Knut can be customized in many ways, to meet your needs. Below is an overview of the settings that you can control, either during setup or at any time later through one of the Knut Apps.
Knut will check the status of all of its sensors at a frequency of your choosing. This is called the recording frequency. The maximum recording frequency is once per second, but this is excessive for most applications. We find that once every 30 minutes is good for most situations. If your application requires high resolution data then once per 15 seconds is useful. Your choice may be influenced by:
- the resolution of data you need for you application
- how quickly you expect conditions to change in a given environment
- how soon after a deviation from acceptable conditions you would like to receive an alert
Note that some sensors are immediately triggered upon status change and can alert you of this change regardless of the frequency of recording that you set in the Knut App. This includes the door switch, accelerometer, and water presence sensor.
Knut will periodically transmit its data to an online storage account (the Knut email account), from which it will then be available to the Knut Apps. This occurs at a frequency of your choosing. Note that when Knut detects an alert condition, it will transmit data to the Apps in addition to sending an alert to your personal email. Data is visible in the Knut Apps only after these data transmissions. Thus, your choice for the frequency of data transmissions may be influenced by:
- how frequently you plan to look at data, in the absence of alert conditions
- how recent you want data to be when you decide to view the App, in the absence of alert conditions
- how long you would like the batteries to last
Data transmissions constitute the primary power draw on Knut’s batteries. We recommend choosing the fewest number of data transmissions per day, which still meets you needs, in order maximize battery life. When transmitting once every two hours, Knut’s batteries should last over six months.*
Alert and Output Settings
In addition to collecting data, Knut can take action when it determines that conditions are outside of an acceptable range. Using a rules-based system, you can define when, why and how Knut will analyze and respond to these situations–like sending alert emails or switching a relay on the breakout board. Basic rules are available with drop-down menus in the Web Setup and the Knut Apps.
Knut rules are structured as logical “if….then…” statements.
- If Freezer Temperature is greater than -20 C then send alert email
- If Sensor X meets condition Y then take action Z
In the basic rules editor you can specify what sensor, what condition and what action you want for each rule.
For analog sensors, which measure along a continuous spectrum, a condition is relative to a threshold value:
- If Freezer Temp is greater than -20 C
- If Battery is less than 15%
For digital sensors, which measure yes/no conditions, the condition is equal to one of their two possible states.
- If Door switch is equal to closed
- If Water detect is equal to wet
You can select an action for Knut to perform when one of these ‘alert conditions’ is met: send an alert message with a subject of your choosing. When Knut is attached to the breakout board, you can also choose to have Knut switch a relay on or off.
Defining Alert Messages
Knut can send a message to your phone or personal email when a sensor enters an ‘alert condition’. This message is sent only when a sensor crosses the threshold into an alert condition. You can specify the subject for the message by choosing what type of alert to send:
- If Freezer Temp is greater than -20 C then send high alert → High temp alert
- If Battery is less than or equal to 15% then send low alert → Low temp alert
- If Water detect is wet then send generic alert → Water detect is wet
A ‘generic alert’ will state the status of the sensor, which is particularly useful for the door switch and water presence sensor.
If you would like to receive a notification when a sensor returns to an ‘acceptable range’, then add a complementary rule for sending a message when conditions are back to normal:
- If Freezer Temp is greater than -20 C then send high alert → High temp alert
- If Freezer Temp is less than -20 C then send normal message → Temp is normal
Remember, you will only receive a single ‘normal’ message when Knut determines that a sensor has crossed the threshold from the ‘alert condition’ to the ‘normal condition.’
Further details about Knut are included in the body of alert emails, including:
- Date and time of the alert (this is the time stamp of the email)
- Name of the Knut
- Name of the Wi-Fi network
- Status of all sensors on this Knut, including battery
- Graph of recent recordings, in both html and .svg formats
Knut updates the Knut App at the same time that it sends you an alert email, so you can see the most recent history and status of sensors on Knut during alert conditions.
A second possible action for Knut to take, when an alert condition is met, is to switch an output on the breakout board. Just as you can create rules for sending alert emails, you can create rules for switching the relay:
- If Garage Temp is less than 45°F then turn relay on
The relay can also be controlled through a button in the Knut App. However, if the relay is linked to a rule then the rule will always take precedence. For example, if the temperature in the garage was 43 F, then Knut would turn the relay on. If you then switched the relay off through the Knut App, Knut would momentarily turn the relay off, but then immediately turn it back on because the conditions for the relay being on are still met: the temperature is below 45 F. You would need to change the rule to get the relay to turn off, or wait until the temperature rose to 45 F.
Advanced Rules Editor
For more complicated scenarios or with custom sensors, you might want to write up your own rule in the “K” scripting language. This gives you the freedom to invent your own, tailored system for Knut to report to you. Advanced rules might be:
- Time sensitive
- Alert only on certain days
- Alert only during certain times of day
- Alert only after a condition is met for a defined amount of time
- Multi-sensor dependent
- Alert only when measurements from two or more sensors are outside of acceptable ranges
Considerations when choosing alert values
When choosing alert values for analog sensors, keep in mind that many of Knut’s sensors are extremely precise and that environmental conditions can fluctuate slightly. You probably want to set alert values a small distance away from the value that you expect to be ‘normal’ or ‘average’. Otherwise, with a threshold of -20 C, you would get alert emails every time the temperature fluctuated by 0.1C.
You can specify global settings for Knut, which affect how data is displayed in the Knut Apps. These include:
- Time zone for each Knut
- Daylight savings time preferences
- Time display preferences
These can be specified during setup and modified at any time in the Knut Apps.
*Note about the battery life calculator: The Knut Apps will calculate the approximate battery life based on your chosen settings for data recording and transmission, to help guide your choice of settings. However, the actual battery life will be reduced by:
- Battery drain during long or repeated setup processes
- Additional recordings triggered by digital sensors (door switch, water presence, accelerometer)
- Sending additional data emails due to additional recordings from digital sensors
- Sending alert emails
- Sending additional data emails when alert conditions are met
We point this out so that you can understand the limitations of the battery life calculator, and also so that you can choose your alert conditions wisely. Do you really want an email when the temperature is 0.1 ºF above the ideal temperature? Maybe, maybe not.