Wemos D1 mini portability problem

Hello blynkers, i need a help. I’m using two sensors on my Wemos D1 mini where one is in 3.3V and other is in 5V, both of the sensors requires at least 3V to operate. Now, I want to make my project portable. That is, I want to use it with some external power source. So, do I need 9V or more to operate the whole system or I can use it with 3.7V or 4.7V lithium-polymer/ion battery? I want to keep it small. So, is there any way to use it by the lithium battery via other components like power module etc.?

Thanks in advance. :slight_smile:


Maybe I can help, but this is not really a Blynk issue, more a general Arduino question. You should maybe try https://forum.arduino.cc/index.php

But, it depends on what shields you have if any. If you have DC power shield then 9V would be fine, if you want to use a 3.7V battery then you need the battery shield.


Or, you could power it from a regular battery pack via usb cable.

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The D1 mini needs 5v as the input. 9V will fry the voltage regulator. I think they can handle 6V max, but wouldn’t risk it. You cannot apply over 3.3V to the 3V3 pin or else you risk frying the esp Chip.

You have a few options, but for simplicity I suggest you get one of these if you want to run off of a LIPO.


Thanks :slight_smile:

Well. Thanks for your suggestion :slight_smile: I’ll use the battery shield. But some sources says that the device can operate on an external supply of 6 to 20 volts; if using more than 12V, the voltage regulator may overheat and damage the device. The recommended range is 7 to 12 volts.
Link: https://docs.zerynth.com/latest/official/board.zerynth.wemos_d1_mini/docs/index.html

Is that true or false?

Or If I use LIPO with this https://bit.ly/2FxHlYo and set the output voltage 5-9V then does it work?

And one more thing, does the battery shield 1.2.0 work with wemos 3.0.0?

I use D1 Minis for almost all of my projects, and I’d never put more than 5v into the Vin pin. But what you do with your hardware is up to you!

I’ve never heard of a Wemos D1 Mini version 1.3.0 and can’t find any reference to it in the Wemos documentation.
The battery shield isn’t exactly rocket science, and as the pin layout of the D1 Mini hasn’t changed across versions, there should be no compatibility issues.

As far as other power supply options are concerned, it really depends on what you’re trying to achieve. Many voltage regulators and buck converters like the one you linked to draw quite a bit of current when in standby mode, so wil drain your battery even when the Wemos isn’t drawing any power.

Andreas Spiess - the guy with the Swiss accent - has done quite a few videos about his research on the issue on his YouTube channel. If you want to learn more then I’d take a look at them.


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Thanks for your kind information. :slight_smile:
sorry, It is 3.0.0

VIN pin means 5V pin on the board?



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A battery shield has a 5v regulator on it, so TRUE (within the range of the regulator - I run a couple off of 12v batteries, so up to 15v when charging).

The actual D1 Mini does not (well, just a 3.3v one - ME6211 Operating Voltage Range: 2V~6.0V) so 6v is the limit on the USB or 5v pin.

Well. Thanks for your information. Can I use Pulse sensor on 5V & LM35 on 3.3V pin both at the same time by using the battery shield with 3.7V LIPO battery? I have to order the shield from abroad so I’ve must ensure it first will it work or not.

And yes, both are analog sensor, so I also have to use an ADS1115 for exapansion of the analog pin. So, I also have to power the ADS1115 too.

Please ensure me as early as possible. It means a lot. Thank You :slight_smile:

Your Wemos D1 Mini will not step 3.7v up to 5v for you.

The D1 Mini has two voltage INPUT options:

  • 5v via either the USB socket or the 5V/Vin Pin. This goes through a voltage regulator to drop it down to 3.3v and powers the onboard ESP8266 chip
  • 3.3v via the 3v3 Pin.

Because there isn’t a diode on the 3.3v input pin, if 5v is applied via USB/Vin then 3.3v will be available on the 3v3 pin.
This ins’t really designed to be a power source for peripherals, but it can be used for that, provided care is exercised. If your peripherals draw too much current from the 3v3 pin then they will burn-out the onboard 5v --> 3.3v voltage regulator.
You’ll know when you’ve done this because the D1 Mini will be dead when powered via the USB or the 5V pin, but will work fine when powered via the 3v3 pin. Also, the voltage regulator chip labelled 4A2D next to the 5V pin (ME6211 in the diagram that @Gunner provided) will probably look rather unhappy :frowning_face:


Thanks for the information. Should I use NodeMCU instead of D1 mini to solve this problem?

Apologies - I was getting this topic mixed-up with a different one, where a user wanted multiple analogue inputs, hence my reply about analogue inputs which made no sense in this topic.

Switching to a NodeMCU won’t help with your power supply issues. The NodeMCU and the Wemos D1 Mini are in effect the same, they simply have fewer digital pins made available. The voltage regulator arrangement is exactly the same between the two devices.


I want to extend the port like this. Will it work?

I’ve also seen some ckt diagram on google like this. How they use multiple sensor on Wemos!! Does it work fine on USB power from PC?

My previous answer in this topic was extremely confusing, as I thought I was responding to someone else about a different issue. I’ve edited that reply and you may want to go back and read it again. Apologies for that!

Your topic is about portability of a Wemos/NodeMCU type of device and it seems you now want to add multiple DHT sensors to that device. Personally, I wouldn’t use DHT sensors as they are slow and inaccurate. My preference is the BME280, but it depends on the environment where it will be used.

Maybe if you told us a bit more about the overall project, and how it will be used, we could provide more appropriate advice.


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Well. Thanks for ur correction. I was very much upset after seeing ur information. Now, I think there is still a hope. :slight_smile:
At first I want to extend the analog input pin via ADS1115 as I want to use two analog sensor that are Pulse sensor & LM35 temperature sensor. Wemos & NodeMCU both provides only one analog input pin. So, I must have to use ADS1115. The circuit diagram that I will follow in the Wemos is shown up for NodeMCU with ADS1115. So, now I want to make this whole system portable. That is two analog sensor is connected with the Wemos D1 on 3.3V & 5V. And I want it to power from an external source like LIPO battery, not from the PC via USB. What can I do now? Will it work with Wemos battery charging shield with 3.7V LIPO battery on it or I need a voltage regulator that can input 3.7V and regulate it to 5 to 20V so that I can specified the required amount of voltage to run the whole system perfectly. :slight_smile:

The ADS1115 isn’t an analogue pin extender, it’s an analogue to digital converter (with programmable gain control if needed). This means that analogue signals will be turned into signals on an I2C bus, that will connect to digital pins on your Wemos - not the analogue pin.

The wiki for the Wemos battery shield, which includes a schematic, shows that it provides 5v output to the D1 Mini:

So you would have 5v and 3.3v available for your sensors.
By default it will provide 5V @ 0.5A, but thers a jumper to allow this to be increased to 1A.
There’s also a jumper to allow the battery to be connected to A0, to allow battery voltage readings. If you go for the ADS1115 then you could bridge this jumper and allow the Wemos to read it’s own battery voltage

Are you planning on using DeepSleep to save power?


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Thanks. :slight_smile: Sounds like I have to know more about these components in detail. :slight_smile:

I’m preety much unfamiliar with the concept of jumper and DeepSleep to save battery.