HYDROS WiFi Outlets

The HYDROS Control system can utilize WiFi-based power outlets as part of its configuration. These outlets can be used to switch lights, pumps, heaters, and other equipment on or off as needed in an aquarium environment. 

The power outlets connect to the Control device via WiFi. Understandably, there are concerns about the general reliability of these outlets and the possibility of a loss of communication.

One thing that should be pointed out is that HYDROS talks to the outlets directly on WiFi. No cloud interaction is involved. Thus, as long as your WiFi hub is operating, the outlets will work even if the outbound Internet connection fails. 

The following outlines some of the safeguards that have been taken to reduce the probability of failure.

Monitoring

HYDROS does not treat the outlets passively. Control 2 and Control 4 devices monitor each WiFi outlet continuously at a rate of at least once a second. HYDROS communicates with each outlet and verifies that it is returning the correct status. If the state is incorrect (for example, if the outlet was switched ON or OFF manually), HYDROS will immediately switch the outlet back to where it should be.

If the HYDROS Control device cannot communicate or verify the status of an outlet, an alarm will go off, and it will send a notification email or SMS text to the user.  This process allows the user to know if an outlet disappears or malfunctions immediately. 

On the Smart Plug WiFi outlets which support current measurement, HYDROS can also verify if the device's current consumption is within the expected range. So, for example, if a heater is supposed to consume 400 watts, an alert can be sounded if it is less than 350 watts (probably will be zero if it failed).

Fault Tolerance

Even though HYDROS monitors all outlets continuously, it is better to avoid communication loss in the first place. HYDROS devices support the ability to have multiple WiFi hubs.  (see Figure 1)

The first drawing is a typical home WiFi environment with HYDROS:

In this configuration, it is clear that if the router/hub in the center fails, all communications will be lost. This scenario is relatively unlikely, especially with a modern, good-quality router. However, anything can fail, and this does constitute a single point of failure. (See Figure 2)

However, reconfiguring the network as follow ensures the single point of failure disappears.

Now we have two WiFi hubs, and each device can connect to either of them. This redundancy allows the network to survive the loss of either hub. The hard-line between the two hubs handle the situation when some devices connect to Hub A and others to Hub B. Installing additional hubs can provide triple or even quadruple redundancy. 

Multiple hubs can also be used to increase coverage area by locating them apart from each other.

Damage Mitigation

Even though the network can be configured to avoid any single point of failure, it is still possible that a total WiFi failure could occur. Of course, HYDROS notifies the user immediately, but perhaps he or she is unable to act on it. This notification would take place even if WiFi or Internet connectivity is lost. In this case, the message will originate from the HYDROS Cloud servers. When communication is lost, the outlet will remain in the last state it was told to be in (if it were ON, it would stay ON).

To further failsafe the system, it is good to take active steps to minimize the potential damage caused by failures. These steps are good recommendations with or without the presence of WiFi outlets. Controllers can fail. Many aquarium controllers are not built to tolerate a saltwater environment. These controllers are subject to internal failure at any point due to salt creep and internal arcing. In a recent incident, many existing aquarium controllers failed due to a faulty software update. Numerous hobbyists lost livestock and equipment as a result. Of course, anything electronic is capable of failing, so it is always a good idea to provide secondary backups for critical systems. 

When using a heater, it is recommended to select one with a built-in thermostat. Set the heater's internal thermostat a little higher than the desired temperature. For instance, if it is desired to have the tank at 78°, set the thermostat on the heater to 80°. The HYDROS system will switch the heater on and off as needed, but the thermostat on the heater will never activate. Since that thermostat is never activated, its contacts will never wear or arc.