LED RGB strip, thermo controlled red to blue

[toxsick]

hi,

i need to make a power supply that can gradient from blue to red based on resistance of a thermo sensor.

12v for red and another 12v for blue , i think gnd is common

i would like to have a variable resistor to able to control where red and blue happen
what would be best way to acchieve this

thx so much

 

[magvitron]

Option 1:
Are you into arduino? if yes its pretty simple to do it. [more info at : https://www.arduino.cc/]
assuming that you have knowledge of the same, You got to read voltage from an analogue or digital temperature sensor such as LM35 , TC74 etc and just make a "PWM" to control the brightness of the LED from blue to red.
Pros:
You could do it with minimal parts and effort.
Easily scalable.
cons:
A bit costly
Option2:
you could fiddle with some op amps and timers , that is read from the sensors scale with the op-amps and adjust the duty cycle of 2 timers controlling the red and the blue LEDs.
Pros:
More parts and effort
Not easily scalable for further improvements.

 

[toxsick]

I want to somehow make a small PSU which makes 1 rail raise voltage and 2nd rail lower based on a resistance band that works around 15degree c to 60 degree c

 

[toxsick]

Will Experiment with some bits, but if anyone has any ideas please help

Arduino might be the way to go... i found a great page, just ordered some bits

 

[magvitron]

resistance band

Whats that?

 

[AnalogKid]

1. What is the maximum current for each LED?

2. What are the manufacturer and part number of the temperature sensor?

If the LED current requirement is low enough, this can be done with one dual opamp like an LM358, one voltage reference like an LM4040, and a few resistors. Linearity will fall off at the temperature extremes.

ak

 

[toxsick]

Hi Everybody,
for anyone else interested.
I found this. I just got my adruino board waiting for mosfets and others parts

Webpage for how to build
**broken link removed**


Youtube video showing it work

I will try and replicate this and will then further try and enhance for my project

I plan to try and rewrite the colour wheel to include red and blue only, disregarding green just to get a smooth BLUE to RED gradient and hope to drive 3x pairs of hot and cold (red->blue) lighting effects from a single arduino board..
considering the board has 6 pwm outputs that will drive 3 pairs of colour
Just got to understand how to seperate the code and allow the use of the 3x onewire thermal probes

I plan on ignoring green led on the colour strip and go only for red and blue.

 

[magvitron]

Dear toxsick,
There are libraries for doing multiple one wire sensors. You just have to get the 'timings' right . With an Arduino in hand you will be surprised how easy it is to implement it. Good luck!