Posted by: @danb

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I was planning to make an IoT sensor using an esp32-s3, but no matter what I do, I can't get it low enough.

Even with disabled pins, disabled wifi and BLE, deep_sleep, I can only get down to 18MA. I have an led that must be running it draws around 1,66 MA out of those 18

Is this also what you guys get?

Do I have to switch to another chip to get a good power consumption, for battery driven devices. 

Or is this simply a bad esp32 board I got? 

I don't know off the top of my head, but have you looked at the datasheet? What sleep mode are you using?

Why do you need an esp32-s3, what is the application, can a lower power MCU do the job?

Hi @danb,

I have never tried to measure or minimise the current for an ESP32-S3. My first thought, was 'dev boards', which are usually chosen for convenient connections when prototyping, aren't usually designed with a requirement of minimal power consumption. A quick Google, by chance, suggests Espressif support this thought:  

https://docs.espressif.com/projects/esp-idf/en/stable/esp32s3/api-guides/current-consumption-measurement-modules.html

which includes:

Current Consumption Measurement of Modules

You may want to know the current consumption of a module in deep-sleep mode, other power-saving modes, and active mode to develop some applications sensitive to power consumption. This section introduces how to measure the current consumption of a module running such an application.

By 'some circuits', a dev board often has a USB converter, one or two voltage regulators, and so on, as well the LED you can see. Disabling these, without breaking the board, may be a challenge.

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The article then moves to considering an ESP32-S3 module, which is basically the part of the dev board covered with a rectangular metal lid, which you may like to read, but will also present challenges, like many connections on a fairly small pitch.

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Also by chance, Google found:

https://www.kiwi-electronics.com/en/seeed-studio-xiao-esp32s3-11429

which mentions:

Please note, I am not recommending this product, as I know absolutely nothing about it, merely copying a relevant part of the advert for you to consider. Also, there may be alternatives ... this one was literally at the top of my first Google search about ESP32-S3 current consumption! I didn't look further.

SEEED is a relatively well-known brand, so I presume you will be able to find a supplier that is convenient to your part of the World.

If this board meets your requirements, etc., at first glance, it looks a better starting point for a low power project, though you may still find your existing board is useful for developing software, etc., whilst it is attached to your PC, and power availability is not a concern.

Just a suggestion.

Good luck with your project and best wishes, Dave

That's perfect. Thanks. 

Actually I found that I could lover the ma usage by 60 percent by removing the camera (even not used it pulled 2 ma) and the voltage breakout board. But year didn't think the dev board it self was such a challenge.

I ordered some other different esp32 boards and also some boards with other processors that should be even lower usage ones. 

Thanks for your comprehensive ansewer. 

@zander it's a freenove board. There is super compressive user guide to projects, but I don't see a datssheet for the board it self. And the power breakout board is almost not mentioned.

I am using deep_sleep,  but the weird thing is.. The board uses 50-60 MA booting. But the weird thing is then it seems to stay almost flat at 18 MA no matter when it's running or when it's in deep sleep. 

I have now ordered other boards with lower power consumption processors... As I read more about it, it seems the ESP32 is not really meant/good for battery driven projects. 

-Dan

@danb There will be a datasheet for the board. I can't really comment much about the rest, but in general, sleep mode numbers are at a minimum confusing. There is a HUGE diference in a dev board (more power) and a raw SOC. BUT it may be harder to work with the raw SOC for a hobbyist.

Not at all sure why you would buy a camera board and then remove the camera. 

Perhaps if you told us what the project is someone here might have some advice.

The best way to save power is to turn off the board. You can find dozens or even hundreds of solutions like that on the net, but forum member Dave (@davee) has a ready to go circuit that goes a step beyond all the other solutions I have found. Highly recommended (at least until I outdo him)

Hi Ron @zander and @danb,

  Just to expand on one point Ron introduces. All (that I am aware of) of the ESP32 family have been sold in three levels of 'expansion':

1. The ESP32 itself, which is a silicon chip microcontroller, with various peripheral parts, such A/Ds, GPIOs, WiFi, etc. included, and hence referred to as an SoC ... System on a Chip. The exact form varies, depending on which member of the family is being considered, but (so far as I have read), it is basically a conventional integrated circuit with fine pitch connections, roughly 6 mm square.
2. The 'module' with a rectangular metal lid. These are apparently made by a modest number of manufacturer's, consisting of a PCB slightly larger than the metal lid, with connections around three of the sides, and a 'postage stamp perforation' style, intended to be soldered to further PCB designed by the final unit designer.  These connections are a finer pitch than the 0.1"/2.54mm pins commonly found on 'dev' boards, but a considerably larger pitch than for the ESP32, itself, making direct connection tricky but feasible with common tools, providing care is taken. Each module contains a number of integrated circuits, typically providing flash memory, etc, in addition to the 'basic' ESP32 device. The module also usually provides a built-in WiFi/Bluetooth antenna and/or a socket for an external antenna.
3. Dev boards, and other boards, such as the SEEED board I mentioned in my previous message, above.

Most forum members would not be in a position to consider using the 'bare' ESP32 SoC, but working with a 'module' looks feasible, especially if the constructor is willing to design a PCB for their application. For special applications, such as minimal power consumption, this is an option to consider, as it enables the designer to produce a design with minimal unnecessary components to increase the power demand. However, it appears that SEEED, and maybe others, are aware of this market opportunity, and may be providing convenient products which may be configured to minimise current demand, whilst providing 0.1" pitch connections. However, the number of 0.1" connections appears limited, compared to the number of module connections, which may be a problem for some applications.

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By the way, the design suggestion Ron is kindly referring to is to be found at:

https://forum.dronebotworkshop.com/technology/power-off-sleep-circuit-based-on-real-time-clock-ds3231/

This assumes that the microcontroller can be powered off for most of the time, and then 'woken up' at a pre-arranged time, to perform its job, such as take a measurement. During each 'wake' period, it is convenient to set the time of the next wake-up, enabling the programmer to create a complex scheme.

Thus, the microcontroller consumes zero power, whilst it is 'asleep', because the power is disconnected by a FET. (No current flow could be detected by my multimeter, with minimum display capability of 0.1 microAmp - FET leakage typically depends on choice of FET, temperature, etc.)

It does not use any sleep or similar modes of the microcontroller, which may obviate certain issues. The processor simply reboots at each power up.

Obviously, it is not suitable for applications that require the microcontroller peripherals to be 'listening' for a wake-up event.

It was prototyped with a Raspberry Pi Pico, but can probably be adapted to most 3.3V microcontrollers.

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Best wishes, Dave

Hi Dave 

This is my died project, do wasn't aware of module type ESPs. Also wasn't aware of the varieties of dev boards... Hence the on board camera. 😂

Your power down circuit seems interesting. As I need a led blinker to run, also if the board is closed down, I actually already looked at the atriny85 (and many othe options).

First I Wil take a look at the modules. So is there anything I need to take into account in those. Can I upload the software the same way, by USB.. Just by soldering the USB wire to the correct pins, or how does the modules work? 

Hi @danb,

  The modules are the same parts as you might find on a dev board or similar. The modules seem to be produced by a number of suppliers, including Espressif, and there are quite a few variations of sizes and types of memories, and other things, so part of the fun, can be establishing exactly what is hiding under the metal lid, alongside the ESP32-xxx, as well as ensuring you know the external connections.

As for connecting them into a circuit, then you might find it useful to compare with a similar dev board, preferably one with the same module, and documentation, like schematics, and decide which bits you want, and which bits are just power drains.

For example, USB on a dev board makes software development easier, but do you need it in the 'finished' product? One approach might be to use one of the USB to serial cards, which can be detached when the module is programmed. You are probably familiar with the idea, but a quick glance at Bill (@dronebot-workshop)'s blog + video on the ESP32-CAM shows the basic approach, as the ESP32-CAM was sold without a USB connection.

https://dronebotworkshop.com/esp32-cam-intro/

Note that the esp32-cam is a 'complete board', not a module, so it included a 5V to 3.3V regulator. Working directly with a module means you must provide a 3.3V supply.

I haven't checked, but I suspect the ESP32-S3 also includes a USB-port built-in ... which may be helpful, but you will probably be wise to provide some protection against ESD discharges. Again, published schematics by Espressif dev boards are a good starting point for ideas. (From memory, again not checked, ESP32-S3 dev boards sometimes have two USB ports, one using the USB port built in to the ESP32-S3, with a small number of protective diodes, etc added in, the second using a USB to serial chip, which connects to a serial port on the ESP32-S3.)

Sorry, this is not a fully tested and documented approach, but rather some random thoughts of where to start. You should appreciate that I am discussing the general approach that you might expect to find in an R&D department of a company considering similar issues and aspirations. On the plus side, it could be a very useful and interesting learning process, that you can be proud of, and maybe use to your advantage in the future. But also be prepared for hitting snags and having to deal with them. 

Whatever you decide, I wish you the best of luck, Dave

Ohh yes you can be sure I value any advice I get here. 

I'm just starting out, never worked with any micro controller programming before and only have very limited knowledge about Discrete electronics. 

So it's all about learning. 

Again, thank you so much for your advice. 

Hi @danb,

   Thanks for the kind reply. It sounds like you are taking on a lot of new ideas at the same time, and that can tough. Try to find a path, that means you move on, in small steps at a time.

e.g. Consider getting the basic functionality of the project working with a dev board, without worrying about power consumption, then see how you can 'transfer' that to a low power arrangement. But remember, this is only an illustration, and may not work, if you can't replicate what you have done, in a lower power scene. So, try mapping out a progression of small steps, to go from your present position, to what you want to end up with.

I don't think there is a simple 'foolproof' method of designing everything at once, but if you try to progress from one working stage, to another working stage, you are more likely to keep moving forward, and gaining experience.

You can always ask more questions, but in general, the more specific the question, the more likely you will get a specific and useful answer.

Best wishes, Dave