ATtiny85 power savings using APDS-9960 proximity sensor as external interrupt

ATtiny85 power savings using APDS-9960 proximity sensor as external interrupt

I am trying to get some clarity on whether or not a proximity sensor using I2C
can create an external interrupt while a microprocssor is in sleep or deep sleep mode.

ATtiny85 low current consumption

It it possible? Or will an external interrupt only work with a push button, etc…?

i.e.

  1. I want to use the ATtiny85 for low power consumption while it’s using 2XAA rechargeable batteries (~1.2V) as a power source.
  2. The ADPS-9960 sensor detects the presence of a hand and the ATtiny85 gets out of deep sleep mode
  3. A tiny motor is activated for a second or two.
  4. The processor goes back to sleep

You'll need to connect the interrupt pin of the APDS-9960 and aktivate PCI on Attiny.

Ok thanks, that clarifies it.

Maybe I am confused, I thought that the LED drive circuit on those sensors was over 10ma at its lowest setting.

Are you sure you want that sensor constantly “ON”?
Also are you sure you can run that sensor off 2.4volts or are you also using a boost converter?

I want to use it for a soap dispensing application so I do want it always on or ready to go on once a hand is there. I've got 4 Simple human soap dispensers at home and all of them have died or aren't working except 1. Their two year warranty has expired.

They also drain 4x AAA alkaline batteries within ~6 months.
So I decided to try to make my own.

I didn't even consider what you mentioned.
Here is the link to the sensor:

Datasheet:
ADPS-9960 datasheet

The URL I'm using to buy:

It says :

Low Power Consumption: 1.0 µA typical in Sleep Mode

You are correct regarding led drive current of 100 mA,
but that will only run once activated out of sleep mode no?

The weird thing it says minimum power voltage can be 2.4 volts, but led minimum voltage can only be 3 volts.
Perhaps I can run off of 3x AA (1.2V rechargeables)?

knightridar:
You are correct regarding led drive current of 100 mA,
but that will only run once activated out of sleep mode.

Exactly, could the sensor detect a hand and trigger the interrupt pin on the ATtiny if it’s LED is asleep?

Oh man :roll_eyes: .
Well that's going to defeat the purpose of the power savings.

I think the lowest the datasheet says it can do is 12.5 mA based on certain test conditions.

I found this it looks impressive regarding deep sleep or sleep mode.
Only problem is Arduino compatibility.
Wish Arduino was using some native hardware that doesn't need any modifications that can operate at really low power in sleep mode without modifications. I've seen some posts online i.e. arduino pro mini with no led, arduino uno atmel chip on breadboard, etc...
Microchip Technology Extreme Low Power (XLP) microcontrollers

I wonder if there are any lower power proximity sensors out there.
PIR sensor, .1 mA static current
I found this but I generally find that PIR sensors are a bit too sensitive. I had a soap dispenser in the past that had a really bad sensor. It would dispense every time a bathroom light was closed. The Simple Human dispensers have a sensor similar to the APDS-9960.
Here is the device for reference:
https://grabcad.com/library/automatic-soap-dispenser-parts-1

I think I found a couple of reasonable alternatives.
They have active states in the uA range I believe.

https://www.digikey.com/product-detail/en/stmicroelectronics/VL6180XV0NR-1/497-14702-1-ND/4854910

https://www.digikey.com/product-detail/en/semtech-corporation/SX9310ICSTRT/SX9310ICSTRTTR-ND/6193187

https://www.semtech.com/products/smart-sensing/sar-sensors/sx9310
This one seems to have the best uA current range in its active state I believe.