Hello everyone!
I wanted to control a bluetooth MP3 player with arduino nano along with a 7 segment display to make a digital alarm clock, which can also work as a portable bluetooth speaker.When I switch on the MP3,it starts playing from a flash drive in a second.So,at the time of alarm,arduino would switch ON the MP3.
At first,Itried to use a transistor to control the power to MP3, but the transistor itself has some potential drop and the the MP3 is not able to get the required power.The sound of the speaker becomes fuzzy and noisy, and MP3 just keeps restarting at bass music.However, it sounds superb even at highest volume when I connect it to the battery directly.
I had some transistors to test with,of which only the BD139 was even able to switch it on.
I also tried to work with a relay,but since it's a coil,again the MP3 was struggling for power.
The battery is 3.8volts 2300mah(yes it's a smartphone battery)
It can easily run all of the components for a quite long time.
According to me, I can't use any sort of constantly power consuming switching circuit. So, I was just wondering if there are any electromachenical toggle switches, that change their state with an electrical pulse and remain in that state till any another signal is received.(unlike the relay, which remains active till the signal is applied.)the concept is similar to an electrical toggle flip flop,but this time,the toggle system needs to be machenical like that of a relay,which could offer zeero resistance.
If there is no such thing in the market,can I make one?
This type of switch can be very efficient in Power electronics and some other applications.
THANKS IN ADVANCE FOR ANY SUGGESTIONS 
Puran