each coil uses 150mAif you use the Arduino power, you may have a dip in voltage.however, there is a away to trickle charge a cap to use that for the power dump to the coil.you cannot change state before it charges, and you cannot energize two at the same time unless you size the caps properly.
Continue with the 330R. Current is only drawn as long as the relays are triggered.It may be possible to drive the relays from the Arduino 5V, but only with big caps (>=1000µF) added, or you risk controller resets or other malfunction. But if you already have a 5V supply, you can power both the Arduino and relays from that supply.
I just followed the code you provided originally and there was a 40 - 1000 ms delay change. So i assumed this was what you meant.
I have removed the revised circuit from within the area entitled test relay circuit and replace that with the relay. This allow me to latch the relay either way, it kept its state after power off!!!
each coil uses 150mAif you use the Arduino power, you may have a dip in voltage.
The option is to have latching relays all around my house, which is powered through cabling in the wall.
Can the relays be Set or Reset sequentially? If so, all that's needed is 150mA. If you have 25 relays and your impulse is 40ms, then it will only take 1 second to update all 25 relays with only 150mA of current.
From this, I feel the best way to control it is:From one main arduino Mega in a central location that sends pulses via cat6 into the roof, into the wall cavities housing the relay circuit?Does this sound like it would work?
That way I could also have a 5v power supply at the main source which I can send out with the cat 6 through the cables.
I'm quite sure it's possible to use just one supply for everything. I would consider using a 7.5V (regulated) DC supply that can be used to power the Arduino through Vin and also provide power to all the relays. For relay power, just use one 1N4004 or 1N4007 diode in series with the 7.5V. This essentially creates a separate 6.8V supply for the relays.
I have an adapter split and a screw terminal end, so I could power the arduino through the jack as normal, then have it split off into screw terminal, then into ground and then hot to diode and then a common hot line?
Is it perhaps better to have the diode at each of the cat 6 end points or would that make the voltage too unreliable on account of voltage drop in different distances of cabling?
Will it limit the longevity of the relays possibly putting them at the end of their tethers for the entire life at 6.5v or is it more like to be less and within the range is within the range?
Would a main arduino and a common 5v power supply , which I step up to a solid 5v -> 500ma at the end of the circuit be better for the life of my project or is there issues with using cheap chinese step up modules.
Should I employ an opto-isolator?
Good question. There are definitely advantages with this. Note that it would make the circuit somewhat more complex. You'll probably need to design your own relay module for this
No ... its within specifications. The main thing that would shorten life span is having the pulse duration too long. This overheats the coil.
Don't forget that the transistor drops 0.3V. So, directly connected we have 7.5 - 0.7 - 0.3 = 6.5V. This is within specifications. In a different application, I have many 12V latching relays that use an 18V pulse (150%) and have been in service without any failures for about 15 years.