Status LED

[jsc]

If you are not running a dual extruder it is pretty easy to get gcode control of the extruder 1 mosfet. I've used that to drive an LED strip, but you would not get RGB control.

For pin assignments, google "Arduino mega pin map", I think that's what you're looking for.

[Tim]

The bed heaters are run by switching the 24V supply through a power transistor. That power transistor is driven on the gate by a logic-level output from the Atmel chip---marked "HEAT-0" and "HEAT-1" for the extruders, and "BED-HEAT" for the bed (obviously). Connect these to various of the R, G, and B leads of the LED (in series with a 200 to 220 ohm resistor---even 5V is too much for an LED!), and it should work. I expect that the Atmel output drivers can probably handle the drive current for the LED without drooping enough to affect the power MOSFET.

The two caveats are (1) I have no idea how easily accessible any of those points is on the RAMBo. I don't see any test points associated with them; and (2) These are pulsewidth-modulated (PWM) signals, meaning that they (like the associated on-board LEDs) don't tell you when the bed is operating, but only when it's drawing current, which is only an occasional pulse once the bed or extruder gets up to the target temperature.

[jsc]

I think the easiest thing is to offload the lighting to your host computer. The host program is already tracking various temperatures. If you use octoprint as a host, you can use their API to query various status information on the printer, and map that to color any way you like.

[Slipshine]

You could run a second temp sensor in to a Adriano Mini and control the RGB from there. Its then a stand alone system.

[innkeeper]

i think a modification of my idea might work...

here is the idea:

use a second switch on top of the current x switch, assuming there is enough room... appears to be...
you may need to bend it slightly to make it close at the samae time or before the homing switch.

use 24v LED RGB strip lighting - pretty cheap on ebay.

24v to common on the new switch. (can get this from the hbp connector)
Mosfet out to the HBP to the (-) negative for red on the RGB strip.
Mosfet out of the Hotend to the (-) negative for green.
leave the blue unconnected.
conneect the + of the RGB strip to the N.O. connection

this will enable lights for hotend and build plate only when the hotend is hommed..., change the startup code to home X as the first command.

G28 X ; home X to turn on warmup lighting

for operational lighting
on a second strip, connect the + of the second strip to the N.C. of the new switch
connect - RGB wires to ground (or just use a white strip)

this will then light when the hot end is not hommed.

i figured why not use a second strip as the cost of the rgb strips are pretty cheap and thre is likely a min length that is a lot longer then you need..
i guess the concept would work with lower voltage led's but.. then you need to add a resistor of the right value in seiries.

what do you think?

[askernas]

I use Octoprint as a host, but since there is a status LED on the RAMBo, I figured it might be possible to connect an LED strip (or some logical version thereof) from that.

I'll dig through the outputs on the RAMBo board and see what I can find..

Thanks =)