Possible to modify LED Christmas tree circuit for dimming?

[bobc]

The LED Christmas tree bought from Walmart is too bright. I'm an electronics hobbyist, so I wouldn't have much trouble modifying the circuit, if I knew what to do, or, if it's even possible, to add a pot or other components, for dimming it. Please have a look at the images and let me know if you see a way to dim it.

Thanks!

 

[Bluejets]

You could try using a small pwm control on the low voltage output to the LEDs .....BUT.....the LEDs might not like the outcome (flickering etc. or too low a voltage for the LEDs to work at all.

There are small speed controls about $3 on ebay etc. but they are limited to around 12v in......you would need at least 35v input.

Use some bluetack over each LED instead.

 

[bobc]

You could try using a small pwm control on the low voltage output to the LEDs .....BUT.....the LEDs might not like the outcome (flickering etc. or too low a voltage for the LEDs to work at all.

There are small speed controls about $3 on ebay etc. but they are limited to around 12v in......you would need at least 35v input.

Use some bluetack over each LED instead.

Thanks for the idea, I will think about the PWM control. Maybe I could incorporate an Arduino for this. Most of my electronics experience is working with Arduino/ESP32 boards, instead of dedicated circuits.

It's a five mode device where two of the modes increase brightness from OFF to full ON over three, and five, seconds. To achieve the brightness cycling, are they using a Relaxation Oscillator circuit with the OpAmp? I don't have much experience with OpAmps, but I'm thinking the combination of the resistors and caps determine the cycle rate and LED intensity. It's probably not as simple as using different R and C values, right? Or, replacing one of the resistors with a pot?

 

[Bluejets]

No requirement for any uc.
As far as the rest, who knows, you have it in your hand not me here.

 

[Minder]

Thanks for the idea, I will think about the PWM control. Maybe I could incorporate an Arduino for this.

It's a five mode device where two of the modes increase brightness from OFF to full ON over three, and five, seconds. To achieve the brightness cycling, are they using a Relaxation Oscillator circuit with the OpAmp?

I did a similar project for a member of a similar site to this, he had three banks of LED's he wanted a slow phase in phase out of each bank color in turn, so only two banks were actually in action at any one time over the three colors.
I ended up using a small 8 pin PicMicro with Peripheral Pin Select (PPS). And 3 PWM Outputs that would ramp up & down via a timer count

 

[bobc]

I did a similar project for a member of a similar site to this, he had three banks of LED's he wanted a slow phase in phase out of each bank color in turn, so only two banks were actually in action at any one time over the three colors.
I ended up using a small 8 pin PicMicro with Peripheral Pin Select (PPS). And 3 PWM Outputs that would ramp up & down via a timer count

Thanks Minder. I will be creating a replacement controller for the OEM controller. Mine will use an Arduino (probably Every) in conjunction with an IC (type undecided), and pot. I'll use the OEM AC/DC transformer, which puts out 29 VDC as input to my controller. The string of 1000 LEDs pull a max of 2A.