I’m one of the first purchasers of the Sparrow. Overall, it does what it’s supposed to, but it’s not perfect.
1. The single worst situation: when its battery was running low and the device was not paired to my iPhone, pairing it caused it to send out an emergency “excessive CO alert” both to me and to my son, who is my alternate contact. It was concerning to both of us, because I’d just had the water heater replaced the previous day. But because my household CO detector did not go off, I was less concerned than I might have been. It appears to have been a “known glitch”, which I learned when I reported that event to Sparrow, but I don’t know if it has been corrected. Such a glitch really reduces the device’s usefulness, because it leads one to disregard it as a “boy cried wolf” situation.
2. The device will become unpaired from my iPhone for no particular reason. Because it uses Bluetooth to connect, it’s understandable that excessive distance between the device and my iPhone will cause a disconnect. But it can be sitting on the same table and suddenly disconnect. That triggers a notification, but it shouldn’t happen, as it isn’t useful if it’s not connected. So far as I’m aware, it won’t signal an anomaly unless paired, even when it’s within normal reception distance.
3. The data graph is difficult to read on a small screen. Because both the horizontal and vertical lines are widely spaced, it’s hard to interpolate when an event happens or how much the measured item has deviated.
4. Because the device is so small, it’s easy to misplace. There should be some way to have a “find my Sparrow” connection that assists to locate it from the phone.
5. Other than the “home” page, there is nothing to warn that the battery is getting low. Referring to my #1 above, I had not looked at the Sparrow app for several days and did not know that the battery was getting so low as to cause any glitches. There should be a notification that the battery needs recharging.
6. On the positive side, the battery lasts a long time. Recharging it is easy enough to do, other than opening the rubber charging port cover is annoying. But there’s no indication when the battery has been fully charged, unless first it’s disconnected from the charger, allowed to rest for awhile, and then the home screen on the iPhone is viewed. Like all rechargeables, if its charging status is viewed while it’s being charged, it shows the input power, and it has to rest for awhile after it’s been disconnected before it shows the actual state of charge of the battery.