Help on I2C question

Looking for a method/device to address as I2C to turn on/off 12+ volts. It needs to be very small and can have an address set. I will have around 50 different addresses to control 3 lights.

Thanks

Clem

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bobcroft over 10 years ago +1

Clem, Not I2C but SPI. Have a look at Majenko.co.uk he does a 32 port IO expander board and up to 4 can be used on 4 wires from the Arduino i.e. 128 IO! I use these to drive banks of 8 relays via opto…

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0 clem57 over 10 years ago

@bobcroft
I could use SPI interface from what you show. Researching that angle. Would like something elegant/simple to do...

@Michael Oldfield
Need to check this one out too because transistors should be rather inexpensive. MCP23008 could be the key to switching these. About how fast do you think this can occur (the switching).

Thanks to all,
Clem
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0 binarygenius over 10 years ago in reply to clem57

The MCP23008 according to the datasheet MCP23008 - Interface- Serial Peripherals can switch at 100kHz, 400kHz and 1.7MHz I²C with the transistors depends on which ones you use but normally very fast and to save on pins you could do a 7x7 matrix and it should only use 8 pins i think if you have a common ground but that would only be 49 transistors. if you where going to use SPI the 595 series shift register at 20mhz could be a cheap option http://www.nxp.com/documents/data_sheet/74HC_HCT595.pdf but can use a lot of memory and you would still need transistors but like i say it is hard to offer solutions without knowing more like how many amps at 12v, what type of load the more info the better.
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0 clem57 over 10 years ago in reply to binarygenius

Looking at 300 LED's at 20 mA each for a total around 6 A if all on with white! Really hope not to do this... I plan on feeding this with old 120V-> 20 volt/6 A laptop regulator rated at 90 watt's into a buck DC to DC down to 12 Volts. Am I crazy? LOL
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0 clem57 over 10 years ago in reply to clem57

Oh I plan on dividing these into groups of 3-6 LED's per cup...
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0 clem57 over 10 years ago in reply to clem57

Oh I plan on dividing these into groups of 3-6 LED's per cup...
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