Computer Speaker
The problem I've always had with PC speakers is forgetting to switch them on and off. I therefore made one which is powered by a spare USB socket.
The speaker itself came out of an old TV and the box was made from bits of old wardrobe.
I got a USB cable from Poundland and chopped the 'far' end off it and then used my continuity tester to find which wires were going to the outer two contacts, which are the power ones, and then plugged it in with a voltmeter connected to them to find out which was positive and which was negative. This may seem like needless pissing about as positive and negative should be red and black respectively but not all cables, especially cheap ones, follow the rules.
Beyond that the amplifier is based around an LM386 IC which along with the few other components needed can't have cost more than a pound.
All I'd wanted was something so I could hear error bleeps, new e-mail alerts and the sound on YouTube videos as if I want to listen to music I can plug it into the hi-fi. However, it sounds far better than expected and is fine for that too.
The same circuit could be used to make a speaker for an MP3 player if it were powered from a battery, anything from 4.5V to 12V would be fine.
The design for the front is available here in PNG format.
The speaker itself came out of an old TV and the box was made from bits of old wardrobe.
I got a USB cable from Poundland and chopped the 'far' end off it and then used my continuity tester to find which wires were going to the outer two contacts, which are the power ones, and then plugged it in with a voltmeter connected to them to find out which was positive and which was negative. This may seem like needless pissing about as positive and negative should be red and black respectively but not all cables, especially cheap ones, follow the rules.
Beyond that the amplifier is based around an LM386 IC which along with the few other components needed can't have cost more than a pound.
All I'd wanted was something so I could hear error bleeps, new e-mail alerts and the sound on YouTube videos as if I want to listen to music I can plug it into the hi-fi. However, it sounds far better than expected and is fine for that too.
The same circuit could be used to make a speaker for an MP3 player if it were powered from a battery, anything from 4.5V to 12V would be fine.
The design for the front is available here in PNG format.
