countdown timer for pump

[miatawnt2b]

This idea is not a difficult circuit. In fact there are kits all over the place to do exactly what you want. A very quick search turned up this.

http://mpja.com/productview.asp?product=6085+KT

Look at the second kit. I'm sure with a little more searching you can buy a kit exactly like the second one listed here for under $10.

-J

 

[miatawnt2b]

My guess is these 3 kits are Velleman.

 

[Randall_James]

I just took a regular appliance timer with the off/on pins and removed all the "Off" ones. "On" pins go every 3 or 4 hours. I use the rotary wheel on the side to kill the pumps and if I forget to turn them on, the "on" pin will be by soon enough

Costs: $8.99

 

[mcurl98]

I did the mod and am happy with it. IMO, the contacts look pretty heavy duty but I wouldn't mind trying a "stock" version. Rick S points out what you need-Intermatic FF32H-or any of their SPDT versions. I have no idea what this means but SPDT allows you to hook it up to do a reverse action-to turn the pump off when you turn the timer. Here they are on Intermatic's site.

http://www.intermatic.com/Default.asp?action=subcat&sid=96&cid=53&did=5

I am going to try one and ordered it from

http://www.electricsuppliesonline.com/infd3.html

they cost twice as much as the non spdt types but might be worth it. I am also going to see if I can switch the 2 hour mechanism with my half hour one. I prefer a half hour dial. Seems like it would work as the whole timer part of the mechanism just lifts out of the timer as a complete unit.

 

[rick s]

mistake. deleted.

 

[BeanAnimal]

I have PIC micro version, as well as one based on a simple 555 timer. Neither ever made it off of the breadboard, but both work just fine. Maybe one day when I have time...

 

[cloudjockey]

I did the count down timer thing about 1/2 year ago. It worked well for about 8 months. I feed my fish one night and went upstairs (expecting the timmer to turn things back on). I got busy the next day and forgot to check my tank. Two days later all my fish dead (about 600.00 worth). I now check my tank twice a day and would never use a "wall timer" from a hardware store. The replays in them are just to small.

 

[Tunjee]

I made a compact plug in version. Used a handy box with a single recep in it. Within the box I wired in a delay on break solid state sensing relay, push button momentary contact switch and an external adjustable knob to change the time from 0 to 15min delay back on. Out of the top of the box is a male plug.

It works great. Here's the relay. It's good for 1.5amps. My pump is less than an amp.
http://www.icmcontrols.com/products/product.php?prod_pk=87