Newbie here. Been reading the forums but want advice before buying parts.
I started wanting to build a robin pv router. I think I can use an arudino with emon tx shield with an output stageI'm I guess if i add an ethernet connection i can then data log via emon cms. Once this is working I have a battery charger I want to control via the same setup once there is enough pv available.
I also want to monitor my hot water tank in 3 places, and the room temperature in 2 rooms. Can I do this with another arudino and connect the sensors directly or will I need another shield? I'm stuck on this one?
Thanks
Re: pv immersion, data logging, tank temperature and room temp needed.
For temperature monitoring, the emonTx shield provides the correct operating conditions for the Dallas sensor(s), namely a pullup resistor on the data line. If you can provide this by some other means, then you wouldn't need the shield.
Similarly for the RF capability. It's entirely feasible to wire up your own plug-in RF module, but it may be easier to use a shield which has been laid out for this purpose.
[Edit] Here is a plug-in RF module that I made a while back, the circuitry is given on this BB page.
Re: pv immersion, data logging, tank temperature and room temp needed.
Thanks for the info regarding the temp sensors. I don't think I need RF as I can run cables between all my points I want to monitor etc. I will need the shield though for current and voltage measurements.
Im still unsure if the UNO is capable of the data logging and running the PV diversion at the same time? Or if I would be better putting my temp monitoring on a separate UNO.
As well as adding a battery charger in the future controlled by the surplus PV, I also want to add a simple 3 x tri coloured LED to give an indication of the water temp in the cylinder controller by the 3 stats I plan to install. The 3 x tri coloured LEDs would relate to the top middle and bottom temp of the tank. Something like green to indicate a temp below 25c, yellow to indicate 25-45, then red to indicate over 45.
Re: pv immersion, data logging, tank temperature and room temp needed.
This "Mk2 Router" code I posted for the emonTx V3.2 should do everything that you want except that only one Dallas sensor is supported. With all the critical stuff hidden away in the ISR, I don't forsee any difficulty with using multiple temperature sensors, but have never tried it myself.
http://openenergymonitor.org/emon/node/10171
The Uno has the same Atmega 328 processor as the emonTx, so will be capable of similar performance.