What Is Live Meter Mode?
Every sensor on LoopString operates in one of three modes at any given time. Understanding these modes helps you get the most out of your sensors without wasting cloud bandwidth or battery on devices where that matters.
Monitoring mode is the default. Your Raspberry Pi samples the sensor at its hardware rate, but the throttle gate — a piece of logic running on the Pi — only publishes a reading to the cloud when a certain amount of time has passed since the last one. How long that gap is depends on your subscription tier: Hobby accounts publish every 30 seconds, Pro every 15 seconds, and Business or Enterprise accounts every 5 seconds. This keeps cloud costs low and is the right setting for long-running, unattended operation.
Live mode bypasses the throttle entirely. Every reading the sensor produces is pushed to the cloud and appears on your dashboard immediately. This is real-time streaming — readings arrive as fast as the sensor itself can produce them, which is typically every one to two seconds. Live mode is designed for short bursts of hands-on inspection, not continuous background operation.
Idle mode suppresses all cloud publishing. The Pi still samples the sensor internally, but nothing is sent to the dashboard. You might use idle mode to temporarily silence a sensor you are not currently interested in without removing it from your flow.
Which Sensors Have a Live Button?
The Live button only appears on sensor cards where near-continuous streaming actually makes sense. These are sensors you interact with manually — you dip a probe, adjust a solution, and watch the reading stabilize. Examples include pH probes, electrical conductivity sensors, oxidation-reduction potential probes, dissolved oxygen sensors, and generic analog inputs.
Continuous environmental sensors like temperature, humidity, and CO2 already push readings frequently and do not benefit from live mode. They do not show a Live button to avoid clutter.
How to Enable Live Mode
Find the sensor card on your dashboard. In the top-right corner of the card, next to the status indicator, you will see a small broadcast icon labeled "Live". Tap or click it once.
When live mode activates, the button turns green and begins pulsing. A countdown banner appears on the card showing how much time remains before the session automatically ends — for example, "Live — stops in 9:42". Readings on the card will now update as fast as the sensor can produce them.
To stop live mode early, tap the Live button again. The card returns to normal monitoring behavior immediately.
Saving a Reading
While live mode is active, a second button labeled "Save" appears next to the Live button. Pressing it does two things at once: it copies the current reading to your clipboard in a format ready to paste into a spreadsheet or lab notebook (for example, "pH Probe: 6.82 pH (3/19/2026, 2:14:08 PM)"), and it logs the reading to your device's Activity Timeline so there is a permanent record in LoopString.
This is useful when you are taking spot measurements during setup or maintenance and want to keep notes without switching to a separate app.
The 10-Minute Auto-Timeout
Live mode is not meant to run indefinitely. Streaming every reading to the cloud uses significantly more Firebase bandwidth than monitoring mode, so LoopString enforces a hard 10-minute limit.
The countdown is enforced in two places simultaneously. The dashboard starts a local timer the moment you enable live mode and will write a revert command to the Pi when time expires. The Pi itself also tracks how long it has been in live mode and reverts on its own if it has not heard from the dashboard — a belt-and-suspenders design that means live mode always stops even if your browser tab closes or loses connectivity.
After the timeout, the sensor automatically returns to monitoring mode. You can enable live mode again immediately if you need more time.
Use Cases
Calibrating a pH or EC probe. When you run a calibration wizard, you need to see the probe's response in real time as you move it between calibration solutions. Monitoring mode, which might update only every 15 or 30 seconds, makes it hard to tell whether the reading has stabilized. Enable live mode before starting calibration so you see each measurement as it arrives. The sensor card will show smooth, continuous updates that make it easy to know when the probe has settled.
Verifying a new sensor installation. After wiring a new analog sensor — a pressure transducer, flow meter, or custom analog input — you want to confirm the signal is being read correctly before deploying your flow for long-term use. Enable live mode, then physically actuate the thing the sensor measures: open a valve, squeeze a tube, apply pressure. Watch the raw values climb and fall in real time to confirm the wiring, calibration range, and units are all correct. Use the Save button to log a few spot measurements for your records.
Diagnosing an intermittent reading. If a sensor card occasionally shows unexpected spikes or dips in the sparkline history, live mode lets you watch the raw stream closely for a few minutes to catch the behavior in the act. You can see whether the anomaly is periodic, triggered by something in your environment, or a sign of a failing probe or loose connection.
Manual spot checks during maintenance. For probes that you dip rather than leave submerged — checking nutrient solution pH before a feeding, verifying pool ORP after adding chemicals — live mode turns the sensor card into a handheld meter display. Enable live mode, take your reading, save it, and disable live mode when you are done.
Troubleshooting
The Live button does not appear on my sensor card.
The Live button is only shown for on-demand sensor types: pH, electrical conductivity, ORP, dissolved oxygen, and generic analog inputs. Continuous sensors (temperature, humidity, CO2, pressure) do not show the button. If you expect to see it and it is missing, confirm the sensor's part type in the Configurator. Also check that your device is online — the Live button is hidden when the device is offline because enabling live mode requires the Pi to be reachable.
I enabled live mode but the reading is not updating any faster.
There is a short delay between enabling live mode and the Pi picking up the change. The Pi checks for mode changes on a polling schedule — up to about 30 seconds may pass before the throttle gate reads the new setting from the cloud. Wait a moment and the stream should begin. If readings still do not update after a minute, check that the Pi is online and that the Node-RED flow was successfully deployed.
Live mode turned off by itself before 10 minutes.
If your browser tab went to sleep, lost focus for an extended time, or your internet connection briefly dropped, the dashboard-side countdown may have triggered an early revert. The Pi independently enforces the 10-minute limit as well. In both cases, simply enable live mode again. There is no limit to how many live sessions you can start back-to-back.
The reading updates during live mode but values look wrong.
Live mode only changes how often readings are published — it does not change how the sensor is sampled or calibrated. If values look incorrect in live mode, they will look the same in monitoring mode. Check sensor placement, probe condition, and calibration settings in the Configurator.
The Save button copies to clipboard but nothing appears in the Activity Timeline.
The Save button fires a background log write to the cloud. If you are on a slow or intermittent connection, the log entry may be delayed. Pull down to refresh the Activity Timeline page or wait a minute. Clipboard copy is local and always works regardless of connectivity.
Live mode is not available on my plan.
Live Meter mode is available on all LoopString subscription tiers including the free Hobby plan. If the Live button is present but appears to have no effect, confirm your flow has been deployed successfully and that the LoopString throttle gate subflow is present in your active Node-RED flow.
Known Limitations
Live mode can only be active for one 10-minute session at a time per sensor. There is no way to extend the session mid-run — when the countdown reaches zero, the sensor reverts to monitoring. You can immediately start a new session if needed.
The Pi polls for mode changes on a schedule rather than receiving an instant push notification. This means there can be up to about 30 seconds of lag between when you press the Live button and when streaming actually begins. This is by design — continuous polling for mode changes across many sensors would itself generate significant cloud costs.
Live mode increases the number of data points written to Firebase RTDB for the duration of the session. On very high-frequency sensors (sub-second sample rates), this can produce a noticeable spike in usage. For most Atlas Scientific probes and generic analog inputs, which sample at one to two second intervals, the impact is modest.