I finally got pictures, but you really can't see what is on them because the room was too dark when I took them. I did some work with the brighness and contrast to try and make the features stand out more, but it also made it look more grainy. I have another picture that stands out well when black and white, so that one is on there too so you can see the shape better.·I'll try and get better pics some other day, but these will have to do.
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Although it isn't shown in the picture, I decided to add a diode to the input pin on the transistor for extra (probably unnecessary) precaution. Also, only one end of the coil actually connected to the transistor and the other end wasn't grounded. I had the output connected to the prop in the same way you would attach a pushbutton, only reversed since I want to find the negative voltage, not the positive.
Since I didn't have my robot engine here, I just used the engine on my lawnmower. I ended up getting mixed results from it though. Blue led, taking the place of the red one above, flickered constantly just as I expected. The red light just seemed to shine solidly. However, when I got the engine to a lower rpm, the red light stopped shining, or would come on for maybe a half of a second and go off again for a while before coming on again. I don't know why this is. When I speed it up again it doesn't have a problem, except maybe for a brief amount of time (very rare). I can't figure out why it is doing this and if my blue flickering light is actually corresponding with the pulses of the spark plug. If you have any ideas for me on how I can find out, or what is wrong with my red light turning off, please tell me. I would like to try this with my propeller·proto board soon with the rpm readings on the lcd screen, but I would first like to know what is going on here before I do so.
Simple code I am using to light up the red led:
pub flash
dira[noparse][[/noparse]0]~· 'set pins to correct input/output
dira[noparse][[/noparse]1]~~
repeat ·outa[noparse][[/noparse]1] := ina[noparse][[/noparse]0] { make it so if the transistor turns on, the light will blink off momentarily. I would have prefered it to do the opposite, but I didn't know how to, so I called·this good enough. }
I solved the problem by changing the resistors. I was accidentally using 1k ohm instead of 10k ohm resistors. I still have a problem with getting the programming to work, though. You can see my post on this here:
I had some friends convince me to strait-pipe my engine, and WOW is that thing loud. Almost so lout I'm worried my neighbors will think it was a gunshot when I try starting it! Maybe I should have just left the muffler on... Anyways I'll get you a vid when the drive train is running (couple days, maybe) so you can HEAR that thing! But for you adults that worry about how many people I'll anger test driving it, I'll make a detachable muffler for times when it should be quieter like at night.
The idea is to use chain drive for the drive system with plans to later add an electric motor and an alternator (for power). I originally made it to be like the Quadrover, but it really has little similarities besides using a gas engine.·The project is·harder than it seems to make, though. Right now I'm stuck on the problem of trying to make my sprocket square so it·won't throw the chain off, and if I don't get a bulk of it done before this trimester ends I'll have an even bigger problem with time. In fact, I haven't even decided how I am going to get steering, but I've been turning it around in my mind lately and I'm starting to get ideas.
If you really decide to do something similar, expect it to take time. Especially if you don't have wheels, chain, sprocket·and other needed parts. But just for your knowing, this type of project is rare for people to do because they give up too soon. I have only heard of two people doing it, Parallax and their Quadrover, and Ken (works at Parallax). This makes it all the less likely that me, a tenth grader who has only made one other robot in his life, would be able to succeed. That is why I prematurely posted that I was going to try this project on my own to try and get help from people who know a lot, but that was before I knew almost no one has ever done it before. And those who have, like Ken, did it in a much different way then me.·Oh well, it is still good to know people have interest even though they are clueless on how to help me.
If you do decide to try this type of project, good luck Cole,·and have fun!
I don't know if I will ever do it right now its in more of a idea state. But I do have an idea for your steering. A couple of guys that I went to collage with built a R/C mower and used a window motor from a car to turn the front wheels. I·attached a picture to·show what I am talking about.·You would need to find some way to attach the the cross bars to the casters. The big down side to this type of sysem is there is no way for the steering to return to center. And with out a switch of some other sensor you wouldn't be able to know where center was. And if you need to find a cheap place to get window motor go to some local Bodyshop and talk to the guys. They are constently throwing out window motors.
Thanks Cole, doesn't look too hard to try. Hopefully I can get working on it Friday or next week. I'm almost done with the drive system so there shouldn't be any problem with it. As for using a sensor to get it centered, I'll just use a pot and make the thing ride down a line to see if it works.
Cool keep me up to date on how its going. I just got a ping and am trying to get to work right. And if there is anything else I can do to help you just let me know.
The drive train runs, but I still need to fix it. With that I will start working on the steering since I now have a motor out of a windshield wiper. I won't be able to get much done until after Thanksgiving, though.
I made a cad image now of what I am going to work on for the next two days before thanksgiving break. It is basically a little more complicated image of what cole gave me.
I just thought I'd keep you guys updated so I got a picture of the frame. In the picture the bars jutting out to the right will hold the steering system like the poor cad picture I made. Some of the parts for it aren't in the picture because I can't attach them until I find the measurements for the front wheels, which I don't have yet. To the left there are square pieces of metal sticking out on both sides, and that holds my bearings and my axle. Although not in the picture, it, along with the sprocket is all ready. I just don't have it on for the pic. Currently I am making a hub for my 16" back wheels, then I'll finish the steering.
Sometimes I just don't know how I got this project (my will-be second robot) started. I had a little knowledge of programming (pbasic) and I'd taken beginning welding before working on this project during the first trimester of Welding II. Now that I've started, I guess I must be either·stubborn or just plain stupid to not to have given up, considering no one has done this before from what I can tell. Now that I've started, there's no backing out. I bet ten bucks I'd be done by the end of the tri!
Just for kicks, I've also included a picture of my first robot, the one I built before the one I am currently working on.
-Just as a side note, I expect the hubs to be completed and functional by Friday.
I was thinking of using pnumatics to operate the breaks. If I did it that way I would probably just use a 12v compressor·like this one and use it to push a piston attached to a brake pad. Anyone agree with doing it this way?
Could be done. Certainly works for trucks, but you would need air storage if you are using a small compressor. Also you may not be able to apply and release the brakes more than a couple of times in a short period. Need time for air pressure to build.
That may be a problem. If it is, I might just add a second compressor since they're not too expensive. As for a storage tank, I was thinking of just making a square box and attaching the same kind of connectors to it that tires have for air to fill it. Think it will work? Maybe a better idea?
I've been thinking about it and I'm not sure if I will be able to easily control the gas pressure. I've thought about using a regulator with a servo or motor controlling it, but with a price tag of close to $100 I can't afford it. Think there's a better way of controlling the breaks? If air doesn't work I might just have to do something different, such as hooking a motor to each brake instead. Please, feel free to add any advice/suggestions.
Thanks to your great support I have decided to avoid using compressed air to operate the brakes and instead use a good old motor. I'll be using a brake system that uses a belt to slow down the axle such as the one found here, however note I will be purchasing a cheaper belt from a store where I live. Also, to save money, I'll be making my own drum and hub for the break. This I have almost completed in my class today.
You also may be wondering what ever happened to me finishing the steering and attaching the back wheels. The problem with the back wheels is I don't have a 3/4" bit required to finish making the hubs. I also need this bit to finish the brake drum. As for the steering, I have just been waiting to make sure the wheels I had were the correct size. I recently purchased the tires for them, so, now that I know I shouldn't find problems in the future, I will finish it up as soon as I take the wheels to school.
Besides all of the things I am doing above, I am also planning on buying a used alternator this weekend so whenever I get some time I can get it hooked up to my engine for power.
If you have any advice for me I would advise spitting now before I get anymore work done!
Also, I just thought I'd tell you I have just about everything to build this bot. The only thing I'm missing is getting my butt in gear. I only have 3 more weeks and I won't be in welding anymore.
Show a picture or explain why you need a 3/4" bit. This would be a very expensive drill, and I'm wondering about the necessity of it. Can the hole be milled? Does it really need to be 3/4"? Can you take the part to a local machine shop to have them drill it for $10? To help with this I'd need to understand the bigger picture. I often work around the tools I have to get the project done - you can do a lot without compromising the project, I'm pretty sure.
Don't worry about the bit problem, I've got it covered. The reason I need it though is because I'm making many of the parts to save on money, and my axle size is 3/4 inch. I'll be needing it to make my wheels hubs, saving me $15 each and to make my·brake drum, saving me ~$25. As for pictures, you can expect a lot of them coming up soon, cuz I have plans to make my hunk of metal capable of actually doing something!
BTW, thanks for the response. I've been feeling like I·was talkin' to empty space!
There is just one thing, whats more important... finishing, or expereincing.
You could expereince alot.. but never finish the project because you have to make -everything- by hand to save money.
Or finishing and spending more than you wanted, but having a realized product?
From what I've read this is a 1-2+ year long ordeal.. which hopefully has produce alot of experience.
Comments
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Pi Guy
http://forums.parallax.com/showthread.php?p=691869
·
Although it isn't shown in the picture, I decided to add a diode to the input pin on the transistor for extra (probably unnecessary) precaution. Also, only one end of the coil actually connected to the transistor and the other end wasn't grounded. I had the output connected to the prop in the same way you would attach a pushbutton, only reversed since I want to find the negative voltage, not the positive.
Since I didn't have my robot engine here, I just used the engine on my lawnmower. I ended up getting mixed results from it though. Blue led, taking the place of the red one above, flickered constantly just as I expected. The red light just seemed to shine solidly. However, when I got the engine to a lower rpm, the red light stopped shining, or would come on for maybe a half of a second and go off again for a while before coming on again. I don't know why this is. When I speed it up again it doesn't have a problem, except maybe for a brief amount of time (very rare). I can't figure out why it is doing this and if my blue flickering light is actually corresponding with the pulses of the spark plug. If you have any ideas for me on how I can find out, or what is wrong with my red light turning off, please tell me. I would like to try this with my propeller·proto board soon with the rpm readings on the lcd screen, but I would first like to know what is going on here before I do so.
Simple code I am using to light up the red led:
pub flash
dira[noparse][[/noparse]0]~· 'set pins to correct input/output
dira[noparse][[/noparse]1]~~
repeat
·outa[noparse][[/noparse]1] := ina[noparse][[/noparse]0] { make it so if the transistor turns on, the light will blink off momentarily. I would have prefered it to do the opposite, but I didn't know how to, so I called·this good enough. }
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Pi Guy
http://forums.parallax.com/showthread.php?p=762886
Also, if you have any better way of doing this, it would be a help if you could tell me that as well.
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Pi Guy
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Pi Guy
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Pi Guy
If you really decide to do something similar, expect it to take time. Especially if you don't have wheels, chain, sprocket·and other needed parts. But just for your knowing, this type of project is rare for people to do because they give up too soon. I have only heard of two people doing it, Parallax and their Quadrover, and Ken (works at Parallax). This makes it all the less likely that me, a tenth grader who has only made one other robot in his life, would be able to succeed. That is why I prematurely posted that I was going to try this project on my own to try and get help from people who know a lot, but that was before I knew almost no one has ever done it before. And those who have, like Ken, did it in a much different way then me.·Oh well, it is still good to know people have interest even though they are clueless on how to help me.
If you do decide to try this type of project, good luck Cole,·and have fun!
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Pi Guy
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Pi Guy
http://www.acroname.com/robotics/parts/R11-6500.html
It·can go from 6" to 35'.
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Pi Guy
will be that kit that I get.
http://www.acroname.com/robotics/parts/R15-SONAR2.html
Also I want to buy this mosfet to drive the electric motor·at slower speeds, and maybe the steering as well.
http://www.acroname.com/robotics/parts/R27-18200.html
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Pi Guy
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Pi Guy
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Pi Guy
I hope this helped you visualize my project,
Pi
Just for kicks, I've also included a picture of my first robot, the one I built before the one I am currently working on.
-Just as a side note, I expect the hubs to be completed and functional by Friday.
Best regards,
Pi
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PG
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PG
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PG
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PG
You also may be wondering what ever happened to me finishing the steering and attaching the back wheels. The problem with the back wheels is I don't have a 3/4" bit required to finish making the hubs. I also need this bit to finish the brake drum. As for the steering, I have just been waiting to make sure the wheels I had were the correct size. I recently purchased the tires for them, so, now that I know I shouldn't find problems in the future, I will finish it up as soon as I take the wheels to school.
Besides all of the things I am doing above, I am also planning on buying a used alternator this weekend so whenever I get some time I can get it hooked up to my engine for power.
If you have any advice for me I would advise spitting now before I get anymore work done!
PG
http://forums.parallax.com/showthread.php?p=785256
Also, I just thought I'd tell you I have just about everything to build this bot. The only thing I'm missing is getting my butt in gear. I only have 3 more weeks and I won't be in welding anymore.
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PG
Show a picture or explain why you need a 3/4" bit. This would be a very expensive drill, and I'm wondering about the necessity of it. Can the hole be milled? Does it really need to be 3/4"? Can you take the part to a local machine shop to have them drill it for $10? To help with this I'd need to understand the bigger picture. I often work around the tools I have to get the project done - you can do a lot without compromising the project, I'm pretty sure.
Ken Gracey
BTW, thanks for the response. I've been feeling like I·was talkin' to empty space!
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PG
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PG
You could expereince alot.. but never finish the project because you have to make -everything- by hand to save money.
Or finishing and spending more than you wanted, but having a realized product?
From what I've read this is a 1-2+ year long ordeal.. which hopefully has produce alot of experience.