Aladin, so far as i do know desktop technological know-how help speaker of mobile phones are not configured with regard programming help floor, therefore it could produce erratic outcomes when attached with desktop technological know-how help above circuit, basically it may even harm your cellphone in desktop science help procedure, it’s why I advised desktop science help use of an optocoupler. hi mr Swagatami would like programming help exchange computing device science help headphone with a sign from de phone speaker, with full amount i can get around 1. 2 volt with a digital multimeter, i can also get a 2. 5 volt dc from de vibrator output however it will trigger for all calls, what minimal amplification stage do i need, is desktop technological know-how help coil essential in this case. i realy need your helpthanksHi Aladin, computer technology help input should be referenced with ground, only then it is going to work, or in all probability you can try using an optocoupler in between computer science help speaker output and computing device science help handle circuit input for desktop technological know-how help triggering. Hi siri assembled computing device science help circuit for lots time however it doesnt work.