/diy/ - Do It Yourself

>>199777
This.

Sup /diy/.

I'm filming the process of turning an age-old analogue, wireless surveillance camera into a wire-bound one. Thought it might be of interest.

http://www.youtube.com/watch?v=km93pIKXNQk

>>157225
Okay.

>>157223

It's duct tape time. Post things that are duct tape.

>>100465
That'd work fine, but you'd have to use the volume control of your Sirius radio rather than the volume control of your head unit.

It'd work just fine, but you of course need to plug the Lol-gitech speakers into the line out connector of your head unit.

First, out of all the silly things you could add to something, you chose blue LEDs. You have no taste.

Secondly, you're adding blue LEDs to something powered by two AA batteries. Blue LEDs have a voltage drop of at the very least 3V. Not only are you not going to get any light out of them without a step-up converter, but you're going to drain the batteries an order of magnitude faster, especially if you do use a step-up converter.

>>94170
Unless you really want to make a class D thing, I suggest going with a traditional amplifier. Broken car radios are a good source of decent amplifier chips to use.

They're nice if you need a very efficient amplifier or want to play with digital input all the way to the output filter. They don't really have any other advantages compared to conventional class A/AB amplifiers.

>>94113
I just look like I'm 12.

>>94115
Because it's far, far more flexible, usable and feature-packed than the original Apple firmware.

>>93514
Gladly.

>>93524
This thing isn't USB compliant. It just uses a USB connector so that I wouldn't have to shred that part of the cable as well. Let me run the power dissipation down for you:

This device is designed to go into a car. I consider 15 V to be a good worst-case-scenario input voltage in cars.

It is a linear regulator taking that voltage down to 5 V during normal operation, and down to 0 V when short-circuited. Its current limit is 1A. During normal operation, it should thus be able to handle dissipating (15 - 5 V) * 1 A = 10 W. 8 W is a more realistic figure to count on, since most cars don't lie at 15 V.

I don't quite see where you get the 2.5 W from. 2.5 W is indeed the maximum power dissipation that the USB standard allows devices to utilise, but it has nothing at all to do with the power dissipated inside of the voltage regulator. Even if we were to limit ourselves to 500 mA, the regulator would still have to dissipate 5 W.

>>93536
The noise is just due to my rather long, unshielded microphone cable that's running parallel with some cables that aren't too friendly toward microphone-level signals.

>>93299

No, but with a voltage regulator capable of delivering 1A, I'd rather not have it overheat if I ever plug anything else into it.

>>93301
I'd argue that it's a quite well-dimensioned heatsink for <8W, given that it's going into a hot car where ambient temperatures of 70 °C aren't inconceivable.

Furthermore, if it's accidentally short-circuited, the power dissipation might even rise toward 15W (picture related, about five minutes of continuous short-circuiting). That's a Tdelta of over 80 °C, and that's not even measuring close to the regulator. To really take that scenario into account, the heatsink should be even bigger (or more efficient).

Also, it was the first somewhat fitting heatsink in the box.

>>93275
It's necessary. That 7805 will put out 8 W or so under full 1 A load.

I'll just place this here.

http://www.youtube.com/watch?v=vK3BiLdvNnc