That'll do!



Your coding skills are really improving David!

Sorry to go OT, but why is the FET's gate dropping resistor needed?

RC-CAM

Don't you always add a gate-dropping resistor?





-Matt

Boy! I can't find the buttons on a camera half the time but I can sure find peoples buttons. I didn't mean to hit a nerve Matt and I sure don't want to fight with you or anyone else. You folks need to grow some thicker hide.

With what little I know about these cameras it would seem that the zoom is positive one way, negative the other, and null stop. I can't see why they would make it more complicated that that. The polarities may be reversed from one camera to another but that's not a big deal. Maybe I'm missing some big stuff here that I should be paying attention to. If that's the case, please enlighten me.

Again, I am not trying to step on toes, I just tell it like I see it. You obviously don't want to hear me when I am trying to hit a vein. If you guys can deal with that, fine. If not, please let me know and I will certainly leave you alone. It's getting to the point that I don't want to post anything because I might rattle someones chain.

Regards, John

Hey,

It is OK. The problem is I don't know what they are doing either. Maybe we could drive the motor directly, probably not. I don't own one of the cameras that anyone would convert for AP that has zoom, which complicates things a great deal because I can't work on the actual device. I am trying to research it and figure it out. Most likely, the case is that we would have to hack the zoom buttons on the camera and drive the buttons like we would the shutter.

Don't stop posting....




-Matt

Don't you always add a gate-dropping resistor?

It depends. On MOSFETs, a low value gate resistor is added to prevent ringing when driven from a low impedance high slew rate source. The exact value depends on the FET gate characteristics (often it is just a few ohms). There have been times where I added a gate resistor when I felt a catastrophic MOSFET failure would cause extensive damage without the adjunct current limiting.

But, with these simple hobby projects, my opinion is that the 2N7000, when driven from the microcontroller, really does not add much value with the resistor in there; saving real estate is therefore possible.

The reason is that MOSFETs are voltage driven -- the gate drive current is nearly nil during operation. On the other hand, BJT transistors are current driven, so they do need base current limiting.

Sorry for the OT.

RC-CAM

I am no EE, I am trying to learn as much as I can however I can. I had seen them used in just about every application (although sometimes as low as 2 ohms) so I just automatically thought there had to be some in there. Your explanation makes sense, we would put it on there for higher rate apps to prevent the "ringing" ie. PWM for an ESC or similar. Thanks alot, that is great to know.

Sorry for the misguidance Ironsides!

Thanks again RC-CAM!






-Matt

That's what I mean. I thought we WERE talking about hacking the zoom buttons. I have the Optio S series camera and am currently using two of Michele's switches; one for power and one for shutter. I had to hack into the camera to use his switches and just thought the same would be true for yours.

It would be nice to do all this from one chip rather than four. It looks like I will have to hack into the camera and use one of his switches for each direction. That still leaves me without a null to stop the zoom where I want it.

As for who would use it. In the year I have been a member of this group I have only heard of two guys actually loosing their plane. I have heard more than that wishing they had zoom control. I know most people have been using simple cameras without zoom but many are moving up. I thought yours was going to be the next switch, not another version of the current switch.

Anyway, it doesn't matter. It gives me my next challenge.

Regards, John

Regards, John

I know we're quickly using up your available outputs, but it might be nice if the camera switch output supported a dual-stage (half-shutter then full shutter) output; closing the prefocus circuit for a few ms then the shutter circuit is probably all that would be needed... I know Extremeone proved it wasn't necessary with the Optio S but other cameras may need it. Then again, someone that knows more than me may know why this would not be necessary.

Good luck with your endeavor. I've been following the other discussion about PICs with an eye toward learning how to program my own stuff too, they could be useful for all kinds of things.

Chris

John,
I can make you a unit that will do what you want "special." You interested? I probably won't be producing it like the onther units because I need to use a larger PIC to control it all, but I will do one for you with zoom and you can test the concept for me. If it works I will consider doing it for more serious production. I am saying I'll whip one up with you shutter, power, and zoom controls to do what you want, but it won't be as small as my other units. PM me if interested.


Chris,
I will look into what cameras use this system and see if I can add it to the features list. I may or may not need it, thanks for the suggestion! If I choose to use it on the production models you will be getting a free unit as I promised earlier.




-Matt

Without reading the other replies (ack, hope nobody has my idea already!) ... what about a mode-change plug for switching from still picture to video mode on the Aiptek SD? It's controlled by a push button, just as the trigger switch it, and it's the *next* from still pictures. To get back to still mode, just reset the camera's power. Could run this line through the USB plug if using an SD card and not wanting to read through the USB port (I have a card reader and leave the camera attached inside the plane). Could always unsolder the USB connections to the board and connect through to the trigger and mode switch, getting around USB interfacing.

Maybe this'll at least stir up some ideas, more spice in the soup...

Dan Edwards

Here is another request for the mode-switch. It would be great to get some video and stills in the same AP flight. Perhaps you could make it recognize 2 or 3 clicks of the gear switch very quickly (too fast for consecutive pictures) as "mode change". An audible tone would be great too.

Another feature that would be nice, at least for people who don't mind this while they are flying... a "throttle cut" that could go inline on the throttle channel, and turn the motor of for like 1 sec when triggering the camera, to avoid the waviness typical of the Aiptek cmos cams. Assuming most AP flyers are using pretty stable planes, a 1 sec throttle cut should not be too disruptive.

And for the "Super Duper AP switch of the FUTURE", I'm talking dream model here (probably none of this is practical, but I'll bet it is possible) :

- Most of the cams I have seen support some kind of digital superimposing of text... I have no idea how this works, but it would be awesome to be able to tap into this with your own input... then make little modules you could hook up to display altitimeter and/or digital compass data.

- Use a gyro to allow a pre-programmed angle of the plane that is optimal for the pics you want... possibly on another channel.. so that when you line up your shot, you can kick in that feature to "tilt the plane" at the proper angle.

I am going to see what I can do about the mode switch without adding too much to size, I might need to move to a bigger MCU for these features. We'll see.

Text superimposing would be next to impossible for now, maybe in the future. Your second idea is more reasonable, and much simpler, but how many people would use it?




Thanks for the ideas and keep 'em flowing!


-Matt

Dang, so someone _sorta_ had my idea already...but I thought more about how to work it.

Same USB plug idea: by pulling up the board mount side of the USB to run functions, will have no wires hanging from the Aiptek modded camera. The USB plug would go to a double servo plug (trigger, mode switch).

Same mode switching idea: using a three position switch, pos is video, neg is still, neutral is camera off. From netural to neg turns camera on, which puts to still mode. From neutral to pos turns camera on, and triggers the mode button once, with a programmed timed delay.

For the pwm trigger, a new invention some friends of mine came up with is to sample the signal and wait for three trigger signals in a row. This keeps inductive spikes from the servos from inadvertantly triggering the camera. We had some trouble with inductive spikes with a Basic II stamp trigger earlier this year.

Power to the camera obviously goes through the USB cable, as on other Aiptek hacks.

Thought I would share my clarifications for the mode stuff. So, maybe there is a new idea there for an Aiptek trigger or maybe ideas for other cameras too.

Dan

I dont know much about these electronics but could you make the switch programmable. Its just an idea. But if it wasnt too expensive I think it would be possible. Just give the features and they couls set up the switch to their preferences. I dont know if this will benefit anybody but I just wanted to share the idea.
So what do ya'll think,
Trent