On 2012-11-26, at 2:40 PM, Bruce N <[email protected]> wrote: > This is very close to what I am looking for but it needs, *"**12 volt DC > power supply with a current rating of 500mA". *The best I can give is a 9V > battery, 4 AA batteries, or some lithium ion battery and I want it to last > few weeks if not few months. I wonder if an old Nokia phone can turn a > stepper or servo just like it does to a vibrator?
You can certainly do this with an old phone. You'll need a bit of electronics, but it's pretty light. Basically you want an output to drive a motor for 'x' seconds/minutes/hours when an SMS is received. The phone will drive the stepper motor for a brief period, and maybe in a weird way (to give you different vibrate cadences). The idea is to catch when it starts vibrating and latch the output for as long as you need. This is called a monostable multivibrator or a one-shot timer. You can make them out of a 555 timer IC, a few transistors or dedicated ICs. Hell you could make it out of an Arduino if you want to get on Hackaday. :-) http://www.circuitstoday.com/555-timer-as-monostable-multivibrator is a very basic circuit and with the CMOS version of the 555, you could run it off the phone's battery or the 9V. It sounds like your motor isn't too big, so you can likely run with a generic NPN transistor or mosfet, and the whole thing should fit easily in the space that 4 AA batteries would take up. That should be enough to get you started on the right track. Feel free to contact me off-list if you need more help. -A. --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
