RGB LED Lighting Controller Ideas

[PaulCa]

So, I find it interesting how quickly the RGB lighting scene exploded. I found the WS2811/WS2812 addressable (pixel) LEDs through electronics and build a few controllers for the them using AVR micro-controllers (used in the Arduino).

However in context of PCs I find they are often very expensive or require rubbish control software.

I got to thinking about translating my electronics LED skills into producing something for my PC.

Would anyone find an LED strip thermometer useful?
What about an LED strip air flow meter?
Or both?
Sound level meter?

I'm thinking about something that has little or no software requirement. The thermometer version would have a trim pot to calibrate the display to the temperature you desire and maybe a button to switch between bar graph, solid, breathing, etc.

Similar for the air flow meter.

They would only require a 5V or 12V rail which can be found on most motherboards, even if you just used an unused fan header, so they will not require BIOS control or even an RGB compatible motherboard. A 12V down to 5V adapter is easily possible for powering off SATA or Molex 12V rails... if not using 12V LED strips.

I am thinking about making these open source projects, but might also sell blank boards or even built boards. But the schematics, PCB layout, bill of materials would all be published online so people can customise them.

Anyone interested in helping with some ideas towards requirements?

 

[Habakkuk]

You sound confident enough soldering and programming - check out the BlinkM MaxM controller; the schematic is in the instruction manual, and the firmware can be flashed to a blank AtTiny84.

The firmware isn't open source but there's an open source equivalent for it.

If you're able to find a place stocking them, then they have a breakout section where sensors & trimpots can be added.

They already come with colour & effects built in.

The LEDs take 12V, the logic takes 5V, making the molex socket ideal.

 

[Habakkuk]

The AtTiny84 takes data & clock (SDA & SCL) lines from an external microcontroller - I haven't figured out how to make that work with USB to be able to instruct the MaxM from the computer for system load or temperature - without a signal the AtTiny84 falls back on white light, then through the spectrum.

 

[Habakkuk]

The FT232H should be able to act as a go-between on the I2C bus for usb>controller - then it's a matter of making the software (which is where I struggle)

Ideally you'd want terminal commands to make it platform-agnostic, then use scripts to set and change the colour - once a colour or effect is set, it's latched & will continue to run without further instructions (have already checked on my project)

 

[ttaskmaster]

Would anyone find an LED strip thermometer useful?
What about an LED strip air flow meter?
Sound level meter?

Potentially, yes... to all three.

even if you just used an unused fan header, so they will not require BIOS control or even an RGB compatible motherboard.

Anything that can essentially be plugged in and colours/patterns chosen via either software or buttons on the unit is a win, in my book.

Anyone interested in helping with some ideas towards requirements?

I can tell you what kind of things I'd like to see available...?
Exactly how they would work, though, is beyond me.

 

[Habakkuk]

Ahh, just saw you said addressable - that controller is not addressable, all the lights react the same.

 

[PaulCa]

I want to start with simple uncontrolled things such as temperature strip. The idea would be for it to have different modes, one mode would make it look like one of those stick on strips you use on fish tanks, another would be solid colour with the colour alone giving you the temp.

Need to research an airflow meter as well to see how practical that is to interface with.

If I am going to go down the control route I will probably go for the ESP8266 with Wifi and implement a REST API, so it's is truely platform agnostic. I want to avoid having to mess about with PC control. Chips like the FT232 and CH386 give you USB to Serial, but you still need to implement something to talk serial on the PC in software, that opens up a can of worms around supporting different OSes, different OS versions etc. and is the main problem, in my opinion with current offerings.

 

[Habakkuk]

Still waiting on ESP8266 on the slow boat from China.

Any reason to use it over the newer ESP32?

 

[PaulCa]

Any reason to use it over the newer ESP32?

Not really, but such small LED controllers would not really benefit from the extra features. The only one I can see as being of use is the extra 2 bits on the DAC. Still they are like £3 each either way.

 

[Habakkuk]

Addressable lighting is going to add complexity to it - is there anything besides christmas tree/running landing lights effects you want?

 

[PaulCa]

It will need a micro controller either way. An ATTiny85 can run up to 96 addressable LEDs off a single pin. The ESP8266 could probably run a 1000 LEDs off a single pin as the limiting factor, believe it or not, is holding all the RGB structure values in memory and the ATTiny85 only has 5k of static RAM.

The plan would be for a single ESP (or ATTiny) with a wheatstone bridge PTC airflow sensor, additional temp sensor (possibly a Dallas One wire sensor for accuracy), these two sensors need to be position-able while the controller can be hidden in the basement or velcro'ed back side of the mobo. This would drive a short LED strip to display both case temp and airflow. The colour could be the temp, the width the airflow. Alternatively it could pulse the digits of the temperatures. Say, 2 lights, then 9 lights = 29*C.

The wheat stone bridge PTC airflow sensor concept is perfect as it has no moving parts and it reads airflow based on it's ability to cool the temperature sensor itself while you pump current through hit. So it's effectively measuring "cooling effect" of your case air.

5V or 12V, there are ways to use both by using a very low drop out 5V regulator which when give n12V will give 5V, but when given 5V will still give out 4.5V, however in you guys experience, how common are 5V headers on motherboards capable of providing up to 1 Amp? Is it best to stick with 12V mollex/SATA/Fan leads for power?

 

[LuckyBenski]

Temperature display would be awesome! Though I'd really want it to show me the temperature of a component like CPU or GPU.

however in you guys experience, how common are 5V headers on motherboards capable of providing up to 1 Amp? Is it best to stick with 12V mollex/SATA/Fan leads for power?

I believe that while USB headers can supply 500mA as specified and some might supply an amp, they might not do this without the USB protocol demanding it i.e. it may limit the current to 100mA without a USB device connected.