This site has the best collection I have found: http://www.embeddedworks.net/wsim3951.html
In the US the T-Mobile pre-paid seems to be the best deal. Similar on sparkfun
Is anybody connecting to the internet via a SIM card? If so what cellular plan are you using? I think I can stay below 1GB a month and I am in the United States (North Carolina). I know there are a few companies offering M2M Data Only plans but I have not been able to organize what is currently available. I also know Twilio is joining with T-Mobile but I have not seen the plan yet. Does anybody have any information?
The arduino should send a "presentation" message when powered up which could be the "on" message. If there is a way to send a "Powering Down" message at the loss of power by using a capacitor, that would be fantastic. In my setup it would have to have enough juice to send the message via the long range radio. I suspect some of the experts on this forum have done something similar to this solution.
I think the issue with the current sensor is the pump would need to be running for it to work and they are looking to know that the pump could run if it needs to.
This page provides a design based on a capacitive voltage detector (like the "pen" you stick in an outlet to see if it has power): http://electronics.stackexchange.com/questions/94782/capacitive-ac-voltage-detection.
Seems plausible but you could also just power the arduino from the GFCI. I would have the arduino monitor a float switch in the sump pump. You could send a signal indicating the water level every 2 minutes.
If the pump dies or is blocked or malfunctions but the GFCI is still powering the arduino you would get a signal that the water level has risen and is going to flood the basement.
If the GFCI trips and your controller does not receive an update from the sensor you could send an email indicating a possible powe failure. This is a tricky alarm and not all controllers can do it. You need to know when the arduino last sent a message to the controller and act accordingly. You also only want to send one email even if the power is out for a long time. And it is nice to send a follow-up email when the arduino comes back online.
I can do some testting also. Happy to help.
Thanks for sharing this! I am hoping to create an all-in-one extension cord plus this meter. I hope this way I can detect when a pump fails or maybe just how much power is being used.
I have read that you when using a CT you must be careful to avoid a voltage build up on the CT output. Is that a concern with this current setup? With a battery powered arduino you are not grounded? In my extension cord project I was thinking I could use the ground from the extension cord.
I am not an electrical engineer so I may be way off here, just trying to be safe.
I think this setup could be very useful. In the high school greenhouse where I have my sensor network there are so many pumps, heaters, air stones, that need to be monitored and an alert sent if they stop working.
I may also try this with the sensebender micro.
@FotoFieber Just the standard serial gateway. There is a nice node-red node for parsing mysensors serial data. I then have some basic code that recognizes the specific data, e.g. node 9 child 10 is the aquaponics water temperature, so that I can store more information in influxd to mak ethe graphs better.
I also have node-red respond to the metric/imperial question. That is basically it.
@Yveaux The install in the greenhouse is basically because the internet connection is costly and not reliable. I have an old linux computer in teh greenhouse for the following reasons: