PDA

View Full Version : technical question for RC gurus


andyathome
09-17-2014, 03:50 PM
ok, I have a rc4wd excavator .
I have fitted a truck sound modual to the excavator.
I am using the left track as the motor start signal and am using the 4th valve (hydraulic bypass)as the speed reference for the sound card.

problem is :that obviously when you activate the arms , bucket ect the motor sound slows because the valve closes to allow oil flow to increase.
what I want to happen is to have the engine sound increase when I use the hydraulics.

is there any way to reverse the signal that comes out of the reciver.
I have made 2 y leads and attached to the reciver as per instructions, so if there is something I can plug in that wont affect the operation of the 4th valve that would solve all my problems.

cheers for your help.
andy

Supermario
09-17-2014, 05:28 PM
I just wanted to comment on a very common misconception about the 4th valve operation on a 4200XL.
The valve is controlled and adjusted with the dial just above the left stick. Once you set it, that's it. The valve does not move while running stick boom and bucket. There is no mix on this set up.
Knowing that, I have no idea why the sound is changing considering that ch is constant voltage?
Sorry I can't be more help.

Excavators don't really rev up and down at all. Just lug a little when working hard. Maybe use a toggle switch function to rev up and idle down when not digging?

Oh, PS. I'm a RC guru wanna be :D:cop::lol:


Mario

Cooper
09-17-2014, 05:56 PM
I agree , when operating a 1:1 ex, usually set the idel up and start digging. Newer models have digging modes that auto throttle up and throttle down after no stick input is sensed for about 30 seconds. But in your case if you wanted you could also split the pump channel for the sound or keep how you have it and just split signal wire and install a siginal reverser before sound card. Commonly used on aircraft in landing gear.

apfubar
09-17-2014, 06:18 PM
I agree , when operating a 1:1 ex, usually set the idel up and start digging. Newer models have digging modes that auto throttle up and throttle down after no stick input is sensed for about 30 seconds. But in your case if you wanted you could also split the pump channel for the sound or keep how you have it and just split signal wire and install a siginal reverser before sound card. Commonly used on aircraft in landing gear.

On some advanced radios auto throttle and the 30sec delay after stick input can be simulated...

If a beier usm rc is used as the sound module this can be partly simulated... Assuming the pump is rc controlled... Just a y line off the pump control line from the receiver... To the usm as well.. When the pump run the engine sound strarts... And stops after x secs(configurable)... Even better you may be able to add the track motors as other inputs... To keep the sound running.

AP

trucker n
09-17-2014, 06:20 PM
Can't u connect to one of the other valves so when working boom or stick it will rev up and down

Dieselchopper
09-17-2014, 06:22 PM
I would use the pump channel to rev up and down.

andyathome
09-17-2014, 09:05 PM
Thanks for the feed back.
I have hookd into one of the valves but the sound would only change when that channel was used.
the 4th valve on my excavator opens when no stick movement and dumps back into the tank this results in my sound card changing revs . It slows when sticks moved and speeds up when no movement it is also proportional so you get a steady decrease in sound when sticks moved.
I like the signal reversing idea.
will give it a try and see what happens. Only way to learn is to mess it up and try again.
cheers andy

fhhhstix
09-17-2014, 09:34 PM
Thanks for the feed back.
I have hookd into one of the valves but the sound would only change when that channel was used.
the 4th valve on my excavator opens when no stick movement and dumps back into the tank this results in my sound card changing revs . It slows when sticks moved and speeds up when no movement it is also proportional so you get a steady decrease in sound when sticks moved.
I like the signal reversing idea.
will give it a try and see what happens. Only way to learn is to mess it up and try again.
cheers andy



Yes the valve does move it acts like an unloading valve so the motor is not under so much of a load when the hyd's are not in use. I have one of the older hoes and have set mine up like the newer ones. So yes the sound won’t work like you want hooked up to this channel unless you go with a servo reverser.

andyathome
09-17-2014, 09:59 PM
Yep. Have just got of phone to the hobby shop. $5 for a y lead reversing signal and all shoud be good.
will post video after postman shows up.

Supermario
09-17-2014, 10:17 PM
I'm a little confused. I didn't want to give in accurate info about how the hoe runs so I double checked , went in the basement. Fired up the hoe and watched the 4th valve while running multiple functions and saw no movement at all?:confused:

andyathome
09-18-2014, 03:10 AM
that's interesting? I was of the understanding it was like a regulating valve for pressure relief , that's how mine works..
how does your pump sound when there is no stick movement.
the noise should ( as mine dose) stay about the same wheter you are digging or not.

cheers andy

Supermario
09-18-2014, 04:12 PM
that's interesting? I was of the understanding it was like a regulating valve for pressure relief , that's how mine works..
how does your pump sound when there is no stick movement.
the noise should ( as mine dose) stay about the same wheter you are digging or not.

cheers andy

The best way I can describe it is, the relief valve controls how much lifting power the machine has and the 4th valve is the flow control to regulate the speed of the functions. The more oil diverted to the tank the slower the functions. Less oil going to tank means more for the valve.
My pump sound also stays almost constant. I've placed a couple marks on the 4th valve servo coupler. Nice day today and Goose19. (Allen ) is in town to play in the pit so I'll get a good look of what it's doing while he operates.

andyathome
09-18-2014, 05:12 PM
http://youtu.be/VR1NbwjUCOU

heres a real quick video of the sound card and see how the revs drop when there is stick movement,
I am going to do the same and watch what the valve actually dose .

cheers for the help , now I am going to go and sit by the letter box and wait for the postman.

cheers andy:bounce:

Supermario
09-18-2014, 06:27 PM
That sounds awesome ! I'm hooked now. I gotta get me one of those :bounce:

Eagle machinery you say?

andyathome
09-18-2014, 06:54 PM
Yeah they have a listing on alliexpress. I think it was $168.00 for everything.
Or email tang at eagle machinery and he will sort you out.
its the same unit in the loader.
she is a tight fit but cut off the tags on the speaker and stick sound card to back of speaker and it will fit. I put some packing foam under the speaker to keep it out of any posible oil spills and used some double sided tape to hold it in place.

cheers andy

RCP57
09-18-2014, 06:56 PM
That sounds awesome! I don't know anything about the mixing capabilities of those TX's but I'm thinking with a bit of playing around you could get the revs to be full out with no stick movement and as soon as a hydraulic function was used have them drop off slightly. This would give it the effect of having the engine bog down when digging hard I think.:confused: Or are the sound cards only good for idle and pinned noise? I've never had a sound unit so I don't know what I'm talking about but I know that would sound cool....

andyathome
09-18-2014, 07:40 PM
I will do a longer video soon but the 4th valve appears proportional and the sound card reacts the same so what im trying to say its just like the trottel on a truck the more you give it the faster the revs.

andyathome
09-19-2014, 12:49 AM
as promised heres an other average video.
have worked out the issues, because the sound card is running off the bypass valve when there is no stick movement the revs are high.
in order to shut sound card down I have to shut off pump and then use a stick, revs drop then use track movement and sound card shuts down :rolleyes:

will see what happens with signal reverser, should be much eaysier to start up and shut down.

https://www.youtube.com/watch?v=Hprhm-bqzXs

cheers andy

Supermario
09-19-2014, 04:19 PM
Oh, PS. I'm a RC guru wanna be :D:cop::lol:


Mario

Well, atleast that part of my post was correct. :o

I want to apologize for giving bad info about the 4200 operation. I'd rather have no info instead of bad info in my trade.
Thanks Travis for catching it and didn't mean to steer you the wrong way Andy. The 4th valve DOES indeed move during functions.
No more answering guru questions for me till someone actually calls me one:cop::lol:

Did your package arrive Andy? The reversing lead work out ok?

andyathome
09-19-2014, 05:53 PM
hey you gave an honest reply, don't beat your self up over it., any help is better than nothing at all.
the thing I have discovered about the whole RC thing is everyone seems to set up their radios how they want them, I know with my stock eagle mach loader, it is running a fly sky radio and you use the pot on the radio to start the sound, same pot on excavator and it seems to have no function on set up?
what I do like about these forums is that everyone is trying to help and the many different ideas that are put forward, if at first it dosent work try the next suggestion.
this is a step learning curve for me as Im a plug and play guy, but the more I look into it the more possibilities I see.
once again thank you to everyone who responded to my dumb question.
RC guru I am not LOL.
and no postman on a Saturday, hes probably playing with his RC cars.

fhhhstix
09-19-2014, 10:06 PM
Well, atleast that part of my post was correct. :o

I want to apologize for giving bad info about the 4200 operation. I'd rather have no info instead of bad info in my trade.
Thanks Travis for catching it and didn't mean to steer you the wrong way Andy. The 4th valve DOES indeed move during functions.
No more answering guru questions for me till someone actually calls me one:cop::lol:

Did your package arrive Andy? The reversing lead work out ok?

No need to apologize you were right on the purpose of the valve and just a little fuzzy on how it actually functioned. This was their cure to the pump having to start under a load. Where as other models with this size of pump use a gear reduction of some sort to start the pump more easily. I plan to put a 4:1 gear reduction motor on mine and go back to a 12V battery. As it sets though I have plenty of power and speed with the stock setup on 7.2V battery packs.