added optional timestamp

src/common/RelativeTimestamp.tsx

@@ -0,0 +1,38 @@
+import { Typography } from "@mui/material";
+import moment from "moment";
+import { useEffect, useState } from "react";
+
+interface Props {
+  /** RFC3339 timestamp string */
+  timestamp: string;
+}
+
+/**
+ * Displays a timestamp as relative time (e.g. "a minute ago", "5 seconds ago").
+ * Uses a subtle, muted typography style.
+ * Refreshes every 60 seconds to keep the relative text current.
+ */
+export default function RelativeTimestamp({ timestamp }: Props) {
+  const [, setTick] = useState(0);
+
+  useEffect(() => {
+    const interval = setInterval(() => setTick((t) => t + 1), 60000);
+    return () => clearInterval(interval);
+  }, []);
+
+  const date = moment(timestamp);
+  if (!date.isValid()) return null;
+
+  return (
+    <Typography
+      variant="caption"
+      sx={{
+        opacity: 0.7,
+        fontSize: "0.7rem",
+        fontStyle: "italic",
+      }}
+    >
+      {date.fromNow()}
+    </Typography>
+  );
+}

src/common/StatusDust.tsx

@@ -3,10 +3,13 @@ import { green } from "@mui/material/colors";
 import { makeStyles } from "@mui/styles";
 import { Device } from "models";
 import PulseBox from "./PulseBox";
+import RelativeTimestamp from "./RelativeTimestamp";
 import { or } from "utils";
 import { useEffect, useState } from "react";
+
 interface Props {
-  device: Device
+  device: Device;
+  showTimestamp?: boolean;
 }
 
 const useStyles = makeStyles((theme: Theme) => {
@@ -48,7 +51,7 @@ const useStyles = makeStyles((theme: Theme) => {
 })
 
 export default function StatusDust(props: Props) {
-  const { device } = props;
+  const { device, showTimestamp } = props;
   const classes = useStyles()
 
   const colors = or(device.status.sen5x?.overlays.map(overlay => overlay.color), []);
@@ -165,6 +168,11 @@ export default function StatusDust(props: Props) {
               </Typography>
             </Grid2>
           </Grid2>
+          {showTimestamp && device.status.sen5x?.timestamp && (
+            <Grid2>
+              <RelativeTimestamp timestamp={device.status.sen5x.timestamp} />
+            </Grid2>
+          )}
         </Grid2>
       </PulseBox>
     </Tooltip>

src/common/StatusGas.tsx

@@ -3,13 +3,14 @@ import { blue, deepOrange, teal } from "@mui/material/colors";
 import { makeStyles } from "@mui/styles";
 import { Device } from "models";
 import PulseBox from "./PulseBox";
+import RelativeTimestamp from "./RelativeTimestamp";
 import { or } from "utils";
 import { useEffect, useState } from "react";
 
 interface Props {
-  device: Device
+  device: Device;
-  // noDust?: boolean;
+  gasType: "co2" | "co" | "no2" | "o2" | "all";
-  gasType: "co2" | "co" | "no2" | "o2" | "all"
+  showTimestamp?: boolean;
 }
 
 const useStyles = makeStyles((theme: Theme) => {
@@ -61,7 +62,7 @@ const useStyles = makeStyles((theme: Theme) => {
 })
 
 export default function StatusGas(props: Props) {
-  const { device, gasType } = props;
+  const { device, gasType, showTimestamp } = props;
   const classes = useStyles()
   // console.log(noDust)
   let colors: string[] = []
@@ -203,6 +204,11 @@ export default function StatusGas(props: Props) {
                   Volt: {device.status[gas]?.millivolts.toFixed(1)}mV
                 </Typography>
               </Grid2>
+              {showTimestamp && device.status[gas]?.timestamp && (
+                <Grid2>
+                  <RelativeTimestamp timestamp={device.status[gas].timestamp} />
+                </Grid2>
+              )}
             </Grid2>
           </Grid2>
         </PulseBox>

src/common/StatusPlenum.tsx

@@ -3,11 +3,13 @@ import { blue, orange } from "@mui/material/colors";
 import { makeStyles } from "@mui/styles";
 import { Device } from "models";
 import PulseBox from "./PulseBox";
+import RelativeTimestamp from "./RelativeTimestamp";
 import { or } from "utils";
 import { useEffect, useState } from "react";
 
 interface Props {
-  device: Device
+  device: Device;
+  showTimestamp?: boolean;
 }
 
 const useStyles = makeStyles((theme: Theme) => {
@@ -25,7 +27,7 @@ const useStyles = makeStyles((theme: Theme) => {
 })
 
 export default function StatusPlenum(props: Props) {
-  const { device } = props;
+  const { device, showTimestamp } = props;
   const classes = useStyles()
 
   const colors = or(device.status.plenum?.overlays.map(overlay => overlay.color), []);
@@ -117,6 +119,11 @@ export default function StatusPlenum(props: Props) {
               {device.status.plenum?.humidity.toFixed(1)}%
             </Typography>
           </Grid2>
+          {showTimestamp && device.status.plenum?.timestamp && (
+            <Grid2>
+              <RelativeTimestamp timestamp={device.status.plenum.timestamp} />
+            </Grid2>
+          )}
         </Grid2>
       </PulseBox>
     </Tooltip>

src/common/StatusSen5x.tsx

@@ -3,12 +3,14 @@ import { blue, green, orange } from "@mui/material/colors";
 import { makeStyles } from "@mui/styles";
 import { Device } from "models";
 import PulseBox from "./PulseBox";
+import RelativeTimestamp from "./RelativeTimestamp";
 import { or } from "utils";
 import { useEffect, useState } from "react";
 
 interface Props {
-  device: Device
+  device: Device;
   noDust?: boolean;
+  showTimestamp?: boolean;
 }
 
 const useStyles = makeStyles((theme: Theme) => {
@@ -50,7 +52,7 @@ const useStyles = makeStyles((theme: Theme) => {
 })
 
 export default function StatusSen5x(props: Props) {
-  const { device, noDust } = props;
+  const { device, noDust, showTimestamp } = props;
   const classes = useStyles()
   // console.log(noDust)
   const colors = or(device.status.sen5x?.overlays.map(overlay => overlay.color), []);
@@ -200,6 +202,11 @@ export default function StatusSen5x(props: Props) {
               </Typography>
             </Grid2>
           </Grid2>}
+          {showTimestamp && device.status.sen5x?.timestamp && (
+            <Grid2>
+              <RelativeTimestamp timestamp={device.status.sen5x.timestamp} />
+            </Grid2>
+          )}
         </Grid2>
       </PulseBox>
     </Tooltip>

src/hooks/useDeviceStatusStreams.ts

@@ -0,0 +1,138 @@
+import { pond } from "protobuf-ts/pond";
+import { useEffect, useRef, useCallback, useMemo } from "react";
+
+/**
+ * Derives the WebSocket base URL from VITE_APP_API_URL.
+ * Matches the logic in useWebSocket.ts.
+ */
+function getWsBaseUrl(): string {
+  const apiUrl = import.meta.env.VITE_APP_API_URL;
+  if (apiUrl) {
+    return apiUrl.replace(/^http/, "ws");
+  }
+  const protocol = window.location.protocol === "https:" ? "wss:" : "ws:";
+  return `${protocol}//${window.location.host}`;
+}
+
+export interface UseDeviceStatusStreamsOptions {
+  /** Device IDs to stream status for (e.g. from the visible devices list) */
+  deviceIds: string[];
+  /** Called when a device status update is received */
+  onStatusUpdate: (deviceId: string, status: pond.DeviceStatus) => void;
+  /** Auth token passed as ?token= query param */
+  token?: string;
+  /** Whether the connections should be active. Default true. */
+  enabled?: boolean;
+}
+
+/**
+ * Subscribes to live device status streams for multiple devices.
+ * Uses the /v1/live/devices/:device/status endpoint per device.
+ * Readings (plenum, sen5x, co, co2, no2, o2, etc.) stream in real time.
+ */
+export function useDeviceStatusStreams(options: UseDeviceStatusStreamsOptions) {
+  const { deviceIds, onStatusUpdate, token, enabled = true } = options;
+
+  const onStatusUpdateRef = useRef(onStatusUpdate);
+  onStatusUpdateRef.current = onStatusUpdate;
+
+  const wsMapRef = useRef<Map<string, WebSocket>>(new Map());
+  const retriesRef = useRef<Map<string, number>>(new Map());
+  const reconnectTimeoutsRef = useRef<Map<string, ReturnType<typeof setTimeout>>>(new Map());
+
+  const connect = useCallback(
+    (deviceId: string) => {
+      if (!token || !deviceId) return;
+
+      const params = new URLSearchParams();
+      params.set("token", token);
+
+      const path = `/live/devices/${deviceId}/status`;
+      const url = `${getWsBaseUrl()}${path}?${params.toString()}`;
+      const ws = new WebSocket(url);
+      wsMapRef.current.set(deviceId, ws);
+
+      ws.onopen = () => {
+        console.debug(`[ws] connected: ${path}`);
+        retriesRef.current.set(deviceId, 0);
+      };
+
+      ws.onmessage = (event) => {
+        try {
+          const raw = JSON.parse(event.data);
+          const status = pond.DeviceStatus.fromObject(raw ?? {});
+          onStatusUpdateRef.current(deviceId, status);
+        } catch (err) {
+          console.warn(`[ws] failed to parse device status for ${deviceId}:`, err);
+        }
+      };
+
+      ws.onerror = () => {
+        console.warn(`[ws] error on ${path}`);
+      };
+
+      ws.onclose = (event) => {
+        wsMapRef.current.delete(deviceId);
+
+        // Don't reconnect on clean close or auth rejection
+        if (event.code === 1000 || event.code === 4001 || event.code === 4003) {
+          return;
+        }
+
+        const retries = retriesRef.current.get(deviceId) ?? 0;
+        const delay = Math.min(1000 * Math.pow(2, retries), 30000);
+        retriesRef.current.set(deviceId, retries + 1);
+        console.debug(`[ws] reconnecting ${path} in ${delay}ms...`);
+
+        const timeout = setTimeout(() => connect(deviceId), delay);
+        reconnectTimeoutsRef.current.set(deviceId, timeout);
+      };
+    },
+    [token]
+  );
+
+  // Normalize for stable comparison: same set of IDs = same string regardless of order
+  const deviceIdsKey = useMemo(
+    () => [...new Set(deviceIds)].sort().join(","),
+    [deviceIds.join(",")]
+  );
+
+  useEffect(() => {
+    if (!enabled || !token || deviceIds.length === 0) {
+      wsMapRef.current.forEach((ws) => ws.close(1000, "disabled"));
+      wsMapRef.current.clear();
+      reconnectTimeoutsRef.current.forEach((t) => clearTimeout(t));
+      reconnectTimeoutsRef.current.clear();
+      return;
+    }
+
+    const currentIds = new Set(deviceIds);
+
+    // Connect to new devices
+    deviceIds.forEach((id) => {
+      if (!wsMapRef.current.has(id)) {
+        connect(id);
+      }
+    });
+
+    // Disconnect from devices no longer in the list
+    wsMapRef.current.forEach((ws, id) => {
+      if (!currentIds.has(id)) {
+        ws.close(1000, "device removed");
+        wsMapRef.current.delete(id);
+        const t = reconnectTimeoutsRef.current.get(id);
+        if (t) {
+          clearTimeout(t);
+          reconnectTimeoutsRef.current.delete(id);
+        }
+      }
+    });
+
+    return () => {
+      wsMapRef.current.forEach((ws) => ws.close(1000, "cleanup"));
+      wsMapRef.current.clear();
+      reconnectTimeoutsRef.current.forEach((t) => clearTimeout(t));
+      reconnectTimeoutsRef.current.clear();
+    };
+  }, [enabled, token, deviceIdsKey, deviceIds.length, connect]);
+}

src/pages/Devices.tsx

@@ -190,6 +190,15 @@ export default function Devices() {
     localStorage.setItem('groupGas', groupGas.toString());
   }, [groupGas]);
 
+  const [showTimestamp, setShowTimestamp] = useState(() => {
+    const stored = localStorage.getItem('showTimestamp');
+    return stored !== null ? stored === 'true' : false;
+  });
+
+  useEffect(() => {
+    localStorage.setItem('showTimestamp', showTimestamp.toString());
+  }, [showTimestamp]);
+
   const [preferencesAnchor, setPreferencesAnchor] = useState<any>(null)
 
   const [{ as, team }] = useGlobalState()
@@ -646,7 +655,7 @@ export default function Devices() {
           if (device.status.plenum?.temperature) {
             return (
               <Box sx={{ marginLeft: 1 }}>
-                <StatusPlenum device={device} />
+                <StatusPlenum device={device} showTimestamp={showTimestamp} />
               </Box>
             )
           } else {
@@ -666,7 +675,7 @@ export default function Devices() {
           if (device.status.sen5x?.temperature) {
             return (
               <Box sx={{ marginLeft: 1 }}>
-                <StatusSen5x device={device} noDust={separateDust} />
+                <StatusSen5x device={device} noDust={separateDust} showTimestamp={showTimestamp} />
               </Box>
             )
           } else {
@@ -682,7 +691,7 @@ export default function Devices() {
           if (device.status.sen5x?.temperature) {
             return (
               <Box sx={{ marginLeft: 1 }}>
-                <StatusDust device={device} />
+                <StatusDust device={device} showTimestamp={showTimestamp} />
               </Box>
             )
           } else {
@@ -700,7 +709,7 @@ export default function Devices() {
           if (device.status.co) {
             return (
               <Box sx={{ marginLeft: 1 }}>
-                <StatusGas device={device} gasType={groupGas ? "all" : "co"}/>
+                <StatusGas device={device} gasType={groupGas ? "all" : "co"} showTimestamp={showTimestamp} />
               </Box>
             )
           } else {
@@ -718,7 +727,7 @@ export default function Devices() {
           if (device.status.co2) {
             return (
               <Box sx={{ marginLeft: 1 }}>
-                <StatusGas device={device} gasType={"co2"}/>
+                <StatusGas device={device} gasType={"co2"} showTimestamp={showTimestamp} />
               </Box>
             )
           } else {
@@ -736,7 +745,7 @@ export default function Devices() {
           if (device.status.no2) {
             return (
               <Box sx={{ marginLeft: 1 }}>
-                <StatusGas device={device} gasType={"no2"}/>
+                <StatusGas device={device} gasType={"no2"} showTimestamp={showTimestamp} />
               </Box>
             )
           } else {
@@ -754,7 +763,7 @@ export default function Devices() {
           if (device.status.o2) {
             return (
               <Box sx={{ marginLeft: 1 }}>
-                <StatusGas device={device} gasType={"o2"}/>
+                <StatusGas device={device} gasType={"o2"} showTimestamp={showTimestamp} />
               </Box>
             )
           } else {
@@ -894,6 +903,16 @@ export default function Devices() {
             </ListItemIcon>
             <ListItemText primary={"Group Gas"} />
           </MenuItem>
+          <MenuItem 
+            onClick={() => setShowTimestamp(!showTimestamp)}
+            sx={{ marginLeft: -0.75 }}
+            dense
+          >
+            <ListItemIcon>
+              <Checkbox checked={showTimestamp} />
+            </ListItemIcon>
+            <ListItemText primary={"Show Timestamp"} />
+          </MenuItem>
       </Menu>
     )
   }