Qingping Air Detector (AKA ClearGrass Air Detector) is one of the best portable devices reviewed yet.
Impressive tech specs and design. Can be used both: as portable and not portable. And in a mixed way too. Good sensors for tvoc, t/rh, co2. High-resolution touch screen, Wi-Fi (that remember all Wi-Fi you were connected to), ambient light sensors, android and ios mobile app. And all that for a bit more than 100$ (incl. Delivery). For this price tag, it is a kind of flawless device. So the minor issues are not critical at all. Like it might have a different CO2 sensor (SenseAir S8 instead of Sensirion SDC30 for example) inside. But since S8 is not bad. It is still ok.
Yet another highly portable standalone CO2 Meter. This one with great battery life. One of the recommended devices. It is not absolutely flawless but is ok to buy. It got fast, accurate, and low power t/RH sensor (Sensirion SHTC3). Its CO2 sensor is kind of average (Cubic 1106 probably). Charging 5v 1A
2400 mAh battery (~20 hours of battery life)
Small and relatively lightweight (8x3cm, 145g)
Calibration can be done manually
Correct t/RH during normal operation
Leading zero in CO2 display
CO2 measurements might sometimes be wrong
CO2 measurements delay is on power on
CO2 measurement interval is 16/4 sec (10 sec average)
t/RH measurements during charging is a bit incorrect
That is quite a long story of smartphone makers are trying to create powerful Qi charging devices. And usually, they are all fails. Wireless chargers are still noticeably slower than wired. And also less power-efficient. And also not reliable. With some previous wireless charging docks, you someday waking up with your phone not charged at all. And there are a couple of reasons for that. First is coils misalignment, which reduces all (speed, efficiency, and reliability). The second is power loss and related overheating (affects speed and efficiency). So what is good about Apple MagSafe 15W Qi charger. It solves the first issue. Coils are now aligned. So you can be more or less sure that you will get your phone charged. But it mostly ignores the second. Qi charger is still overheating. And that is slowing down the charging process. Yes, it is an aluminum body, and that is kind of good news. But that is definitely not enough. So for a period of 3-5 hours of wireless charging, you will get 15W only for a short period of time. Usually, it is about 5-7 minutes. And the most interesting part there is 7.5W charger may charge faster than the 15W charger just because of less initial overheating.
So the usual charging may look like graphs below
That is just about 4 hours. But results may vary a lot. That is highly dependent on temperature (room temperature, phone temperature, table temperature), on do you charge with a charger below or above the phone. Do you use a case or does the phone do some background tasks. Do your air moving in the room. It impacts Qi charging speed much more if compared to wired charging.
Wired charging from same 20W power adapter:
It is for the same conditions, same case, same temperature, same table. Just about twice faster. And power consumed is 14.5Wh instead of 22Wh to charge an iphone 10.78 Wh battery (while phone is on, but not in use). That is about 3 times more energy lost on generating heat.
So How to get 15W we pay for? That is easy :). You need to place the phone (without a case) in some cold place with airflow for at least the first 30 minutes of charging.
And if you got proper cooling you will get something like:
Still a bit worse than wire charging in the room. But anyway we got our 15W Qi. It exists and it is fast. (That is kind of sarcasm).
So what is wrong with Apple Magsafe Charger?
it is slow
it consumes more power
it is expensive
One more thing.. about power consumption. Idle power consumption is also might be an issue. Lightning cable inserted in 20W AC adapter consume much less power (0.0025W) in idle mode (when you do not charge anything) than MagSafe charger (0.34-0.5W). So if you kind of eco-friendly person you better plug out the MagSafe charger every time you are done with charging.
It is several years already I trying some Air Quality monitors. And I think it is time to post some of the results. So here it is. Overview of some Air Quality monitors tested so far.
For me perfect device is the one:
measure multiple parameters
display information locally
has a battery and can be used as a mobile tool
is an IoT device with Wi-Fi connectivity and mobile app
not cost a fortune
Some of the requirements are cannot (or at least not easy to) be met simultaneously. A lot of advanced sensors with Wi-Fi connectivity and good mobile application make the device expensive. Battery and battery charging circuits usually affect temperature and relative humidity measurements. Active airflow improves measurement speed and quality but makes devices noisy. So there is no single perfect device yet to cover all Air Quality Monitor use cases. That is why I choose some devices I like more by category.
IoT Air Quality Monitors
Best IoT Air Quality Monitor “award” goes to AWAIR 2
So as you can see above the device is not perfect. It is noisy, that is how good airflow and better measurement quality and speed achieved. Some Sensors are not the best in class, that is how the price is lower than 200$. For more details see AWAIR 2 Review.
✔️ quiet, more parameters (CO, O3, NO2), iPad app ❌ expensive (330$), cheaper sensors, no local display
AirVisual Pro (Node)
✔️ large display, outdoor data for PM2.5, battery, iPad app ❌ more expensive (280$), fewer parameters (no VOC)
Netatmo Smart Home Weather Station (Urban Weather)
✔️ quiet, weather station (external t/RH module), iPad app, 180$ ❌ fewer parameters (no PM2.5, no VOC), poor CO2 sensor
Again, as it was with the best IoT device, this one is not perfect. It is noisy, it has no Wi-Fi/Bluetooth/etc, humidity measurements may show -10% RH on high humidity tests, but still, it is better than some others and good for the price.
Old school device with separate analog temperature and humidity sensors, Old model of CO2 sensor. No other air quality sensors present. Need to be always plugged. But still one of the best in measurement quality.
Dienmern DM601 is a portable air quality monitor with two options available DM601A and DM601B. The difference is in additional HCHO sensors. Model DM601A has no HCHO sensor onboard.
The device has SHT30 temperature and humidity sensor but measures temperature wrongly due to device self-heating and poor thermal design (see thermal photos of DM601A). The battery is 3000 mAh that gives about 5 hours of both charging time and battery life (see details).
Most of the sensors inside DM601 are unbranded. No Wireless connectivity. Usability is average. Measurements (except temperature) are more or less ok.
Multi-sensor (CO2, PM2.5, TVOC, HCHO) air quality monitor with Bluetooth and Wi-Fi.
Applications are available for iPhone, iPad, Android phones.
By its design Air Mentor is not a portable IoT device. It has no battery. It has no display. So it is an alternative to uHoo (and to some extent to Netatmo). If compare Air Mentor 2s to uHoo: Air Mentor 2s have HCHO sensor. But uHoo measures CO, O3, NO2, pressure instead. Netatmo is actually a weather station with an external t/RH sensor, that also measures air quality by CO2 parameter only. Air Mentor 2s got a more expensive CO2 and t/RH sensors than both Netatmo and uHoo.
Temperature and Humidity sensor (SHT30) is both good itself and placed correctly on the bottom of the device with some gap from the mainboard. More or less as it is recommended by the Sensirion guide.
There are some issues with the current versions of mobile applications. For example, you cannot connect the device to Wi-Fi access points using iOS devices (it works using the Android version). Russian localization is not complete. Trend data from cloud not always loading (for both iOS and Android).
Hti HT-401 is the most portable CO2 meter I have. It is small and simple. It is only 75 mm in diameter and 25 mm in depth. Weight is 62 g. That is including 14250 (1/2AA) 300 mAh battery. Its only button is power. It count 30 seconds before actually show the CO2 level. And it automatically power off after 30 minutes.
Four-digits LED display only shows CO2 level and 3 emoticons ?<600ppm ?600-1200ppm ?>1200. That is it. No settings for emoticons limits. No setting for the power-off timer. Not display temperature and humidity, nor time and date. Just one sensor inside and that is well known SenseAir S8 LP. That provides correct readings. Changing the environments not impact accuracy. The device is relatively cheap (I bought it for about 75$ without battery on Aliexpress)