Recently, I decided to check all proprietary home automation and go DIY using arduino.
Of course, problems, as all my relays are controlled using 12V signal and the arduino spits out 5V. Obviously, solution: MOSFET.
What I would love to find, but failed so far, is to find a MOSFET PCB with maybe 10 modules, addressable individually and placing an addressing latch in between. So, the arduino puts an address 'HIGH', the latch picks the right MOSFET, the latter 'closes' the 12V circuit for a fraction and the relay is switched.
Is this a good solution? Where do I find these things? Or am I not making any sense?
What current does eash relay need? A couple of ULN2803 or ULN2003's might be sufficient - they could
be driven from 595 shift registers to reduce the number of Arduino pins needed.
Couple of TPIC6C595 (100ma sink/output) or TPIC6B595 (150mA sink/output) will let you control up to 16 12V relays with just 3 signals from Arduino. They are shift register with open drain Mosfet output, very easy to use.
CrossRoads:
Couple of TPIC6C595 (100ma sink/output) or TPIC6B595 (150mA sink/output) will let you control up to 16 12V relays with just 3 signals from Arduino. They are shift register with open drain Mosfet output, very easy to use.
As OP hasn't indicated what current the relays are taking, apart from either a couple of mA or
200 - 300 mA, is also a 'couple', of course.
I would be careful as to suggesting any particular device, at this point. The TPIC6C595 or TPIC6B595 suggested, are great devices but will die very quickly if his relays require 200-300mA.
CrossRoads:
Couple of TPIC6C595 (100ma sink/output) or TPIC6B595 (150mA sink/output) will let you control up to 16 12V relays with just 3 signals from Arduino. They are shift register with open drain Mosfet output, very easy to use.
