I ran into a very frustrating problem last night while trying to work on some scripting within Indigo for controlling the LED colors of a new LED strip. I had no problem with actually controlling colors using the built-in UI tools for updating colors, but a slightly more complex usage presented a major problem.

The issue started with a need to save the current state of the individual RGB values in the LED strip, before I apply a change, such as when a notification occurs. This is to ensure that after a notification “flash” occurs that the colors will go back to the same values they were before the notification.

Via scripting, I had no problem getting the values. The problem occured when I went to restore the values. As it turns out, I struggled with this issue most of the night until I finally figured out that it was a difference between how the UI treats RGB values and how they are actually stored in the device.

The problem is that I was retrieving RGB values that were based on a scale with a minimum of 0 and a maximum of 255, but when I passed these values back the UI was converting those numbers, incorrectly, into values on a scale of 0 to 100. Eventually, I realized that before I can restore the individual color values, I must first convert them to the UI’s scale.

In addition, and perhaps I confused this with that issue, before I figured it out, I also had problems changing the color more than once in the same script. This may have been more of a timing issue (a kind of race condition) so I split the two scripts into seperate actions with a 5 second dely for the second script.

Here’s the first script that reads the LED strip’s color values and stores them into Indigo variables. The last line changes the RGB settings to display a yellow color, for notifications.

dev = indigo.devices[1681458792]
indigo.variable.updateValue(indigo.variables[872936515],value=unicode(int(dev.redLevel)))
indigo.variable.updateValue(indigo.variables[770189775], value=unicode(int(dev.greenLevel)))
indigo.variable.updateValue(indigo.variables[753658911], value=unicode(int(dev.blueLevel)))
indigo.variable.updateValue(indigo.variables[1059165341], value=unicode(int(dev.brightness)))
indigo.dimmer.setColorLevels(dev, 100, 100, 0, 0)

The first ID used represents the Indigo ID for the LED strip. The other four IDs are for the Indigo variables. All of these devices are unique to my Indigo setup, my devices and my variables. The correct values can easily be acquired by right-clicking (or Control-click) on the item within Indigo to select the ‘Copy ID’ option.

The next part of the script restores the value of the individual color variables. It first converts each value to an integer (all Indigo variables are stored as strings, so they must be converted for this type of usage) and then do some simple math to convert the RGB values to the appropriate scale. The original equation I found had more components but I removed them since the minimum value in both scales is always zero; by removing the zeros it had no effect on the final calculation.

Note that RGB values being set should be integers as well, before being used to actually change the color values.

dev = indigo.devices[1681458792]
valRed = ((int(indigo.variables[872936515].value) * 100) / 255)
valGreen = ((int(indigo.variables[770189775].value) * 100) / 255)
valBlue = ((int(indigo.variables[753658911].value) * 100) / 255)
indigo.dimmer.setColorLevels(dev, int(valRed), int(valGreen), int(valBlue), 0)

So far, this seems to be working properly.