Use this forum to chat about hardware specific topics for the ESP8266 (peripherals, memory, clocks, JTAG, programming)

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By lucasromeiro
davydnorris wrote:This is a *really* interesting discussion...

I have now started looking at the sensors I use to see if they are capable of running at 2.8V and the only one so far that is not is the INA219 voltage/current sensor, but there's an INA223 that looks to be the same measuring wise but is 2.8V supply friendly

Running everything at 2.8V (and many of my sensors are already running at 1.8V) could really extend low power life span

Which sensors do you use?

I use a lot of temperature and humidity sensors.
My work at 3.3v
User avatar
By lucasromeiro
rudy wrote:
lucasromeiro wrote:In this case do you only power the ESP or power other circuits like sensors, LCD, buzzer, leds, etc.?
When you used only one MCP1700 and did not behave well, were you only feeding ESP or had other things together?

I had one sensor, for detecting tilt/orientation. Plus an OLED display.


hello Rudy!

Do you can provide more information?
It is Very beautiful!

How long does it work ??
How big is the battery?
Which regulator did you use?

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By rudy
#82800 I made this a little less that two years ago. I wanted a remote that I could control a couple of ESP relays in the house. I wanted to to use a bigger enclosure so I would have more buttons for additional units. I also wanted a display so I could get some more information. I looked through my stock of displays. I have some 20x4 character displays but considered it too big an heavy. I have a lot of color TFT displays but I didn't want to spend a lot of time developing software for it. I wanted something quickly. I had oled displays and have used them before, software development for it would be simple and quick. I have other monochrome 128x64 lcds but I thought I would have to do more development for them. They were a consideration.

I then looked at my stock of enclosures and tried to match an appropriate LCD plus the required space for some button switches, size to be determined. I loved how well the 0.96" oleds fit into the small enclosure. I wasn't able to use as many switches as I would have liked. I did a dry fit of all the pieces and it all worked so well I just had to do it.

I posted to the User Projects forum with the details. More pictures showing the insides. You can see the 3.3v regulator at the bottom of the ESP. I have two stacked together on that spot.

I have a switch on the side of the enclosure in series with the battery. I wanted something quick and decided that if I decided to leave the switch on if I only wanted to use sleep mode. It does automatically go into sleep but I tended to just use the switch and not worry about discharge of the battery. I had do a sleep current test but I forget what it was. Not as good as I had wanted. The battery is only rated at 300mAH. The batteries I bought were not out of China (Israel I think) and I had more confidence in the rating.

While this was to be a quick project, it still took a lot of work. I did want it too look as good as possible. I took my time drilling and filing so that it was as good as I could do. I was expecting to show it at work so I wanted it to look as close to professional as possible.

I had plans to make a circuit board(s) to integrate all the parts and to make a few more of these. I bought some displays without the attached pcb. I would still like to do it but I doubt if I will for some time. To many other thing with a higher priority.

In the end I don't use that remote anymore. Originally I wanted something with more switches. I didn't want to have to go through menus to turn something on or off. Instead I use the one below. It is based on the capacitive touch board available cheaply out of China. I use the back of the board as it is flat and I can match the surface of the lid. I haven't done anything as far as a better looking label yet. Green paper dots for some contrast with the felt tip marker.


I had a box that was the right size. The box just fits a 18650 battery without being excessively thick. It uses the same oled as the above remote. Currently I display the action and the RSSI values from my router to this remote. And from the target relay and the router. On the bottom row I display the countdown timer used to go into sleep mode. 1 turns on relay 1. The switch position below it turns 1 off. A is for all on for three lamps in my living room. 5 is an individual relay, not included in the A-all.

This above remote isn't as small/cute as the one above. I just find it more practical for controlling more relays.

Speaking of relays. I had threw together four wired modules-power supply-relay boxes. But I wanted to make a pcb to make a batch of "standard" relay modules. And that turned out to be the ones below. Currently one red status led. The other is a 1 Watt white led. So I can use it for a night light without having to plug anything into it. The power supply had the extra capacity so I decided to use it.

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Last edited by rudy on Thu Jun 13, 2019 8:57 pm, edited 1 time in total.
User avatar
By davydnorris
rudy wrote:I'm more than a little skeptical when it comes to the 2.8 volt operation rating. From my testing with ESP12E modules, I was getting unreliable operation when the voltage dipped below 3.0 volts. Dipped is not the right word. A very short duration glitch.

The 2.8 volt spec for the chip might be correct. But the implementation might not be good enough when power, measured elsewhere is at the minimum rated voltage.

As an example of how a part doesn't meet spec because of the implementation.

I would do some serious testing before using a 2.8 volt regulator in a product with the ESP8266.

I have switched from the AIThinker ESP12F modules to the Espressif WROOM02 modules, mainly because of the number of certifications they have - makes it so much easier to get my own products certified in various countries. Along with this there have been good and bad sides:
- the shared SPI pins are not exposed on the WROOM02 which means I can't use them for both I2S input and SPI devices. This is a shame because sometimes I need to save I2S input data on an SD Card
- the units are well made and are officially rated at 2.7V ~ 3.6V

So as long as care is taken with board layout (as you very nicely demonstrated in that thread above), I think it should be possible with this unit. I will be bench testing the idea before doing any big jumps though!