making things move?

     jrmertz I have heard if people using old electric clocks connecting to the second hand for movement. You can get them for A few dollars at flea markets and yard sales. Choo Choo Kenny

Well, I've animated some things, etc. 

I buy Tamiya gears - they are plastic but nice.  You can also go to an hobby shop that sells and services remote control cars, boats, and airplanes and they usually have gobs of gear,s shafts, cams, etc.  

Finally, you can buy gearing 12V motors rather inexpensively, so often you do not need to make a gearbox, etc.  I animated the Lone Rider horse on the front of Woodland Scenics grocery store, and used a came I made installed on a 2 RPM 12V motor I bought for $9 on Amazon.  I also shop for the gears there, too.

For about $10 and available at hobby shops, Tamiya makes a variety of DIY gearboxes including a DC motor.

http://www.tamiya.com/english/...rboxes/kit700P01.htm

Since you probably don't need much torque to rotate a scenery component, you will be able to adjust speed over a wide range by adjusting the DC voltage.  To that end you can use an adjustable DC voltage regulator module that you can get on eBay for a few dollars (post on the Electrical Forum to explore that aspect of speed control).

If you know what RPM you need you can find DC gear motors for less than $2 (free shipping) on eBay.  Search ebay for "DC gear motor"; even if you don't like eBay it's a good way to see what's out there and you can buy from a US source for a few dollars more.

I like the Tamiya too........

But the last few times I wanted to motorize something I found motors on ebay with a gear-head attached. They are available ib many sizes, speeds and voltages. $10 got me 2 last order.....very nice units.

I would like to take this to the next step. Looking for something like this

with feedback, I'm looking to drive Gabe the Lamplighter by using feedback

from the motor so I know where he is at. I'm trying to avoid end switches.

any idea's ?

You can use model airplane servos. 

You can find them on e-bay and the electronics to drive them.

I use model airplane servos.  Here's one I used in the remake of the Tie-Jector to allow command control of the ejection process.

John - Curious to know what you are using for a servo driver.  Thank you.

Pete

also curious how you tell the servo to move?  Also, do they just automatically move back and forth or can you set the travel path?  Typically they move very quickly it seems from reading can they be slowed down?

Pete, I built a one-off hand wired circuit to drive this from the smoke output of the ERR MC2 board.  It supplies power and also triggers the generation of the two frequencies for the PWM drive to the servo.  All I needed was on and off, so it is just a relay.  When I click smoke on, the ejector starts tossing ties, smoke off and it stops.

Here's the circuit and how the board was mounted in the unit.

So as not to clutter up this thread, here's the original thread where I describe this project, hopefully it answers any questions.

Command Equipped Tie-Jector

Lionel stole my thunder as the next year they introduced the TMCC version, but I already have mine.

 They move full speed to the new location, if you have smarts driving the PWM, you can slowly ramp it up to change the servo speed.  I have "dumbs" driving it, so it's bang-bang control.

If you are considering the servo route and want to explore, I recommend getting a servo tester from eBay for $1.45 (free shipping from Asia).  You apply 5V DC to the tester and it generates the "magic" (pulse-width-modulated) signal to move the servo around. 

http://www.ebay.com/itm/Multi-...;hash=item2ec08a8ef6

Here it is in action showing the 3 modes.  1) uses the knob to manually set angle, 2) sends the servo to the mid-point angle, 3) sweeps the servo back-and forth (so-called windshield wiper mode).

As shown below, most servos come with an assortment of "arms" to adapt the servo shaft to whatever you're driving.  Since servos don't have 360 degree motion range you might need gears to extends the sweep angle.  As shown below one style or "arm" would allow you to fasten a round gear to effect this angle extension.  Plastic gears are very inexpensive from your LHS or eBay.

Servos are mechanically limited in angle of motion.  Many companies that sell servos for DIY robotic applications sell modified servos where the mechanical stops are removed and you end up with a DC gearmotor that spins freely.  Obviously you lose angle control since you are left with a DC gearmotor (reversible) but the small packaging and integrated gear mechanism is essentially impossible to duplicate if you tried it yourself.  You can also modify most servos yourself to make a DC gearmotor.  

When buying just a DC gearmotor think ahead to how you will mount it and how you will attach your load to the shaft.  Again, what's nice about servos (or servos modified to become DC gearmotors) is they come with a set of "arms" which be quite handy.  And note the two mounting holes on the servo body in the photo. 

Wow!  lots of good info and things to think about!  Thanks everyone!

Stan, I bought the servo tester and a handful of the servos in the smaller sizes, looking forward to doing more project like the Tie-Jector.   Maybe it's time for that waving engineer we were discussing.

I'll be the first to congratulate you on a realistic waving engineer.  The articulation of a human wave is something I've never figured out at 1/48 scale.  Simple 1 DOF swinging animations like the conductor lantern are no problem but the multi-joint shoulder-elbow-wrist motion is something else again! If you're serious, please start a thread on it; I think you'd want to consider magnetics.  Given the limited space available in a cab and the negligible forces to move body parts on a plastic figure, a servo would too big and strong.  I'm thinking strategically positioned coils and some tiny Nd magnets might be a starting point.  The key is you have essentially unlimited power (Amps) in an engine to drive the coils.  Also, I think a microcontroller would be needed to generate realistically slow drive waveforms rather than bang-bang control.  I expect your report on my desk by end-of-business!

Oh yes, I forgot to add that "nothing is so easy as the job you imagine someone else doing..."

I think you're exactly right Stan, I'm thinking more along the lines of a simple wave.  You're also right, that project wouldn't require a serve.

I'm thinking of the servos for stuff like opening and closing doors on command or animating stuff in a car. 

I first need to do a board that decodes the TMCC serial data and work out the kinks, then I can use the PWM outputs to drive servos.

Is it time for some of us (computer nerds) to design and build a servo controller/sequencer board?

What would you want in a servo controller/sequencer board?

How many servos would you want to control from one board?

How would you want to trigger the servo movement?

@ Lee Willis

how about a video on how ypu animated the riding horse?

that was the first thing I thought of when I saw the IGA store.

Jon

A major issue is coming up with a specification for the board and how it's programmed.  The easy part would be building the board, but how do you customize it's operation for novice users that don't program?

Stan - have you ever used those servo testers?  If I understand correctly, I would just need apply power to the tester and that would tell the servo to move?  Do they remember there last setting between cycling power? IE: if it is set to wiper mode, and I cut power, will it be back in wiper mode when power is re-established.

That's my thumb in the video.

I just tried it.  Unfortunately it always goes to the Manual mode when you initially apply power.  It then takes 2 button presses to go into Windshield Wiper mode.  So for a layout accessory you'd need to cobble together some widget that generates 2 pulses to simulate those button presses.  Such a circuit is not difficult to make (maybe $1 in parts) but would require soldering, component assembly, etc. which sort of defeats the purpose.  That is, minds as well build a Windshield Wiper servo driver yourself that only operates in Wiper mode.

And, yes, I did open it up to look at their circuit.  I concluded it uses a microcontroller chip so it's not something that can be readily modified to, say, force it into Wiper Mode on power up.  Actually I was looking under-the-hood to see if there was an easy way to modify the wiper rate but same stonewall applies.

Bummer!  I was hoping it was going to be as simple as using that tester device.  When I wiper mode it would just go full speed?  Or does the dial control the speed at all?

Perhaps I need to post in the electrical forum on the parts need to make my own wiper circuit with schematic.  I believe I could possibly assemble one if not too difficult, but I have no idea what would be needed.

Exactly what I was thinking.  Even low cost Arduino modules for $5 or $10 can drive a half-dozen servos for "free" since the servo pulse signal is "just" a basic, low-frequency, low-current digital output.  So as GRJ says, the hardware is the easy part. 

OTOH, I can imagine something like the timer modules on eBay that cost $1.50 (free shipping from Asia).  You apply 5V, it generates a pulse output with two controls.  This one does not generate a servo compatible signal but it's a concept that I think might be of value to O-gauge modelers who don't want to mess with programming.  I'd think you'd want to include an AC-DC converter to generate 5V DC so it can run off Accessory AC power.  Then maybe 1 control would set the sweep angle (range of operation) and the other control would set the sweep rate.

But to jrmertz' point about "memory", upon application of power, some cheaper servos momentarily jerk toward some random position even if you send it the exact command to go to the last angle it was at when power was removed.  This may or may not be an issue since it happens only once per operating session.

If you find gears intimidating, try using pulleys. The down side is that pulleys require more room.

that sounds like exactly what I could use.  It would make servos a much more viable option for making things move and I see lots of potential for them already.  this thread has given me all kinds of ideas on making things move, with gears, motors, pulleys, and now servos!

I built a simple 555 circuit that did bang-bang control between two points with one of these, it was for my Tie-Jector upgrade to allow me to activate the ejection mechanism.  That might be good for simple animation.

Is this a continuation of this thread?

https://ogrforum.com/t...gabe-the-lamplighter

I thought you solved that by adding stacked cams on the motor shaft with each cam "programmed" by cut-out patterns to perform the timing and sequencing thereby eliminating the need for the limit-switches on the tower itself.   I was hoping to see a video of your result.

It appears the above thread is now locked but I saw another recent thread where the moderator unlocked a thread upon request.

Stan, if you have something on-topic for a locked thread, Rich will usually unlock it.

Well, I did some web searching looking for a simple circuit to sweep a servo back-and-forth over an adjustable range and over an adjustable speed...but no joy.  Yes, the technologists would just say to use a 50 cent microcontroller chip and write some code, but nothing is so easy as the job you imagine someone else doing...

So in the Gabe thread above, Stoshu shows how a cam attached to a slowly spinning DC motor can be used to activate actions based on the angle of the motor.  So I was thinking a DC gearmotor with limit-switches at two angle position could simply toggle the polarity of the DC voltage to the motor.  Thus, the motor would slowly rotate in one direction, hit one limit switch, then reverse and slowly rotate in the other direction, hit the other limit switch.  Ta da!

In other words, this would be like the bump-n-go trolleys that reach an end-of-travel and a switch reverses the DC voltage to the motor.  No servo (and its magic control signal) required.

The speed of a DC gearmotors is easily controlled by the voltage.  OTOH the speed servo rotation is extremely fast, say, 100 RPM or more if you tell it to go to the other end (i.e., if you don't have the ability to smoothly/slowly sweep the control angle).

Yep, with the servos, you have to be in "active" control of the PWM stream to achieve smooth movement.

 I started in that direction and it was quickly becoming a big cluster #$%#$

 Then I discovered the evils of Arduino. It got me hooked. All I did was wire in

 the relay contacts in parallel with the button controller.  So Gabe climbs to the

top. Light go on, Then he slides down and lights go off.

The only problem was it still took to long for him to climb. Very few stood around

to watch. It was a fun first project though...

 Frank.

 Try this link....

 http://arduino-info.wikispaces.com/

 You should plan on being the a while. a LOT of stuff here for

 beginners and a like. Great site....

Perhaps request the moderator to re-open your original thread.

So you used an Arduino to generate the couple dozen or so solenoid pulses.  How did you know when to stop the pulsing?  Since solenoids can be driven very quickly (several times per second) could you elaborate on why it took so long for Gabe to climb (thereby boring the casual observer)?

If you use a geared motor, I'm thinking you lose the ability to have Gabe drop via gravity since the motor mechanism would prevent him from free-falling.  So you'd have to drive the motor in reverse to lower him.  Seems to me you could remove the solenoid ratching wheel and drive the wheel with a DC gearmotor (or servo motor).  If you use an Arduino you could even pulse a DC gearmotor to make it look like he's climbing.  You'd then put a limit switch on that wheel to sense when he's at the end of travel to tell Arduino when to stop.

If you're using the Arduino, you can also use stepper motors, they're dirt cheap on eBay and are an easier to precisely control option.

 John.

 Do stepper motors provide feedback ?

 As far as the Gabe thing goes, I was going to remove the ratcheting mechanism

and for now use a front bumper wench off an RC car. The problem becomes feedback. So maybe a pot off the end of the shaft so I know the position of the figure. It's just a thought for now.

Servos would be great but have limited travel distance.

Stepper motor sound interesting, I'll have to dig around on Ebay later.

I'm interested in the feed back for normal operation also for the possibility of

power loss in mid stroke.

Stepper motors by themselves don't have feedback, but they do move s known distance for each step.  You can have a microswitch or optical sensor at one end of the travel and index to it on power-up, then you can count steps and always know where you are.  If you use a drive belt that is capable of slipping at the limit, you can also just step in one direction enough to insure you're at your index point at power up, then you know where you are until the next power cycle.

Given the low price of RC servos, those would be my choice if possible, they have positive position knowledge by the PWM value being transmitted, so you don't really need any index point.

Thanks John....

This has been a most interesting post! I have been thinking up of several scenes that would incorporate moving figures, although I have been thinking more of gear motors, and not very familiar with electronics, this has given me much to consider! I think having people working, moving etc. would add a special depth to a layout, not only for my personal enjoyment, but for visitors as well!

Uncle Al