It is certainly a very valid observationThis is very useful if we need to power certain sensors or peripherals at 5 volts, especially if it requires a power supply that is very close to the exact 5V (as is the case of the MH-Z19C CO2 sensor that needs to work, according to the manufacturer's specifications, a voltage between 4.9 and 5.1 volts). With the MH-Z19B you're lucky because its input range is wider (although it's so close to the limit that it's almost certainly not working for some people and they're getting jumpy values), but with the MH-Z19C it's not." In fact, in any project that needs 5V (motors), you need a dedicated power supply, you can't pull from Vin (from what I've been reading). In fact, the fact that it gives voltage when connected to micro USB is a by-product, not a specification. The Vin/GND is there to supply it with "unregulated" voltage between 5V and 12V. "I have been doing some research and it turns out that the ESP is incapable of supplying 5V. Specifically, the user said the following in his comment: In this article I talk about the example of powering an NDIR CO2 sensor but it is equally valid for any other type of sensor or actuator you want to power. It also applies to boards like the Wemos D1 Mini, ESP32 DevKit and the like. I decided that it was a very interesting topic and one that could be used for much moreThe article you are reading is the result of this, and I was able to cover it minimally (every time I tried to explain one point I realised that I had to explain others in order to make sense of it).īasically, the issue was, whether we can use the external power input of a NodeMCU for powering peripherals operating at 5 volts.Įverything I explain in the article is also valid for Arduino but with some caveats that I will discuss later (because there is not just one Arduino, but many, and you have to look at each one, because they are different). I started to reply to the comment and as I wrote, the reply became longer and longer and I realised that I needed more resources to answer it (images, video, a richer format, etc). Recently, the user Jesús, made a comment in the blog, specifically in the article of the Home CO2 Meter with wifi, really interesting. On many occasions, in our projects, we power our microcontroller via a USB cable connected to a mobile phone or computer charger and we need to power peripherals (sensors, screens, displays, LEDs, etc.) that operate at 5 voltsCan we do this without any problems through the NodeMCU? 3.5 Does this mean that we cannot use the MH-Z19C powered by Vin?.3.4 Powering the Senseair S8 LP via the Vin pin.3.3 Powering the MH-Z19C via the Vin pin.3.2 Powering the MH-Z19B via the Vin pin. ![]() 3.1 Powering the MH-Z19 via the Vin pin.2.2.3 What voltage does the Vin pin provide when powered by USB?.2.2.2 Do the 5 volt power supplies give 5 volts (sic)?.2.2.1 Are 5 volt devices powered at 5 volts (sic)?.2.2 From the point of view of what we connect to Vin (sensor, LEDs, buzzer, or whatever):.2.1 From the point of view of the NodeMCU and the USB port (computer/charger):.1.3 A special case: Powering the NodeMCU V0.9.CO2 Gadget Boxes, 3D Printed and without 3D printer.CO2 meter on your mobile phone with ESP32 and Sensirion SCD30 sensor.CO2 Meter TFT Colour Display with TTGO T-Display Sensirion SCD30 - The CO2 Gadget.CO2 on a giant screen for bars, restaurants, classrooms and the like.Full colour touch screen for CO₂ meter Wow!. ![]()
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