The ISD 1820 10 second recoding module has an amazing capability. You can use this $2 module as a flood alarm.
Use a JST connector and plug it to the loop playback jumper. Extend the wires by soldering extra lengths of wire. Put the wires to where you want to detect moisture. Attach a power source of 3 to 5 v and plug in the speaker. Record a playback warning message. When water is detected, the loop playback pins are bridged (as water is a conductor) and playback of your alarm message is sounded. The playback will stop when the contacts are lifted out of the water, or when the battery is dead.
Of course, the recording module can be used for other functions but this use is particularly useful to me.
Here's the eBay link for the module from Angelsport2010:http://www.ebay.com/itm/121...
You can also buy it on Amazon. If you want to use this as a water detector, buy the version with the jumpers, not the ones with the switch for loop playback.
If you are interested in a soil dryness sensor, watch this video:https://youtu.be/Gz_aQUi_mUw
Click here to subscribe to this channel: http://www.youtube.com/subs...