Make the Combine Sensors helper be super useful

It could be used to add not just sensors, but offsets, find difference between sensors, combine sensor values in different amounts and much more. All it would take is this:

for each sensor value, add a “multiplier factor” for it in the UI with default value of 1.0. Before summing its value, multiply it by the scale factor. Example:
Combine two sensors, set the scaling factor for one of them to -1.0. Now it takes the value of the difference between the two. Send the output to a Threshold helper, and now you can trigger alerts when two values diverge too much.
As well as this, you could set the relative importance of various sensors depending on the scale factor, then sum them and check against a threshold.

What would supercharge this is the ability to add offsets. I have discovered a way to do this, but it may not be so obvious. I created an input number helper - you cannot currently set a constant value, so I just added a tiny range. This broke the Combination sensor, so logically I imagined input numbers weren’t allowed. After a bit of experimentation, I tracked the problem down to not having the same Unit of Measurement as the other sensors. Once I updated this for the input number, then it worked as I’d intended, adding a constant offset to the sensor value sum. In this case, a negative offset.

A couple of small changes would make this really nice.

  • allow input numbers to have constant values, not vital, but it would just be neater.

  • be more lax with units of measurement, as outlined above.

  • alternately, make a new helper: input constant, which takes on whatever Unit of Measurement is
    appropriate in context.

I think this is all possible using the existing templates