Sentry Gun Project

[POLAND_SPUD]

I am not an expert on this but wouldn't it be easier to use RC battery packs or simply more than 4 AAs ?

[jackssmirkingrevenge]

That's what I had in mind, but I want to establish that it will work with small servos before adding moar amps, lest I burn something out.

[jrrdw]

Have you checked for a signal going to the servo's? These look like Furtba's, heavey duty or not you should have gotten something from them.

If data sheets didn't come with them you can get them from www.towerhobbies.com or from manufactures website of course.

[Technician1002]

Often the info to create a servo signal is easier to understand and more in depth on a hobbyist site. They even will include circuits to create the signals to drive servos.

A rate gyro for your bot uses the rate of turn to create a correction to the servo signal. When you intend to go straight, it will detect a rate of change and send a correction to turn it the other way. When you intend to turn, the control signal signals the servo to move and a controlled rate of turn is established. Too fast or too slow of a turn is corrected.

If you do not wish to work with pulses, a Wii remote has accelerometers. The Motion Plus is a rate gyro that measures the rate of rotation. I believe it can output an analog rate of rotation signal. The bare accelerometers on the Wii remote do output an analog signal. They are encoded and transmitted by Bluetooth to the console.

http://www-cdr.stanford.edu/dynamic/servo/

http://www.horrorseek.com/home/hallowee ... ervos.html

http://www.physorg.com/news104502773.html
http://hacknmod.com/hack/how-to-cheap-a ... -nunchuck/

The motion plus is a 3 axis rate gyro unlike a RC gyro that measures rotation rate on only one axis. For the price it is a bargain if you like to hack electronics.

[Coodude26]

That's what I had in mind, but I want to establish that it will work with small servos before adding moar amps, lest I burn something out.

Amps are pulled from a power source, it's not like they're shoved into the circuit or anything. Are you sure you don't mean volts?

[jackssmirkingrevenge]

Amps are pulled from a power source, it's not like they're shoved into the circuit or anything. Are you sure you don't mean volts?

I plead ignorance when it comes to electronics, but from what I see in the RC world they usually keep the voltage in the same 9-6 range while upping the capacity of the cells.

Have you checked for a signal going to the servo's? These look like Furtba's, heavey duty or not you should have gotten something from them.

When unconnected, I can move them by hand, but when plugged in they become stiff as a board and bright green.

From a servo forum:

I can make the HS-645MG go to 2.2A by trying to force it out of position, it’s datasheet does not give a stall current, just a much lower “running current” of 450ma (no load maybe). Most of the other servo’s I have here are “similar” in what they draw. An MG996R can draw 2.5A

That is far beyond what 4 AA rechargeables can supply, and from what I've read this particular type of servo has heavy gears and therefore quite a bit of inertia.

For the price it is a bargain if you like to hack electronics.

Sadly I lack the skills and the time/enthusiasm to learn, this is what attracted me to this sentry gun system to be honest - program already written and constantly being updated, and off-the-shelf parts.

[dewey-1]

Here is the problem! You need to change protocol jumper!

[jackssmirkingrevenge]

How do I do that?

Are you saying I should remove the blue thingy and move it to the position you circled, ie the one in my photo is in the wrong position and the one in yours is correct?

[dewey-1]

You sound like a women now! "Pull the blue thingy"

That picture is from "Sentry Project" photo.
Pull the blue jumper off and reposition it like in the photo.
He must be using the Pololu protocol in his software.

Pololu Mode: When jumper is open (no shorting block), that is the Pololu protocol used for controlling multiple serial devices. In this mode, the
servo controller can be on the same serial line as other devices such as our Dual Serial Motor Controller. This mode also allows access to all of the special features of the servo controller, such as setting speeds, ranges, and neutral settings.


http://www.paintballsentry.com/Instruct ... roller.htm

[jackssmirkingrevenge]

HAHAHAHAHA! SUCCESS!!!!!!!!



Thank you so much Duane, you're a genius!

You sound like a woman now!

I'm giggling like a schoolgirl now

[youtube][/youtube]

yay!

[dewey-1]

You should be be with statements like blue thingy!!!!!!!

Glad to help you.

Now to to see some serious progress and pictures/video.

[jackssmirkingrevenge]

You should be be with statements like blue thingy!

When it comes to electronics beyond a simple lightbulb circuit I am ashamed to say I am a woman

*ahem*

Yes, time to make that 1mm BBMG work reliably and fit it in a turret

edit: I couldn't wait, here's a very vague mock-up using blu-tack and a toy M16 I calibrated the servos on the target screen based on the servo movement limits, basically the motion is following the cursor being moved around the screen

[youtube][/youtube]

[thedeathofall]

So Jack, why exactly do you have doll sized guns laying around your house?

Great job on the servos though. Cant wait for the finished product.

[POLAND_SPUD]

@thedeathofall
sometimes you ask a question, then you get the answer to it and you regret asking... this might as well be the case

@JSR
...

[jackssmirkingrevenge]

*innocent whistle*