Sleep or switch Attiny85 oled screen on a coin cell?

Other Hardware General Electronics
1

Hello, I'm debating on what to do with my attiny85 temperature snesor project. Because it is on coin cell and it has a Oled screen should I put a Power switch to turn it all off to save power or put the attiny85 to sleep and have a transistor on the power of the oled screen and just tell the attiny85 to turn it on to take a reading? I know it takes time for any temperature sensor to catch up with the room temperature and take a reading then display it on screen.

So what does the comunity think? Full power switch or sleep mode for attiny85 and a transistor to turn off the oled screen?

Joseph

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Does the OLED screen not turn off on command?

3

Hey Paul, I don't want to make this into a programming question. But no it doesn't. I tried different libraries online to get the oled working on the attiny85. However none of them didn't work out. I did find one where everything is all in the sketch including the library part to make the screen works is in there. Not even sure I can make the screen go to sleep. So at the moment Not sure to be honest.

joseph

4

I would be surprised if an OLED screen would work for more than a few minutes on a coin cell, if at all.

Coin cells are intended to be used in applications that rarely draw more than a couple of mA, and sleep most of the time.

5

I got 1 hour from it. Only displaying temp numbers thats all. But you are right not good for a project like this.

Joseph

6

Is it possible to change the Oled to an LCD display?

7

What screen did you have in mind that would be better?

Joseph

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OLEDs should be more efficient than a LCD since you are only generating the light that is needed, rather than illuminating all and blocking much of it off.

9

If you make the display turn on at demand 1 hour is plenty of lifetime. To read the value 2 second are plenty of time. 1 hour of runtime means 1800 readings; one year with 5 readings per day.
Using a button to power the whole device for as long as the button is pressed is a good way if you can do the temperature measurement quickly enough.

LCD without backlight needs nearly no power.

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The problem is it is on a attiny85 and only 4 pins available. Not sure which lcd I can use being only 65% of the sketch memory is taking ip by the oled and thermistor. Which mostly of that taking up is by the oled itself.

Joseph

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if you are using OLED, use a MOSFET as a switch and turn it on only when you need to display something. The best thing is to cut the power altogether. The sleep mode of LCD controller ICs still consumes current as well as other sections in the LCD.
Here is one example of ATTIN85 driving a 16x2 LCD.
for best power performance, you have to find it via LCD suppliers themselves (if it is for a commercial project)

12

Hello, I have been thinking about that to add the mosfet or transistor of some kind. Thank you

Joseph

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Here is a question for the community. From what I’m seeing what if I run the string vcc off of one of the pins? Looking at the datasheet it is 40ma. I know the oled is at 70ma if all pixels are populated. But sense I’m running only 2 lines of code maybe that’s about 20 to 30 ma.

Joseph

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