Uma parte da revisão foi traduzida automaticamente.
Hi All, It can be hooked up to a simple usb/serial converter (only 4 wires required). Make sure the data lines (Tx and Rx) use 3V signalling. Running a simple powershell script the data is displayed. Script: [Byte[]] $request = 0xff, 1, 0x86, 0, 0, 0, 0, 0, 0x79 [Byte[]] $res = 0, 0, 0, 0, 0, 0, 0, 0, 0 $port = new-Object System.IO.Ports.SerialPort COM57,9600,None,8,one $port.Open() $port.Write($request, 0, 9) Start-Sleep -Milliseconds 50 For ( $i = 0; $i -lt 9; $i++ ) { $res[$i] = $port.ReadByte() } Write-Host "CO2: $($res[2] * 256 + $res[3]) ppm, Temp: $($res[4]-40) C" $port.Close() Display: CO2: 876 ppm, Temp: 24 C If you try it, please set the port parameter (COM57 in my case) according to your system. Bleph
Is it a fiber fabry perot interferometer that exploits the absorption of the infrared ray of CO2 ? Is it necessary to remove the protective film on both sides of the sensor before use?
This is a MH-Z19B 0 - 2000ppm Not a 0 - 5000 ppm Confirmed with an oscilloscope. Seems accurate I am very pleased. Just remember to calculate for 2000 ppm.
Seems to do what it says on the box. Inside with a gas heater (with flue) on I got (with the script above, cheers) an uncomfortably high reading >1200ppm so I took it outside and got 385ppm after a few minutes, which seems right. So I have a window open now :-)
Folha de dados em alguns aspectos enganadora. Finalmente consegui pô-lo a funcionar. Agora, ele mostra resultados razoáveis. A qualidade parece boa.
it arrived in 2 weeks, in a good packaging. It works well. good deal.
Works as specified, worm up phase is longer than 3 minutes, but under 5 min. Supplycurrent is quit high with peaks, but on average also as specified.
Я иногда задавался вопросом, почему в зимюю пору утром бывает тяжелая голова. Прошлой зимой даже купил увлажнитель воздуха, думал это из-за сухого воздуха. Купив этот датчик и собрав прибор я понял что голова тяжелая из-за высокой концентрации СО2. В квартире с пластиковыми окнами за ночь конценрация СО2 поднимается до 1500-1800 ppm. Если окно оставлено на проветривание то концентрация СО2 на превышает 600-700 ppm. Рекомендую отключить автокалибровку и делать калибровку вручную раз в пару недель.
Eventually I got this working with my Raspberry Pi-0w, we can use this for teaching respiration etc. in schools, the quick response to perturbation is helpful. CO2 concentration as expected, but I didn't yet check quantitative accuracy. Need to solder pins but connects straight to pi serial uart, no extra interface needed, although pi serial config is tricky. You can find sample python codes on internet (but check carefully for characters lost on copy-paste). Seems robust, working non-stop for days.
Estava tudo bem com o envio. A soldagem dos pinos foi um pouco difícil. Ele funciona bem junto com um TTGO ESP32. As medições estão entre 400 e 1000 ppm em uma sala onde eu trabalho. A única desvantagem ao trabalhar com a bateria, as medições vão para o máximo, o consumo de corrente é de cerca de 150-180 mA, portanto, talvez a bateria esteja fraca.