Device Health Card

Who it’s for

Fleet and asset operators tracking many devices ask “is this device healthy, or does it need a look?” and want the answer from one compact tile rather than three — a battery gauge, a signal bar and a last-seen stamp stacked on every device. On a fleet of any size that is three widgets’ worth of space per device, and still no indication when a device has simply gone quiet.

What it does

A LoRaWAN sensor reporting battery 68, RSSI -95 and SNR 8.5 shows a green 68% battery bar, a signal reading of -95 dBm rated Good under the LoRaWAN preset, and SNR 8.5 dB printed on the footer beside it.

• Combines battery level, signal strength and last-seen time into one bordered card, in place of three separate built-in widgets, and adds a stale indicator none of them has alone.
• A status chip in the corner reads OK, Low or Crit, reusing the same thresholds and color the battery row already computed, so the chip and the row underneath it can never disagree.
• Auto-detects whether the bound signal value is dBm or a percent, and rates it Excellent/Good/Fair/Poor against a radio-specific scale for LoRaWAN, Cellular or Wi-Fi.
• Reads last-seen from whichever bound key reported most recently by default, so it needs no timestamp key of its own.
• Names the exact reason when there is nothing to draw — no keys bound, keys bound but never reported, no readable value, or every section switched off — instead of a blank placeholder.
• Shows one bound device at a time; it does not summarize a fleet, so pair it with a list or map view for the wider picture.

How to set up

Data keys

Key	Role	Type	Description
Battery level key (batteryLevel default)	Main value	Timeseries	Optional — the whole battery row disappears if this is left unbound or Show battery row is off
Charging key (charging default)	Charging flag	Timeseries	Optional — adds a bolt badge to the battery reading
Signal key (rssi default)	Main value	Timeseries	Optional — read as dBm or percent depending on Signal mode
SNR key (snr default)	Secondary reading	Timeseries	Optional — printed on the footer next to the signal tier
Last-activity timestamp key (blank default)	Last-seen source	Timeseries	Optional — leave blank to use the newest timestamp among the other bound keys instead; if set, it must hold a millisecond epoch value

The card accepts at most five data keys, so all five rows above fit on one datasource. Hide any row you do not use with its own Show toggle rather than leaving the key unbound.

Signal

Setting	Default	Effect
Signal mode	Auto detect	Decides whether the bound value is read as dBm or a percent, before any threshold applies. Auto treats a negative reading as dBm and a zero-or-positive reading as a percent
Radio preset (dBm thresholds)	LoRaWAN	In dBm mode, sets the Excellent/Good/Fair cut-offs for the chosen radio: LoRaWAN -85/-105/-118, Cellular -75/-90/-105, Wi-Fi -55/-67/-80. Does not apply in percent mode

How to customize

Battery

• To hide the battery row — turn off Show battery row.
• To move where Low or Critical fires — set Low below % (default 50) and Critical below % (default 20).
• To recolor the three battery states — set Healthy color, Low color and Critical color.

Signal

• To hide the signal row — turn off Show signal row.
• To hide the SNR reading on the footer — turn off Show SNR. This is separate from the signal row itself.
• To override the tier cut-offs regardless of preset — set Excellent at, Good at and Fair at; leave any blank to fall back to the preset.
• To change the printed unit — set Signal unit override.

Last seen

• To hide the last-seen row — turn off Show last seen row.
• To read last-seen from a specific key instead of the newest bound timestamp — set Last-activity timestamp key.

Display

• To show or hide the status chip — toggle Show status chip. It reads OK/Low/Crit from the battery thresholds, or No data plus how long the silence has lasted once the card goes quiet.
• To flag a silent device — set Dim the card after no data for (minutes). It ships at 1440, one day. Set it to 0 to turn dimming off.
• To fit the card to its own tile automatically — leave Auto-scale text and spacing to card size on (the default); turn it off to pin one fixed scale, which is what you want if you have set your own font sizes.
• To match your dashboard’s fonts — set Device name text, Value text and Row label text.

Tips

• Set Dim the card after no data for a little longer than the device’s own reporting interval. A LoRaWAN or NB-IoT sensor that checks in every few hours will otherwise get dimmed for reporting normally.
• Raise an alarm on the same battery key at your Critical below % value, so a dying device gets noticed even by someone who is not watching a dashboard.