20081115

Nov 15, 2008

David

    I took the System out for testing at a local park and found out just how much of a piece of shit my Toshiba A75 was. After that I bought an Acer Aspire One (windows version) for $350 and it's a hell of a lot better, cheaper, and smaller. It's great to know that a laptop that cheap will work, plus they can only get cheaper.

    I've also made some major speed (faster frame rates) improvements on the software and the ability to switch between color and grayscale motion detection. it's turning into a pretty awesome system.

    I've decided to focus on selling the Software + Servo Controller kit first, for a couple hundred or less. I can sell those while I perfect the hardware. That doesn't mean version 9 isn't working out. It is, but I want to test it some more.

    I haven't done that much research into it, but if someone knows of a gumstix setup that has video input and a serial (rs232) port send me a link. I might be able to use them a cut the system cost down even more.

 

Progress

Nov 6, 2008

David

    Got the remote control installed. it works great. the new laptop battery is in but I'm not sure if it works right because it'll just switch off sometimes (while still saying it has a good charge when you turn it back on). maybe it's a loose connection.

    What's left to do before I can sell them? implement a few hardware improvements, get the custom servo controller made (to take care of the pirating issue), get a good obfuscator (so the source can't be read), form the LLC, and copyright the software.

    The final product will require you to have a laptop, install the software and mount a gun of your choice. If you think, 'oh, that sucks, I don't have laptop.' guess what, if I sold it with a computer it would cost at least $500 more. so think about it, you'd be paying for a computer anyway, why not get a used laptop yourself? that way, you have the ability to remove it from the sentry when you're done playing with it and get more use out of it.

 

Testing is going well

Nov 1, 2008

David

    I've got that remote control and a new laptop battery coming in the mail. when they get here I can finally take it out to a local field for some better testing. My back yard is too small and if I put it in my front yard it will scare the neighbors... I'll probably have to cops called on me when I take it to one of the local parks/fields too. fuck it.

    I've made a motion activated sprinkler for those people who want something cheap to keep pests off their lawn. The idea has already been patented and I saw one company that sells them but I'm going to make them anyway since they're so damn easy/cheap to make. I should be able to sell a few, here and there, to bring in some extra cash.

 

Looking for a cheap, 1Ch., DC, RF receiver/transmitter combo

Oct 30, 2008

David

    The best thing I found so far is this. The problem is, if it looses power, it will need to learn the transmitter code again. It works the same way as a garage door opener. What I need is something like it but it would need to be one channel instead of two, accept 7.4v input or lower (on the Rx board), and use dip switches instead of the modern 'learn' method. That way, it can be powered off of the battery pack and the whole system can be manually turned off and on without the need for re-learning (the dip switches determine the code). that product is perfect for a permanently mounted system though. If I can't find anything I'll just settle for that and it'll just be annoying pressing the learn button every time I take it out to use it.

 

New Prototype (Ver. 9)

Oct 27, 2008

David

    I would really love to be done designing these things and start making a little money off of all the hard work I've put into this project. But at the same time, I can't sell something I know will have major (hardware) issues. With that in mind, I've made yet another prototype (check the 'Prototype History' page). It's mostly based off of version 5. While it looks very promising (to me), I'm also well aware that I initially thought the same thing of the previous versions. So we'll see how testing goes...

Updates

Oct 24, 2008

David

    I've added legs to the case to reduce camera shake. (There's a bigger pic on the Prototype History page.) These legs can be removed without tools by removing 4 thumb screws. I'm using a Pololu servo controller now. with this controller I get higher servo resolution and most importantly, the ability to adjust the servo's speed. You always want the servos to move as fast as possible but if the Sentry's on soft/unstable ground you can slow down the speed a little to prevent it from shaking. So far, in testing, I haven't had to use it.

    I'm gearing up towards making another video so if you have some specific scenes/scenarios/demonstrations you'd like to see shoot me an email.

The calibration overhaul is done

Oct 18, 2008

David

    That was a hell of a lot harder than I thought it would be. I spent all my free time since the 10th working on the new formula. I ended up using Trig for most of it (that's after I spent the time learning (basic) Trig of course). It was worth it though because now the camera doesn't have to be centered nor do it's axes have to be parallel with the turret's axes. Here's a comparison of the old calibration process vs the new one:

Old Calibration:

1. mount the gun, turn on the laser, center the servos, and enable calibration mode

2. take apart the waterproof camera enclosure to get to the camera

3. adjust the camera until the laser is on the image center

4. try to guess if the camera's axis are straight with the camera and adjust if needed

5. aim to the left edge of the image, click a button, and do the same for the top, bottom and right edges

6. put the camera enclosure back together.

7. test for correctness using mouse aiming

8. realize that the camera's axes weren't quite lined up with the turret's axes and go back to step 2.

New Calibration:

1. mount the gun, turn on the laser, center the servos, and enable calibration mode

2. aim the turret at the image center and click anywhere on the image to store it's values.

3. aim the turret anywhere along it's X axis, far from center, and click the spot on the image where the laser is pointing

4. do the same for the Y axis and you're done.

now the gun and camera centers don't need to be lined up, and the tilt of the camera (if any) is not an issue either.   

To clear up some common misconceptions, calibration only needs to be done when you're using the sentry for the very first time, if you re-install the software, or any time you mount a different gun to it. mounting the turret to the base should not require re-calibration.

    The next issue to be resolved is camera shake. because the turret is so light, the momentum of the turret's rapid movements sometimes causes the case to shake (depending on how solid the ground is). I've already implemented a basic software fix that pretty much takes care of the issue but I want to make sure that there isn't more that could be done before I call it resolved. Then I can finally get some video of it shooting model airplanes out of the sky.. :)

 

Calibration

Oct 10, 2008

David

    The increased responsiveness and torque the 7.2v NiCD provides is amazing. the previous method of using the laptop's usb port for power was convenient, but clearly a bad idea. the new added portal voices are great and the overall hardware setup is much nicer looking and easier to use than ever before. while all that  worked out well the gun to camera alignment (calibration) is too much of a pain in the ass and too time consuming to be acceptable. Sure, I could solve that by copping out and making it so it comes with a pre-calibrated, permanent, gun and camera, but then you would loose the ability to mount anything you wanted on it (and that's half the fun). I've got a software solution that should fix the problem and I'll be working on that tomorrow and this weekend.

 

Version 8 is done

Oct 5, 2008

David

Just got done building it (more pics on the history page). I only had the time to do a basic systems check. As soon as I get the chance, I'll take it out for calibration and testing. If it passes, this might be the one I finally sell to the public. it costs roughly $500 in material and parts so anybody trying to sell one of these for more than $1500 is ripping you off, big time. I've even seen RC paintball setups that cost much more than that (EMT Turret) and all they are is RC! it's pathetic! The Sentry is battery powered and the whole thing, including the camera is paintball/rain-proof. I keep a close eye what little competition there is out there and make sure I offer the same features, and then some, for half the price or less. I could have easily taken a shortcut and paid a machine shop to make them but, as I said before, the price would at least double.

I also wanted to say thanks again to those of you who have donated. donations paid for about half of this build. if the sentry tests well i'll start on a new video.

 

Possible hardware solution

Oct 1, 2008

David

Finding a Hardware solution that's inexpensive, simple, easy to deploy, light, and is it's own case, has been tough. for example, in the most recent video, the case, by itself, weighed 60lbs, cost $300 to make, and took 2 days to fabricate. that obviously won't work. since then I've toyed around with all types of ideas trying to meet the criteria I just mentioned. after messing with different suitcases and briefcases I finally came up with the idea to use an ATX case to package everything in. the bigger ones seem to be the perfect dimensions to hold a laptop (ironic isn't it? a laptop in an ATX case) and the gun assembly. this is the case I've had my eye on ($99):

I would have to gut it and waterproof it from the inside (sounds hard but it is really easy and inexpensive). when the sentry is deployed, the gun + camera assembly will quick mount to the top and then be removed and put inside when packed up. This may seem odd, but to me, compared to all the other designs I have tried,  this has some key advantages. when it's deployed it's footprint is slim (to fit in tight spaces [also a tripod adaptation can be made if needed]) and tall (to see above tall grass etc.). it also costs less and looks better than a hand made equivalent. also, other hardware like batteries, ammo and possibly an air tank could be put in there too. but hey, if you see something cheaper that looks as good and has similar dimensions email me, otherwise I'm going to get to work on it.

On another note, in the next video, I want to do a scene where it's Anti Aircraft  ability is demonstrated (against RC aircraft of course :). I'll probably have it shoot down one of those Styrofoam gliders (paintballs will blow it to pieces) from 50+ ft up and maybe a small heli or two.

Some improvements worth mentioning..

Sep 25, 2008

David

I've found more Portal Turret mp3s that I didn't have. I added those in and changed the code a little so you can also use you own audio files if you want.

Moving slowly won't save you anymore. The detector has been significantly modified so that it can track very slow targets and also ones that have recently stopped moving. this is particularly helpful in situations where a person is slowly peeking out from behind an obstacle. The changes have also significantly improved it's range. In optimal conditions, it can track a person walking at hundreds of feet out and well beyond the accurate range of a paintball gun.

Calibration is simpler to perform and adjust. Need to get a better laser though..

I've thought of a interesting design I'm going to start building soon. I need to draw it out in more detail first. Finding the best design has been difficult. I could easily just cop out and have a machine shop make it. But then I would have to charge customers out the ass to make up for the machine shop doing the same to me. So, the trick is to come up with a design that can be built for very low material costs, looks good, is durable, is it's own case, has room for a laptop, is light, can be set up quickly and simply, and is not too time consuming to make. The cheaper I can make them, the cheaper I can sell them for which would equal more units sold (which also means more personal injury lawsuits) Will eBay allow these on their site?

I'm going to change strategies on friend/Foe ID. Instead of saying 'this color is the enemy,' I think I'll make it do the opposite whereas, 'this color is friendly and everything else is a valid target.' (that way i get sued more) There are scenarios where this would be better and others where the opposite method would be better so I'll do both and make it a user option.

 

I've been reading about newer Tracking Algorithms

Sep 16, 2008

David

I've come across research papers describing Object Tracking Algorithms which perform far better than my own, in several areas, and with fewer limitations. Unfortunately, the authors of these papers love to explain their ideas and concepts in the most complicated way possible, while in most cases the ideas they are conveying can be greatly simplified without loosing the key concepts. when I do finally grasp what they are trying to convey, beyond all of their statistical formulas and jargon, I always get pissed at the amount of effort I had to put in to understanding what was essentially a much simpler concept than they made it out to be.

Solution for much greater Range

Sep 4, 2008

David

I thought of a way to dramatically increase the range while still using only one camera and also get a 90 field of view. the problem, as always, is i can't find a piece of hardware that meets my needs. i need a webcam that has around a 3x OPTICAL (not digital) zoom and does at least 640x480@30fps for around $100 or less. for some reason that's really hard to find. it might also be possible to make a zoom lens that will work on most cameras. i don't know, but if you do or know of a optical zoom webcam, email me. (i've already seen that one that has a 7x non adjustable zoom built in [that's too much zoom] and the VX-6000 which is advertized as having an optical zoom but doesn't)

Another solution would be a webcam that will allow higher resolutions than 640x480 when used in 3rd party programs. just because a camera (Microsoft VX-6000) can do 1.3MP video streaming using the program that came with it (LifeCam) doesn't mean it will let you have that high of a resolution using any other program. All the cameras I have tested either do 640x480 or 320x240 when used by 3rd party apps (Skype, AIM Yahoo IM, etc.)