The ULN2003 chip on that driver board can handle up to 50V so you will not fry the chip with 12V. You might fry the chip by drawing too much current so make sure the motor you connect to it will not draw more current than the chip can handle. The jumper is probably there to provide the correct current limiting resistors for the leds at 5 and 12 volts.
My steppers arrived today and I quickly tested them at 5 volts. They work well enough, but don't have a whole lot of torque. I'm not sure what I will do with them, but I will think of something.
One technique to increase torque is to momentarily switch to a higher voltage at the beginning of each step. Okidata printers used 5V steppers and a switched 35V supply to do this. A blocking diode on each supply and a transistor to turn on the high voltage is all that is required.
My steppers arrived today and I quickly tested them at 5 volts. They work well enough, but don't have a whole lot of torque. I'm not sure what I will do with them, but I will think of something.
My steppers arrived today and I quickly tested them at 5 volts. They work well enough, but don't have a whole lot of torque. I'm not sure what I will do with them, but I will think of something.
Actually, I found them to be slow but torquey for such a little part, and running off 4 AA batteries. They will be a pretty good match for an erco bot, or the Little Robot (tm). If fact, they might be OK for a Jamie Mantzel spider tank.
I debated stocking these as the way these arrived from China didn't impress me.
After giving them a good check and repackaging them the way I would have preferred to receive them, I've put them in stock. They'll cost you more than $3.00, but will be shipped from here in Ohio. (Hit the "propellerpowered" link in the signature)
I debated stocking these as the way these arrived from China didn't impress me.
After giving them a good check and repackaging them the way I would have preferred to receive them, I've put them in stock. They'll cost you more than $3.00, but will be shipped from here in Ohio. (Hit the "propellerpowered" link in the signature)
Jeff
if i may suggest, bundle these as:
two of the cheap steppers
one of the cheap ultrasonic rangefinder
one of the cheap blue tooth
this is the exact BOM for the LittleRobot(tm) project.
at least two schools have asked where to get the package, and are hesitant to order from china
could you get by if you charge only $20 for such a bundle?
That's a great idea! It's hard to keep those bluetooth modules in stock as they sell almost as fast as I can get them, but you are right, this would make a great bundle. I will pursue this..
That's a great idea! It's hard to keep those bluetooth modules in stock as they sell almost as fast as I can get them, but you are right, this would make a great bundle. I will pursue this..
Jeff
one more item in the bundle:
the small assortment of colorful jumper wires with pins and sockets. or maybe a second bundle of just jumpers and a bread board. this combo helps a lot when i am messing with the steppers and quickstart
I bought 2 of these, they work fine. Now I'm wondering what I can do with them... I'm new to robotics, but familar with the Propeller.
I'm asking for some advice on where to buy gears, wheels, mounting hardware, etc. to experiment with these motors. I've tried Googling, but apparently I can't come up with the approprate search terms. I know they have 5mm shafts, and I can find couplers and mounting hubs, but (so far) nothing like the gears in this video.
I'm asking for some advice on where to buy gears, wheels, mounting hardware, etc. to experiment with these motors. I've tried Googling, but apparently I can't come up with the approprate search terms. I know they have 5mm shafts, and I can find couplers and mounting hubs, but (so far) nothing like the gears in this video.
Could you get a 3D printer and make your own gears & stuff?
Harbor Freight Tools 20% off coupons (for casters, etc.)... check.
Nuts, bolts, screws, batteries, wire... check.
Bandages... check.
Sensor & bluetooth modules... on order.
Many thanks for the info... looking forward to making my own robot.
Somewhat ironic note: I'll get to finally play with Forth... which was originally implemented on an IBM 1130... which I'm emulating (almost) with a Propeller.
I used erco's code in post #14 and it seems the steppers have good torque going clockwise (looking at the end of the shaft), but easily slip and quit turning going counter clockwise.
I used erco's code in post #14 and it seems the steppers have good torque going clockwise (looking at the end of the shaft), but easily slip and quit turning going counter clockwise.
Both of my steppers act the same.
Has anyone else noticed this??
I have been experimenting with both propeller and picaxe code routines and the error you describe above only happens when i wind up the speed, the coils need a certain pull in time...
Try increasing the delay between successive coil activations .....
I have been experimenting with both propeller and picaxe code routines and the error you describe above only happens when i wind up the speed, the coils need a certain pull in time...
Try increasing the delay between successive coil activations .....
Thanks! Certainly makes a difference.
Using half-step phase sequencing provides good torque...
CODE CORRECTED - somehow the code was corrupted when I pasted it?!?!
' {$STAMP BS2}
' {$PBASIC 2.5}
' The 28BYJ-48 requires 512 8-step half-step sequences to rotate 360 degrees
Phase VAR OUTA ' phase control outputs
StpsPerRev CON 512 ' whole steps per rev
idx VAR Word ' loop counter
lup VAR Word
stpIdx VAR Word ' step pointer
stpDelay VAR Byte ' delay for speed control
Steps DATA %0001, %0011, %0010, %0110, %0100, %1100, %1000, %1001
Setup:
DIRL=%00001111 ' make P0..P3 outputs
stpDelay = 1 ' set step delay
Main:
FOR idx = 1 TO StpsPerRev * 8 ' one revolution
GOSUB Step_Fwd ' rotate clockwise
NEXT
PAUSE 500 ' wait 1/2 second
FOR idx = 1 TO StpsPerRev * 8 ' one revolution
GOSUB Step_Rev ' rotate counter-clockwise
NEXT
PAUSE 500 ' wait 1/2 second
OUTL = 0
'GOTO Main
END
Step_Fwd:
stpIdx = stpIdx + 1 // 8 ' point to next step
GOTO Do_Step
Step_Rev:
stpIdx = stpIdx + 7 // 8 ' point to previous step
GOTO Do_Step
Do_Step:
READ (Steps + stpIdx), Phase ' output new phase data
' DEBUG DEC idx, " ", DEC stpidx, " ", BIN4 phase, CR
PAUSE stpDelay ' pause between steps
RETURN
I have some, but haven't used them yet. I'm assuming function/gearing is the same, just different motor supply voltage. Typically higher voltage motors will have more & finer windings to keep the power about the same. You can run higher voltage to the 5V motors for more torque, that's often done. I used 7.4V on mine.
I have some, but haven't used them yet. I'm assuming function/gearing is the same, just different motor supply voltage. Typically higher voltage motors will have more & finer windings to keep the power about the same. You can run higher voltage to the 5V motors for more torque, that's often done. I used 7.4V on mine.
OK, thanks, I shall up the volts a bit. I'm not expecting miracles, but a bit more umph would be useful.
The control boards that came with the 5V stepper look plug compatible with the 12 V stepper, but the 12 V model might have some more torque.
the ones i got have a jumper. its set at 5v and works fine. could it bet that the jumper is just for th led's? maybe leaving the jumper off would disable the led circuit? i'm not at my bench, i cant check at the moment
the ones i got have a jumper. its set at 5v and works fine. could it bet that the jumper is just for th led's? maybe leaving the jumper off would disable the led circuit? i'm not at my bench, i cant check at the moment
IIRC the jumper on the board is used to connect the common of the flyback diodes to the supply voltage, per the schema on p.2 at http://www.parallax.com/Portals/0/Downloads/docs/prod/motors/Stepper_Motor_27964.pdf . The ULN2003 can operate on any voltage up to ~30V, so it could be the same board supplied with 5V and 12V motors. I don't have a board in front of me, but it's likely that the LED current is supplied by the microprocessor-supplied control signal and not related to the 5V or 12V motor supply voltage.
Comments
No torque? Try full step (2 coils at a time) per http://www.parallax.com/dl/docs/prod/motors/Stepper_Motor_27964.pdf
~2 ms per step.
Not compared to NEMA 17 Pololulu 1200 steppers http://www.pololu.com/catalog/product/1200 NEMA 17 Pololulu 1200 steppers,
but what do you want for $3?!?!
Actually, I found them to be slow but torquey for such a little part, and running off 4 AA batteries. They will be a pretty good match for an erco bot, or the Little Robot (tm). If fact, they might be OK for a Jamie Mantzel spider tank.
prof_braino, it was more observation than a complaint. I just need to find the right application for them.
After giving them a good check and repackaging them the way I would have preferred to receive them, I've put them in stock. They'll cost you more than $3.00, but will be shipped from here in Ohio. (Hit the "propellerpowered" link in the signature)
Jeff
if i may suggest, bundle these as:
two of the cheap steppers
one of the cheap ultrasonic rangefinder
one of the cheap blue tooth
this is the exact BOM for the LittleRobot(tm) project.
at least two schools have asked where to get the package, and are hesitant to order from china
could you get by if you charge only $20 for such a bundle?
Jeff
one more item in the bundle:
the small assortment of colorful jumper wires with pins and sockets. or maybe a second bundle of just jumpers and a bread board. this combo helps a lot when i am messing with the steppers and quickstart
Price drops about a penny per week. How low can they go?
Same with uS sensors, $2.03 now http://www.ebay.com/itm/New-Arduino-Ultrasonic-Module-HC-SR04-Distance-Sensor-/271040722464?pt=LH_DefaultDomain_0&hash=item3f1b493620
I bought 2 of these, they work fine. Now I'm wondering what I can do with them... I'm new to robotics, but familar with the Propeller.
I'm asking for some advice on where to buy gears, wheels, mounting hardware, etc. to experiment with these motors. I've tried Googling, but apparently I can't come up with the approprate search terms. I know they have 5mm shafts, and I can find couplers and mounting hubs, but (so far) nothing like the gears in this video.
Thanks in advance,
Walter
Could you get a 3D printer and make your own gears & stuff?
Just saw two notches in a square of 2x4, and stick them on there.
Make two wheels out of any old plastic dinner plates, or old CD's etc.
At first I made couplers with set screws and all, but just holes that are a little too small work fine.
All you need is an ultrasonic module, and you are set up for an erco-bot or LittleRobot (LittleRobot uses forth, ercoobot uses plywoord)
I could, but then I'd have to sleep in the shed for spending that much money.
Seriously, I'm on a low budget, $50-$100 would be my limit.
Walter
Cheapest Possible Robot project
http://code.google.com/p/propforth/wiki/CheapestPossibleRobot
Plywood.... check.
Harbor Freight Tools Tools... check.
Harbor Freight Tools 20% off coupons (for casters, etc.)... check.
Nuts, bolts, screws, batteries, wire... check.
Bandages... check.
Sensor & bluetooth modules... on order.
Many thanks for the info... looking forward to making my own robot.
Somewhat ironic note: I'll get to finally play with Forth... which was originally implemented on an IBM 1130... which I'm emulating (almost) with a Propeller.
Walter
I'll try a different seller if I decide to get more....
Both of my steppers act the same.
Has anyone else noticed this??
Try increasing the delay between successive coil activations .....
Thanks! Certainly makes a difference.
Using half-step phase sequencing provides good torque...
CODE CORRECTED - somehow the code was corrupted when I pasted it?!?!
' {$STAMP BS2} ' {$PBASIC 2.5} ' The 28BYJ-48 requires 512 8-step half-step sequences to rotate 360 degrees Phase VAR OUTA ' phase control outputs StpsPerRev CON 512 ' whole steps per rev idx VAR Word ' loop counter lup VAR Word stpIdx VAR Word ' step pointer stpDelay VAR Byte ' delay for speed control Steps DATA %0001, %0011, %0010, %0110, %0100, %1100, %1000, %1001 Setup: DIRL=%00001111 ' make P0..P3 outputs stpDelay = 1 ' set step delay Main: FOR idx = 1 TO StpsPerRev * 8 ' one revolution GOSUB Step_Fwd ' rotate clockwise NEXT PAUSE 500 ' wait 1/2 second FOR idx = 1 TO StpsPerRev * 8 ' one revolution GOSUB Step_Rev ' rotate counter-clockwise NEXT PAUSE 500 ' wait 1/2 second OUTL = 0 'GOTO Main END Step_Fwd: stpIdx = stpIdx + 1 // 8 ' point to next step GOTO Do_Step Step_Rev: stpIdx = stpIdx + 7 // 8 ' point to previous step GOTO Do_Step Do_Step: READ (Steps + stpIdx), Phase ' output new phase data ' DEBUG DEC idx, " ", DEC stpidx, " ", BIN4 phase, CR PAUSE stpDelay ' pause between steps RETURNhttp://www.ebay.com/itm/New-12V-4-phase-5-wire-stepper-motor-28BYJ-48-12V-/180831286591
The control boards that came with the 5V stepper look plug compatible with the 12 V stepper, but the 12 V model might have some more torque.
OK, thanks, I shall up the volts a bit. I'm not expecting miracles, but a bit more umph would be useful.
http://education.yahoo.com/reference/dictionary/entry/oomph
the ones i got have a jumper. its set at 5v and works fine. could it bet that the jumper is just for th led's? maybe leaving the jumper off would disable the led circuit? i'm not at my bench, i cant check at the moment
I would have gone with the "umph" crowd until I read the Urban Dictionary definitions...I DON'T want my robot to have THAT!!!!
Oomph (while accepted by my iPad spell checker) reminds me of "object oriented miles per hour" which makes no sense at all.
IIRC the jumper on the board is used to connect the common of the flyback diodes to the supply voltage, per the schema on p.2 at http://www.parallax.com/Portals/0/Downloads/docs/prod/motors/Stepper_Motor_27964.pdf . The ULN2003 can operate on any voltage up to ~30V, so it could be the same board supplied with 5V and 12V motors. I don't have a board in front of me, but it's likely that the LED current is supplied by the microprocessor-supplied control signal and not related to the 5V or 12V motor supply voltage.