Author Topic: R/C Auxiliary Functions Switching Question.  (Read 3826 times)

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Offline John Candy

R/C Auxiliary Functions Switching Question.
« on: January 19, 2010, 03:32:13 PM »
My part-built kit for GWR AEC/GRCW diesel railcar has been lying in the corner for about 4 years!
Part of the reason has been indecision over how to control the directional lights and whether a realistic sound card could be fitted (these cars were powered by two AEC London bus engines and had two-tone horns).

The R/C unit is a 6-channel Futuba 2.4GHz and the ESC an Electronize unit.

Just made an 'impulse buy' of a ' R/C two-way switcher' from Andy Quirot in Jersey ( www.quirot.com ) which 'provides two separate switched circuits from one proportional or switched (centre off) R/C channel'. Instructions/diagram attached which states 'each of the two outputs can be driven independently'.

Questions:-
1) Will this device simply switch the two circuits on and off simultaneously (or throughput power proportional to the 'stick' position)?
2) What happens when the 'stick' position alters from 'forward' to 'reverse'?
3) Can it be setup so that it can switch two independent sets of LED lights to illuminate to suit direction of travel?

Only having needed previously to use R/C for speed control I am a bit in the dark!

Hoping someone can illuminate both me and the railcar!

John.
My fellow Members, ask not what your Society can do for you, ask what you can do for your Society.

Offline cabbage

Re: R/C Auxiliary Functions Switching Question.
« Reply #1 on: January 19, 2010, 04:04:46 PM »
Errrmmmm...

There is an easier method of doing this.

A diode from each one of the motor lines charges a capacitor.
The capacitor discharges through a reed relay.
The reed relay is then fed to a DPDT relay -which reverses the lights.

No multiplexing is required -just brute force electromechanicals.

regards

ralph

Offline Moonraker

Re: R/C Auxiliary Functions Switching Question.
« Reply #2 on: January 20, 2010, 12:17:53 AM »
John,

I make a diesel soundcard which has a two tone horn and I think is suitable. It is compatible with your controller and can be heard on and purchased from www.mylocosound.com. Current price is £39 but is increasing to £45 on 1st Feb due to the sterling exchange rate. So get in quick if you want one at the old price.

Regards
Peter
Peter Lucas

Offline John Candy

Re: R/C Auxiliary Functions Switching Question.
« Reply #3 on: January 22, 2010, 06:40:34 AM »
Thanks Peter.

I am in touch with Peter Spoerer who lives in the neighbouring county and am ordering both diesel and steam cards.
I propose using an electronic switch of the type in my original post (rather than an electro-mechanical servo switch) to activate the horn/whistle.

Regards,
John.
My fellow Members, ask not what your Society can do for you, ask what you can do for your Society.

Offline John Candy

Re: R/C Auxiliary Functions Switching Question.
« Reply #4 on: January 22, 2010, 08:18:32 AM »
Ralph,

Proposing to adopt following solution for the lights!
Using the electronic switch (which, according to r/c stick position, sequentially energizes either the first or both outputs) plus two DPDT relays.

'Relay 1' (R1) in de-energized mode powers the red LEDs at each end (in energized mode it feeds output power to 'Relay 2' (R2) and extinguishes red LEDs).
'R2' in de-energized mode feeds power to 'forward running' white LEDs plus red 'tail' LED (but only when 'R1' is energized to provide the output supply).
'R2' in energized mode receives power feed via 'R1' (also energized) and illuminates 'reverse running' light pattern.

In terms of r/c stick position, this translates into:-
When stick is 'off' both relays are de-energized and 'R2' receives no output power via 'R1' and red lights displayed at both ends (i.e.'parked' mode) via outputs from  'R1'.
When stick moves to position '1', 'R1' becomes energized (feeding output power to 'R2' which remains de-energized) and the lights are illuminated in 'forward running' mode.
When stick moves to position '2' , both relays are energized and the lights are illuminated in 'reverse running' mode.
The white and red LEDs at both ends are each independently connected to the relay outputs.

I haven't yet converted this into a circuit diagram, so cannot be 100% certain there will be no feedback/cross connections to upset the lighting patterns.
You will probably tell me that this is an over-complicated arrangement but I hope you are not going to tell me the logic is flawed!

Regards,
John.
My fellow Members, ask not what your Society can do for you, ask what you can do for your Society.

Offline cabbage

Re: R/C Auxiliary Functions Switching Question.
« Reply #5 on: January 22, 2010, 12:13:04 PM »
John,

Your basic logic is fine -but your design is horribly complex! Why are you using separate white and red LEDs when you can get a red/white LED? The less components you have -the less there is to go wrong...

regards

ralph

Offline John Candy

Re: R/C Auxiliary Functions Switching Question.
« Reply #6 on: January 22, 2010, 12:39:49 PM »
Ralph,

Thanks for confirming that I am not yet 'brain dead'.....these days I sometimes have my doubts!

The GWR railcars had four lights each end (in the same arrangement as the lamp irons fitted to steam locos) but the centre bottom was red, while all the others were white.
Therefore it is necessary to use four single colour LEDs on each end.

Regards,
John.
My fellow Members, ask not what your Society can do for you, ask what you can do for your Society.