Christmas Tree Watering With A 32bit Microcontroller
Setting Up
So my plan is to get some 0.1" header strip and glue it to clothes peg with some flying wires. I can then clip the clothes peg over the side of the casting my tree is mounted in so that the 0.1" header will stop touching the water when it drops below a predetermined level. If I can sense the current, or lack of then the water stops shorting out the contacts, I can raise some kind of alarm.
Experiment 1
The first thing to do is see if I can measure a current through water with *just* the mbed. In the days of D&T there was always a transistor involved.
Experiment 2
To detect that the tree needs more water, we are looking for a falling edge on my DigitalIn. Since the tree drinking process is slow, and the refills are not often i probably dont have to worry to much about debouncing and stuff. However, I do want to send multiple reminders, so I might just activate a ticker when I detect the water is low, and deactivate it when is filled.
Experiment 3 - Some alert system
Okay, I say "some".. I have a good idea 😊
At the moment I am highly inspired by Rolfs work on the HTTP Client. I Have a Netgear HomePlug adaptor (XE103) and there is one hooked up to my broadband router, so I *could* get onto the internet pretty easily.. there is a socket right behind the Christmas tree, and I am using a BoB with an RJ45 connector. Coincidence? I think not 😊
Experiment 4
For this experiment I paid a visit to [url=http://www.txtlocal.co.uk]http://www.txtlocal.co.uk[/url] and registered and account. They have very nice APIs which allows you to send and receive SMS messages in all sorts of ways, the one that is of interest is via PHP script.
To do..
* Add some cool video clips
* Figure why I got nothing when the HTTP call ran in a ticker
[Source]
Christmas Tree Watering
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