humidifiers and led on relay

Hi i am currently building humidity tanks with led lighting. I am new to arduino and while ive done some research i cant seem to figure it out. I am trying to wire up 4 dht22 humidity sensors to the mega2560 to control an 8 channel relay board 4 of the relay channels will control 4 seperate ultrasonic humidity sensors to keep a certain humidity sensor. and the led lighting will be on the other 4 relay channels controlled by a clock module to keep the lighting on at certain times of day. I feel decently comfortable i can get the code working if i can figure out how to wire it up. can any one help me out?

Read how to use this forum, it is a sticky post on the top of each forum
read #7 about how to post code.
then post your code.

Hi,
Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html then look down to item #7 about how to post your code.
It will be formatted in a scrolling window that makes it easier to read.

Hi
i am currently building humidity tanks with led lighting.
I am new to arduino and while ive done some research i cant seem to figure it out.
I am trying to wire up 4 dht22 humidity sensors to the mega2560 to control an 8 channel relay board
4 of the relay channels will control 4 seperate ultrasonic humidity sensors to keep a certain humidity sensor.
and the led lighting will be on the other 4 relay channels controlled by a clock module to keep the lighting on at certain times of day.
I feel decently comfortable i can get the code working if i can figure out how to wire it up. can any one help me out?

Sorry had to open it up to get your points.
Have you written any code.
You need to do this in stages and there are many tutorials on how to connect the DHT22.
Attempt and get working just using one DHT22 first and work up.

And many more if you google arduino dht22 tutorial

Tom... :slight_smile:

connect the relay module to 8 of the digital pins, connect the grounds.

if you can get the relays to click, you got the wiring right

you CANNOT power the relay board from the MEGA. you MUST use a separate power supply.

if you look at the blink example, just change pins to a relay. and extend the time to a couple seconds.

I got my wiring down but as far as the separate power supply for the relay board I tried soldering bus wires with

female connectors to a 5v 2.0A charger with no luck connected gnd to gnd and power to jd vcc. maybe my relay

board is bad cause it wont power on whatsoever. Maybe my board is bad or i did my external power supply

wrong.

Hi,
Do you have a DMM?

Tom.. :slight_smile:

Well, I really don't seem to be able to understand the following:

I am trying to wire up 4 dht22 humidity sensors to the mega2560 to control an 8 channel relay board 4 of the relay channels will control 4 seperate ultrasonic humidity sensors to keep a certain humidity sensor

I have not yet read or know about ultrasonic humidity sensors, they must be amazing!
How can you possibly control sensors ? Sensors are devices used for sensing, not controlling.

Are you trying to say you will use four DHT22 temperature and humidity sensors to control some humidifier pumps or solenoid valves to then supply water into an air flow to maintain humidity to a setpoint ?
If that is correct, why did you not then write this ?

Please describe in more accurate detail what you are needing to do and what devices you are wanting to use to achieve the desired result.


Paul - VK7KPA