What is Motor-stop on Cleanflight and should I use it?
This is initially a very subjective question but I will try to make it more objective.
So what is Motor-stop?
Motor-stop is a very simple function that is found on the Configuration page of Cleanflight (going to stick with Cleanflight as its actively developed)
as described here - it is - "Don't spin the motors when armed."
So why do you want this option on?
This is where its going to become controversial. When you don't have this option selected, every time you arm your multirotor the propellers spin slowly so you know when its armed and when its not. Sounds like a good option yes?
Here is some ideas I have.
When ever you connect a battery to a multirotor, consider it armed - just like a gun. If you want to check if a gun is armed or not you carefully point it some where safe and pull the trigger. Use this same method on the multirotor. Consider its always armed - make sure no fingers are near and the copter is in a safe position and and blip the throttle. If the props spin - its armed and disarm if necessary then unplug the battery to remove risk.
The other problem is that because its not a standard, people assume that if the props aren't spinning its not armed. As above the only way to be sure is test via a safe blip of throttle or disconnect battery.
The other issue I see is motors spinning after a flip or crash for seconds before its disarmed. I know many copters that have crashed out of site only to be burning esc and motors due to spinning in the dirt and grass.
Moving a copter that doesn't have motor_stop is also more dangerous.It will spin and can cut you if you bump the rudder stick to the right. If motor_stop is on you not only have to bump the throttle stick but also throttle up (this used in conjunction with my tutorial below will warn as well before this happens)
How else can I be reminded if I have armed or not?
Well luckily for you I am going to share with you in this blog my audio alert for arming and disarming on a Taranis. Using this method you can use your audio memory to remind you if it is armed or disarmed by a voice saying so at each arming sequence.
You can do this directly on the radio or use a copy of OpenTx from http://www.open-tx.org/downloads.html
Download the OpenTX speaker from http://www.open-tx.org/2014/03/15/opentx-speaker/
Using OpenTX Speaker create a sound file for the words arming and disarming (or whatever sound you would like to associate with these functions)
Either go to the Taranis model menu or configure open TX with the following switches
What we are setting up here is logical switches that will turn on if the throttle is down and the rudder is either fully to left or the right. This will allow us to determine if you are arming or disarming.
When we have sticks in the arming position we call special function 1 to play the word or sound we created previously every 1s. This one will play out arming..arming..arming while you hold the sticks. I usually find once it says it three times I am ready to fly.
The same thing happens when we disarm with the disarming sound playing.
You can change the timing parameter to play less often or just once if your prefer but I like this setting as I know for the counts of playback the arm or disarm has happened.
So to sum it all up - I prefer to treat a battery connected copter as a loaded and armed weapon rather than firing rubber bullets to remind you its armed. I have a audio reminder to remind me what its last state it was in and a short blip will confirm if I'm not sure.
In the end the choice is yours :)