variable duty cycle dc motor timer 1

[robertlondon]

Can any one help with the design of a timer that would turn on a small DC motor for 1 minute, followed by a variable 20 - 40 minute rest period, to cycle continuously.
I am fully competent in building the building side, but the maths involved escapes me.
Thanks in anticipation.

 

[MacGyverS2000]

A 555 is probably the easiest solution...

 

[analogkid2digitalman]

There are off the shelf units to do so if interested, digital time delay cycle timers that have programmable on/off times and number of cycles to execute with the option of repeat indefinitely.

Wheels within wheels / In a spiral array
A pattern so grand / And complex
Time after time / We lose sight of the way
Our causes can't see / Their effects.

 

[robertlondon]

Thanks,analogkid2digitalman .
Any pointers to who, and how much?
Alternatively, would still be interested in just the circuit diagram.

 

[ScottyUK]

Robert,

Check out relays from the likes of Crouzet and Omron. Their multifunction timer relays have the functionality that you seek, and they may have a specific type which is cheaper and does exactly what you want without the other features.

Expect to pay about 70GBP or so. The economics really depends how you value your time building it against the ease ofa ready-made solution. 70GBP doesn't buy much development time at commercial rates.




----------------------------------

If we learn from our mistakes,
I'm getting a great education!

 

[amorrison]

Search "Google images" using - 555 "duty cycle"

About 30 schematics.

 

[analogkid2digitalman]

Macromatic TR-63xxx or TR-65xxx repeat cycle timers, about $90 from Newark

http://www.macromatic.com/literature/catalog/pdf/2003_Macromatic_Catalog.pdf.

Also came across an Amperite 12DF/FHDFA for about $55, also from Newark.

These may be overkill (handle up to 10A loads), just a suggestion if you need a minimum of hassle.

Good Luck

-Pete

Wheels within wheels / In a spiral array
A pattern so grand / And complex
Time after time / We lose sight of the way
Our causes can't see / Their effects.