Pic Based Servo Cycler

[Gary Warner]

I needed a break from the Hamster...

I've made a servo cycler of sorts.

It has:

3 buttons ("UP", "DOWN" & "CENTER"), RED LED and GREEN LED.

Sounds simple, and it is.

On start up, the output is centered at 1.5ms. GREEN LED is lit.

Press the UP or DOWN adjust buttons and it moves the servo one way or the other at a slow rate. The RED LED is on, GREEN LED goes off.

At 100% deflection, the adjustment stalls for .75 second (denotes end of normal travel). After this .75 seconds, the servo continues to 125% travel and the RED LED blinks, indicating a position greater than 100%. If adjust is 1.5ms (center), GREEN LED will be lit as well as the RED LED.

Press the CENTER button and it returns to center (1.5ms) and the GREEN LED is lit, RED LED is off.

Press the adjust UP and DOWN buttons together and the cylcer begins to cycle from .8 to 2.2 ms at a fast rate. Both GREEN and RED LED's are lit. Pressing the adjust UP or Down will re-establish manual control over the servo. Pressing CENTER button will send the servo back to 1.5ms dead center. The GREEN LED is once again lit after pressing the CENTER button.

It's about 1" x 1.5", weighs 2 grams, fits in your pocket and is computer accurate (PIC12F629).

Find center, normal limits of each direction and extended limits with ease. Accurate independent of battery voltage, unlike 555 style servo cyclers (i.e. ACE Servo Driver).

Plug in your 4 cell receiver battery and servo. That's it.

Assembled: $15 + $3 Shipping and Handling (US).

Limited time offer. Anyone want one?

Send request to: warner1@airmail.net and include "Cycler" in the topic, or post your comments here.

BTW, the Hamster is moving to a dual PIC - it's a pain (but it will be worth it!).

Gary
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[Gary Warner]

For those who have e-mailed me, I'm sending these out next week.

[Gary Warner]

Here's the manual:

Gary
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[mlachow]

Why don't you add a few features like dual servo outputs.

"Commercial" version of this is the JR MatchMaker JRPA915 which allows for cycling 2 servos either by cycling or by moving the position with a pot. There is a detent on the pot for center.

My ideal tester would also include a current meter.

[Malc C]

Why don't you add a few features like dual servo outputs.

"Commercial" version of this is the JR MatchMaker JRPA915 which allows for cycling 2 servos either by cycling or by moving the position with a pot. There is a detent on the pot for center.

My ideal tester would also include a current meter.

[toung in cheek mode] - And while your at it Gary, add a few more servo outputs (up to 8) and an optional plug in interface lead to allow direct connection to a PC (via USB would be nice), so that when provided with custom software (which you too design and will show the volts and amps each servo draws) you can control up to 8 servos from the PC before installing them into the model. It could also double up as a SSC for robotics projects :) - Oh and keep the price down to the $15 too as we want value for money ;) [/toung in cheek mode]

:rolleyes:

[Gary Warner]

Why don't you add a few features like dual servo outputs.

"Commercial" version of this is the JR MatchMaker JRPA915 which allows for cycling 2 servos either by cycling or by moving the position with a pot. There is a detent on the pot for center.

My ideal tester would also include a current meter.

That's cool little driver. For $30 ($40 list) it's not a bad deal.

I don't care for having to move servo wires to go from sweeping to adjusted position. I'd be interested in knowing what they use for a drive circuit. If the adjustment resistor has anything to do with RC time constants it probably drifts as the battery voltage changes.

I do like the dual servo drive. This looks like it's just a parallel connection to the second servo - very doable with mine with plenty of PCB space available.

Whose servo driver indicates current? I'd like to see what is said about it by someone who's actually using one.

Gary
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[Gary Warner]

[toung in cheek mode] - And while your at it Gary, add a few more servo outputs...[/toung in cheek mode]

:rolleyes:

Funny.

[Gary Warner]

Why don't you add a few features...



Ok, I thought about it...

It would be a simple and good idea change to make...

I can change the code so that the <-- and --> buttons would vary the sweep speed in the sweep mode. Good idea.

Gary
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[Mikael Pedersen]

Whose servo driver indicates current?

That would be mine :D
Well, I made a servo tester a couple of years ago, and we had quite a discussion here in this group about possible features. I bet you could be inspired by some of the ideas we had back then:
http://www.rcgroups.com/forums/showthread.php?t=188882

[Gary Warner]

That would be mine :D


Did you find the current readings were a practical feature? How did it effect what the average modeler would do?

After looking at the tread, I'm reminded about a 2 channel RC car radio I bought. There were over 50 pages of instructions to tell you about all the options (I think it was a MARS radio). It was a mind boggling this to see how much can be done with just two channels. :eek:

Did you ever produce your cycler?

Nice job on the cycler, to say the least.

Gary
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[Mikael Pedersen]

Reading the current isn't something I do frequently. However, it did help me pin down a power problem in one of my planes. This one airplane used up its battery pack in no time, compared to the rest of my "fleet" (my one other plane). It turned out to be a single servo that consumed quite a bit of current, even when sitting idle. But other than that, it seemed to work just fine.
Apart from that, I tend to use the voltage readout much more than the current.

And sure I produced my tester..... But only a single one for myself :D I do know of a handful or two of people around the world that have made their own, based on my design. And my webserver log indicates plenty more downloads, but I rarely hear from those.

[Acetronics]

;) Hi, Gary

Here is THE thing you're looking for ...

http://www.electroniquepratique.com/article.asp?mag=EP&num=278&article=11

and with some little prog mods, it can show a 10µs / s signal change :eek: .... to test potentiometer wear !!!

Alain

[Gary Warner]

Mikael,

That's cool, finding a bad servo that way. Sounds like it saved you a lot of trouble (and maybe a plane).

Alain,

That's a new one for me. I've seen many fine examples since I've started this project. I was considering making a version that had all the bells and whistles, but would but be for my use. All in all, I think the two mods I want to incorporate (adjustable sweep speed and two servo drive) will bring mine up to par with what's commonly used and sold.

Gary
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[Gary Warner]

Mods to Cycler...

I made the code changes that allow for variable sweep speeds and hardware changes that allow for two servos to be driven at the same time.

For the people waiting for their orders, I expect to ship this new order next week.

Gary
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[Gary Warner]

The second batch is now ready to ship. Sweep speeds can now be set at 10 different speeds, from about 8 sweeps per second, down to about 45 seconds for 1 sweep (1400 steps full range). Manual adjustment resolution is 280 steps full range. This ultra slow sweep is a good way to test the response to miniscule changes. Some servos are better than others at fine accuracy, and this test shows it well.

The new ones also have that dual driver plug. I like it. It's very handy for aileron setup. Also, it's good to see if one servo is faster than another in the sweep mode.

Still 4 cells only. The PIC has an absolute voltage rating of 6.5 volts. Don't exceed this.

Gary
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[Gary Warner]

Oh, here's the manual for version 2

[VinceHaworth]

Anyone out there know where I can get the pic code for a DIY version? ;)

[Acetronics]

Anyone out there know where I can get the pic code for a DIY version? ;)

Hi, Vince, :rolleyes:

Can you read a little French ????

Code for a 16F628 + Pcb + placing + Manual available ...

Alain

[VinceHaworth]

Hi, Vince, :rolleyes:

Can you read a little French ????

Code for a 16F628 + Pcb + placing + Manual available ...

Alain

Not too good on French, sorry.
I have found what I need ... rc-cam has a suitable circuit. Top guy !!! :cool:
http://www.rc-cam.com/servotst.htm