PowerFunctions controlled pneumatic

[SuperCow]

I've finally have completed my project.

A Powerfunctions controlled pneumatic system.

With my system you can control a pneumatic switch, or a steering system.

The motor I'm using is a Servo motor.

The controller board exists out a ATtiny84 and a power converter.

Attached is the Infra Red receiver to received the commands from the Lego remote.

You can connect 2 servo motors, just like the normal lego receiver.

You can select the 4 channels via a dipswitch (and an additional 4 channels that's hidden in the protocol)

And there is a special function to set the center, left and right position of the servo.

The controller is 4 by 4 nops.

Some photo's

Video

[Milan]

I see that you invested pretty much time and effort in creating this device. I like that. And I like how good it operates. Will you try it in some MOC?

One thing that will make people to step back from this is non-lego parts, but that is a personal issue.

nice video, btw, and nice work, man!

[SuperCow]

I've had an idea to make an excavator, making it completely remote with the PF system.

I have to make an extra controller, and order some more servomotors.(and time)

About using non legoparts, Well some thing are simply impossible to make, or its getting very large.

This is possible with mind storms. But the mind storm motor is very big, and the controller too.

And the best thing about it, is I've learned a lot more about micro-controllers :D

[allanp]

WOW this is great. It would be wonderful if lego produced something like this. It could be used everywhere like steering, pneumatic control, trains (for lots of things), changing gears remotely, and many other things. Well done

[Blakbird]

I've finally have completed my project.

A Powerfunctions controlled pneumatic system.

With my system you can control a pneumatic switch, or a steering system.

The motor I'm using is a Servo motor.

Some photo's

OK, I can see that you are controlling an R/C servo with a Lego I/R transmitter. You are using the servo to turn an axle. What does this have to do with pneumatics? There are no pneumatics in your photos. There are some in the video, but I can't see how your system interacts with the pneumatic system. Does it simply move the existing LEGO pneumatic valve? If so, can't you already do this with a LEGO motor (even though it would be much bigger)?

[SuperCow]

OK, I can see that you are controlling an R/C servo with a Lego I/R transmitter. You are using the servo to turn an axle. What does this have to do with pneumatics? There are no pneumatics in your photos. There are some in the video, but I can't see how your system interacts with the pneumatic system. Does it simply move the existing LEGO pneumatic valve? If so, can't you already do this with a LEGO motor (even though it would be much bigger)?

True, I'm calling it a pneumatic system, as that was my main goal to archive. The servo is connected to a Lego valve.

The problem with a normal motor(you can even use the micromotor) is control, and precision/speed.

Without using a nxt you can not determine the center position.

When I give a forward/backward command from the remote, the servo turns so far till the valve is open(up or down).

until i release, the servo goes automatic to center.

And with precision, when you use the valve manually, you can open it slightly to move the piston slower. This is also possible with the servo.

[Jetro]

Sounds like the precision control might be an advantage over solenoid valves (which is what I'm playing with) although the solenoids can be controlled by regulating open/close time.

[Blakbird]

True, I'm calling it a pneumatic system, as that was my main goal to archive. The servo is connected to a Lego valve.

The problem with a normal motor(you can even use the micromotor) is control, and precision/speed.

Without using a nxt you can not determine the center position.

When I give a forward/backward command from the remote, the servo turns so far till the valve is open(up or down).

until i release, the servo goes automatic to center.

And with precision, when you use the valve manually, you can open it slightly to move the piston slower. This is also possible with the servo.

Thanks, that makes a lot more sense now. What size and type of servo did you use? I've got a whole bucket of pico, micro, and sub-micro R/C servos laying around that could be used for something.

[SuperCow]

I used a mini servo 9g 1.3kg torque.

As you can see in the first photo it fits nice in 4 by 4 studs (most difficult is to align the shaft to the lego holes)

I used a micro motor pulley on the servo shaft.

And then you need a controller to translate the Lego remote signals to servo pulses.

I don't know if there is a interested, but I can release the code in the micro-controller I wrote.

[Brickthus]

True, I'm calling it a pneumatic system, as that was my main goal to archive. The servo is connected to a Lego valve.

http://farm3.static.flickr.com/2584/404736..._ca745d80c9.jpg

The problem with a normal motor(you can even use the micromotor) is control, and precision/speed.

Without using a nxt you can not determine the center position.

When I give a forward/backward command from the remote, the servo turns so far till the valve is open(up or down).

until i release, the servo goes automatic to center.

And with precision, when you use the valve manually, you can open it slightly to move the piston slower. This is also possible with the servo.

You should use the servo as an input to this system, connecting it to the red input beam to create a 2M movement.

That way, the servo position would translate directly into the position of the pneumatic cylinder, with reasonable accuracy.

Video here.

Mark

[allanp]

And with precision, when you use the valve manually, you can open it slightly to move the piston slower. This is also possible with the servo.

That is just brilliant. It already has an advantage over a solenoid valve in that it can be used to control many other things besides pneumatics. But to have proportional control as well is fantastic (especially for steering and pneumatics) . What would you use as a transmitter for this kind of control? Could you use the existing PF train remote or would you have to create a new one? Either way i'm liking what I see very much

[SuperCow]

Mark: I will try to rebuild your Continuously Variable Pneumatic Control and hook up the servo.

allanp: Well it supports the fully power functions protocol.

I haven't got a train remote, but currently it supports the "combo direct mode" (pf remote)

and "Combo PWM mode" (lego hasn't released this remote yet), its the same as the train remote, but it will lose signal after 1-2 sec.

My own build:

I have thought about solenoid valve, Fishertechnic has one, with is almost compatible with lego(9v same hose system).

Only to get good control you need 3 solenoid valves and they cost about 20 euro a piece, above my budget.

[Burf2000]

SuperCow : I really like what you have done, I hope to see you selling them soon :) I am planning a big pnematics thing at the moment where the values need to return to center. The only idea I had so far was to use the little technic blocks that came with the lego ice hocky sets. I seen people use them for steering on cars :)

[allanp]

I have wondered about using these. Does anyone know if the are strong enought to return both motor and valve to centre whilst being weak enought to allow the motor to operate the valve?

[Burf2000]

I made this espically for you :) A video showing one in action

[Brickthus]

I made this espically for you :) A video showing one in action

I see - you have a hockey player centring spring to return the valve switch to the middle position.

Needs a bit of extra motor power to move the spring as well as the valve switch lever.

Mark

[Burf2000]

I see - you have a hockey player centring spring to return the valve switch to the middle position.

Needs a bit of extra motor power to move the spring as well as the valve switch lever.

Mark

Yeah, I used a rubber band as the cog ratio ment it would always be better on one side than the other

[allanp]

I made this espically for you :) A video showing one in action

Aw wow thankyou for the video

It's off to bricklink I go,

It's off to bricklink I go,

To buy some return to centre thingy's found in the hockey sets for use in my pneumatic creations that you have demonstrated so well in your video,

It's off to bricklink I go!

[Burf2000]

Aw wow thankyou for the video

It's off to bricklink I go,

It's off to bricklink I go,

To buy some return to centre thingy's found in the hockey sets for use in my pneumatic creations that you have demonstrated so well in your video,

It's off to bricklink I go!

lol, they are about $1 each I think else you can get them in a hockey set off ebay for about £1 + p&p

Hope you found the video useful, let me know if I can help

[Jetro]

I've got a couple of those and used one for a return centre steering once, but I have to try this and see what I can do with it.

[allanp]

lol, they are about $1 each I think else you can get them in a hockey set off ebay for about £1 + p&p

Hope you found the video useful, let me know if I can help

Your video was very useful as it demonstraits that the RTC spring is powerful enough to move both motor and valve back to the centre, thankyou.

Looking at bricklink it seems anybody that is selling them either only has one (I would like at least four) or is charging a high price. Haven't looked on e-bay yet tho. Still got a few other projects to finish before I try this but i'm deffinately gonna try it sooner rather than later, can't wait.

[Burf2000]

Glad it was useful mate, anything else you want me to build :) I am going to work on a compressor with auto power next. So once it reaches a certain pressure it stops, been done millions of times before but i need one for my next project

[allanp]

Glad it was useful mate, anything else you want me to build :) I am going to work on a compressor with auto power next. So once it reaches a certain pressure it stops, been done millions of times before but i need one for my next project

Yes i've built a few of those. I like to build them so they stop just before the tubes start to pop off!

Have you tried building any pneumatic power steering systems before? It's easy enough if you have a mechnical link between the two halves of the circuit to give you feedback on the position of the second half of the circuit in much the same way as the recent design by Mark Bellis. But I wan't to build one that has no mechanical linkage, only pneumatic tubes, similar to the kind of steering system you get in heavy machinery. It's proving tricky because I want the steering angle of the wheel to stop relative only to the position of the steering wheel regaurdless of what mechanical forces there might be acting to prevent the wheels reaching it's desired steering angle. It's also gotta be small and compact enough to prevent it spoiling the overall look the MOC's I intent to implement this system into. Haven't really given much thought to the solution yet but I understand the problem and I think it's a cool challenge for my next project.

[Brickthus]

Yes i've built a few of those. I like to build them so they stop just before the tubes start to pop off!

Have you tried building any pneumatic power steering systems before? It's easy enough if you have a mechnical link between the two halves of the circuit to give you feedback on the position of the second half of the circuit in much the same way as the recent design by Mark Bellis. But I wan't to build one that has no mechanical linkage, only pneumatic tubes, similar to the kind of steering system you get in heavy machinery. It's proving tricky because I want the steering angle of the wheel to stop relative only to the position of the steering wheel regaurdless of what mechanical forces there might be acting to prevent the wheels reaching it's desired steering angle. It's also gotta be small and compact enough to prevent it spoiling the overall look the MOC's I intent to implement this system into. Haven't really given much thought to the solution yet but I understand the problem and I think it's a cool challenge for my next project.

If you didn't want a mechanical linkage back to the steering wheel, you could use 2 of my mechanisms, one for the steering and one for the steering wheel. The two in a feedback loop, feeding each other's red beam positions (with one reversed to make a feedback loop) would have a similar effect to one with a mechanical linkage to the blue feedback beam, but there would be more tendency to overshoot the target position because of the extra lag introduced by the inertia of the extra cylinders and valve switches.

I have 2 mechanisms in a steam engine configuration but 2 in the remote-control configuration would be a useful experiment. I'll try 2 with red beam connections and static blue beams and see if it works.

Meantime I made a mid-stop mechanism suitable for steering a few years ago, though it has less controllability because the only feedback is via tubes. It can be cascaded, so you could have 2 switches (on the right) for control, a cascade stage (in the middle) for the steering wheel and a smaller final stage (on the left) for the steering.

Many people want to control the world with one finger, but until TLG produces smaller valves with no deadband and cylinders that are as wide as usual but half as long, we have to put a bit more stuff into the mechanisms than we'd like!

Mark

[Junpei]

SuperCow could you cut a hole in the switch (where the pivot point of the lever is), take off the micromotor pulley, and attach the motor axle directly to the lever pivot? Hopefully that was well explained.

Edit: If you did that you could also cut off the lever part all together, making it the size of a 1x2x2 1/3 brick.

Edited June 19, 2013 by TwentyLeggedHen