6 proportional channels

[adamatronic]

Im trying to find a 2.4ghz transmitter, which has 6 proportional channels or one which can be modified to have 6 channels, the guy at the model shop suggested the DX6i, and i already have the Futaba 6ex, if anyone knows if either of them can be modified, or can suggest something else, please let me know.

Cheers

[Lead Wings]

You could try one of these to hack your existing radio when they come in stock.

I'm planning on hacking my Jr 2610 (2106) when I get mine.

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8354&pb=1

[Ron W3FJW]

You will need to use only the Assan receivers with that module. No others are compatible. This would be a better buy & may work with your Futaba.
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8286&Product_Name=X8_2.4GHz_Combo_pack_for_Futaba__W/_Module_&_RX

[adamatronic]

The problem i have is that i need 6 proportional channels instead of 4 proportional and 2 switched, how can i make the switched channels proportional?

[Ron W3FJW]

IIRC, back in the old days, we used to replace the switches and resistors with a pot of the same type and sized the same as the ones on the joysticks. Don't know if that's applicable to the new digital radios though. Don't know why not, but, some of the more knowledgeable forum members will have to chime in with some words of wisdom..

[adamatronic]

Ive tryed that, that is how i have done it the past, but the 2.4ghz models dont seem to want to play! help

[Ron W3FJW]

They might be using digital encoders instead of pots then. Never had a system open to have a look see, but would make sense I guess..

[Bruce Abbott]

The 'encoder' in modern radios is usually a microcontroller with an internal multi-channel A/D convertor. Chances are that the firmware will be configured to accept analog control only on those inputs that were designated as analog at the design stage. If a channel requires a switch then that input would probably be set to digital mode, as fewer external components are then required. Even if the switch input is analog, the firmware still has to interpret the voltage as a switch position, so it won't do any good to replace the switch with a pot!

You might have a chance if there is another version of the same radio which has analog input on that channel. If you are lucky, the manufacturer uses the same firmware for both versions, and provides a jumper or software configuration setting to select whether the input accepts a switch or a pot. Hovever, I have examined both a 6EXH (72MHz) and my DX6i, and could not find any configuration jumpers or relevant software settings. I suspect that the manufacturers have designed these radios to perform only the functions provided and no more.

[David T]

I agree with Bruce's comments but a ray of hope perhaps. A 3 position switch on a modern Tx could be analogue (with the centre position effectively the same as a pot fixed in the mid position). This configuration would probably be connected to some SMD resistors on the PCB. You'd have to identify these and how they connect to positive voltage and ground and to the MCU. If lucky, you replace those with your pot.

For more channels you could meddle with the signals entering the RF module but you'd need to understand MCU's to do this.
David.

[rc404]

The 'encoder' in modern radios is usually a microcontroller with an internal multi-channel A/D convertor. Chances are that the firmware will be configured to accept analog control only on those inputs that were designated as analog at the design stage. If a channel requires a switch then that input would probably be set to digital mode, as fewer external components are then required. Even if the switch input is analog, the firmware still has to interpret the voltage as a switch position, so it won't do any good to replace the switch with a pot!

I don't quite follow your last statement, can you explain it a little more please?

Is there a way to tell whether it was set up as analog or digital? I would measure the voltages on the switch terminals with the switch both closed and open. If it is digital, I would expect with the switch open for one terminal to be at ground and the other at logic high (pulled there by a pull-up resistor). When closed, I would expect both terminals to be at ground. Or maybe the other way around, both high, if there is a pull down resistor.

But if it was analog, I would expect the switch terminal that goes to the microcontroller to have intermediate voltages that would be different when the switch was open vs closed based on a voltage divider. But it wouldn't be ground in either case. What I would be curious to try is for one of the main stick pots, measure the voltages on the center terminal for the stick at both extreme positions. If the voltages at the switch looked similar to the stick, then wouldn't it likely be analog and just a matter of putting a relatively small value pot in place of the switch would work?

[Jappa_Indy]

Bruce is correct.

They will not use the ADC'c for the switch inputs, which are digital (on or off).

The reason being is A/D conversion hogs a LOT of precious CPU time and squeezing the normal channels in is a tall order to begin with. So they will not waste the A/D time on a "digital" channel.

However, there may be a few that will work by swapping for a pot. I had an Esky radio that it worked on.

It will be tough on a Futaba radio though as their MCUs are usually marked for them and there is no way of knowing what it is to see if the switch is connected to one of the A/D inputs. If the MCU is identifiable and the switch is connected to one of its A/D channels, then it MIGHT work, depending if its configured as analog or digital in the firmware. Not that Futaba would "allow" anyone to do this though. They want you to go uy a 14MZ.

A 3pos switch channel may work also as stated above, but the same applies. It may be connected to an A/D through a resitor or two digital inputs or ?