Tamiya MFC and stick radio set-up question

[Gazzalene 171]

There is a similar question to this but not fully answered. So sorry if familiar.

When using a Tamiya MFC unit , the throttle sticks crossways movement , activates other functions AND the steering sticks upward/downward movement also activates functions.

I realise that modern radios with digital trims can work with this system not just analogue.

Rather than using the sticks for these other functions (indicators and horn) can they be moved to a switch,if the radio is programmeable? If so would this need a 2 position OR 3 position?  I am sure the switch is doable BUT not sure on the switch type.

[Mad Ax 9313]

In theory you could do this, but you would need to have enough programmability in your radio to do it.

For example, the horizontal axis on the left stick controls the gears.  With the trims in neutral and the EPA set to 100%, 1st gear will be 100% left, 2nd will be centre, and 3rd will be 100% right.  You could quite easily set this up with a 3-way switch acting on a spare channel, and plug that channel into the gear select channel (J7) on the MFC.

However there is a catch.  To go enable or disable remote trailer leg mode, you need to slide the left horizontal trim full-right, then move the stick full right, then release.  This allows you to control the remote trailer leg servo (or the tipper trailer actuator) with the right vertical axis.  If you aren't using the remote trailer legs, this is no big deal.  However if you are using the remote trailer legs then you would need to configure some way to send full right trim + full right stick (around 125%) to your gear select channel.

Now if you have a fully programmable radio, you could configure a momentary toggle switch that sends 130% right to the same channel as the gear select switch.  You would use this momentary switch to toggle remote trailer leg mode.

Alternatively you could use a second 2-way switch to trigger a rate select (often labelled Dual Rate in radio config) on your 3-way switch, i.e. when the DR switch is Up, the 3-way gives 125% for trailer leg operation, and with the DR switch down, you get 100% for changing gears.

You also have revving mode operated by the left stick.  That is, if you put 125% into the gear select channel, you can rev the engine freely.  Again you could set this up with another momentary switch, or use the 2-way DR switch as per above.

Now you have to consider right vertical axis also.  100% up plays a continuous horn and 100% down plays a short horn.  As with the gear select, you could wire this up to another 3-way switch channel.  125% up toggles hazard lights on/off and 125% down cycles headlight settings.  Most radios will let you configure the DR switch to apply to multiple channels, so you can flick on the DR in order to turn on your hazards or change light settings.  If you had enough momentary switches and a fully-programmable radio, you could in theory have a momentary switch for every special function, but most radios don't have that many switches.  Personally I think it would be the nicest way to do things.

Remember that if you have trailer legs or a tipper actuator, the right vertical axis also operates the tipper / leg servo.  The trailer legs should be fine to operate from a 3-way switch but I don't know about the tipper (I'm not sure if if has a proportional response or if it's just on/off like the trailer legs).

A lot of cheaper multi-channel radios only have two toggle switches.  One is a 2-way that you'll need for the DR switch, and the other you could use for gear select OR horn / lighting.  However, these radios often have knobs as well as switches, which can be assigned to channels.  You can easily replace a knob with a 3-way switch - all you need is a 2-pole 3-way switch and two resistors to make a voltage divider, you de-solder the pot, solder in the voltage divider.  There's usually enough room in the case to put the switch where the pot was.

[Gazzalene 171]

Mad Ax, thanks for the detailed and easy to follow explanation.

This is my reason for asking AND I realise this is way more work than using the trims and cross axis control. I have bought a Flysky i6 radio which is six channel and can be flashed to have 10 channels! all this for £30! As standard 4 channels (on sticks) 4 switches ( 1 threeway, 3 twoway) and 2 rotary knobs. Not all assignable.

Do the easy flash and all switches and rotaries assignable. Just see a vid where 2 more switches can be fitted to run from channel  3 and 4, making the radio a true 2 stick radio,which I like the idea of. could end up with throttle and steering on sticks,then 6 switches and 2 rotaries. Its a aero and heli radio also so mixing and DR are quite good.