Forum Sensor.Community

How to power the air sensor kit

I’m a noob in electronics but managed to build the air sensor kit #1 with the guide. But… the guide stops to soon. It doesn’t give examples how to power the sensor outdoors. Can you guys help me with some options?

  1. Using the power outlet indoors, but I need to drill a hole for the micro USB cable.
  • i’m reading on the internet about needing a repeater when using a cable > 5m?
  1. Using the power outlet outdoors
  • Can’t find a waterproof 230v to micro-usb adapter
  • Can I use a extender box (like this) where i put the USB-adapter in the box? Or is it going to give heat problems?

Thanks in advance!

  1. Using the power outlet indoors, but I need to drill a hole for the micro USB cable.

It is not necessary to make a hole if you pass it through a window near with the rubber gaskets and better if the USB cable is flat, as recommended in Kit1. Now I am testing and I have a wide cable and it does not cut.

Try using a slim usb cable. It can fit nicely even with closed windows!

Powering Sensor Kit at distances over 5 meters may be tricky in some situations. SDS011 to work properly requires at least 4.7V. Lower voltage may result in wrong readings - mostly because of different fan speed and laser performance (I’ve tested that in my LAB). Also please take in consideration that some dev boards (eg. NodeMCU V2) have protective diode between USB and 5V pin - that will add 0,2-0,3V of voltage drop. A valid option may be finding 5,2V USB power supply.

However where ever I can I use D-Link 5V 1,2A power adapters made for LTE routers. They are cheap, available in large quantities and they give nice 5,15V. Also they are designed for 24/7 operation. Build-in overcurrent protection is additional safety feature. Among tested units are AMS1-0501200FV and CF0605-E which we use extensively in Nettigo Air Monitor Project (500+ pcs and counting, not even one faulty power adapter).

With NodeMCU V3 at distance of 11 meters I’ve tested this configuration:

  • 2 pcs x DC 5m extension cable (2x0.5mm²) with barrel jack 2.1/5.5 connectors
  • 1 pcs x DC barrel jack to micro USB adapter
  • 1 pcs x D-Link 5V 1,2A power supply

Anyway it’s better to power on 5V rail directly. If cables are really long you may consider supplying 9-12V and using Step-Down converter near the sensor.

Long time ago I’ve made a board for powering sensor over long distances. With barrel jack connector and additional capacitor:

But we abandoned this conception and went straight to NAM 0.3 with enclosure instead water pipes.

As @Denis pointed out - you don’t need 230V power outlet outside. Flat cables are squished between window rubber gaskets without a problem.

I’m developing this

can be used with a 12V to 5V buck converter.

Thanks to all replies! We are getting a few steps further!

The spot i want to put it is not near a window, and there are no outside power outlet solutions yet, so i’m looking for other solutions… do you guys see the possibility of using a small solar panel & a powerbank (of sorts)?

P.S. I dont know how to edit the first post/ topic start so i’ll try to summarize it as follows;

I don’t think it is practical to use batteries and solar power, at least, not here in the UK (latitude 51 degrees) in winter.

I have a typical setup. SDS011, BME280, DHT22, ESP8266. It is powered from Li-ion batteries - a pair of Soshine INR 26650 5500mAh. Running exclusively on battery I get about 4 days and 9 hours before the system shuts down. The DHT22 dies first, then about half an hour later the ESP8266 dies.

I can recharge the batteries through a TP4056, and I monitor the battery charge/discharge with an INA219 device. A DC-DC converter keeps a steady 5.1V for the SDS011.

The whole system draws about 80mA. When the SDS011 bursts into life consumption goes up to just over 100mA.

I have a solar panel rated at 6V 1.67A (340mm x 220mm). In theory one hour of full bright sun should give me enough energy for about 15hrs runtime. The reality is that there is not enough bright full sun to keep the system fully charge and running day after day in winter. I have to supplement the solar charge with some mains charging.

Last December we had just 3 hrs of full bright sun in the whole month.

If you want to see a .csv file of data from today showing the charge/discharge follow this link. Sunrise is about 8 a.m. You can see the current from the battery dropping from about 80mA. There was fluctuating cloud cover until lunch time when it clouded over properly. Mains charging started about 4 p.m.

I hope this is of interest.