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How do I control a 12v warning light using a signal from my USB port?

I am thinking of putting one of those revolving emergency lights on the side of my server cabinet, to be triggered by voltage from a USB port on one of my HP blades. The revolving light is 12v and has a seperate power supply, so I just need some sort of USB controled switching relay.


11 Replies

steveastrouk (author)2011-10-27

Trouble with Maxim, is they sucker you into a nice design with their superb
- and we aren't volume makers - and THEN tell you that the lead time is 32Weeks, unless you order 10,000 pieces (yes this happened)


iceng (author)steveastrouk2011-10-27

They are wonderful at free samples but just try to get an order.

Most semiconductor manufacturers have sample stock & product stock
and no way to go between.

iceng (author)2011-10-26

Did you ever " Hello world " one of them ?

jj.inc (author)2011-10-26

You could try a cheep keyboard with a relay hooked to the scroll lock light which then flicks on the light. If you wan't to get really DIY

steveastrouk (author)2011-10-26

As A says, there's the parallax board, but TI also do "demo kits" for the MSP430 which are also USB driven - and they can be had for 10 bucks.


iceng (author)steveastrouk2011-10-26

Does TI supply FREE editor like P-Basic Software ?
If they do it's a great deal:-)
If not it's a TI RIP :-(


steveastrouk (author)iceng2011-10-26

Well mine came with something, I can't remember what: it would have been sufficient to bang an LED on /off over USB. Not a chip family I have actually used a right lot, though its on my List of Stuff to Play With.

You could always use a single FTDI FT232 serial to USB chip, and wiggle the RTS lines in code, or the even funkier FT2232, which allows you to do I2C and SPI directly with the device.


iceng (author)steveastrouk2011-10-26

Sorry for showing my wounds,
TI got me twice with $oftware.

steveastrouk (author)iceng2011-10-26

I always get stung by Maxim, and their delivery times.....

iceng (author)2011-10-26

Yes, ..... Talks Basic through the same port.

iceng (author)2011-10-26

This $25 micro, now on sale, a mosfet and 5 lines of  code will be able to work your server rotator red light. .  .  .  .  .  A