I'm working on a little invention. I have a small 5 volt computer fan. It will run off 3 triple A batteries. To conserve energy I need it to only turn on for 1 minute every hour or something close. Lastly the timer/controller needs to be really cheap and really small (no bigger than the size of a AAA Battery). Does any one have an idea what type of "Timer" or "Controller" need? Where I might get one?

Thank you,
Brett

 

Check post by JPK777. If you want it small, use surface mount parts. Would need more decoding or a 555

 

I'd go with a 4060 on this one, but you'll need transistors to drive it.

How much electronics background do you have?

 

This would seem to me to be an ideal application one of the smaller micro-controllers like one of PIC10F series (SMD 6pin SOT-23 package).
The PIC would need no support components other than maybe a transistor/FET to drive the fan and one bypass capacitor.
It could spend most of its time asleep thereby consuming very little power (somewhere in the order of 10 to 100 of microwatts) while not actually running the fan.

 

Yes you should try a small PIC unit. Even for a hobbyist the investemnt needed for starting development are small. You may pic up cheap programmers on Ebay also. I will recomend PICKIT 2 Starter Kit.

 

Go for a CD4060 with long delay circuit. Will consume abt 5uA. That would be the cheapest idea for you as well as quickest. The size will be abt of a AAA battery, provided you solder it closely packed.

 

Thank you for all your help. This is amazing. I don't have much electrical engineering experience. Will all of these options require programing?

 

How would a 4060 work in this situation? Don't all outputs have a 50% duty cycle? The OP is looking for ~1/60. Also, would the CD4541 be simpler because it has an internal reset, or doesn't it have the right functionality?

 

Either should work by adding a 555 for the 1 min; 4060 can also giva approx 1 min. [ 56.2 sec] by decoding 9th-14th stages. Would be helpfull to know fan current. Timing components approx. 1M,470k & .1uF

 

for decoding 4060 use 3X3 in AND[ if there is such], 6 inputs,8192,4096,2048,1024,512,256=1 min.+_.

 

I think 555 with a PNP transistor to drive the fan would do teh trick. Compoenet 555, 3 -4 resistors a couple of capacitors, and you should be up and running..

 

007, have you measured leakage of a 3600 uF cap? I am rght now measuring a 3000 uF cap @ 25V and it is holding @ infinity, but at the same time its charging with a 9 V battery in series with 470k, afraid a 1M timing resistor would be swamped; back to drawing board. One 555 for an hour, but would need another for the minute.Hang in there, we need all the help we can get.

 

Woops!!, stage 11 is not available, would give two 1 min pulses at end of each hr., adding stage 8 [128 ], would give two 1/2 min, 3 min. apart, pulses /hr-OK? CD4073 3 X 3 in AND.

 

Thank you for all your help. This is amazing. I don't have much electrical engineering experience. Will all of these options require programing?

Only the micro-controller solution involves any programming so it may not suit you, but if you have any familiarity with micro-controllers (or don't mind learning) then it is the simplest and most efficient way meet your requirements of small size and very low battery drain.

 

One min on, 59 off. PNP output transistor selection depends on motor requirements as does R3. All subject to review.