Hello,
I hope I'm posting the question in the correct forum.
There is something weird in my project and I hope you will be able to help me.
I built a controller for my aquarium. The controller includes:
Control 8 SSRs (using 8 digital pins) - each digital pin is connected directly to specific relay, and all relays are connected to the Arduino's GND.
Control 4 Opto relays (this is the board: DC Opto-Isolated Output Board) - the relays board gets his 5V and GND from the Arduino and there are 4 digital pins connected to the relay board.
I'm using 2 AC-DC adaptora (1000MA), both of them configured to 12V:
The first one is for the Arduino, and the second one is for the 4 pumps.
My problem is:
Today was the 3rd time I saw smoke coming out from the transformer, every time it was a different transaformer (I already bought 4!).
Can it be something I did or is the cheap transformers' blame?
What can I check in my project? Is there any suspect? Is there any chance I'm overloading it?
What can I check in my project? Is there any suspect? Is there any chance I'm overloading it?
I would think you are overloading the power supplies. Motors can draw much more than 1000ma when under load. You need to measure the current the pumps are using when operation.
Yes that would be the obvious cause. Running 4 motors off a 1A supply sounds like too much to me but you need to measure what you are drawing with a current meter.
Please notice that 1 out of the 3 adaptors that were burned was actually the one that connected to the arduino and not the one that was connected to the pumps (also the relay board is getting its 5v from the arduino).
Is it possible that I overloaded the adaptor that connected to the Arduino (keeping in mind all the digital pins and boards that connected)?
Please notice that 1 out of the 3 adaptors that were burned was actually the one that connected to the arduino and not the one that was connected to the pumps (also the relay board is getting its 5v from the arduino).
You are probably lucky you haven't burned ou the voltage regulating chip on your arduino powering relays thru it.
Please notice that 1 out of the 3 adaptors that were burned was actually the one that connected to the arduino and not the one that was connected to the pumps (also the relay board is getting its 5v from the arduino).
You are probably lucky you haven't burned ou the voltage regulating chip on your arduino powering relays thru it.
Do you think I should supply the 5V and GND from different place that is not Arduino?
What is the max mA I can draw from the 5V pin (not the digital pins but the 5V pin located near the GND pins)?
What is the max mA I can supply the Arduino board? If I'll found 12V 2A adaptor, will it damage the board?
What is the max mA I can drap from the VIN pin?
How can I "calculate" how much current I need? is it something like that:
(NUMBER_OF_USED_PINS*40) + (MA_FOR_THE_PH_BOARD) + (MA_FOR_THE_RELAY_BOARD) + (MA_FOR_LCD) + (MA_FOR_RTC)
or there is a difference between things that draw current from the 5V pin and things that draw current from each digital pin?
I must use 12V becuase my pH board should get 12V and I operate it from the VIN.
There is a series diode between the power jack and the Vin part of the circuit to protect against reverse polarity. That diode is rate at 1A so don't draw ant more.
OK...
It's a bit complicated for me, but slowly I think I'm getting it
I didn't understand the first article.
I'll use 12V 2A adaptor to power the following things:
pH Board --> powered directly from the VIN (I should not draw more than 1A for this board).
20X4 LCD --> powered from the 5V pin.
RTC --> powered from the 5V pin.
12V Relay board --> powered from the 5V pin.
DS18B20 (temerature) --> powered from the 5V pin (and also connected to pin 52)
2 Float switches --> powered from the 5V pin (and also connected to pins 22-23)
I'm really sorry for all these questions, but I'm really frustrated and don't understand.
So how is that supposed to work? I suggest you split the 12v power supply such that 12v is supplied seperately to the arduino Vin and to the other gizmos.
All the current from the 5v pin also goes through the Vin diode as well so the whole thing needs to run less than 1A. You are better powering your external board direct from the power supply and not going through the arduino's power jack.
I did some tests and I found the following (now I just need to understand what that means :))
I plugged the 2 multimeter probes: the black one into COM and the red one into mA.
I broke the GND in the circuit and touched it using one probe. The other probe was connected to the GND in the Arduino.
I switched the multimeter to "200m" and I saw the following number: 46.8
It is important to say that all digital pins where in LOW status, but the 12V (from the VIN) was connected.
What does this number mean?
The next test I did is for the 4 pumps:
I plugged the 2 multimeter probes: the black one into COM and the red one into 20A.
I broke the GND in the circuit and touched it using one probe. The other probe was connected to the GND of the wall adaptor.
I switched the multimeter to "20m" and I saw the following number: 0.74
What does this number mean?
Last question:
Grumpy_Mike:
All the current from the 5v pin also goes through the Vin diode as well so the whole thing needs to run less than 1A. You are better powering your external board direct from the power supply and not going through the arduino's power jack.
My wall adaptor has several connection types, can I use 2 connection at the same time (one to the Arduino and one to the pH board)? Will this be better for the Arduino?
All 4 motors were running when I tested it, so I guess each one takes about 180.
what about the arduino?
danofri:
I plugged the 2 multimeter probes: the black one into COM and the red one into mA.
I broke the GND in the circuit and touched it using one probe. The other probe was connected to the GND in the Arduino.
I switched the multimeter to "200m" and I saw the following number: 46.8
It is important to say that all digital pins where in LOW status, but the 12V (from the VIN) was connected.
What does this number mean?
I must say that your help is amazing, many many thanks!!
It means that it is taking 46.8 mA, this is typical and nothing to worry about.
The setting on your meter is the full scale or maximum it will show then the number is simply scaled to that.
I think that either you have wired up something wrong or you need to get better quality power supplies, ones that will give what they say they will.
OK...
I ran some tests and these are the result (all tests were done when the red probe was connected to exit called "mA" and not 20A and the multimeter is on 200m):
Arduino + RTC + LCD --> 16.9
Arduino + RTC + LCD + 1 digital pin connected to SSR --> 24.4
Arduino + RTC + LCD + 2 digital pins connected to SSR --> 32.3
Arduino + RTC + LCD + pH board --> 46.9
Arduino + RTC + LCD + 1 digital pin connected to 12v relay board --> 22.2
How can it be? is there any chance that I should multiple these number by 10 to get the real current?
BTW, when I tried to connect the red probe to the exit called "20A" and switched the multimeter to "20" it didn't write anything.
"200m" - this is the mode name in my multimeter. The red probe is connected to exit named "mA".
In addition, I have the following modes: 2m, 20m, 200m, 20.
BTW, in the tests above I broke the circuit between my breadboard and the GND pin in the Arduino, is it OK?
When I tried to break the circuit between the power supply and the Arduino, i got different numbers:
Arduino + RTC + LCD + pH --> 97
Arduino + RTC + LCD + pH + 1 digital pin --> 102
Arduino + RTC + LCD + pH + 8 digital pins to SSR + 4 digital pins to12v Relay boad --> 180
