Can i run all these sensors and how to divide arduino 5v

1 x Light Intensity Sensor Module 5528 Photo Resistor
1 x RTC Real Time Clock DS3231 I2C AT24C32 Board Module
2 x DS18B20 Waterproof Digital Probe Temperature Sensor
1 x DHT11 Digital Humidity & Temperature Sensor
1 x Soil Hygrometer with a LM393 driver board
2 x 5V 2 Channel Relay Module, powered from separate source but still require 5v from board?

So i have enough i/o pins etc, but most of these sensors will require 5v from the board which got me thinking if they were all using resistance to measure what ever they are sensing is this something to be concerned about?
Also how do i join the, just connect them all together to a wire coming from the 5v board?

Regards jon

You'll definitely need to use an external 5V supply for all of those. First get a decent 5V regulator or switch mode power supply, then connect that to all of the sensors as well as the 5V pin on the Arduino.

Which Arduino do you plan on using?

... and connect all the ground wires together.

I'd also have a look at the datasheets for all those parts and add up the total current consumption before buying a regulator or power supply.

Cheers for the quick response guys, my arduino will be powered from a 12v atx psu, so i might as well use the 5v from the psu too? So i would hook up all the 5v vcc from the sensors to the 5v psu then, then the arduino will just calculate what voltage is coming back in from the i/o pins?

Just to get this right, i would also connect all the grounds from the sensors to the ground of the psu or arduino?

Regards

To prototype all this stuff and get it all working I suggest purchasing a breadboard and some male-female and male-male jumper wires. The breadboard will provide power rails for you to distribute your power while testing.

chefslot: Cheers for the quick response guys, my arduino will be powered from a 12v atx psu, so i might as well use the 5v from the psu too?

Unless you have stuff that powers from 12V then I wouldn't use that at all.

Just use the 5V rail from the PSU to power everything (make sure everything is 5V).

Ok, i was going to power the arduino through the jack, i don't believe i can do this with 5v can i? I thought it was in the range of 7 to 12, the usb input will be in use for if i have to change code as the arduino will be in a hard to reach place, so when i want to adjust anything i will hook it up to a laptop via usb to a female usb that will come from the arduino. So this leaves me with the 5v socket then.

How much tolerance in the 5v are we talking, ok if it goes to 5.4v?

chefslot: Just to get this right, i would also connect all the grounds from the sensors to the ground of the psu or arduino?

All sensors and the Arduino need a common ground.

You can power the Arduino through the jack at 12v (still connect grounds together), or can supply 5v into the 5v pin to bypass the regulator on the Arduino. There has been some debate on the 5v pin supply method, but my understanding is that this is safe to do.

chefslot: How much tolerance in the 5v are we talking, ok if it goes to 5.4v?

5.4v is below the maximum rating for a 328p based board.

Make a sketch of your intended wiring, take a picture, crop and downsize to something reasonable, then post it here so that the really clever people can have a look. Guidelines for adding a photo (and how to get the best replies to a question) are all on the forum (somewhere :) )

As @npkamen says, a breadboard is a good investment.

Yeah i have got a breadboard just a cheap fleabay one.

Ok here we go. So i thought i will give some enlightenment before i post up a drawing to help talk through my goals. This is a little over kill i know but once i started i couldnt stop. I have a 3ft fish tank that i’m planing on turning into a paludarium, but i have gone a little over the top here as i started getting into micro climates a little too much. I will dial in the parameters first before adding any animals etc so please dont worry.

All my gear will be ran from a mini desktop case, so i have thought about heat and the safety side of this too. It will be mounted in a old pine dresser, space is tight so i’m worried about heat and venting air that will have highish humidity.

So to start of with i will need lighting, using a meanwell apc 35 500. I think i went ott on the LED side of things but have got them so i can switch to different effects from blues to reds to whites. That side of things is ok, it’s more about the control off items now.

So the RTC will give arduino the time, just in case of any power failures.

The arduino will turn on relay #1(NO) that is wired to Relay #2 (i might be able to get rid of this relay if i can program a good sketch) which will be set to (NC). This will open if one of the two temp sensors in the case and above the LED’s reaches a certain threshold. So in effect it is a safety device in case my equipment gets too hot or my fan above the LED’s stops working.

Fan #4 will be mounted above the active LED heatsink. Stupidly?? I thought this would be fun to operate via a light sensor rather then adding this to a sketch via timer. The fan speed is set to a manual pc fan controller that nicely fits in my case ^^

As you can see i haven’t given power to the sensors as of yet, and yellow is +12v and red is +5v. This is going to get complicated but i do enjoy the learning curve.

The moisture sensor to measure the dampness in the moss and just above the waterline will be a easy notification with a led to signal to me, but it is another sensor that require juice. I also will have the other fans on but they will be assisting air circulation around the dresser front to back and the case to eliminate any heat or damp patches.

Sorry, but I don't feel confident about giving advice on any project involving mains voltage. As a hobbyist I am not qualified nor have relevant skills or indeed the indemnity insurance needed to provide any further help.

Best of luck with your project.

The other problem i think i might have is going to be temperature in the summer, the winter is quite easy to deal with as i can add aquatic heating elements and it is generally easier to warm up rather than to cool. Also humidity in the uk is generally high. So hoping to use the humidity temp sensor placed discretely behind a rock or some wood to activate a cheap peltier dehumidifier. This should allow for cold air to pass into the tank if needed. I was going to look into a fogger as well, but like i say unless i need 95% plus relative humidity then i think i should be ok with the natural evaporation and perspiration of the plants.

The buck converter will take 12v and step it down to 9v, and around the 2A mark. once the sensor reaches a value over a threshold will then activate a relay where the cooling part of the peliter has a heatsink in the air ducting, lowering air temperature. I’m planing of having the air ducting at a steady flow so one less thing to worry about.

I’m also planing to rig up a phone and a 12v dc charger to remotely get email updates as well, as using andriod there are loads of software that will take a picture and send to my email over wifi. I did say i went over the top.

Sorry for the long posts here.

Martin-X: Sorry, but I don't feel confident about giving advice on any project involving mains voltage. As a hobbyist I am not qualified nor have relevant skills or indeed the indemnity insurance needed to provide any further help.

Best of luck with your project.

Hi Martin, thank you for being honest, it is all going to be ran from a RCD. I haven't skimped on anything that is on the 240v side, a meanwell LED driver, the psu is a bronze rated(it looks after it's self), all is grounded and grounded again, the whole unit will be tested as extreme scenario with heat temputure gun and power consumption, the electronics are placed higher than water and well vented the only mains power is the LED driver being switched from the relay, and the relays are operated via Optocouplers. But thank you very much anyway, believe me the 240v side was the easy part.

Regards jon