Just a short intro on this great and cheap network box that I found on ebay for $30-40. You can connect to it 8 DS18B20/DS1822 based temperature sensors, one Honeywell HIH-4000 series humidity sensor, plus few relay. And if you get in to it could program it to do automation tasks (home automation, IP relay, hydroponics, weather station, etc).
For $30 you can get this board called WebControl (8 ports), its made by cainetworks.com There are two version PLC and BRE. You can find on Ebay. The major problem is that during power up they will fire relays. Have used this for garage door, but had problem that it would open garage door during power up. Solution at bottom of this post.
WebControl™ has 8 digital inputs, 3 analog inputs(based on 10bit A/D converter, full scale 0-3V), up to 8 optional DS18B20/DS1822 based temperature sensors, one optional Honeywell HIH-4000 series humidity sensor, 20 custom definable timers to combine and define its 8 digital output in any sequence of those combined input.
The user manual for PLC version and BRE version.
If you are not sure which one to get, get PLC version.. PLC has been more updated and has large number of users creating codes for it..
Solution to power up problem by Support Team at CAI Networks, Inc.
Thanks for writing to us. The processor during power up do reset on all the
output. That is probably the cause for the power on trigger.
If you could delay the power going to the relay board for a fraction of a
second, that will be fine. Otherwise, you will have to modify the
WebControl board by adding a 2.2k resistor and 47mF capacitor connected in
series. Between the 5V regulator and 16 pin AUX connector, there is a chip
marked U5, if you look the chip pin 22 now is grounded. Using a soldering
gun to desolder pin 22, and connect a wire from chip pin 22 to the resistor
and capacitor. The positive side of the capacitor connects to 3/3.3V
regulator output, the other end of the resistor connected to the ground.
By this modification, the output during power on will be disabled for about
0.5 second. That is good enough to get rid of processor reset caused spike
in the output.
+ Fix temperature sensor, sample PLC code link or link2
+ Moco is a scaleable software system for monitoring and control of analog and digital I/O points. link
+ Weather station link