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I've got my Boe-Bot! — Parallax Forums

I've got my Boe-Bot!

The_N3rdThe_N3rd Posts: 34
edited 2005-04-07 19:55 in BASIC Stamp
···· Hi, everybody!· I finally found some time to post a new thread.· As you know, I have had my boe bot for a couple weeks now, and have been having fun with it.· It's been like Christmas around here.· First I got my boe bot along with an accelerometer, I also got a SSIR module, and a video module.· I can't say thanks enough to everyone who has supported me.
···· I've been experimenting with programs, running some·neat circuits, and just having a lot of fun.· I can't remember many questions right now, but there were a few things·I wasn't sure about.· I want to try to hook it up to things around the house,·but I really don't feel like frying the stamp.· How much power can I let the stamp handle (high and low pulses), and what could be some things to try to hook it up to?· Can I hook the stamp up to electric motors·found in·remote control cars, or do they pull to much current?· I guess I want to know·to what extent the BS2 can go to.
·························· turn.gif



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the NERD, Kelie B.

Post Edited (Nerdy NASA boy) : 3/30/2005 1:01:05 AM GMT

Comments

  • JonbJonb Posts: 146
    edited 2005-03-30 01:03
    You really want to be carefull what you connect the stamp to. You could however run a small dc motor through a FET/transistor/relay rated for the amperage the motor draws. I use the L298 for driving motors, which allows forward reverse and variable speed. This is called an H-bridge driver. Run a google search you'll find alot of info and pre-made boards for controlling DC brushed motors. If you've noticed, servos are driven from the power supply, and not the stamp. The stamp provides the PMW signal needed to position the servo or in the boe's case direction and speed of rotation.

    General rule though, dont drive loads directly from the stamp. Some people even avoid running LEDs directly from stamps or for that matter any microcontroller. Better safe then sorry.
  • BeanBean Posts: 8,129
    edited 2005-03-30 01:47
    Kelie,
    Boards like the homework have 220 ohm resistors in series with all the I/O pins. This is a good idea when your starting out because it keep the amount of power drawn from the stamp to a safe level. Till you are more familar with the stamp I would recommend putting a 220 ohm (RED RED BROWN) resistor between the stamp I/O pins and anything you are trying to control.

    Bean.

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    "SX-Video Display Module" Available Now.

    www.sxvm.com

    "A problem well defined, is a problem·half solved."
    ·
  • The_N3rdThe_N3rd Posts: 34
    edited 2005-03-30 23:13
    ·
    · Hi!· ·I think that I will go with transistors or FETs. I know that I should know this, but I don't know exactly how to identify transistors and put them into a circuit.·I do·understand how they work, but I don't know how to hook them up to the stamp.·Could I have some suggestions?
    ········································ confused.gif

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    the NERD, Kelie B.


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    · "The current scenario of the origin of life is about as likely as the assemblage of a 747 by a tornado whirling through a junkyard."
  • Paul BakerPaul Baker Posts: 6,351
    edited 2005-03-30 23:34
    Take a look at this thread: http://forums.parallax.com/showthread.php?p=521472 replace the motor with whatever your trying to control. You may need to add a resistor inline with your load to control the current flowing through it.
  • The Dead BugThe Dead Bug Posts: 73
    edited 2005-03-30 23:52
    Kelie, go to Parallax.com and under "Stamp Documentation" find "Stamps in class tutorials". There you can download the "What's a Microcontroller" text. This is THE BIBLE that every budding Stamper needs to go through to really learn the system. Here is what is listed on page 265:

    trans.jpg

    It may keep you busy for a week or two, but it will equip you to do so much. It will answer many questions beginners in electronics have. Also you are welcome to check out my blog! [noparse]:)[/noparse] </shameless>

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    Name: Bruce Clemens

    Work:· Clemensb@otc.edu
    Good Stuff on my Blog: http://theDeadBug.journalspace.com
  • The_N3rdThe_N3rd Posts: 34
    edited 2005-03-31 01:19
    I was wondering, where should I get some transistors? I've got a few from an old electronics project lab, but not shure what kind they are.

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    the NERD, Kelie B.


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    · "The current scenario of the origin of life is about as likely as the assemblage of a 747 by a tornado whirling through a junkyard."
  • The Dead BugThe Dead Bug Posts: 73
    edited 2005-03-31 01:37
    I'm sure your local radio shack (yucch) still sells 2n2222 and 2n3904.

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    Name: Bruce Clemens

    Work:· Clemensb@otc.edu
    Good Stuff on my Blog: http://theDeadBug.journalspace.com
  • The_N3rdThe_N3rd Posts: 34
    edited 2005-03-31 01:44
    We stoped at radio shack the other day, but it was one of the small ones that had practically nothing for the hobbyist. I supose I'll have to go to the other one sometime.
    By the way you're website is cool! I'm working on one right now, but I have not touched it ever since I got my robot! I guess that I'm too busy now.

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    the NERD, Kelie B.


    ·· =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=

    · "The current scenario of the origin of life is about as likely as the assemblage of a 747 by a tornado whirling through a junkyard."
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-03-31 03:54
    Nerdy NASA boy said...
    We stoped at radio shack the other day, but it was one of the small ones that had practically nothing for the hobbyist.
    Kelie,

    ·· I once stopped at a small Radio Shack, only to be told by the Salesman that they didn't stock that kind of stuff there.· I decided to look around anyway.· Eventually I came across this 10 drawer metal cabinet thing built into the wall.· I read the front and the drawers were labeled, "Resistors," "Capacitors," etc.· Eventually I realized there was a Catalog/Guide above the thing that was laying down.· I read it and it told me the drawer that the part I needed was in.· You should've seen the look on the salesman's face when I walked up to the counter with the part he said they didn't carry.

    ·· The point is, they often don't even know what they have.· Sometimes you gotta look around.· I have also found in some Radio Shacks, "Surprise Grab bags," chocked FULL of components worth much more than the $5.00 to $15.00 that they were marked.· I suppose most Radio Shack stores don't do this.· But I have often seen clearance tables, also stocked with goodies the average non-nerd wouldn't know what to do with, but that is Gold to us nerds.· smilewinkgrin.gif

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • The Dead BugThe Dead Bug Posts: 73
    edited 2005-03-31 04:16
    Hence one of the first posts on my blog: Radio Shack Sucks...
    thedeadbug.journalspace.com/?entryid=5
    Bruce

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    Name: Bruce Clemens

    Work:· Clemensb@otc.edu
    Good Stuff on my Blog: http://theDeadBug.journalspace.com
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-03-31 06:14
    Bruce,

    ·· You have to give Radio Shack credit for trying to get electronics parts and more diverse items, like robotics into most of the stores,· Remember, you can't blame the store for the employees who don't care about their jobs.· That's what I think I see...I still shop there for things I need in a hurry.· Heck, I recently bought a pair of SONY Bookshelf speakers there.· They were cheaper than Circuit City, Best Buy, etc.



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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • The Dead BugThe Dead Bug Posts: 73
    edited 2005-03-31 16:09
    Yes, Chris, you are right. At least some stores do have some things, and·I need to take the "glass half full" approach.

    I worked at a Radio Shack while in college, and I have seen the decline. It simply frustrates me·that the company has clearly abdicated on the original idea of being an electronics do-it-yourselfer's supplier. Granted there is much more money to be made in selling cell phone plans and digital TV, but if you are going to have parts, at least try to educate your staff in what they are...

    I live in the third largest city in Missouri. There used to be several places in town·where·I could walk in and buy electronics components from (at least semi-) knowlegable staff. Now Radio Shack is all that is left. My bachelors degree is in business management, so·I do understand that RS is simply reacting to the market, and the other electronics companies that are now gone didn't. I guess I don't blame RS, I just sort of lement that they haven't developed what could be a neich (sp?)·market for them now.

    They are a big enough company that they could do that even if it is not a huge profit center for them. As for now, I'll just do all my electronics shopping on the web...I do love seeing that Fed-Ex truck pull up [noparse]:)[/noparse]

    Bruce

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    Name: Bruce Clemens

    Work:· Clemensb@otc.edu
    Good Stuff on my Blog: http://theDeadBug.journalspace.com
  • Beau SchwabeBeau Schwabe Posts: 6,557
    edited 2005-03-31 16:45
    Dead Bug,

    We have something in common..... I to many many moons ago worked at a Radio Shack and have seen the same decline, although when I was there we were just making the
    transition to electronically process credit cards rather than paper slips and carbon copies. (grin) When I first applied at Radio Shack, I remember going into a room with about
    15 other applicants, where they drilled us on math skills, electronic skills, etc. I seriously doubt that they do this anymore, at least to the degree they used to. I believe this
    to be part of the decline. I understand that Radio Shack simply reacts to the market... ( The sole drive behind the name/number/address campaign that people hate ) ...but
    if you do not have any intelligence behind your stock selection other than market driven reaction, eventually you end up with many "pieces" of products that are useless without
    the whole which end up collecting dust and are discontinued and placed in a grab bag. For example I might "need" a specific component and find that item just fine at
    Radio Shack, but because I can't find another component that should work with the specific component I would drop the component that I was able to find. A purely market
    driven economy would dictate that eventually the component that I was able to find would be eliminated.

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    Beau Schwabe - Mask Designer III

    National Semiconductor Corporation
    Latest Company News
    (Communication Interface Division)
    500 Pinnacle Court, Suite 525
    Mail Stop GA1
    Norcross,GA 30071
  • Paul BakerPaul Baker Posts: 6,351
    edited 2005-03-31 17:56
    Kelie, I have used www.radioshack.com several times to locate a nearby store that has what I want in stock. For instance, going to thier online section for transistor and analog components: http://www.radioshack.com/category.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F011%5F002%5F017%5F000&Page=1

    then clicking on the 15 NPN transistors (#276-1617) http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F011%5F002%5F017%5F000&product%5Fid=276%2D1617#

    then clicking on "In store: Check availibility" and my zip code (22303) shows there are 10 Radio Shacks within 5 miles that have it stocked.

    Now Radio Shacks are notorious for not maintaining proper inventory of thier components, so it is a definate possibility that they don't actually have it in stock, but if you find that out, have the salesperson call the other area Radio Shacks to have them do an in store inventory check, then go there. I've found many salespeople will not physically check the stock if you call, but rather look in their computer inventory, which is frequently off, but if you have another RS sales person ask for a manual stock check they'll do it, if you ask them to. I typically say something like "Can you have them manually check the stock? Radioshack.com said you guys would have it and you don't,·I don't want to run over there and find thier computer inventory is wrong too"
  • steve_bsteve_b Posts: 1,563
    edited 2005-03-31 20:55
    A lot of RS's up here in Canada are getting out of the 'component carrying' business! To be honest....they do charge a lot and most ppl are finded surplus shops to get their goods at! RS might be good for single items...but if you are going to buy parts....buy bulk! I don't buy less than a hundred resistors at a time from electrosonic or digikey or whomever!
    BUT....the nice part of RS's up here dropping the electronic components....grab bags galore! Some junk but some good stuff!! OF course, I've got too many misc bags of old caps and inductors/chokes...that I really don't know what to do with them! lol

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    ·

    Steve
    http://ca.geocities.com/steve.brady@rogers.com/index.html
    "Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
  • Paul BakerPaul Baker Posts: 6,351
    edited 2005-03-31 21:04
    In general if you picking up more than ~$20 worth of components it is better to buy online, otherwise the ~$5 shipping and handling charge doesn't make it worthwhile, though if thats the only source it may be your only option. A few months ago I was looking for a 74LVS1G57, a configurable single gate. NewarkInOne was the only source I could find and the shipping was just over $7 for a $0.40 part, I picked up 20 of them just to make the overhead cost worth it.

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  • The_N3rdThe_N3rd Posts: 34
    edited 2005-04-02 18:06
    ·I'm finally on spring break!· A week of free time to mess around with my bot.· I can’t believe the big discussion about radio shack that I started.· I wonder what would happen if I asked which microcontroler is the best.· Well, anyway, when I went to the radio shack down the road, I wasn’t joking, they had almost nothing.· I stayed there probably 20 minutes trying to find a couple things like transistors and capacitors.· Like Chris said·Eventually I came across this 10 drawer metal cabinet thing built into the wall.· I read the front and the drawers were labeled, "Resistors," "Capacitors," etc.”· I too looked in those drawers, but still there was very little of anything.· There were also things in there that should have been in another drawer.· Anyway, when I stopped in there the guy said that I could have them order parts that I needed, and that’s probably what I'll do.··Like I was told, I downloaded the “What is a Microcontroler”·pdf,·and·once I get those transistors, and some other parts I don’t have, I'll start experimenting.·

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    the NERD, Kelie B.


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    · "The current scenario of the origin of life is about as likely as the assemblage of a 747 by a tornado whirling through a junkyard."
  • Beau SchwabeBeau Schwabe Posts: 6,557
    edited 2005-04-02 20:52
    Kelie,

    "...the guy said that I could have them order parts that I needed" Instead of going to the trouble of ordering through a Third party
    in this case Radio Shack.... See if you can find what you are looking for through Mouser or DigiKey you might find that they are
    cheaper than Radio Shack anyway.



    I think that my last straw with Radio Shack was when I bought a toggle switch for something, and the guy asked me if I could
    accessorize that with a cell-phone. I really did not know how to respond to this poor sole behind the counter in a way that I thought
    would make sense to him. Monkeys I tell you nothing but Monkeys!

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    Beau Schwabe - Mask Designer III

    National Semiconductor Corporation
    Latest Company News
    (Communication Interface Division)
    500 Pinnacle Court, Suite 525
    Mail Stop GA1
    Norcross,GA 30071
  • BeanBean Posts: 8,129
    edited 2005-04-02 22:13
    I agree, I think RS really started going downhill as soon as the started selling cell phone plans.

    Who remembers the old "Free battery of the month" program they used to have.
    You used to get those red zinc carbon batteries.

    Bean.

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    "SX-Video Display Module" Available Now.

    www.sxvm.com

    "A problem well defined, is a problem·half solved."
    ·
  • The Dead BugThe Dead Bug Posts: 73
    edited 2005-04-03 00:33
    I remember that, Bean, they had the battery plan going when I worked there. Incidently, the week I started working at RS was the week they got in their first TRS 80.
    Fresh from the electronics program at Cal Poly, I was thrilled. But the manager and the stereo-pushers just stared at it wondering what to do with it!

    Another scheme the RS I worked at used was the promise that "If you give us your name and address, you'll be entered into a monthly drawing for this great AM FM radio!". Of course in my first 6 months I worked there, we never had a drawing. Only after I confronted my manager and told him that I would no longer ask for names and addresses under false pretenses, did he tell me to grab some receipt out of the back of my receipt book and contact them to get their &*$! radio.

    Bruce

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Name: Bruce Clemens

    Work:· Clemensb@otc.edu
    Good Stuff on my Blog: http://theDeadBug.journalspace.com
  • The_N3rdThe_N3rd Posts: 34
    edited 2005-04-07 17:47
    Sorry that I haven't replied for so long, I've been earning some money lately.
    Remember how I became interested in basic stamps? I borrowed a book about building battlebots, and it talked about basic stamps.· But before I was interested in stamps me and a couple of friends wanted to (and still do) build a battlebot. Well, the other day, we stopped at Jade's (a machine shop down the road) and I mentioned battlebots.· He said he had some DC motors somewhere.· he dug some stuff out, and gave me this big 5-10 pound motor that came out of a HUGE servo.· I turns out that it has a TON of torque, but is fairly low speed.· He also found a box of stepper motors.· Eight of them have four wires, and two of them have six wires.· These things are fairly big (a couple inches in diameter) and are obviously DC.·
    The two small ones are 33 ohms, 42v, and moves 1.8 degrees a step.· The eight big ones are 1.1 ohms, not sure how many volts, and move 1.8 degrees a step.
    I was wondering how I could use the stamp to control them?·Any good links?
    ··Once I get to radioshack I can·finally get some stuff that I need.· I think that·I am going to build a nice sized H-bridge to try and control that big·servo motor I got from Jade.·
    ······ Thanks

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    the NERD, Kelie B.


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    · "The current scenario of the origin of life is about as likely as the assemblage of a 747 by a tornado whirling through a junkyard."
  • Paul BakerPaul Baker Posts: 6,351
    edited 2005-04-07 19:55
    Kelie,

    Congrats on your surplus find. If the big motor is indeed servo, then no H Bridge is required. The revolution is dictated by the PWM signal you send to the servo. If its a straight DC motor then an H-bridge would be a benefit. WRT the stepper motors, your 6 lead motors will likely be unipolar and your 4 lead motors will likely be bipolar. Heres a link that describes the two and the signals required to run them: http://www.cs.uiowa.edu/~jones/step/types.html·(general home page is http://www.cs.uiowa.edu/~jones/step/·)
    The Bipolar will require an H-Bridge to control the windings, the Unipolar doesn't.

    Many people opt for getting a controller board for stepper motors, though you will likely gain more knowledge if you do it yourself, just remember to isolate your outputs (like discussed in previous posts above)·to prevent heavy loads from zapping your stamp (an Hbridge will provide you the isolation required, just remember to isolate when your driving the unipolar).

    PS be sure to read http://www.cs.uiowa.edu/~jones/step/circuits.html·for ideas on driver circuits, for unipolar they suggest using a darlington array, for the bipolar they suggest forming an H bridge around a 74LS125 or 244 (among other suggestions such as dedicated Hbridge cips)

    Post Edited (Paul Baker) : 4/7/2005 8:05:27 PM GMT
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