Forum Update - Announcement about May 10th, 2018 update and your password.

Motor won't spin! Help!

Hey, everyone!

I have a question. I can't make a regular motor run in the Propeller chip (I have the Activitybot). What I want the robot to do, after detecting heat, is make him blow out a candle with some fan blades that I will put on the motor. I can't make it spin without connecting it to a direct output which pulls power away from the other devices even when I connect it to a 3.5 volt output. I figured out how to make the IR sensor detect heat, so I'm using the IR sensor for heat detection. :)

P.S. I am new to the forums.

Comments

  • 24 Comments sorted by Date Added Votes
  • Welcome to the forums, Chip!

    Tell us more about your fan motor, i.e. what voltage is it designed to run on; how much current does it draw?

    -Phil
    “Perfection is achieved not when there is nothing more to add, but when there is nothing left to take away. -Antoine de Saint-Exupery
  • Just about any motor large enough to spin a fan for blowing out a candle will draw too much current from the Propeller's I/O pins. You could certainly rig something using a transistor, and this will be the least expensive method. You can find basic connections with any Web search, including past posts here.

    If you're looking for something quicker, the single-relay module will about do the trick:

    https://www.parallax.com/product/27115

    You can probably use one of the unused servo header pins on the Activity Board. Set the power jumper to 5V.
  • Just about any motor large enough to spin a fan for blowing out a candle will draw too much current from the Propeller's I/O pins. You could certainly rig something using a transistor, and this will be the least expensive method. You can find basic connections with any Web search, including past posts here.

    If you're looking for something quicker, the single-relay module will about do the trick:

    https://www.parallax.com/product/27115

    You can probably use one of the unused servo header pins on the Activity Board. Set the power jumper to 5V.

    Well, I don't know about the idea for the I/O pins because it is a two-pin motor which is why I hooked it up to a 3.5V output. Should I post a pic of the motor?
  • Welcome to the forums, Chip!

    Tell us more about your fan motor, i.e. what voltage is it designed to run on; how much current does it draw?

    -Phil

    I don't exactly know how much voltage it draws. I guess it varies with however much voltage you put to it. Would a picture of it help?

    And, thanks for the welcome!
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 21,925
    edited April 24 Vote Up0Vote Down
    What kind of fan is it? If it's a computer vent fan, it probably runs on 12V. Yes, post a picture of it, please.

    In any event, you will not be able to drive it directly from a Propeller pin. As Gordon suggests, you will need a transistor driver.

    -Phil
    “Perfection is achieved not when there is nothing more to add, but when there is nothing left to take away. -Antoine de Saint-Exupery
  • What kind of fan is it? If it's a computer vent fan, it probably runs on 12V. Yes, post a picture of it, please.

    In any event, you will not be able to drive it directly from a Propeller pin. As Gordon suggests, you will need a transistor driver.

    -Phil

    Here's a photo. Please note: I put the solid core wires on myself.
    1920 x 1280 - 1M
  • 1. Can you measure the resistance between the leads?

    2. Does it run fast enough when you connect it directly to the 3.3V power supply?

    3. If not, how about 5V? (It may actually be a 1.5V motor.)

    4. Is there anything printed on the motor to give you a clue as to its ratings?

    -Phil
    “Perfection is achieved not when there is nothing more to add, but when there is nothing left to take away. -Antoine de Saint-Exupery
  • Chip_McCallahanChip_McCallahan Posts: 10
    edited April 24 Vote Up0Vote Down
    1. Can you measure the resistance between the leads?

    2. Does it run fast enough when you connect it directly to the 3.3V power supply?

    3. If not, how about 5V? (It may actually be a 1.5V motor.)

    4. Is there anything printed on the motor to give you a clue as to its ratings?

    -Phil

    I just checked the motor. I can't find any mark on it that will give me any idea. I think I said that I hooked it up to a 3.3 volt output (I may have said 3.5, but I meant 3.3) and it drained power away from the other devices.

    Yes, I would say it runs fast enough when connected to a 3.3 volt output, but, like I said, it drains the power from other things, so I don't know what to do.

    The resistance is about 2.6 ohms.
  • ercoerco Posts: 19,149
    edited April 25 Vote Up0Vote Down
    Probably a 3-6V motor. Per others' comments, your Propeller board will need a transistor switch and/or relay to get your motor runnin'. That's as easy as it gets, you just need on/off, no reverse or speed control.



    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • erco wrote: »
    Probably a 3-6V motor. Per others' comments, your Propeller board will need a transistor switch and/or relay to get your motor runnin'. That's as easy as it gets, you just need on/off, no reverse or speed control.



    Thanks, but how do I control the on/off and where do I wire the transistor switch?
  • If you have no experience in electronics a transistor circuit may be frustrating. To most of us here it's a simple 5 minute circuit, but you'll need to collect several components -- at a minimum transistor, one or two resistors, a diode. This is why I suggested the relay. The documentation shows how to activate it. (It's for a BASIC Stamp, but the Propeller is basically the same.)

    If you really, really want to use the transistor, know that Google is your friend. Type in a search like 'turn motor on with a transistor' and read the pages and look at the images.

    There might be some diagrams here but not all of the images are working right in the forum. Lots of stuff missing. No matter; this is a small piece of the Internet.

    On the voltage to use: you probably know you want a very strong gust of wind to blow out the candle. Even if it's a 1.5V or 3V motor, hitting it with 5V for a second will cause no harm to the motor, but ought to extinguish the flame, assuming the fan is in front of it.
  • ercoerco Posts: 19,149
    Gordon McComb. Fanning the flames of robotics for over 30 years!

    (Psssssst: Hey Chip: You're getting tips from the Master: Gordon is a bestselling author of more than 65 books and thousands of magazine articles.)

    We're all GMc fanboys here. :)

    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • If you have no experience in electronics a transistor circuit may be frustrating. To most of us here it's a simple 5 minute circuit, but you'll need to collect several components -- at a minimum transistor, one or two resistors, a diode. This is why I suggested the relay. The documentation shows how to activate it. (It's for a BASIC Stamp, but the Propeller is basically the same.)

    If you really, really want to use the transistor, know that Google is your friend. Type in a search like 'turn motor on with a transistor' and read the pages and look at the images.

    There might be some diagrams here but not all of the images are working right in the forum. Lots of stuff missing. No matter; this is a small piece of the Internet.

    On the voltage to use: you probably know you want a very strong gust of wind to blow out the candle. Even if it's a 1.5V or 3V motor, hitting it with 5V for a second will cause no harm to the motor, but ought to extinguish the flame, assuming the fan is in front of it.

    I have had experience with electronics, so this should not be too much trouble. I have actually put 3 volts to the motor and it spun fast enough to extinguish the candle.
  • ercoerco Posts: 19,149
    For simplicity and bang for the buck, grab a few of these relay modules for 77 cents each: https://www.ebay.com/itm/5V-1-Channel-Relay-Board-Module-Optocoupler-LED-For-Arduino-PIC-ARM-AVR-HF/382438731142

    Relay needs 5V, which may as well be your fan voltage too. Provides complete isolation between micro and switched power, you could control some big stuff with this setup.
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Relays are good. Nice and safe with the optocoupler.

    I wonder if they have any DPDT relays? Would be handy for motor control.
  • Any idea how long the motor would need to run?

    If it doesn't need to run for long then why not have a large capacitor always charging and run the motor off it when needed.
  • ercoerco Posts: 19,149
    Relays are good. Nice and safe with the optocoupler.

    I wonder if they have any DPDT relays? Would be handy for motor control.

    Totally agree, but have only ever seen SPDT relays on these cheapie 5V modules, anyway. Good enough for on/off in this application.

    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • ercoerco Posts: 19,149
    See also https://forums.parallax.com/discussion/comment/1436752 for a 77_cent solution which is cheaper & better than a relay.
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Thanks for the help, everybody! I also got a suggestion for a torroidal vortex. The problem I have with that is that it might block the ultrasonic sensors. Is there any way that I can re-position the source for the vortex (it's made out of a soup can)?
  • Chip_McCallahan,

    Look at one of Erco's infamous flamethrowers which use a servo to press down the button of an aerosol can.

    You could use a can of air as a fire extinguisher.
  • ercoerco Posts: 19,149
    Torroidal vortex?

    For a candle flame, an air cannon can giveth life, and also taketh away.

    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Genetix wrote: »
    Chip_McCallahan,

    Look at one of Erco's infamous flamethrowers which use a servo to press down the button of an aerosol can.

    You could use a can of air as a fire extinguisher.

    There's a thought. If I can't get the motor to work, I might be able to try that. Thanks!
    erco wrote: »
    Torroidal vortex?

    For a candle flame, an air cannon can giveth life, and also taketh away.


    Well, I got a suggestion from my dad about how to throw the smoke ring. Have a servo push a spring-loaded rod down and when the servo arm goes past the point of the rod that's being pressed, then it should fly up and hit the elastic covering for the cannon, therefore making a torroidal vortex.
  • Genetix wrote: »
    You could use a can of air as a fire extinguisher.

    There's a thought. If I can't get the motor to work, I might be able to try that. Thanks!

    If this project follows the basic Trinity robotic fire fighting rules, you get extra points for using a small CO2 canister or other non-air means of extinguishing the candle. Water works too. The rules book points out fighting fires with air isn't really practical in the real world, and they reward robots that use a more realistic approach.

  • Genetix wrote: »
    You could use a can of air as a fire extinguisher.

    There's a thought. If I can't get the motor to work, I might be able to try that. Thanks!

    If this project follows the basic Trinity robotic fire fighting rules, you get extra points for using a small CO2 canister or other non-air means of extinguishing the candle. Water works too. The rules book points out fighting fires with air isn't really practical in the real world, and they reward robots that use a more realistic approach.

    I actually got the inspiration to do this from a Servo magazine. There was an article about this that said almost exactly the same thing you said. I just decided to use air to do this which is why I posted this discussion about not being able to get a motor to spin. I don't know if I said this before, but I'm doing this for a 4-H project.
Sign In or Register to comment.