E-Ink won't work because it needs up to 4s to refresh (I want to build a clock).
7-segment-LED ist too power consuming.
OLED is too small.
So there is Nokia 5110 (1mA plus up to 4x10mA backlight as far as I read).
Or a 7-segment-LCD. But I can't find any numbers on power consumption. I'd like to use something like that but they are not even shielded.
Can anyone help me out with power consumption and/or a link to a shielded version?
There are several things to consider. I assume your clock is battery driven.
The LCD itself will not consume much current. The datasheet of the DOGS102 mentions about 250uA (https://www.mouser.de/datasheet/2/127/dogs102-6e-6338.pdf). The LED backlight will consume 200 times higher current (40mA to 80mA).
If this should be an alarm clock (you did not mention this), then you probably need a backlight, but you need to spend some programming effort to disable the same after some seconds.
Another method to extend battery life is to use a stepup converter. Assume you use a pro micro Arduino with 3.3V. So you may consider to use 2x AAA cells for your setup, which should provide 3.6V with fresh batteries. I guess it will stop working with about 2.5V or so. At this time you probably only took half of the energie of the batteries, so wouldn't it be cool to let your device run until the two AAA are at 0.8V?
I have recently used this device to extend the lifetime of my own clock: XC9142B33CMR-G Torex Semiconductor | Mouser Deutschland
Oliver
olikraus:
The LCD itself will not consume much current. The datasheet of the DOGS102 mentions about 250uA (https://www.mouser.de/datasheet/2/127/dogs102-6e-6338.pdf). The LED backlight will consume 200 times higher current (40mA to 80mA).
I want to use another LCD (segmented), because it's bigger and less expansive. I now found out, that it consumes 2.54 mA per square centimeter - for the linked LCD it would be 10uA.
It's reflective but may be available in other flavours (transflective, transmissive) as well.
Adjustable brightness of backlight would be nice, but I'm not quite sure if I need it at all.
How do you connect a LCD without a shield?
If this should be an alarm clock (you did not mention this), then you probably need a backlight, but you need to spend some programming effort to disable the same after some seconds.
No I plan on building a chess clock.
Another method to extend battery life is to use a stepup converter. Assume you use a pro micro Arduino with 3.3V. So you may consider to use 2x AAA cells for your setup, which should provide 3.6V with fresh batteries. I guess it will stop working with about 2.5V or so. At this time you probably only took half of the energie of the batteries, so wouldn't it be cool to let your device run until the two AAA are at 0.8V?
I have recently used this device to extend the lifetime of my own clock: XC9142B33CMR-G Torex Semiconductor | Mouser Deutschland
Would be nice, but this drains the board with another 1.2mA - or only if the voltage drops below 2.5V?
I plan on building a chess clock.
Hmm, I suggest a hardware switch, which disconnects the power source.
Would be nice, but this drains the board with another 1.2mA - or only if the voltage drops below 2.5V?
Indeed it is a little bit difficult to understand the datasheet here. My own clock now runs since 350 days without power down. The microcontroller only put itself into sleepmode as often as possible. Initial voltage (2x AA) hand been 3.6V, it is now at 2.5V... still running.
Oliver
Pardon but I'm trying to build a clock as well but have not been able to keep the display on, losing all display data. What do you put to sleep in the mpu?
I'm using a 5v Mini Pro [@16Mhz], powered by an AdaFruit Powerboost 1000C using [4.8v NMHi], a ChronoDot RTC, driving an AdaFruit OLED 16x2 display.
Thanks in advance.
Ernie
egfowler3:
Pardon but I'm trying to build a clock as well but have not been able to keep the display on, losing all display data. What do you put to sleep in the mpu?
There is no general answer and unfortunately, there is no Arduino function for this.
But the answer will be in the datasheet of the microcontroller. For my project I have use a STM32L0 uC, so whatever i did there, can not be used for the Pro Mini.
Oliver