💬 Air Humidity Sensor - DHT

[Digdogger]

Hi,
I would like to use this example and reduce power consumtion by removing the regulator on the mini Pro and the power led.
If we remove the regulator, we can power the board with 3V on Vcc. It will be OK for the mini pro and the NRF but the DHT22 needs 3.3V minimum. The solution will consist to use a step up boost module. What is the current consumtion of the step up boost?

[gohan]

I don't know about DHT22, but NRF24 can work down to 1.8 or 1.9V so you can connect it directly to battery (take a look ad EasyPCB)

[AWI]

@Digdogger it's better to get rid of the DHT and use something more reliable and operating at lower voltages. Like si7021, sht21 or Bme280

[Digdogger]

Thanx for your answers. @AWI, the BME280 looks great and not expansive i will replace the DHT by this one. Thank you.

[jwosnick]

@Digdogger
Out of curiosity, do you expect there to be a big savings in power consumption by removing the regulator and power LED? I've never used the Mini Pro (the smallest I get to is the Nano) but I understand it already is very efficient with power usage.

[Digdogger]

@jwosnick: please take a look here: http://www.home-automation-community.com/arduino-low-power-how-to-run-atmega328p-for-a-year-on-coin-cell-battery/.
You'll see that the current saving is significant (almost 40% saving)

[gohan]

@jwosnick
Arduino is efficient for a live node, but for a battery powered sleeping node voltage regulators have a small drain on battery; led also consumes some power. The Nano has also the usb chip that is powered but not used that also increases battery drain. So, as rule of thumb, everything that is not really used/necessary will drain some battery over time.

[mfalkvidd]

@jwosnick with the led and regulator, battery life on 2xAA is about three weeks. Removing them will usually give you 2-5 years.

[jwosnick]

@mfalkvidd

Thank you. I didn't realize the differences were so stark.

I have some Pro Mini 3.3V units on order and hope to convert my sensors to that platform, when they arrive.

[hashem25]

hello I ran it but i didnt see anthing except the garbage in com monitor

[Nca78]

@hashem25 said in 💬 Air Humidity Sensor:

hello I ran it but i didnt see anthing except the garbage in com monitor

Hello, you need to change the baud rate at the bottom right of the Arduino serial monitor window until you see clear text.

[hashem25]

thanks it works

[anno]

How do i get 2 dht22's working in the code?

[gohan]

If you already have one, it is a matter of just repeating your code for the first sensor and just change the pin number where you connected the second one

[ianatkin]

This example doesn't seem to be included in the latest library version - am I being blind or is this deliberate?

[mfalkvidd]

@ianatkin that is correct. Follow the instructions under the "Example" headline on the build page.

[ianatkin]

@mfalkvidd Thanks :)

[mfalkvidd]

@ianatkin you're welcome. Great to see a new forum member :)

[godwinguru]

Is it the same code that i will burn to the controller circuit. Can someone help me with a little explanation on the code for the controller circuit so as to be receiving the temperature values

[MrVince]

Hi ! Thank's for working :)
I add the libraries in "MySensors external examples" to Arduino IDE but when I want to compile I have this one log error :

DhtTemperatureAndHumiditySensor.ino:43:25: fatal error: MySensors.h: No such file or directory
compilation terminated.

In MySensors folder's libraries, I have a MySensor.h, without 's' . This is one? Do I forget something?

Thanks