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:I have found that most sensors have a low power or stand by mode - in many it's simply a case of not talking to them, or sending a power down command. In others it's an enable pin of some sort.

I have found a set of sensors that I can control with either a single GPIO pin tied to all the chip enables, or via software - I haven't needed any external components.

My latest design uses the ISL91107IR buck/boost converter, however I am considering going back to just a straight LDO - my last rev used the NCP186A, which is not in your (awesome!) list:

Range voltage: 6 V Max
Max current out: 1 A
Quiescent current: 90 uA
Drop out voltage: 100 mV

Several things have made me rethink using the buck/boost:
- the ESP chip will actually operate at lower than 3.3V. I've heard people using as low as 2.8V to power them successfully. Most of my sensors are already using 1.8V and the ones that aren't can also operate with 3.0V or less
- when the input voltage drops below the threshold on the converter, the boost circuit draws more current to make up the voltage difference. On both solar and battery circuits the increased current draw pulls the supply voltage even lower, so you end up in a death spiral, and the increased current drains the power source even faster.

So in the end, it may work out you get better life by dropping your ESP supply voltage to to 3V or even 2.8V if you can, and using a normal high performance LDO instead.

I need to do some more experimenting...

Now I understand why I did not use the voltage regulator you mentioned in the list. His package is extremely difficult to weld. Can you solder manually without problems?
User avatar
By lucasromeiro
rudy wrote: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.


Impressive! Thanks again Rudy!
Excellent job
User avatar
By davydnorris
lucasromeiro wrote:...
Now I understand why I did not use the voltage regulator you mentioned in the list. His package is extremely difficult to weld. Can you solder manually without problems?

I am lucky enough to know a great hardware designer with a reflow oven :-)

The NCP186A unit comes in a DFN12 package which is *just* able to be done with a very fine tip iron but an oven is the best.