hello,
i already have multiple core branches running across the flat (12,24V), i wanted to get rid of the batteries powering philips hue motion sensor

1) already installed on 12V branch , 3.3V pololu brick.

2) the chatgpt advised that 3.3v it too much and it might be better to dump it to 2.7-2.8V
using the following components

Core

• U1: MCP1700-3002 (3.0 V LDO)
• C1 (input cap): 1 µF ceramic (X5R/X7R)
• C2 (output cap): 1 µF ceramic

Optional safety drop

• D1: Schottky diode (e.g. 1N5817, BAT54)

Is that a correct recommendation/ and should i proceed with that, could you advise?

Thank you!

 

I don’t know how much current it takes but a silicon diode would probably suffice to drop 3.3V to 2.7V.

 

@Jerry-Hat-Trick i think like 100-200mA

 

An IN4004 diode should work, it’ll handle up to 1A current

 

Since really FRESH small batteries may deliver 1.65 volts initially, that is the voltage that I will pick to use. So the output oftwo fresh batteries with no load would be 3.3 volts. Then the "Phillips Hue Motion sensor" includes U1: MCP1700-3002 (3.0 V LDO) which is a regulator, it appears. So a supply of 3.3 volts should work quite well. With the connected device including that 3.0 volts regulator, why drop the supply voltage below that??

 

If you are not certain, consider the LM2596 DC/DC converter module, inexpensive and widely available. Up to 35V input can be dropped to anywhere between 1.25V and 30V. In your case I’d use a 12V input and adjust the output to 2.75V

 

If the current draw is as low as 100mA, how long will the two AA batteries last?? So MY GUESS , based on the supply battery size, is that the current draw is less.

 

With the connected device including that 3.0 volts regulator, why drop the supply voltage below that??

i just googled if the device is powered by 2x AAA , its better to replace with DC of 2.8-3V and it has less impact on its internals. no clue tho.

 

An IN4004 diode should work, it’ll handle up to 1A current

hello and that diode dump 3.3V to 3V? could you elaborate a bit how to connect it? thanks!

 

hello and that diode dump 3.3V to 3V? could you elaborate a bit how to connect it? thanks!

Connect the diode anode to the +3.3V supply. Connect the cathode to your circuit. The diode will drop about 0.6V so you get 2.7V. The cathode is the end with the silver band painted on it

 

Why is that small difference in voltage critical?? IS the aplied voltage ACTUALLY THAT CRITICAL??? SERIOUSLY!!!! Is the voltage THAT CRITICAL??? AND, if the voltage is critical, what is the negative result of it being either TWO TENTHS OF A VOLT HIGH, or possibly LOW???
IF there is an actual undesireable result, please tell us what that negative result is.
I am asking this question seriously!! Most battery powered devices are tolerant of deviations in the battery supply voltage, so I am wondering about the "philips hue motion sensor" . I AM NOT AT ALL FAMILIAR even with what such a device is, or what it does. So can it be explained what a philips hue motion sensor actually does and what it is??
I understand what "hue" is and means, and I understand quite well what a motion sensor is, and how they work. BUT " hue motion sensor" is a totally unknown entity to me. THus I am asking for an explanation.

 

@MisterBill2 i dont know.

https://www.philips-hue.com/en-us/p/hue-motion-sensor/046677570972

chatgpt answer:

Why it doesn’t work the way you expect

The Philips Hue Motion Sensor is designed specifically for:

• 2× AAA batteries (nominal ~3V total)
• Very low, stable current draw
• Internal circuitry optimized for battery discharge curves, not a fixed PSU

Key problems with using a 3.3V PSU

1. Voltage mismatch (subtle but important)

• Fresh AAA batteries = ~3.2V (1.6V × 2)
• Nominal = 3.0V
• A PSU at 3.3V is higher than expected most of the time
  → This can stress or damage components long-term

2. No regulation/protection designed for PSU input

• The sensor likely has minimal voltage regulation
• It expects the natural voltage drop of batteries
• A PSU provides constant voltage, sometimes with spikes/noise

3. Risk of damage or reduced lifespan

• Overvoltage (even small) + continuous supply
• Possible overheating, erratic behavior, or failure

4. Physical + electrical differences

• Batteries provide:
  • Soft startup
  • Internal resistance (limits current spikes)
• PSU provides:
  • Hard, immediate current → can stress circuits

If you really want to do it (safer approach)

If your goal is to avoid changing batteries:

• Use exact 3.0V regulated supply (not 3.3V)
• Add:
  • A diode (drops ~0.2–0.7V depending on type)
  • Or a low-dropout regulator (LDO) to 3.0V
• Ensure:
  • Clean DC (low ripple)
  • Correct polarity (obviously)

 

OK, now I see that the use of the word "HUE" does not relate to color sensing at all, but is strictly a word selected to use as a name. Quite interesting indeed.

 

I also see that CHAT does not know more about this device than my friend's cat knows.

 

I also seriously doubt that 3.3V will be a problem for operation of the device.