Making a pager motor pulsate on/off @ 1-2sec using 1.5-3V

[chewy]

I need the smallest solution to enable a tiny motor to go on for about a sec then off for about a sec or two, how can i do this in the most simple way with a very very small space, a 555 timer is just too big. Can i use a crystal or oscillator and how so?
Please help

 

[Scubasteve]

It would be best for you to use the 555 timer for this.. I believe you can get it in a tiny package and then just use surface mount, you need to use a transistor to buffer the load.

Steve

 

[mstechca]

Try this:

Make an astable multivibrator using two transistors and then take the output of the multivibrator and feed it through the base of another (output) transistor. The collector (of the output transistor) goes to the +ve power supply and the emitter, to the motor and the motor to the -ve.

Since you are tight on space, If you can, try to find small resistors (usually found on hard drives) that look like squares. They are about 5mm by 5mm. If that is too small, you can use the standard 1/4 watt resistor and have it stand up so that you only use about 5mm board space instead of 1cm when the resistor is laid down.

Most people use electroylic (<- fix my spelling) capacitors for flip flops of your requested speed, but you can get away with a resistor of a few megs and a capacitor of about 1nf. Use the equation 0.7 * r (in ohms) * c (in farads) to find out waiting times.

How much space do you have? It can't get much easier than that.