Apart from specialised small brands (as Railboss, RCS, etc) products, the usual R/C systems on the market (Futaba, Spektrum, Hitec) are designed either for airplanes and helicopters or for model cars and buggies. Therefore I found none of them completely satisfying for model railways.
The main reason is that the four main chanels are handled through two joysticks eachone handling two channels. Usually they are all automatic spring centered except one (the gas throttle)
My purpose was to transform my Hitec transmitter with four sticks, each one dealing with one chanel.
When I looked at the inside, I was upset by the small size of everything. As I am quite reluctant to circuit welding (some bad experiences ending in burnout!), I put as a constarint rebuilding the device with no unwelding.
The other constraint was thge fact I am not a mechanic and all the pieces should be either straight from the shelves or made with a Trotec laser cutting machine available in the fablab.
Let us see the result :
BEFORE:
AFTER:
The chanels distribution I planed is the following:
for live diesels :
Chanel 1 : PWM ESC
Chanel 3 : Engine throttle and engine cut off buttton
Chanel 2 : Direction
Chanel 4 : if used : engine start or temporary battery operation
Chanel 5 : Lights on/off
Chanel 6 : if used, horn
for electric driven locs :
Chanel 1 : PWM ESC
Chanel 2 : Direction
Chanel 5 : Lights on/off
other chanels available for miscalleneous uses.
If ,in the future, I am bold enough, I shall modify the Chanel 6 buttons which are not at all convenient for railway usage, but I am a bit afraid of chirurgical operations !
Let's see the operation from the inside:
As you can see I did not touch the electronics, just cut some straps to loosen the potentiometer wires.
Here is a detail of the potentiometer mounting:
The principle is very simple and comonly used in R/C's:
for each chanel you can choose either a position keeping device with the spring on the rackwheel on (as in the picture below) or a spring self center positioning (as on the right hand side on the picture above). The tightness of the spring is adjusted with a headless bolt.
The main trouble has been finding the convenient spring. I finally found small clothes pegs, the springs of which could be easily adapted.
The device is made of PMMA:
Some of the PMMA parts:
partly assembled:
The sticks have been boroughed from my other Hitec transmitter. I will by a new set with my next order from Hobbyking.
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