{"id":2745,"date":"2016-04-21T14:49:08","date_gmt":"2016-04-21T21:49:08","guid":{"rendered":"https:\/\/www.circuitspecialists.com\/blog\/?p=2745"},"modified":"2016-04-22T09:40:43","modified_gmt":"2016-04-22T16:40:43","slug":"emergency-cell-phone-charger-circuit","status":"publish","type":"post","link":"https:\/\/www.circuitspecialists.com\/blog\/emergency-cell-phone-charger-circuit\/","title":{"rendered":"Emergency Stepper Motor Cell Phone Charger"},"content":{"rendered":"

Emergency Cell Phone Charger Using Stepper Motor<\/h3>\n

A stepper motor<\/a> may be used to recharge batteries in your cell phone to\u00a0allow a short emergency call should you find yourself in a remote area with a\u00a0dead cell phone. This short guide will walk you through building your own DIY Emergency Cell Phone Charger.\"out<\/p>\n

Although any DC motor would theoretically work in this\u00a0application, stepper motors are well suited for use as a generator due to the\u00a0small size and powerful magnets used.<\/p>\n

The circuit consists of the stepper motor outfitted with a crank handle to\u00a0allow the user to rotate the shaft with a minimal amount of effort.\u00a0The output\u00a0alternating current produced is then rectified by a bridge rectifier and large\u00a0electrolytic capacitors<\/a> are used to store the energy produced.<\/p>\n

An additional\u00a0concern is ensuring that the voltage is limited to 5 volts so as not to damage the cell\u00a0phones lithium ion battery.\u00a0This was accomplished with a low drop out 5 volt\u00a0linear voltage regulator<\/a>.<\/p>\n

Various motors were tested to determine the optimum size for this\u00a0application. We found the\u00a015.0 kg-cm 6 Wire NEMA 23 Step Motor<\/a>\u00a0to be ideal for this project.<\/p>\n

Although the largest size motor would produce he maximum\u00a0amount of energy, the system could get unwieldy and may require an\u00a0excessive amount of effort to turn the crank.<\/p>\n

\"emergency<\/p>\n

 <\/p>\n

The schematic diagram of the cell phone charger\u00a0can be seen below.\u00a0\"emergency<\/a>The unit was constructed on a perfboard<\/a>\u00a0and was tested to get a feel for how much effort would be required to charge\u00a0the battery enough to make a short emergency phone call.\"emergency<\/h4>\n

It was noted that\u00a0several minutes of \u201ccrank\u201d time was sufficient to allow a short phone call.<\/p>\n