Combining two switches for a function

mwm wrote: There are a number of different ways to combine switches and/or channels in an "and" condition. But in order to get normal behavior when the all the conditions aren't true, you need to use a virtual channel to do the and. Then add a mixer to the aileron mix that uses the virtual channel as a switch, with a fixed curve for the appropriate output value to deploy the crow brake. That way, when your virtual channel goes on, it deploys. Otherwise, you get the normal behavior.

mwm wrote: The easiest way to do an and is to string together mixers with the switches as SRC and a MUX type of "max". So for MIX2 and GEAR1, you'd have two mixers with MIN/MAX curve (if you read the tutorial, you'll know I like those for switch sources) and a SRC of GEAR1 and MIX2, respectively. The first one has a mux type of REPLACE, and the second of MIN. So the only way to get a value of 100 for on is if both of the switches are on, thus having a value of 100 making it the min.

mwm wrote: Adding THR=0 as a condition is then straightforward - add a mixer that is only on if THR=0. Are you sure you want 0? That's the mid-stick value, and -100 is the minimum value. Anyway, to get only 0 on you want an ABS curve, scale of -100 offset of 1 (from memory - you may want to check the offset). That way this mixer will only be >0 and hence on if THR=0. And the MIN mux type will get the behavior you desire.

mwm wrote: With that, I think you can figure out how to make it also depend on FMODE.

justme wrote: Just one remark: you mentioned applying a fixed curve to the AIL mix - wouldn't this then mean that I cannot control the ailerons with the stick any more when crow brake is enabled? I was thinking of just moving the 0 point of the normal aileron mix to a given value (say 60% up), but letting them still being controllable with their normal expo curve via stick.

You're right, I forgot the %-sign - THR dependency shall be to THR off=-100, not mid-stick position. Do I understand correctly this would require another virtual channel to be set up for replacing my currently configured MIX=2 correlating flaps=100%? And coming back to the first question, I'd then need to take this mixer's output instead of directly MIX=2 as an input for my virtual channel for the crow function, getting all the functions chained one after another? This would then imply the nice behaviour that for cancelling an approach, I'd only need to disarm my THR HOLD (I have intentionally not configured sticky throttle hold) with the gas stick remaining in full position.

(((MIX2 and GEAR1) and THR = -100%) and FMODE2)

mwm wrote: No, but I left out the details for that because I wasn't sure what "move the zero point" meant. You'll have a mixer on the aileron channel with the switch being the virtual channel that implements the AND. I assume it's on the aileron channel because deploying the crow brake seems to involve that channel. You can set it to a fixed value with a fixed curve and a mux type of replace. You can add a fixed value (my best guess at what "move the zero point" means) with a fixed curve and a mux type of add. If the value isn't fixed, you can use the appropriate curve type. etc.

You don't need another virtual channel. You need one virtual channel to act as a switch. That virtual channel needs one mixer for each condition: one for the MIX switch, one for the GEAR switch, one for THR, one for FMODE. The first mixer uses a muxtype of MIX, the rest of REPLACE. You can think of it as:

(((MIX2 and GEAR1) and THR = -100%) and FMODE2)

where each and is done by one mixer.

(FMODE0 and THR= -100% and MIX2) = FLAPS100% (only deploy flaps (on channel 5) fully if flight mode is normal and engine is off)
FLAPS=100% AND GEAR1 =CROW (only activate crow brake (raising ailerons on channel 2 and 6) if flaps are already fully deployed)

justme wrote: But here I'm a little bit lost again - how can I use just one mixer for all my combinations if I'd need the intermediate results also for activating functions?
I'd like to have the following

mwm wrote:
That's my bad. I hadn't realized you needed the intermediate results. Yes, you'll needed a virtual channel for each result you need. Note that you can get extra "virtual" channels by setting the number of output channels to higher than you actually use and using those extras. You have to do that to get to them in the mixer. After you get them set up, you can turn the number of output channels back down.

justme wrote: I saw in one of the development boards that you were thinking of a principle to define flight modes independently and make mixers depending on the selected flight mode directly - this would be something I'd appreciate indeed as it would really reduce the amount of needed virtual channels when you want to define functions depending on the flight mode, as far as I understand until now. Is this something you still follow up or is it more a dead idea?

mwm wrote:
I moved it to the back burner because I never figured out a way to do that that I thought worked noticeably better than what we have now. I tinker with it every now and then, but haven't even gotten close enough to start writing code. There are a number of alternative ways of doing this that become possible if some of the things on the horizon ever get done.

mwm wrote:

justme wrote: But here I'm a little bit lost again - how can I use just one mixer for all my combinations if I'd need the intermediate results also for activating functions?
I'd like to have the following

That's my bad. I hadn't realized you needed the intermediate results. Yes, you'll needed a virtual channel for each result you need. Note that you can get extra "virtual" channels by setting the number of output channels to higher than you actually use and using those extras. You have to do that to get to them in the mixer. After you get them set up, you can turn the number of output channels back down.