RC mixing

[steelefist]

Hi. I'm new to RC equipment but I'm building a project. Basically I have 3 motors. 1 big forward/reverse drive motor. 2 smaller motors for steering. One controls the left wheel and one the right, but they are also mechanically connected through a differential.
Can I make 1 stick of a transmitter power all 3 motors for forward. All 3 motors for reverse. Only the small 2 motors (in opposite directions) for left. Only the small 2 motors (in opposite directions) for right. So the big motor isn't active for turning

[Roboteernat]

I would have to think a bit of custom electronics would be needed, a nice little arduino reading in the pwm signal from each channel of receiver then manipulating the output pwm to suit...

[TechAUmNu]

We use an mbed to do our motor control which is basically a more powerful arduino. I think concussion does the same. Don't think you can get this working on rc controller mixing although there is quite a lot of options on the dx6i controllers that most of us use so it could be possible.

[ralf.96]

It sounds possible, but an entry level computer-tx like a dx6 might not have enough mixing options for it. I would only recommend it if you know your tx very well (rc-plane background would help a lot). Providing support about more complex tx mixing via internet usually doesn´t work.

[Tramp]

If it’s small scale and your using 2 channels (channel 1 steering and channel 2 throttle) would it be possible to, take the channel 2 throttle output (from the Rx/receiver)directly to the large motor esc, this channel 2 could also then be teed into a ‘signal mixer’ (Mtronics do one) along with channel 1(steering). Out of the signal mixer would be x2 tank drive channels, from the mixer these channels could go to two individual esc’s which would each control one of the steering motors,

I suppose the the issue with this is that going forward or reverse all the motors would turn together, because of this each of the motors would have to be balanced as in a 400rpm main motor would have to have matching 400rpm steering motors or they would be constantly fighting each other, drawing current with no real gain (maybe even burning out motors)

im not an expert, this is just theory and I haven’t tried it!

[Deathly Hallows]

Rather than starting a new thread I want to ask some basic questions about mixing.

I am currently using a Dual channel Sabertooth with built in mixing which is brilliant but more expensive than other options and if I build more bots I need to understand my options.
I see various people talking about mixing on the controller to varying degrees of success.
I also see some comments online about mixer units and some talking about v-tail like this or this or those Tramp mentions here

If I am right then this model may be exactly what is needed to solve the original question in the thread - here

Anyone have experience plug in mixers?
Advantages disadvantages of in RC mixing vs in TX mixing

Thanks

[R9000]

Advantage of TX mixing: No need to buy a mixer. Just get a good TX and it will pretty much last you forever, on all your robots.
Disadvantage of TX mixing: You have to keep changing models on the TX if you have different robots with different trims and mixes.

Advantage of plug-in mixing: Inverse of the TX's disadvantage. Plug and play, don't need to change stuff on the TX mixing-wise.
Disadvantage of plug-in mixing: It's just another bit to buy, and another bit to go wrong. Case in point, Alex (owner of Bruiser) at this year's Insomnia was using a plug-in mixer. It stopped working properly halfway through the event, so I lent him my TX instead, that has inbuilt mixing.

My advice? Just get a decent TX with two mixes and memory for multiple models on it. Should be all you need.