This is a general question. I’m asking for any ideas.
I have been working on a project which places Imps (Joel’s C3V0 and P3V3) on battery in remote greenhouses (wide area wi-fi coverage) to alert farmers to overheating in manually-vented greenhouses.
For the last two months my friend has had one deployed, posting temp data to Xively, with an alert in place for over-temp conditions. Problem is, it was too reliable…he got out of the habit of checking it online every day to confirm the battery was still good and the Imp was posting data to Xively.
Bad news is the battery died of course, and the greenhouse overheated without sending him an alert. Now he’s wondering if he lost the tomato plants. He was relying on receiving an alert and wasn’t confirming the device was online every day.
My question is this. While we can use Xively to activate alerts on over-temp conditions, what I could really use is some mechanism to monitor the timestamp on the most recent Xively data…and send an alarm if the timestamp gets too old (meaning battery died or device went offline).
Or, I could use some other mechanism you suggest. Ideas?