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About to begin robotics

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  • Duane DegnDuane Degn Posts: 10,494
    edited 2014-04-29 14:44
    whiteoxe wrote: »
    But it makes me wonder why if IR can sense distance to a wall why does it need to bump into it anyway ?

    It was to demonstrate the robot learning to avoid bumping into things on its own. The robot didn't know which IR sensor pointed which direction.

    It was more of a theoretical machine learning experiment rather than an attempt to program a robot that was good at avoiding obstacles.

    I think it's a very cool idea but I'm not sure how practical it is.
  • whiteoxewhiteoxe Posts: 794
    edited 2014-04-29 14:46
    I just compared continuous rotation servos on this site with the biggest electronic hobbyist site in Australia and Parallax was around $16.00 and Aussie Jaycar was $29. you blokes have it good :)
  • whiteoxewhiteoxe Posts: 794
    edited 2014-04-29 14:53
    erco wrote: »

    yes great , they don't post to Australia ... so ill get them to send it to my brother stationed in Mongolia for the time being :) haaaa
  • Duane DegnDuane Degn Posts: 10,494
    edited 2014-04-29 14:57
    whiteoxe wrote: »
    I just compared continuous rotation servos on this site with the biggest electronic hobbyist site in Australia and Parallax was around $16.00 and Aussie Jaycar was $29. you blokes have it good :)

    Continuous rotation servos have only recently (as far as I'm aware) been available for sale (the ones with the BOE-Bot were probably one of the first available to purchase already converted to CR). Back in the good old days, the only way you were able to get a CR servo was to make it yourself.

    Many servos are really easy to modify to CR. Some are not so easy and some don't have a full gear and can't be make into a CR servo.

    There are lots of directions on the internet how to modify a servo to CR.
  • whiteoxewhiteoxe Posts: 794
    edited 2014-04-29 15:24
    Can you tell me whats the diff between the proximity sensor and the IR ? ps. Duane, are you having a late night, its 8:30am here :)
  • whiteoxewhiteoxe Posts: 794
    edited 2014-04-29 16:19
    Another post about servos and vs DC motors... this is because i have a couple of unused dc motors that would drive a platform. I looked up the
    HB-25 Motor Controller($49) and it was pretty expensive especially if i need two. I think many of you probably make your own motor controllers ? but even so, the Continuous servo motors would have to be superior for lots of platforms because they would more easily keep track of rotations ?
  • Duane DegnDuane Degn Posts: 10,494
    edited 2014-04-29 16:55
    whiteoxe wrote: »
    Another post about servos and vs DC motors... this is because i have a couple of unused dc motors that would drive a platform. I looked up the
    HB-25 Motor Controller($49) and it was pretty expensive especially if i need two. I think many of you probably make your own motor controllers ? but even so, the Continuous servo motors would have to be superior for lots of platforms because they would more easily keep track of rotations ?

    The HB-25 is for BIG motors. Small motors can be controlled with a chip like the L293 or SN754410.

    CR servo don't have position control. Instead of telling the servo which position to move to with a pulse, the pulse in a CR servo tells it how fast to turn.

    To find the position of a CR servo or a motor using a conventional h-bridge circuit you need encoders. Here's one of my attempts of adding encoders to a servo. It's of course much easier to add an encoder externally.

    CR servos are popular with hobby robotics because they're so easy to control. Just the single control wire. A h-bridge circuit usually requires at least two control lines per motor.
  • Duane DegnDuane Degn Posts: 10,494
    edited 2014-04-29 17:01
    whiteoxe wrote: »
    Can you tell me whats the diff between the proximity sensor and the IR ? ps. Duane, are you having a late night, its 8:30am here :)

    I'm not sure about your question. There are lots of different proximity sensors. Some proximity sensors use IR and there are several different ways the IR is used in proximity sensors. I didn't look carefully to see what type Jim the Hermit used.

    No, It's not late. It's presently 6:01 PM here. Dinner is smelling good.
  • whiteoxewhiteoxe Posts: 794
    edited 2014-04-29 18:02
    ok, so im going to need a h-bridge like you linked to and an encoder... im sure ill figure all that out, i have enough books here still not read to guide me :)
  • whiteoxewhiteoxe Posts: 794
    edited 2014-04-29 20:16
    erco wrote: »
    Great score for $20, whiteoxe. A Scribbler is perfect to jump into robotics and learn BS2 programming. Lots of sensors to keep you busy for a while, then when you're ready to hack it you can open the case and do your own thing. At $20, you can cut a few holes in the body and splice into a few wires without worrying too much. Keep the IR LEDs & receiver & speaker as-is. The "hacker port" gives you access to the 3 I/O pins to the red LEDs. IMO the 3 light sensors are the least useful and thus, first to go. You may or may not want to keep the line sensors.

    Plenty of info out there and in the forum. Hopefully you get all the documentation with your bot. See info.hobbyengineering.com/specs/PX-ScribblerHackHint.pdf

    Here's an article I wrote: http://www.botmag.com/index.php/take-charge-of-your-scribbler-robots-ir-capabilities

    tHANKS FOR THE GOOD LINK, IVE BEEN LOOKING AT DIFFERENT SENSORS FROM DIFFERENT WEBSITES, CAMERAS THAT CAN TELL COLOR dam caps lock sorr6y,, Have you seen avid on you tube of fantasic new robots that can play soccer, they are very humanoid but look around 10 inched tall. they were playing soccer and using a big red ball for the robots to chase ? They were great to watch, i would think you would be looking at many hundreds of dollars at least to buy one. When they fell over they used there arms and legs just like a human to stand again.
  • whiteoxewhiteoxe Posts: 794
    edited 2014-04-29 20:36
    The two types of distance sensors are linked here

    they to be be very different http://www.parallax.com/product/28015 utra sonic ping sensor no IR

    http://www.parallax.com/product/28995 ir sensor very cheap
  • whiteoxewhiteoxe Posts: 794
    edited 2014-04-29 21:57
    Duane Degn wrote: »
    The first link in post #10 leads to thread on how to make an inexpensive Propeller robot. One could get a Propeller robot up and running for about $50.

    Duane, i have the P8X32a quick START BOARD AND THE GADGET GANGSTER propeller platform , I think the gadget gangster board looks a lot friendlier ? Im off to buy some of that foam board to start cutting later this afternoon :)
  • whiteoxewhiteoxe Posts: 794
    edited 2014-05-01 15:22
    Duane Degn wrote: »
    I'm not sure about your question. There are lots of different proximity sensors. Some proximity sensors use IR and there are several different ways the IR is used in proximity sensors. I didn't look carefully to see what type Jim the Hermit used.

    No, It's not late. It's presently 6:01 PM here. Dinner is smelling good.

    Duane , I was looking at this to compare to an IR sensor ? --> http://www.parallax.com/product/28015

    But this could be interesting and quite cheap ---> http://www.parallax.com/product/28032
  • GenetixGenetix Posts: 1,547
    edited 2014-05-01 16:19
    The PIR is a passive device while the Ping))) is an active device. Also the PIR will only tell you something is there while the Ping))) will tell you its how big it is and how far it is.
    For a robot the Ping is the preferred device since you can use it similar to Radar. Here in the US, Radio Shack is selling the Ping))) for less than $10 if you can find one. I don't know about outside the US. The Ping))) also comes up occasionally as a Daily Deal.
  • whiteoxewhiteoxe Posts: 794
    edited 2014-05-01 16:41
    Thanks ! Good to know, Im wondering which type the Pain Robot with the BS2 had ?
  • ercoerco Posts: 20,009
    edited 2014-05-05 21:15
    whiteoxe wrote: »
    for $20 + a few bucks postage ill find out if i enjoy robots real cheap.
    whiteoxe wrote: »
    maybe if i find another $20 Scribbler I could put them in a room together and soon see who was a brave or cowardly robot

    I have bought several "previously owned" $20 Scribblers. Getting multiple bots to interact is a whole different programming experience.
  • whiteoxewhiteoxe Posts: 794
    edited 2014-05-05 21:42
    Im still smiling at getting the Scribbler for $20. It wasn't even used, i asked the seller if he had moved on to bigger and better but he told me he hadn't really found the time to use the robot. I've just put the basic stamp manual on my Kobo so ill be reading a lot more but I like the look of the graphical GUI to program it with. I've played with it without connecting the robot. I've got a bit going on so it will be another couple of days before i connect and program.

    There are a whole bunch of useful looking PDF's on the Scribbler CD, putting them on Kobo now.


    edit: This is almost funny, I gave my last computer away to a relative over 12 months ago. I just tried to plug in the Scribbler and realised that my computer does not have a serial port, i looked 4 times :) I run win 7 (and liux) so i rang the local pc parts shop UMART very good online ordering. I can get a serial port card with two serial ports on it not expensive at all , or could I get one of those things that plug into the USB and it then gives you a serial port connection. Forget about price, which way would you go ?
  • PublisonPublison Posts: 12,146
    edited 2014-05-06 07:57
    whiteoxe wrote: »
    I can get a serial port card with two serial ports on it not expensive at all , or could I get one of those things that plug into the USB and it then gives you a serial port connection. Forget about price, which way would you go ?

    I would go for the Parallax product, since it works, but shipping costs might influence the purchase in OZ.
  • ercoerco Posts: 20,009
    edited 2014-05-06 10:46
    Per Jim, a USB-serial adapter is the way to go. Many do not work with a BS2, so stick with a Parallax or FTDI-based adapter. Ebay's your friend. Are you Oz- or UK-based?
  • whiteoxewhiteoxe Posts: 794
    edited 2014-05-06 15:05
    Its OK, wonderful actually, but thanks for your replies. And I am OZ based, Queensland.

    I pulled out some storage boxes, some of the stuff I knew I had but some surprises... and found all the electronics i haven't given away to the Electronic club in the next suburb. Not a single LED, but props and boards with props, basic stamp, picaxe chips and boards, breadboards of all sizes, stacks of different coloured wires for using on breadboards and connectors, packets of resistors, smartcard reader and the cards from parallax a few other bits and pieces like battery boxes.

    Lastly I found a serial port card that is what had me worried yesterday. It should be fine.

    Thx for the advice anyway. Could still be handy.
  • whiteoxewhiteoxe Posts: 794
    edited 2014-05-06 15:16
    erco wrote: »
    I have bought several "previously owned" $20 Scribblers. Getting multiple bots to interact is a whole different programming experience.
    Kinda Funny :) I have a mean streak, I have one robot afraid and the other two chasing it down(just how to make the mean robots not get confused and chase each other i'm sure there's a fix for that :)
  • ercoerco Posts: 20,009
    edited 2014-05-06 19:31
    whiteoxe wrote: »
    Lastly I found a serial port card that is what had me worried yesterday. It should be fine.

    I'm interested to try one. It's worth $4 to see if it works. PCI slot based, 2 serial ports, claims Win7/8 compatibility:

    http://www.ebay.com/itm/2-Ports-PCI-to-COM-9-pin-Serial-Series-Port-RS232-Card-Adapter-/291084499518?pt=US_Internal_Port_Expansion_Cards&hash=item43c5fcfa3e
  • whiteoxewhiteoxe Posts: 794
    edited 2014-05-07 01:55
    erco, that looks exactly like what i have..... i'm pretty sure i got it over a year ago easily at the closest online store to me. i felt unwell today so was a good excuse not to pull apart my pc :)
  • ercoerco Posts: 20,009
    edited 2014-05-07 10:30
    I ordered one, but it won't be here for a while. Please report back when you find out how & if yours works, and include some details on your computer and OS. Obviously you have a desktop (are you and I the last ones?) with an empty PCI slot. This card clearly ain't an option for the laptop crowd.
  • whiteoxewhiteoxe Posts: 794
    edited 2014-05-07 19:20
    Im still under the weather a bit, but ill try to climb out of bed and install the card today and program the robot. Ill email you soon as its all working(or not)
  • whiteoxewhiteoxe Posts: 794
    edited 2014-05-08 02:07
    Its 7pm, im outa bed, I might open up the PC qand try out the serial ports before i go back to bed later tonight. Then in the morning ill let you know what happened !!!

    Have you ever used an Arduino ? Cause I was just offered one by a brother who has done a lot with his Raspberry Pi but isnt interested in the Arduio anymore. My home made robot will either be prop controlled or maybe even Arduino ?

    The reason being is that for both the prop and Arduino there is so much code already to download and use for sensors, motors ,whatever.

    The basic stamp homework board i could use but that is going to be harder to find code, there isn't any library's of basic stamp code are there ?
  • ercoerco Posts: 20,009
    edited 2014-05-08 16:44
    Prior to Arduino, the BS2 was probably the best-known processor around (hey, if you had one in storage, you should know that!) with tons of projects, code & documentation around, much provided in Parallax's own fine books, forum, and website. There are still lots of BS2 resources available, though probably not as well-organized as the Object Exchange.
  • GenetixGenetix Posts: 1,547
    edited 2014-05-08 17:47
    There is plenty of code as well as a number of accessories for the Boe-Bot which uses a BS2. Robotics with the Boe-Bot has all the code you need to get started using the BS2.
    Parallax has an Arduino shield for the Boe-Bot or you can use the Propeller Activity Board on the Boe-Bot.

    The BS2 and Propeller have been around for years and won't disappear anytime soon.
  • whiteoxewhiteoxe Posts: 794
    edited 2014-05-08 22:52
    Hi erco, I've been slack last night and busy today, dad was back from a golfing holiday in america and the folks visited me as I was trying to figure out how to undo this newfangled case. its only got one slot on the outside of the case left to add another card. I hope wheni get it open there is room with all the other card i have in it such as graphics cards and WiFi.but really with both win 7 and liux it should act just as if it came with a serial port. but then there is i guess a small chance it might not. and thanks for the instruction about all the BS2 support.
  • whiteoxewhiteoxe Posts: 794
    edited 2014-05-09 22:14
    Gidday Erco !, I am writing because I was going through some unopened packets I got from Parallax long ago without opening. Found just a couple more things. A packet containing a Propeller DIP Plus kitsome almost clear packet contains LEDS, digital number readout resistors and other parts I cant make out, obviously a parallax kit of some sort, might have a prop in there for all i know, ive got enough going on without wanting to open it now.

    I haven't put the serial card in which I was going to do today but I have programmed the Scribbler and got it going forwards,backwards and going in circles, which made me very happy I am not hard to please, was great to see it finally do something!!!!

    There was also a #28030 Parallax USB to Serial Adapter which i cut open plugged in and watched it install itself on Win 7 PC, I immediately connected the Scribbler and used the 64 bit GUI that one where you use the pictures to program it :) . So Im putting the screws back in the PC case and ain't in any hurry to install that card anymore. I must have spent a fortune at some point. I guess a plus here is that I can now also use my laptop.

    I don't know why I bought a Gadget Gangster prop platform and a Prop Quick Start card, and Prop DIP Kit, I must have had bigger plans at the time or just wanted to buy stuff :) I should have just purchased a prop homework board but I'm not complaining. The last thing I did with the Gangster was connect a nokia phone screen to it to display text. That screen will be here too probably.

    But the best part of it all was watching the Scribbler run about(even if it looked very confused) because I read nothing on how to use the tool I just played with it and placed commands there very randomly.
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