

[Justin2398]

Also the cheapest way of doing this

 

[Les Jones]

You could use a plug in timer and just plug the power supply that feeds the motor into the timer. If you really want it to behave as you describe (After the set time the motor starts and runs for ever.) the just setting the start time (On time.) and not setting the off time should work.

Les.

 

[Justin2398]

After the timer goes off I would like it to run for a couple of seconds stop for about twenty and then run in the opposite direction for a couple of seconds

 

[Les Jones]

That's a bit more of a specification but not complete. Is the initial time setting a time of day or a time from powering up the unit. Do you need to be able to adjust this time / delay. What sort of order of time is the initial delay or if it is a time of day is it less than 24 hours from the start or is it years from the start. Does the couple of seconds time need to be adjustable or is it a fixed value ? Does the "about 20 seconds" time need to be adjustable ? How accurate to the times need to be ?

Les.

 

[JimB]

Justin
Welcome to ETO.
Please in future use a more meaningful title than "Beginner", that tells nothing about what you wish to discuss.
As you can see, I have edit the thread title.

JimB
One of the ETO moderators.

 

[Justin2398]

The time is when started like say after fifteen minutes the motor would start and yes they are fixed times the run time is not as important as I could adjust what it is doing by the gears but the time it stops for should be 20 seconds

 

[Les Jones]

Hi Justin,
I think using a microcontroller and two single pole change over relays (Or an H bridge chip.) would be the cheapest solution but if you have no experience of programming there would be the time needed to learn how to program the microcontroller that you choose. To build it using normal ICs I would suggest using a CD4060 (Oscillator and 14 stage binary divider.) to generate a pulse every 2 seconds and then use three CD4017 (decimal counter / decoder.) to count these pulses. Use gates to decode a count of 450 (2 seconds x 450 = 900 seconds = 15 minutes.) The decode of 450 would be valid for 2 seconds which would drive the motor in one direction for 2 seconds. You would then have some more gates to decode a count of 461 (15 minutes + 2 seconds + 20 seconds.) This decode would be valid for 2 seconds and would drive the motor in the other direction for 2 seconds. Use more gates to decode a count of 462. The output of this gate would be used to inhibit the CD4060 so the count then stopped. There are many other ways to achieve this.

Les.

 

[Justin2398]

Wow ok seems a lot harder than I thought but I'm sure I can figure it out and it sounds like I have a lot to learn. Thanks for your help Les.

 

[AnalogKid]

A few more details - what is the power for the motor (12 Vdc, 120 Vac, etc.) and what is the current or power. This helps to define the output part of the timer.

Is this the pattern you are trying to achieve:

1. Apply power.
2. Nothing happens for 15 minutes.
3. Motor runs in one direction for 3 seconds.
4. Nothing happens for 20 seconds.
5. Motor runs in the other direction for 3 seconds.
6. Everything stops.

?

ak

 

[Justin2398]

Analog kid,
That is exactly what I want to do, but I want to be able to choose from different time intervals at step #2

 

[Les Jones]

Hi Justin,
You are still adding things to your specification. When you ask how to do something you need to specify EXACTLY what you need. My suggested way using 4000 series logic becomes very messy if you want to change the value of the "15 minutes" as all of the values decoded would have to change. Does the "15 minutes" need to be adjusable from 1 microsecond to a number of centuries with a resolution of one microsecond or better ? (I know these are probably silly numbers but they could be valid with the limited information.) You will probably need some way to display the set time delay and push buttons to increment and decrement the value. (You would need to display many digits in the silly example I gave.) If you did not need accurate adjustment you could just use a potentiometer with a scale or if you just needed a small number of discrete values you could nse a multi way switch. As AK says you also need to give some indication of the power supply and the power rating of the motor and it's type. (My suggestion of two changover relays or an H bridge chip would only be suitable for a permanent magnet DC motor.) In a lot of cases on this forum the hardest part of giving help is finding out what the question really is rather than working out a solution.

Les.

 

[AnalogKid]

There is nothing more easy to answer, or more difficult to create, than a decent question.

ak

 

[Justin2398]

Just a couple of time increments maybe 30 minute increments( 30, 60, 90, 120) and ya I would need some sort of buttons displayed to be able to choose from the different times or a switch

 

[Misterbenn]

If you want a quick solution with a smaller learning curve I suggest buying an arduino with a motor shield. With this the hardware will already be done for you and all you need to do is the trivial task of writing a delay script

 

[AnalogKid]

Everything you describe can be done in random logic, but it will take some fortitude to get through it. A 2 hour timer, starting with a 32 kHz watch crystal for reasonable accuracy, is 236 million clock ticks per period, or a 28 bit counter, 2 CMOS chips. Bringing out the time periods you describe means replacing the last 2 bits with a 4017 (1 chip) to get the 4 states. A rotary switch can select one and drive an LED, or another 4017 can drive selection logic (3 chips). Then comes the other three timers.

ak