Dear All,

I am a newbie and I am trying to find info for my project. I am building a controlling system governed by Dr. DAQ (http://www.drdaq.com/datalogger.html) to switch on/off some heater (http://uk.rs-online.com/web/p/tank-heaters/6151615) and some pump (http://uk.rs-online.com/web/p/centrifugal-pumps/7632544) This implies using some relays (346-895) and this (http://uk.rs-online.com/web/p/solid-state-relays/2002042) respectively.

Now here is the problem:

the card logger works at 3.3V and the relay works at 3.5V so I need an amplifier.

I have been told by they company selling the Dr DAQ I need this relay driver (http://uk.rs-online.com/web/p/darlington-transistors/7514288/) but then again people from electronic department (I work for a uni) said is needed also a DC-DC converter (http://uk.rs-online.com/web/p/isolated-dc-dc-converters/7330929)

question is:

am I doing it right? is there any other product that would do the trick to interface that card with that relay?

Please be kind as I don't know much about electronics


Regards

Paolo

 

For the 346-895D, you should just be able to drive directly from your MCU but I think an opto-isolator might be a good idea. For the other one, you would need a driver, but a small transistor or mosfet might do the trick. Again, I'd be tempted just to use an opto-isolator.