Custom servo slower

[hyperdyne]

I went out and bought the hyperion servo slower, and boy does it stink! They simply pulse the servo slower, which results in loss of torque and jerkiness. I really couldnt stand how poor a job they did. Not sure if others out there do the same thing, but I didnt want to find out.

So I decided to make my own, a super smooth servo slower with retract times from 0.75-16sec. Slew times are selected via a pushbutton instead of a crappy pot (which you have to have a tiny screwdriver with you at all times). LED feedback light also illuminates.

At 16 sec I was surprised how smooth it was. I am happy with the results. I made it so the board even has 2 slowed outputs, one is half the rate of the other. I put it in my executive jet, and the front gear retracts at half the speed of the back gear. I really like the effect. I thought it would be cool on a warbird too, where the gear hardly ever retracted at the same speed.

Anyway, not sure if anyone else is interested in such a circuit. I have some PC boards left over from my run. Just thought I would show what some sweat and tears could do when the easy consumer route is flawed.

[Gary Warner]

Nice job. I assume the second slower port has a function in your setup. Can you explain? Is it for door sequencer? I can't quite see it in the picture, but it that a PIC controller?

I get some requests for servo slower’s. As of yet, there hasn't been enough demand for me to produce them for profit.

[Chippie]

[QUOTE=Gary Warner]Nice job. I assume the second slower port has a function in your setup. Can you explain? Is it for door sequencer? I can't quite see it in the picture, but it that a PIC controller?
QUOTE]


Looks like a pic to me from the logo ;)

[phil_g]

I can just about make out 12F675 unless my eyes have finally gone...

Did you include a panic override in case you have a flame-out & need to drop them quickly?

Nice board, wish my pcbs were as neat :)

Cheers
Phil

[hyperdyne]

The second slower output I use for a second gear servo - makes the gear retract asymmetrical. But you can use it for whatever you like, it would work for a door sequencer also!

Yes I am using a pic in the circuit.

phil, I dont have a panic override (yet). I thought about it, as I wanted something like it on my exec jet. That would most likely take another channel, unless I did something like override if you toggled the gear switch back and forth once quickly. That would probably work just fine, and it could be added pretty easily!

[mike50]

phil, I dont have a panic override (yet). I thought about it, as I wanted something like it on my exec jet. That would most likely take another channel, unless I did something like override if you toggled the gear switch back and forth once quickly. That would probably work just fine, and it could be added pretty easily!
I did that in mine. If I detect Down-Up-Down (or Up-Down-Up) in .5 seconds then I drive the gear to the end at full speed. Flipping the switch in that way is easily achievable, but I'm not sure that you'de want to do that in an "emergency"...usually flying the plane is more important.

I also added a feature you might consider. When the servo reaches full up or full down it then backs off by 100 microseconds. This allows you to setup the linkage to fully engage the up/down locks even to the point of stalling the servo. The backoff then unstalls the servo.

Mike

[hyperdyne]

Not a bad idea Mike. I like the backing off, just enough to disengage a noisy servo. I would think 100us is quite a bit at first blush, I guess its only 10% of the max range.

Anyway, I agree with the emergency issue. Not sure I would have the time to key this in if things were that dire.

[jeffs555]

Anyway, I agree with the emergency issue. Not sure I would have the time to key this in if things were that dire.

Since the slow function is just for visual effect, why not do it the other way around. Have the down-up-down triger the slow mode.

[mike50]

Not a bad idea Mike. I like the backing off, just enough to disengage a noisy servo. I would think 100us is quite a bit at first blush, I guess its only 10% of the max range.

Anyway, I agree with the emergency issue. Not sure I would have the time to key this in if things were that dire.
I tried different amounts of backoff and 100us seemed about right. Here is a link to a video. http://www.rcgroups.com/forums/showpost.php?p=9378940&postcount=193
This is with a 100 microsecond backoff. BTW, it is not my plane, but I built the servo slow down device. Here is a link to the microcontroller hardware...I used the same circuit for the slow down device as for the servo reverser - different software. http://www.rcgroups.com/forums/showthread.php?t=575173

Mike

[mike50]

Since the slow function is just for visual effect, why not do it the other way around. Have the down-up-down triger the slow mode.
That is an interesting idea...I hadn't thought of that.

Mike