How hard/$$$

[RoboChan]

Hello i joined this forum a while ago hoping i could build a really cool robot for $10 and found out i cant after getting a arduino BBB and trying to learn programming, so gave up but kept the dream. I now plan on selling my aquarium and having about $300 for a cool robot. I have trouble programing but i make up for it, building.

How much would just the electronics in this cost http://www.robotmarketplace.com/products/IL-SRV1Q.html My dream is to make a vehicle that can travel up and down steps under the control of my laptop with a camera to see. I can get motors and make a chassis but i am at a loss on how to program or exactly what to buy. Later i would also love to incorporate the turret from http://www.societyofrobots.com/robotforum/index.php?topic=9652.msg79218#new. I just need to know if i am dreaming larger than my budget will let.

Thanks,
Chandler

[cooldog]

well first of all robot marketplace parts are WAYYYY to over priced or anything other then battle bots and industrial size stuff.

what you could do is use the $50 robot board with UART upgrade and then bluetooth. so it can be controlled by ur laptop.

or you could buy the AXON I/II and add bluetooth to it.

for the camera- get a wireless camera off of ebay and a A/V connector for your laptop to see it.

[RoboChan]

What would the total cost be? $100 for axon and how much for bluetooth and motor driver? How do i find out the amps a given motor pulls?

[little-c]

V=IR. P=VI.  volts your running it at, risistance of motor. or look at data sheet/power specs

[RoboChan]

I have 2 power wheel motors that run on 6 volts. How do i find the amps?

[waltr]

I have 2 power wheel motors that run on 6 volts. How do i find the amps?

Insert a small resistor (1 to 10 Ohm) in series with the motor and battery. Then measure the voltage drop across the resistor and use Ohm's law to calculate the current. Do this with the motor free running then totally stalled. Just keep the time short s the resistor and motor don't over heat.

[vinito]

For what it's worth I'll throw in $.02 worth of my perspective.
First off, I'm a hobby junkie. I'm getting old too, so I've been through dozens of hobbies over the years. Of all the hobbies I got into (including aquariums, hehe) electronics/robotics has proven to provide by far the maximum "fun return" per dollar invested. You can buy a handful of components for a few bucks and use a short list of tools to put them together in many different ways.

The fun for me is learning how to program microcontrollers. That is literally hours of edutainment for free.

It sounds like you have a yearning in your gut for some kind of end result. If you have plenty of money and can just afford to go buy it, then I guess you can do that. To me that is missing out on the fun though. I'd suggest you step back and take a look at what you really want. It may not seem like it standing on the bottom step, but it's the act of climbing that provides the fun, not being at the top of the stairway. Again, it doesn't seem like it before you do it, but making a cheap micro do the simplest thing is actually a lot of fun. Once you've mastered several variations on how to blink an LED, then you move on to the next thing you want to make it do and just keep plugging along. This may take you a few hours or a couple weeks depending on how much time you have. If you've zipped through figuring out how to make a bunch of different sensors work and made lights come on, different types and sizes of motors spin, manipulated pixels on an LCD display, etc., then congrats for you. In that case, by then you'll have a lot more programming and circuit design chops and that will no longer be a weakness for you.

Seems to me that if you could afford to just go buy a $500 robot, then you'd then be left with programming the micro anyway at that point. With no "building blocks" of coding under your belt yet, the complex coding it would take to make a robot behave differently would be overwhelming to me. Keep in mind that technology keeps whizzing ahead. If you bought a bleeding edge robot today and waded through learning to program it for a long time, then by the time you get it together some other new gleaming product will be available for less money leaving the one you bought to retire in its dust, but you already spent your wad so still wouldn't be able to go for the new one.

I'm not trying to talk you out of robotics. The opposite is true really. You might do very well with heading straight for things like you linked to. I'm just offering a few thoughts from my own perspective. I have had tons of enjoyment learning this stuff, and after a little over a year I have a couple of bots under my belt and a dozen little experiment projects in the works. It's a blast. Well in a geeky sort of way at least, but I'm not the bungee-jumping sort so...

[RoboChan]

i am in no way ever going to buy a kit or compleate robot. I want to make something like that in my own way, i can change if i want to. I have bought an arduino bare bones board soldered it 3 times over to get it to work and made a led blink, used a photo sensor to change the brightnes using pwm.
I now want to build a wireless bot with my own parts. I dont have $500 i have 300 to make a 500 dollar bot my own way if that makes sense.

Thanks for your time,
Chandler

[vinito]

Yep that's cool.
That's a basic premise of... well most things really. It either takes money or time to do something. If you have money then you can hire others to create things for you. No money means you get to plan, design and build for yourself. I'm in the latter camp, and I've been here so long that I don't even have an end goal of any type.

It would obviously be cool to create a slick robot with advanced capabilities and sell a bunch to police forces nationwide, or to create a revolutionary device to aid the physically handicapped. But I'm nowhere near there and I'm just learning the next little step at a time and seeing where this takes me. I'm just calling it a sort of dedicated piddling around and it sure is fun. Plus I've got various widgets here & there that I dreamed up to automate and/or increase the "slick factor" of things. Nothing complicated, but sometimes it's the simple things...

A friend of mine now has an automatic feeding/watering system for his chickens. I got sick of him complaining about being so tied to them for so long, so we spend a day figuring out and making it work. Now he can go on vacation on a whim. I'm still too broke to tag along and I stay home, but at least I don't have to hear about those ball & chain chickens, hehe.

It's cheating for me to take this position though in a way because I'm a machinist by trade and I have a full machine shop here at the house. In an effort to be fair  , I do help the local robotics club as often as I can with machining needs. I always wanted to learn to do stuff with electronics so I'm finally working my way through it now. It's very cool. And my "electronics teachers" from the robotics club are learning a fair bit of machining tidbits too. It's working out pretty good.

[RoboChan]

I race go karts and when things break (happens often) we have to machine whole new parts for them. My dad's work has every tool you could think of and he has tought me how to use most of them but i have ben lost on electonics and programming so thats where i always have queastions.

If i went the cheap way and just used my arduino BBB what would a bluetooth and motor controller cost?

[vinito]

Well in my opinion you're tripping over your shoelaces a bit. There are only so many IO on the BBB since it's based on a 28-pin chip.
The BBB is a pretty cool board though so I'd do as much with it as you can. You have it already and it's a pretty neat device. Trying to make it control motors, RF via bluetooth, and likely some other motions and sensors, you'll run way short of IO I think. I say "I think" because I don't actually know and that's just a guess on my part. One of the interesting challenges with embedded micros is figuring out how to do several things with limited IO. I'm pretty green so if I run out, I just tend to think about moving to a chip with more fingers.

So, if you can't wait and just want to dive into the deep end and see what it's like, maybe take a look at the Teensy (Link). I've been looking it over for several months and haven't picked one up yet. But it looks pretty cool indeed. It's very small but seems to have lots of nice capability due to the AVR chip it's based around. The Teensy ++ (as opposed to the "regular" Teensy) is the one to go for. It has a boatload of IO (compared to what I'm used to anyway). And it needs no additional serial or USB circuitry since it's built-in to the chip. He has an add-on so you can use Arduino software to code for it. I'm not trying to sell you stuff, but that seems like a pretty economical board to use if you need a bunch of IO pins. Personally I'd just use the BBB to get my circuit and coding chops honed on each module one at a time - get the motors going, get the RF working, get some sensors reading something, play with sounds, lights and displays, add a few buttons or array to do something useful, then make the sensors or maybe the RF affect the motors, etc. Once you are pretty secure with all that, then pick up a power-board with a bunch of IO and begin to put the whole smash together. By then, the coding and circuit design will be much easier to deal with. It doesn't take long, especially if you're young (I'm pretty old & crusty).

I can't recommend any sources for bluetooth since I haven't messed with it or looked into it at all. As for motor controllers, if you're talking basic DC motors (which you can do a LOT with) it depends on the size of course, but a simple H-Bridge is what keeps popping up over and over on my trail. Look at the Robot Room site (link). He gives an explanation of how the H-bridge motor driver works and tons and tons and tons more. It's a great site for learning about this stuff. In short, H-bridge motor controllers are common, cheap and easy to whip up.

I get lost on the electronics and programming too. But it's so fun to learn that I don't care if I'm an expert with it right now or not. I like building stuff in the machine shop OK, but I really like piddling with this electronics and coding. Sure there is burnout now & then when I just need to get away from it for a while, but I can spend hours and hours on it even if I don't have an end goal in sight. The little goals along the way make themselves clearly evident as I go.

[RoboChan]

If i used my BBB and got
Bluetooth Modem - BlueSMiRF RP-SMA  $64.95
2.4GHz Duck Antenna RP-SMA             $7.95 
Bluetooth USB Module                        $12.95
2 Servo - Full Rotation                       $27.90


That's $113.75 total plus $9.39 shipping from sparkfun. I could make a cool bluetooth PC contolled robot car. That's only 2 of my 6 pwm. If i wanted to i could add a CMUcam or a Blackfin camera with pan & tilt. Theres my end goal right there, right?  The only thing i do not understand is why i have to pay over $70 for bluetooth. Can i use a xbee to do the same thing as a blue SMiRF?

Thanks,
Chandler

[vinito]

I haven't got much into RF other than hacking a Vex system, but it seems to me that if you can get two transceiver modules from sureelectronics off eBay for about $30, then you should be able to get simple one-way communication arranged for even less. Don't let not knowing about something cause you to blow a bunch of money you don't have if you don't have it. Sure it would take a little effort to figure out how to make some kind of Rx/Tx system communicate the way you want to, but that's part of the fun and it really helps a lot to know what's going on anyway. It's not like you'd need to build it from scratch (which in my eyes would be a monumental effort).

As for bluetooth vs. zigbee, again I wouldn't know. RF is something I haven't looked into much at all. Both systems are considered short-range (relatively) so I don't know if either one would be suited correctly for RC control of a car anyway, though it should work fine if you didn't plan to get a long ways away from it. A robot vehicle is a whole nuther thing from a model plane though, so maybe the distance envelope would be fine. I just don't know either way.

I agree that $70 is quite a chunk for that one feature. Even worse if it turned out not to be what you needed. I'm not sure where to tell you to turn, but I know I would be looking around at alternatives for a while on that bit.

I hate to promote sales of cheap chicom anything what with the world situation being what it is, but it's hard to ignore what is available in the electronics department from that part of the world via eBay. I've picked up several items that way and it has worked out well every time. Most of the time I've found the stuff I was looking for being offered with no additional shipping charges, so it turned out to be very affordable for me when I otherwise would have just been staring at a blank bench. The nice thing about eBay stuff with no shipping is that you can just buy one thing and not feel the need to "pack the box tight" to avoid being gouged by shipping. Sparkfun is a great source and I like to support them too (and I've bought a lot of things from them over the years to prove it), but maybe search eBay and see what kind of RF modules show up. As with anything on eBay, look at feedback ratings and all that to make sure the seller seems like a pretty good bet before you spend any money.

[RoboChan]

Thank you for your time agian. You have helped very much.

From what i have read the bluetooth's range is about 300 feet, which in my case is plenty. I just want something to drive around my house and school. Every exaple of xbee has used 2 controllers and 2 xbees. If you need that much hardware, why not get blueSMiRF?

For now i think i will just build a wired robot and add bluetooth later. I just relized my BBB dosent have USB so it will not work with my new computer. Instead of getting a parrel to usb cable, why not just get a new board? I looked on ebay and there where arduino megas for around $40. That should give me plenty of IO. As for a motor controller, i think i will just go for servos.
What are some other "unique" robots i can make besides just line follower, wall avoider... and so on? I want to build a "vehicle" typ robot.

Thanks,
Chandler

[vinito]

A couple of guys could sit around for a couple of hours and dream up a pretty long list for that.
My approach would be to come up with something for a versatile chassis that you could attach various sensors, motors, camera, etc. to. This would allow you to try a bunch of different things and switch from one thing to another relatively quickly, rather than having to do some time-consuming physical build each time you wanted to try something new.

A couple of things that come to mind:
Swarm robots are kind of interesting. They move around based on randomness or various input, are "aware" of others nearby and minimize collisions, but move around kind of similar to the way a flock of birds would - i.e. no one is "in charge", or rather the responsibility of position and direction switches around depending on the shape of the swarm. This would be interesting from a coding perspective. You could use the same collection of robots and just adjust the code and see how behavior of the swarm changes. They need some kind of sensor like a beacon or something so the swarm can be held together. These would be relatively inexpensive bots but you need at least three to make a swarm, so...

You could make something that comes on and "entertains" the family pet every so often during the day while everybody is away. It depends on your pet though and the wrong one could net you a piled collection of slobbery components greeting you on your return.

For me, the standard list of line-following, maze, sumo and the like are interesting enough because just making them do what they do is challenging enough. I won't win any originality awards this year, but maybe some future year. You never know.

[RoboChan]

I just got a call for my fish tank so money may be coming in soon  .

I may just get an ebay arduino mega some servos and sensors, mix them up and see what happens  .

I still want to know how much the "turret" in http://www.societyofrobots.com/robotforum/index.php?topic=9652.0 cost and if xbees can conect to a computer or only other xbees.

[dellagd]

FYI heres a cheap wireless camera :
http://dbroth.com/2-4ghz-mini-wrlsscolrcam-w-micrphn
and trust me on this... I spent a week trying to find the cheapest one that doesnt have a like 2 foot range

[RoboChan]

Thanks looks great, ill keep that in mind 

[vinito]

I have this to offer regarding Arduino Mega:
I love the Arduino concept. It has really exploded the amount of info and number of people getting into micros and robotics. There are pros and cons about this, but from my perspective the pros far outweigh any cons about it.

I don't know this for sure either since I don't have one, but as far as I can tell from my limited exposure, the Mega is more of a spinoff and not really a phenomenon in its own right like the original Arduino is. In other words, I haven't seen the wealth of information and projects with it that we've all seen with Arduino.

In light of this, it might behoove you to consider alternatives to Arduino before branching out from it into a Mega. The Teensy I referred and linked to earlier is similar to the Mega in terms of IO and you can even use the Arduino software to program it (OR the Teensy programmer OR AVR Studio - whichever you prefer). It uses an AVR chip which means the programming structure will be pretty much compatible with Arduino or other stuff written for other AVR chips. There are likely other boards out there which have similar capability. The Teensy is just what I have stumbled across and it looks pretty interesting and capable. And I really like that it has USB functionality built right into the chip. This contributes to the thing being such a small form too which is nice in itself, plus the fact that it matches a breadboard grid removes that one fatal flaw in Arduino that curiously never got fixed before it got itself established.

Having said that, my guess is that eventually the "being related" part of Arduino Mega will translate to becoming more popular than the Teensy will ever be, plus there are 8 fewer IO pins on the Teensy (46 rather than 54). But neither of those facts bother me much. Either one would be fun to have and work with. After a while, the "development board" nature of Arduino, Mega and/or Teensy doesn't matter much at least to me. It's easy to hook things up and be agile with your design process, but along the way I picked up a programmer and like to use AVR Studio rather than Arduino software anyway, which just requires an ISP connection (provided for on ALL AVR chips). Even if you're breadboarding your project, those monster chips do not come in a DIP format though and some kind of board would be required by me just to access the pins (such as the BBB, Teensy or Mega boards).

The Mega was pretty expensive when it first popped up and I don't understand why it hasn't come down any. One thing about the Teensy is it costs less than half the Mega, so if I wanted more IO I'd buy two and have them just communicate via I2C for still less money and have 92 pins at my disposal. I'll tell you right now though, if I needed 92 pins for something, I'm not sure I could wrap my head around the coding necessary for a project of that size, at least not in the near future.

There may be good reason justifying the Mega's cost though and I would not be the guy to recommend for or against since I don't know that much about it. My point is, it's worth a little researching before buying either one in my opinion.

[Ro-Bot-X]

Hi Chandler,

Bluetooth is worth the money expense only if you want to control the robot with your cell phone or other Bluetooth gadget. It costs that much because of royalties of the patent. For a robot that will talk only to the PC, I would go for XBee modems. A complete XBee system ( 2 XBees + XBee Explorer + USB Explorer) will cost you the same amount with the Bluetooth system (BlueSmirf + USB dongle). But with a XBee system you can upload your sketches wireless. That may come out handy. Also there are Arduino variants that already have XBee socket onboard or you can get a shield. Don't forget to check out the Seeed Studio Depot, you can get a complete system for less. They have an interesting Serial Port Bluetooth module and a Bluetooth Bee.

The cheaper radio link modules need a bit more work on the software part, as you need to create your own protocol to deal with errors and stuff. I don't recomend it unless you know what you're doing.

Edit: Seeed Studio has a Mega for only $46.50. Take your pick.
XBee can be used to talk to another robot or to the computer. You need a USB Explorer on the computer side and a regular Explorer on the robot. You mount the XBee modules of your choice (more power = more distance) on the Explorer modules.

[vinito]

Ah.
I take it back (at least part-ways)
I see that the Seeed Studio Depot (linked by Ro-Bot-X above) sells the Mega for about $20 less than most folks, so hopefully that means the price is finally starting to drop.

edit: I see he knew this too, hehe. We're all over it man!

[RoboChan]

http://www.trossenrobotics.com/p/Xbee-Communication-Starter-Kit.aspx?feed=Froogle
That's a little bit more than bluetooth but i can see how uploading programs wirelessly could come in handy. For now i plan on making a good platform down first. I think i may need another microcontroller and some sensors to play with and save my money to go wireless then add a CMUcam3 or a blackfin. For the drive part i need to find the amps these 2 motors pull, that i have and make a decision on a motor controller or just servos. I am notplanning for this robot to be a fast build but i just want to plan the major components out and see how much i may end putting into this. This robot may cost more than one of my go karts . As for programing i know i am going to need help and i am very happy to have found this forum.

On a side note do any of you think used parts would be a possiblility? I could buy old robots parts to help fund the next robot the person is building.

[Ro-Bot-X]

I'm not sure about your motors, but perhaps this kit from Trossen Robotics can help you since it has everything you need: integrated H-bridge, integrated xbee, works with arduino, includes the  computer side xbee and explorer, includes the hardware programmer and uses ATmega644. See it here: http://www.trossenrobotics.com/p/arbotix-robot-controller-starter-kit.aspx

Or, you can get only the arbotiX controller: http://www.trossenrobotics.com/p/arbotix-robot-controller.aspx or the Mini Robocontroller: http://www.trossenrobotics.com/p/mini-robot-controller.aspx

You can get the arduino library from here: http://code.google.com/p/robocontroller/

Another neat thing is the ArbotiX Commander, a xbee based gamepad style remote controller:
http://www.trossenrobotics.com/p/arbotix-commander-gamepad.aspx

[RoboChan]

The arbotiX Robocontroller Starter Kit is very cool.

As soon as i sell my fish tank i will start getting parts.

I think i am going to build a mini sumo robot for the 2011 http://www.nationalroboticschallenge.org/ and learn to program and if that works out hopfuly i will have some more money and build from there. I think i am going to use a  Seeeduino MEGA or something like that. I would like to use a sharp ir and hs311 servo like STAMPY and add 2 photoresistors to stay in the ring. As for movement i would like to use a DFRobot 4.8-46V, 2A Dual Motor Controller and my motors i have.

This seems like a good project to me but i always change what i want to do.