This guide raises an alarm when a climate sensor leaves its own temperature range. The range lives in a limits property: the product holds the default for every sensor, and a sensor that needs another range overrides it. One alarm rule watches every sensor, and an email goes out when an alarm is activated and when it clears.

Before you start

• A product whose devices write a temperature field to a Data Bucket tagged with device, such as the env_sensor product and its climate bucket of Provision a device fleet. A product bucket with a fixed ID has the tag. This guide uses the sensor greenhouse_01.
• For the API calls, an access token (YOUR_TOKEN) that can manage products, devices, endpoints and alarms. YOUR_SERVER is iot.thinger.io on the free Cloud account, or the domain of your private instance. For the CLI, the thinger CLI signed in to your account.

Steps

1. Set the default range on the product

   Give the product a limits property with the range of most sensors, {"min_temp": 5, "max_temp": 30}. Every device of the product inherits it. In the console, open the product on its Properties tab and add it (see Set a value for every device), or use the CLI:

   thinger product property-set env_sensor limits '{"min_temp": 5, "max_temp": 30}'

   

   The default range in the Properties tab of the product

2. Override the range of a sensor

   Give greenhouse_01 its own limits, {"min_temp": 10, "max_temp": 35}, in the Properties tab of the device (see Properties), or with the CLI:

   thinger device property-set greenhouse_01 limits '{"min_temp": 10, "max_temp": 35}'

   The device value wins over the product value. Delete it to use the default again.

3. Create the email endpoint

   Create the alarm_email endpoint of Send an email. Its subject and body take the rule, the event, the device and the values from the alarm, so it serves this rule and any other.

4. Check what the rule will read

   Before you create the rule, read its two sources. The rule ID in the path does not need to exist yet. The limits source must return one entry per sensor, with the value of the device or of the product:

   POST/v1/users/{user}/alarms/rules/{rule}/test-sourceAPI reference

   curl -X POST "https://YOUR_SERVER/v1/users/YOUR_USER/alarms/rules/climate_range/test-source" \
     -H "Authorization: Bearer YOUR_TOKEN" \
     -H "Content-Type: application/json" \
     -d '{"name": "limits", "source": "device_property", "device_property": {"property": "limits", "product": "env_sensor"}}'

   Send {"name": "climate", "source": "bucket", "bucket": {"id": "climate", "mapping": ["temperature"], "group_by": ["device"], "aggregation": {"period": "15m", "type": "mean"}}} to check the bucket source: one entry per sensor with its mean temperature. In the console, the Test Source button of each source does the same once the rule exists.

5. Create the rule

   The rule reads the 15-minute mean temperature of each sensor and its limits, and compares them every 5 minutes:

   • activation: IS OUTSIDE RANGE from limits.value.min_temp to limits.value.max_temp, in 2 checks in a row;
   • normalization: IS WITHIN RANGE with a margin of 1 degree, for 15 minutes, so a temperature on the limit does not raise and clear the alarm on every check;
   • the alarm_email endpoint on activation and normalization, and a reminder every 4 hours.

   In the console, go to Alarms > Rules, click Add Rule and set these values in the form and its tabs (see Alarm rules). The Activation tab holds the condition, the confirmation and the notification:

   

   Activation of the rule: outside the limits of each sensor, 2 checks in a row

   With the API:

   POST/v1/users/{user}/alarms/rulesAPI reference

   curl -X POST "https://YOUR_SERVER/v1/users/YOUR_USER/alarms/rules" \
     -H "Authorization: Bearer YOUR_TOKEN" \
     -H "Content-Type: application/json" \
     -d '{
       "rule": "climate_range",
       "name": "Temperature out of range",
       "description": "15-minute mean temperature outside the limits of each sensor",
       "enabled": true,
       "config": {
         "severity": 3,
         "check_interval": { "value": 5, "magnitude": "minute" },
         "data": { "sources": [
           { "name": "climate", "source": "bucket",
             "bucket": { "id": "climate", "mapping": ["temperature"], "group_by": ["device"], "aggregation": { "period": "15m", "type": "mean" } } },
           { "name": "limits", "source": "device_property",
             "device_property": { "property": "limits", "product": "env_sensor" } }
         ] },
         "activation": {
           "conditions": [ { "operator": "and", "type": "value_check", "field": "climate.temperature", "comparison": "outside", "min": "limits.value.min_temp", "max": "limits.value.max_temp" } ],
           "confirmation": { "mode": "sequence", "sequence": { "value": 2 } },
           "notifications": [ { "type": "endpoint", "id": "alarm_email" } ]
         },
         "normalization": {
           "conditions": [ { "operator": "and", "type": "value_check", "field": "climate.temperature", "comparison": "inside", "min": "limits.value.min_temp + 1", "max": "limits.value.max_temp - 1" } ],
           "confirmation": { "mode": "timespan", "timespan": { "value": 15, "magnitude": "minute" } },
           "notifications": [ { "type": "endpoint", "id": "alarm_email" } ]
         },
         "reminder": { "type": "interval", "interval": { "value": 4, "magnitude": "hour" }, "notifications": [ { "type": "endpoint", "id": "alarm_email" } ] }
       }
     }'

6. Evaluate the rule

   Open the rule, go to the Evaluation tab and click Evaluate. Each sensor appears in one tab, with its temperature and its limits under Values: Activations for the sensors out of their range now, Normalizations for those inside the range with the margin, and No Action for those in between. The API does the same with test-rule (see Test a rule).

7. Send a test email

   In the Activations or Normalizations tab, click Notification on a sensor. The alarm_email endpoint sends a real email with the values of that sensor.

Result

Every 5 minutes the rule compares each sensor with its own range: greenhouse_01 raises an alarm below 10 °C or above 35 °C, and the other sensors of the product below 5 °C or above 30 °C. After 2 checks out of range, the alarm appears as Activated in Alarms and ops@example.com receives an email with the subject [activation] Temperature out of range on Greenhouse 01. While nobody acknowledges it, a reminder arrives every 4 hours. When the temperature stays 1 degree inside the range for 15 minutes, the alarm is Cleared and a [normalization] email arrives.

To change the range of a sensor, or of every sensor, change the limits property: the next check uses the new values, with no change to the rule.

Troubleshooting

Symptom	Cause	Fix
Evaluate lists every sensor under Skipped with missing data sources	One of the sources returns nothing for them: the bucket has no device tag or the source does not group by it, the sensors wrote nothing in the last 15 minutes, or there is no limits property on the device or its product.	Check each source with Test Source.
A sensor is never activated although it is out of range	It is disabled, or it is not in the env_sensor product.	The property source only reads enabled devices of the product in its filter.
Evaluate warns that the activation expression failed to initialize	A value, min or max is a number instead of a string, or is empty.	Write the values as strings: "30", "limits.value.max_temp".
The alarm is activated but no email arrives	The endpoint is disabled or failed.	Test the endpoint in Endpoints and watch its endpoint_call_response events.

Next steps

Alarm rulesConfigure every part of an alarm rule, from data sources and conditions to confirmation and reminders, and test it before you enable it.Alarm notificationsWhat alarm rules send to your endpoints when an alarm activates, clears or reminds, with every field of the payload and email and webhook examples.AlarmsDefine alarm rules that watch bucket data, device properties or connection status, and notify through endpoints when a condition is met.PropertiesStore configuration and state as named JSON values on devices, products, asset types and groups, projects and your account, and read them from anywhere.