Turn OFF 5V OUTPUT Arduino - Project 150mA or More

Hello guys.

First, this is my first topic, i searched about my "issue" in the forum, and i dont find it.
Second, sorry for bad english.

So, i have a project of a Meteorological Station that use a Micro SD Module, that consumes about 50~100mA, and a YL-83 that consumes 100mA. Totally 150~200mA, almost max of Arduino 5V output(i know it, i can put fire on my arduino).

The Station must be in field, so its fed by a Solar Charger Shield[(Photovoltaic panel )by seeed studio), and a Li-Po 720mA. I think you already know the problem. The system will be shutdown at rains and at night. I am already using D2 and D3 in a Anemometer, so attachInterrupt(pwr_down_mode) its not a possible(even the Sleep mode dont power down the 5V output pin).

The problem is: I can not connect the sensors at the I/O pin, will burn my ATMEGA. And i know i just can not turn off my 5V OUTPUT by code.

So, what can i do here? Any solutions will be welcome.

Thanks.

Use a P-Channel MOSFET to switch the power to Micro SD Module and the Rain Sensor YL-83, and use an NPN BJT to switch the MOSFET:

58684ccd4a294b41f4875984bd09c04dff502da5.png

When using a P-channel MOSFET, sending a LOW will turn it on, and sending a HIGH will turn it off. The BJT is there to both invert that signal and make it so it’s not so critical what voltage levels the MOSFET will switch with.

This arrangement is what is known as “High Side Switching” because the switch is between the positive power and the load.

http://forum.arduino.cc/index.php?topic=117332.0

Power saving techniques for microprocessors
Don’t use power-hungry displays (eg. indicator LEDs, backlit LCDs)

a Micro SD Module, that consumes about 50~100mA, and a YL-83 that consumes 100mA.

I think you are mistaken. You have misread the data sheets or other information on these modules and you have not measured the actual consumption yourself with a multimeter. I do not believe these modules will consume that much current. I think each will require a few mA. You may be able to power them from an Arduino digital output without any transistors.

Measure the consumption of each component in different operating conditions and with some different micro sd cards. You may find that they actuallu consume very little and are not worth switching off, compared to the consumption of the Arduino. You should focus your efforts where you can make most power savings.

BillHo:
Use a P-Channel MOSFET to switch the power to Micro SD Module and the Rain Sensor YL-83, and use an NPN BJT to switch the MOSFET:

58684ccd4a294b41f4875984bd09c04dff502da5.png

When using a P-channel MOSFET, sending a LOW will turn it on, and sending a HIGH will turn it off. The BJT is there to both invert that signal and make it so it’s not so critical what voltage levels the MOSFET will switch with.

This arrangement is what is known as “High Side Switching” because the switch is between the positive power and the load.

http://forum.arduino.cc/index.php?topic=117332.0

Power saving techniques for microprocessors
Don’t use power-hungry displays (eg. indicator LEDs, backlit LCDs)

Hello, thank you for the reply. I’m learning about eletronic, and sorry for the ignorance, but, how this is works?
Edit: I’m searched about the Transistor. So, i can use a NPN, right? The micro SD 5V goes to the 5V OUTPUT arduino(directly), and the GND goes to the transistor. Then it controls, Am i right? I found the TIP 122 here closely(Brazil its hard to find anything). But i have a question. Can’t i use just the NPN?

PaulRB:
I think you are mistaken. You have misread the data sheets or other information on these modules and you have not measured the actual consumption yourself with a multimeter. I do not believe these modules will consume that much current. I think each will require a few mA. You may be able to power them from an Arduino digital output without any transistors.

Measure the consumption of each component in different operating conditions and with some different micro sd cards. You may find that they actuallu consume very little and are not worth switching off, compared to the consumption of the Arduino. You should focus your efforts where you can make most power savings.

Thank you for the reply. But yes, the Micro SD Module can consume even more when its transferring de datas. The Yl-83 i’m not sure, because i don’t find the datasheet, but the sellers page tells 100mA(i dont have a amperimeter to measure the real consumption). Even if the YL-83 dont consums this, the Micro SD does, so, i can not use a I/O pin. My module its not the same, but here explains: https://cdn-learn.adafruit.com/downloads/pdf/adafruit-micro-sd-breakout-board-card-tutorial.pdf

But how much does the sd card module use when it is not reading or writing? It could be 0.5mA, you don't know because without a multimeter you are blind. How can you know if you have achieved low power, or made an improvement, if you cannot measure it? A £10 multimeter will be all you need.

As for the rain sensor, I think you have misread the vendor's description. It says it can source or sink 100mA through its digital output, but with that connected to an Arduino input that output current will be almost zero. The module itself will use a few mA

You need to find ways to reduce the current used by the Arduino that is what will consume most of your battery charge.

l3m0np13:
i dont have a amperimeter to measure the real consumption

Learning electronics without having a multimeter is a bit like learning parachuting without having a parachute, its not going to end well.

PaulRB:
But how much does the sd card module use when it is not reading or writing? It could be 0.5mA, you don't know because without a multimeter you are blind. How can you know if you have achieved low power, or made an improvement, if you cannot measure it? A £10 multimeter will be all you need.

As for the rain sensor, I think you have misread the vendor's description. It says it can source or sink 100mA through its digital output, but with that connected to an Arduino input that output current will be almost zero. The module itself will use a few mA

You need to find ways to reduce the current used by the Arduino that is what will consume most of your battery charge.

The problem is: The current limit of Arduino is 200mA. The rain sensor itself will be running at 100mA full, because will be connected in 5V, like a said in the Topic: "150mA or more", i will put anothers sensors... I'm searching alternatives to switch off the 5V...
But thank you for the Reply.

srnet:
Learning electronics without having a multimeter is a bit like learning parachuting without having a parachute, its not going to end well.

I can not agree. Off course, a multimeter it's essential in eletronics, but almost all the Arduino sensors/modules/shield have a datasheet, so, in this case its not like fully necessary.
Thank you for the reply.

I can not agree. Off course, a multimeter it's essential in eletronics, but almost all the Arduino sensors/modules/shield have a datasheet, so, in this case its not like fully necessary.

While a data sheet tells you what you should have a meter tells you what you do have. There is a world of difference between those two things. In fact a meter is often insufficient and an oscilloscope is a must.

The current limit of Arduino is 200mA.

That is the total limit of current sourced or sunk by the output pins. You are not doing this.

The rain sensor itself will be running at 100mA full, because will be connected in 5V,

No, you are not understanding what current the sensor will take.

Why ask questions if you are going to argue with people who know a lot more than you?

Sir Grumpy_Mike, please. I was just justifying myself, definitely not arguing with those people. Maybe with my bad english you misunderstood me, sorry for that. I started with Arduino only a phew months ago, and came here only for guidance for my project.

l3m0np13:
Hello Sir. Sorry for send you a PM for that. About your answer in the topic http://forum.arduino.cc/index.php?topic=429534.msg2961376#msg2961376.

My question is: I can use only a TIP122 transistor in the project? If not, why?

Thank you!

You can't use TIP122 to switch the power of the sensor and SD card, because it is a NPN Epitaxial Darlington Transistor that will drop at the Collector−Emitter Saturation Voltage 2 to 4V, so your sensor may not operate.

PS: don't send PM to ask for help.