question about overheat and power input

hi sorry for my bad english,
i read this topic,
about overpower input that makes your arduino (regulator?) overheat,
the heat will turn the arduino off by itself and eventually it will fail the machinery.

so i have this 3 alternative power input :
A. 12V-1.0A adapter to the power input,
B. 5V-2000mA, smartphone charger to arduino usb input,
C. 5V-1000mA, smartphone charger to arduino usb input, i have it somewhere, but somebody seems using it, so i dont have the picture in this moment

and my project is
-1 x arduino mega 2560
-1 x relay to 10A 8 channel
-10 or more limit switch (the cable is up to 2 meter)
-1 x i2c + lcd 16x2
-1 x keypad 4x4

this project control some solenoids based limit switch in a small production machine,
the machine will work 24/7,
i afraid the arduino will get heat and the machine will go wild,

the question is :
-the arduino capable enough to run 24/7 right?
-will the microcontroller generate heat when operating? (the microcontroller require a heat sink?)
-what power input i should choose?
-if arduino get overheat and turn off, what state will happen to the pins???
-any other tips?
and thanks for reading

note : for the pictures, i like to put pic on the post, but there no option to add it

Hello,

You need to do the math.

Add up the current your different devices will need.

and my project is -1 x arduino mega 2560 -1 x relay to 10A 8 channel -10 or more limit switch (the cable is up to 2 meter) -1 x i2c + lcd 16x2 -1 x keypad 4x4

What relay board are you using?? That is the only device using a lot of current.. Show us that board.

Here is more detailed information about the power issues:

https://arduinoinfo.mywikis.net/wiki/QuickRef#DETAILED_POWER_CONSIDERATIONS:

and this may help:

https://arduinoinfo.mywikis.net/wiki/Arduino-Project-Planning-Electrical

terryking228: Hello,

You need to do the math.

Add up the current your different devices will need.

What relay board are you using?? That is the only device using a lot of current.. Show us that board.

Here is more detailed information about the power issues:

https://arduinoinfo.mywikis.net/wiki/QuickRef#DETAILED_POWER_CONSIDERATIONS:

and this may help:

https://arduinoinfo.mywikis.net/wiki/Arduino-Project-Planning-Electrical

thanks for reply, for the math i don't know how to count it, i am not an electric guy, so i put the devices list in the first post, for the relay board, i can't show the picture on this reply, you can see it in my first post at the attachment, note for board i just put 1 channel, for other channels i will add it later

Hi,

OK, that relay board is powered by 12V , right??

The SIGNAL Arduino Outputs to the relay board need very little current, usually less than 5 mA (.005A).

So it looks like you could use the external power supply to (separately) power both the Arduino Mega and the relay board.

terryking228: Hi,

OK, that relay board is powered by 12V , right??

The SIGNAL Arduino Outputs to the relay board need very little current, usually less than 5 mA (.005A).

So it looks like you could use the external power supply to (separately) power both the Arduino Mega and the relay board.

i dont know about "relay board is powered by 12V" you talking about, that i know that : vcc on the relay go to 5V on the anduino, gnd on the relay to gnd on the arduino, and in8 go to selected pin on arduino,

what 12v? can you explain why power the Arduino Mega and the relay board must put separately?

edit : after i google it, turn out i using 12 volt, i will buy new one today, btw how do you know it was 12v?

The relay board may draw more current than the Arduino board can supply without burning something on the board. The relay board VCC needs to take power from other than through the Arduino, which can be a wire from the same supply that feeds the Arduino… you may need to splice that wire. If you won’t splice then 2 power supplies will work. The ground of the relay board needs to also connect to Arduino GND as well as that supply ground. Ground is what all voltages measure against.

“for the math i don’t know how to count it, i am not an electric guy”

Then you must stick to plans that will work and not substitute a thing until you do learn the laws and math. Don’t invent any circuit until then.

... the question is : -the arduino capable enough to run 24/7 right? -will the microcontroller generate heat when operating? (the microcontroller require a heat sink?) -what power input i should choose? -if arduino get overheat and turn off, what state will happen to the pins??? -any other tips? ...

  • An Arduino can indeed run 24/7. I have a countdown to retirement clock that has been running nonstop (on solar power no less) for more than a year.

  • ATMega 328p microcontrollers will generate a small amount of heat. With normal use, you won't be able to detect it by touch.

  • Of the power supplies you mentioned, the 1A or 2A, 5 volt supplies seem most suited to run your Arduino. You will use a separate power supply for the relays.

  • If the Arduino overheats to the point of shutting down, it means that something has gone very wrong with your circuit. Likely the pins that were involved with the over-amperage will likely not be reliable anymore, and the processor chip should be replaced.

  • The rest of this thread has supplied some very good 'other tips."

GoForSmoke: The relay board may draw more current than the Arduino board can supply without burning something on the board. The relay board VCC needs to take power from other than through the Arduino, which can be a wire from the same supply that feeds the Arduino... you may need to splice that wire. If you won't splice then 2 power supplies will work. The ground of the relay board needs to also connect to Arduino GND as well as that supply ground. Ground is what all voltages measure against.

"for the math i don't know how to count it, i am not an electric guy"

Then you must stick to plans that will work and not substitute a thing until you do learn the laws and math. Don't invent any circuit until then.

i just know that relay consume so much electricity, thanks for reply

ChrisTenone: - An Arduino can indeed run 24/7. I have a countdown to retirement clock that has been running nonstop (on solar power no less) for more than a year.

  • ATMega 328p microcontrollers will generate a small amount of heat. With normal use, you won't be able to detect it by touch.

  • Of the power supplies you mentioned, the 1A or 2A, 5 volt supplies seem most suited to run your Arduino. You will use a separate power supply for the relays.

  • If the Arduino overheats to the point of shutting down, it means that something has gone very wrong with your circuit. Likely the pins that were involved with the over-amperage will likely not be reliable anymore, and the processor chip should be replaced.

  • The rest of this thread has supplied some very good 'other tips."

-if i just need to replace 10 dolar every year, it quite cheap( thus next year maybe the machine owner will use PLC)

-if the heat in safe range, i dont need to add the heat sink,

-it will okay with usb 2A?

-for the overheat, i think it will very small change if you said like that,

thanks alot for the reply, i appreciated it

Kucingmiow: i just know that relay consume so much electricity, thanks for reply

We use very small power through these controllers that the current needed to move the mechanical relay parts (solenoid and contacts) compares as big.

Relays generate some heat every time they switch ON/OFF. It is good to put in the code something to make sure that the relay(s) may never be switched too often in a short time to let that heat dissipate.

I have relays to switch mains power (house 120/240VAC). I have FETs (field effect transistors) to switch Amps of DC, they can switch at high frequency with no problem at all.

how do you know it was 12v?

Your photo shows 12V DC relays on that board.

Yes, better to just get a 5V board..

Here's some info: ---------------------( COPY )--------------------- EXAMPLE: Opto-Isolated 4 Channel Relay Board

See more details, applications on our WIKI here: http://arduinoinfo.mywikis.net/wiki/ArduinoPower#Optically-Isolated_Relays

With high-current relays, AC250V 10A ; DC30V 10A NOTE: Each relay draws about .08A (80ma) so about 4 relays are the maximum you should run from the Arduino +5V supply. (Running from USB it may be less). More than 2 relays: we recommend you use a separate 5V supply for the relays.

NOTES: If you want complete optical isolation, connect "Vcc" to Arduino +5 volts but do NOT connect Arduino Ground. Remove the Vcc to JD-Vcc jumper. Connect a separate +5 supply to "JD-Vcc" and board Gnd. This will supply power to the transistor drivers and relay coils.

If relay isolation is enough for your application, connect Arduino +5 and Gnd, and leave Vcc to JD-Vcc jumper in place.

NOTE: It is sometimes possible to use these relay boards with 3.3V signals, IF the JD-VCC(RelayPower) is provided from a +5V supply and the VCC to JD-VCC jumper is removed. . That 5V relay supply could be totally isolated from the 3.3V device, or have a common ground IF opto-isolation is not needed. If used with isolated 3.3V signals, VCC (To the input of the opto-isolator, next to the IN pins) should be connected to the 3.3V device's +3.3V supply. NOTE: Some RaspberryPi users have found that some relays are reliable and others do not actuate sometimes. It may be necessary to change the value of R1 from 1000 ohms to something like 220 ohms, or supply +5V to the VCC connection.

NOTE: The digital inputs from Arduino are Active LOW: The relay actuates and an LED lights whe the input pin is LOW, and turns off on HIGH. See the Wiki article for how-to assure relays do not activate at power-on time.

Schematic Diagram: HERE http://arduinoinfo.mywikis.net/w/images/c/ce/OptoRelay4X_Wiring.png

and HERE http://arduinoinfo.mywikis.net/w/images/d/d2/OptoRelayChannelDataE2.jpg

GoForSmoke: We use very small power through these controllers that the current needed to move the mechanical relay parts (solenoid and contacts) compares as big.

Relays generate some heat every time they switch ON/OFF. It is good to put in the code something to make sure that the relay(s) may never be switched too often in a short time to let that heat dissipate.

I have relays to switch mains power (house 120/240VAC). I have FETs (field effect transistors) to switch Amps of DC, they can switch at high frequency with no problem at all.

it makes me scared, the project that i do is to use the relay to control about 0,5 to 0.75 second between on-off, maybe i will put heatsink or a fan on it

thanks for the reply

terryking228:
Your photo shows 12V DC relays on that board.

Yes, better to just get a 5V board…

Here’s some info:
---------------------( COPY )---------------------
EXAMPLE: Opto-Isolated 4 Channel Relay Board

See more details, applications on our WIKI here:
http://arduinoinfo.mywikis.net/wiki/ArduinoPower#Optically-Isolated_Relays

With high-current relays, AC250V 10A ; DC30V 10A NOTE: Each relay draws about .08A (80ma) so about 4 relays are the maximum you should run from the Arduino +5V supply. (Running from USB it may be less). More than 2 relays: we recommend you use a separate 5V supply for the relays.

NOTES: If you want complete optical isolation, connect “Vcc” to Arduino +5 volts but do NOT connect Arduino Ground. Remove the Vcc to JD-Vcc jumper. Connect a separate +5 supply to “JD-Vcc” and board Gnd. This will supply power to the transistor drivers and relay coils.

If relay isolation is enough for your application, connect Arduino +5 and Gnd, and leave Vcc to JD-Vcc jumper in place.

NOTE: It is sometimes possible to use these relay boards with 3.3V signals, IF the JD-VCC(RelayPower) is provided from a +5V supply and the VCC to JD-VCC jumper is removed. . That 5V relay supply could be totally isolated from the 3.3V device, or have a common ground IF opto-isolation is not needed. If used with isolated 3.3V signals, VCC (To the input of the opto-isolator, next to the IN pins) should be connected to the 3.3V device’s +3.3V supply. NOTE: Some RaspberryPi users have found that some relays are reliable and others do not actuate sometimes. It may be necessary to change the value of R1 from 1000 ohms to something like 220 ohms, or supply +5V to the VCC connection.

NOTE: The digital inputs from Arduino are Active LOW: The relay actuates and an LED lights whe the input pin is LOW, and turns off on HIGH. See the Wiki article for how-to assure relays do not activate at power-on time.

Schematic Diagram: HERE http://arduinoinfo.mywikis.net/w/images/c/ce/OptoRelay4X_Wiring.png

and HERE
http://arduinoinfo.mywikis.net/w/images/d/d2/OptoRelayChannelDataE2.jpg

thanks for the reply,
i don’t know where i can find 5v adaptor, maybe i just need to break down my old smartphone cable charger,

but for now i will using the 12V-1.0A adapter that i add “the picture” in my “attachment” as power supply for relay,
i just have to buy 12V female jack power, and add some cable,
and now the relay and the arduino have 2 separate power supply,

Kucingmiow: it makes me scared, the project that i do is to use the relay to control about 0,5 to 0.75 second between on-off, maybe i will put heatsink or a fan on it

thanks for the reply

If you switched more than 20, maybe 50 times in 0,75 then it might be cause for such concern. Or switch more than 10/sec for many seconds. Compare to FET that can switch in less than a microsecond for a lifetime be the same as always ON. So perhaps the software only lets the relay switch 5x/sec at fastest.

GoForSmoke: If you switched more than 20, maybe 50 times in 0,75 then it might be cause for such concern. Or switch more than 10/sec for many seconds. Compare to FET that can switch in less than a microsecond for a lifetime be the same as always ON. So perhaps the software only lets the relay switch 5x/sec at fastest.

yes, my relative just come to see my project 2 hour ago, i don't know what the english called for the job, he is a tv repairer in the free times, i ask him many times in this year, eventually, he comes to my place, thank god, he said to me "don't use the relay, that thing not reliable", then he said he will buy some ac transistor, i forget what it called, something like "theriax"?, and bring it to me tomorrow, i don't know what it is, but i will show it to you if you want to if it comes to my place for now, the "relay problem" is temporary solved

and thanks for the reply

Triac. Also look up solid state relay (SSR) -- but much more expensive than a relay which yes being mechanical wears out sooner and is more expensive than some triacs I have seen.

Ask about microswitches. How long to wear out the internal buttons of PC mouse? Planned obsolete, buy a new one. If replaced with something else it would last far longer. You can make better with cheap parts, harder part is making them smaller too.

Maybe you learn some physics along the way. It can rub onto you if you care at all. Ask your relative.

GoForSmoke:
Triac. Also look up solid state relay (SSR) – but much more expensive than a relay which yes being mechanical wears out sooner and is more expensive than some triacs I have seen.

Ask about microswitches. How long to wear out the internal buttons of PC mouse? Planned obsolete, buy a new one. If replaced with something else it would last far longer. You can make better with cheap parts, harder part is making them smaller too.

Maybe you learn some physics along the way. It can rub onto you if you care at all. Ask your relative.

so triac is solid state relay (SSR)?
yes triac is expensive, about 8 to 12 usd each,

i google images “microswitches” the 90% result is limit-switches and other is micro button,
is that i looking for?

for learning physics, i don’t know where to start,
i know transistor is gate, capacitor is mini battery, resistor to limit the watt, for other i dont know what is it,
i never good in physics or electrics

and thanks again for the reply

Kucingmiow: so triac is solid state relay (SSR)? yes triac is expensive, about 8 to 12 usd each,

SSR is more than just a triac. When you see prices, electronics that can carry more current cost more than same part that can carry less. A 1/4 watt resistor is cheaper than a 1 watt resistor like a little car costs less than a big one.

i google images "microswitches" the 90% result is limit-switches and other is micro button, is that i looking for?

You can use them but I exampled them as mechanical and will wear out sooner than non-mechanical switches/buttons.

for learning physics, i don't know where to start, i know transistor is gate, capacitor is mini battery, resistor to limit the watt, for other i dont know what is it, i never good in physics or electrics

Basic electrics and electronics is physics inside. Start with your relative who must know how electricity works probably better than myself. You will get to know a thing or two here and there, build a literacy on the subject and words you know will bring you into conversations and texts where more and more you get sense and develop understanding. You don't have to do it fast, it will happen if you keep working with electronics.

How did you learn to use computers? If you took a course, how much more do you know since?

GoForSmoke: SSR is more than just a triac. When you see prices, electronics that can carry more current cost more than same part that can carry less. A 1/4 watt resistor is cheaper than a 1 watt resistor like a little car costs less than a big one.

You can use them but I exampled them as mechanical and will wear out sooner than non-mechanical switches/buttons.

Basic electrics and electronics is physics inside. Start with your relative who must know how electricity works probably better than myself. You will get to know a thing or two here and there, build a literacy on the subject and words you know will bring you into conversations and texts where more and more you get sense and develop understanding. You don't have to do it fast, it will happen if you keep working with electronics.

How did you learn to use computers? If you took a course, how much more do you know since?

GoForSmoke: SSR is more than just a triac. When you see prices, electronics that can carry more current cost more than same part that can carry less. A 1/4 watt resistor is cheaper than a 1 watt resistor like a little car costs less than a big one.

You can use them but I exampled them as mechanical and will wear out sooner than non-mechanical switches/buttons.

Basic electrics and electronics is physics inside. Start with your relative who must know how electricity works probably better than myself. You will get to know a thing or two here and there, build a literacy on the subject and words you know will bring you into conversations and texts where more and more you get sense and develop understanding. You don't have to do it fast, it will happen if you keep working with electronics.

How did you learn to use computers? If you took a course, how much more do you know since?

after you said that, you have a point, but i think i don't have future on soldering job,

by the way, i look the internet about SSR on the internet, it quite cheap, about 5 or 6 usd for 4 channels,

then i remember about your words

"The relay board may draw more current than the Arduino board can supply without burning something on the board. The relay board VCC needs to take power from other than through the Arduino, which can be a wire from the same supply that feeds the Arduino."

-is the SSR still require large amount of watts than the arduino? (compare mechanic one) -is the SSR is more reliable than mechanic one if i using it of 0.5-0.75 second?

and thanks for reply

What current the part can carry, how much electric flow can go through it without burning it up is big part of the cost. The flow of electric current causes heat.

A resistor or SSR with small capacity costs less than one with more capacity. So you can't find just the name of a part and consider the price of that one typical of all with the same name.

SSR's are solid state and may switch fast with no ill effect. A low capacity SSR will be much cheaper than a heavy duty SSR but -all- SSR's are the solid state with ability to switch fast up to the limit of each.

When I tell of a resistor rated in watts that is the most electric it can take in terms of voltage times current which is watts which equals power.

Power in watts is voltage x current. Voltage is the push, the electrical pressure that moves current (flow of electrons). This is a bit simplified but for what you do, it applies. Current moving in that pressure makes the heat. Parts that can take more heat are "bigger" and cost more.

Ohm's Law (where law is what is always observed in the real world) is the relation of voltage, current and resistance. You start with voltage and current, resistance comes in (only superconductor has none) and making heat becomes more understandable. But for now you need to see that parts that have more capacity for current flow cost more. You don't have to calculate that.

I have cheap relays to switch up to 10 Amps of house power (here 120VAC) able to run many things. Tiny power from Arduino can turn the relay ON and OFF, and I am careful to not make it do that too frequently for long. For about $2 I have a switch that can flow a good deal of power. An SSR with equal capacity typically costs much more but sometimes a discount can be found (so can a fake, some deals are steals and some steal you) and for me, I got the relays since I don't need to turn ON/OFF even 1 time per second.

What is practical depends on what you require done. You also need total circuit given, you are not ready to design. If SSR is a must have then your circuit needs one with capacity to do the job and every other part to do its job, you are not ready to find those out so you get help here and from your relative who knows. I am limited in my hardware knowhow, others here will help you better, I just try and keep you from the worst and tell you there is hope.

With an Arduino, some wire, a low-rated resistor and capacitor and a bit of foil a sensor can be made that detects a finger close or touching. It can sense through wood or plastic and be used as a button with no moving parts. It has a very long lifetime. But think that this thing uses an invisible electrical field that meshes with your own invisible electrical field to detect your finger, it is a touch button even if it's a bit crude and it demonstrates the truth of electric fields in and around us all. Wonder about that!