The 8 Channel I/O (8 Relay Version) has 8 SPDT relays and 8 opto-isolated inputs. This device has many applications and we couldn't possibly list them all, but here are a few examples The relay can be used to turn on and off a sprinkler system, automating a hot tub, or low-voltage lights. The inputs can be used to monitor magnetic window switches or garage door position.
The relay board requires external power of 9-24VDC. This can be provided through our Universal AC Adaptor (not included), or you can provide your own power supply. The power supply must provide between 9-24 volt DC on a 2.1mm center-pin positive connector. Alternatively, this power can be supplied from upstream on the 1-Wire network although this method is not recommended for this device.
Note: The DS2408 1-Wire chip used on this device has a total of 8 I/O lines so a total combination of 8 relays or inputs can be used at one time.
The relays can control loads of up to 2 amps and 240VAC. Please see the User's Manual on the More Info tab for more detailed specifications.
Posted by SimonH on 9th Apr 2013
I've had been running the 8 channel I/O board for over 2 years using the relay outputs to switch 24V AC (for my heating system zone valves) and it's been very reliable. The first problem I've had has been today when LEDs were lit but not all the corresponding relays were energized - that turned out to be a failure of the external power supply (not one by HobbyBoards).
This is a great bit of kit - I'll probably buy another. I only wish HobbyBoards produced some cheaper/smaller 4 or 2 relay versions as I have several other places I could use them :)