I am pretty sure it is all in contract negotiations. I was once a warehouse manager and my main job was to work out the best possible shipping rates I could get. UPS, Fed Ex and yes, believe it or not, USPS all are vying to ship your product. We were shipping thousands of individual VHS tapes via USPS at about $.25 each with our Bulk Mail contract. I assume it is similar in China although Government most likely has their say in it also. Several years ago Roadway Trucking tried a small packaging service. As long as you kept up a steady flow of shipments on a daily basis they kicked UPS's butts. However, they did not last long!!!!
Another amazing fact is that many Ebay China items are drop-shipped. One guy does the Ebay business and takes the orders, and another guy far away ships it from his warehouse (sometimes in Thailand). Both guys get paid somehow. Talk about lean operating margins.
Several years ago Roadway Trucking tried a small packaging service. As long as you kept up a steady flow of shipments on a daily basis they kicked UPS's butts. However, they did not last long!!!!
Roadway Package Service was bought by Federal Express and became FedEx Ground.
These things are just crying out to be used in a small differential drive robot platform. I'll get to it eventually, but surely someone without beautiful twin baby girls will beat me to it! Don't let me be first here...
Erco, you finally wore me down. I just bought two stepper motors for $5.02. I shall see how much torque they have and if they can be used for anything.
I can die happy now, Martin_H! Didja get a cheapie ultrasonic sensor too?
I've always stayed clear of steppers, cuz they're a pain and need so many I/O lines to control them. But it's a challenge and it should go straight without encoders. Plus, I have this BS2 from a Mystery Bag that yearns to control a robot... 8 lines for two motors leaves 8 free lines for sensors. Not too bad. I'll probably make it processor-swappable.
You previously convinced me to buy four of those and haven't used them all up yet!
I have a plan for a cheap robot that involves hobby plywood, one ultrasonic sensor, two stepper motors, and a microcontroller. I've got plenty of the later to chose from as I have one unused Prop proto board, a BS2 from the mystery bad, and one that shall not be named.
I bought a few of these for the Propellerpowered site.. I can't say I'm impressed enough with the quality to put them in as standard product..
Worth $2.50, yeah, maybe, but I doubt I'll stock them as regular stock. The ones I bought will likely hit the Bargain Bin soon to wash them out.
I'm thinking of ordering several really cheap servos I saw on ebay yesterday.
less than 3USD delivered! amazing. And in cute transparent blue plastic
cases...I just love see through enclosures. Comes with all the little attachments
for the shaft too.
Step_Jump....... i could not resist either and just bought two for $6.44 inc p&p... these motors kick a far punch and are able to drive my "Etch-A-Sketch" board project (still in progress) without battering an eyelid.
Just experimenting with the different modes of driving...... the LEDs are 'brill' for debugging .....YAY
XLNT call on the Etch a Sketch, I must appropriate the twins' unit for evaluation! These steppers def have plenty of torque at low RPM, as my quickie BS1 robot shows:
This $1.50 encoder (a rotary knob) would be da bomb for manually driving a stepper. The stepper would rotate proportionally to the knob, and you could change the ratio in software, sort of a virtual gearbox. I'll do it unless Duane beats me to it!
Lovin' it! Great job with the gear drive, I was thinking direct drive with no encoders, but you're way ahead of me. You're almost done, I want to see yours in action, Boss!
You're almost done, I want to see yours in action, Boss!
You mean .......like this......numnumnum
[video=youtube_share;VIjAjfS8yWY]
OkOk the drive wheels need to be tightened ..... even so the tracking is mm perfect .....
The Parallax "P" you see in the video i over-wrote 5 times to check ....indeed its very accurate....
The Steppers are not the fastest, however with the set up you see in the video i am getting circa 5000 step on X axis and circa 4000 on the Y (good enough for me)......
State of the art! Great job, you pulled that off in record time. Besides programming shapes to draw, you can make a datalogger. Check out this guy's temperature logger, which monitors the plunging temperature of his ice cold Guiness beer in the embedded video:
I had not thought about that direction, graphing , yes very neat and fitting display unit........
Next on the cards is to hijack some CNC graphics and work_out how to extract and "Prop A Sketch" them.
BTW :- i bought another 4 steppers :-) i could not resist ..... i have found out that the pin headers will plug straight into my RBBB propeller board ie the board forms a chassis and with wheels attached makes for a quick robot.
We are in step, my stepper brother; I bought 3 more earlier today for $2.47.
I'll get to this Etch a Sketch when I can. So many cool projects, so little time! I'm working up a cool little stepper demo board you'll see here soon.
Fabulous work, Bro. I'm a fan of the Gareth channel. Now where's that Like button?
Or maybe a new mod to your rover...... Here is something i tested this evening.......
.
I cooked up a chassis with 2 steppers back to back - a pingpong ball and a UV Led strapped under the axle.
Software simple drives and draws a box with 89.9(ish) degree corners onto a sheet of UV sensitive vinyl.
I am gobsmacked how well they are tracking :-)
OK, question is about 5 volt and 12 volt models, whats the difference?
The units I recived have 5-12v silk screened on the board by a 4 pin header. There's a + and a - by two pins, and a jumper on the other two pins.
Since I order the 5 volt units, I stuck my 5 volts + and - to htese pins and it works. Wheee!
But what about 12 volts? Will connecting 12v to these pins fry the little beggar?
Can I switch the jumper and connect 12 volts to the next set of pins?
Is the voltage jumper more to do with the resistors for the LEDS, or are there different 5 volts and 12 volt ul2003 chips?
The resistors on the 5 volt drivers I have look like yellow purple brown so I think they are 470 ohms.
Comments
Roadway Package Service was bought by Federal Express and became FedEx Ground.
So they're real, and they do get here eventually.
These are going in this experiment
http://code.google.com/p/propforth/wiki/CheapestPossibleRobot
How is everybody else using these?
http://www.ebay.com/itm/5V-Stepper-Motor-28BYJ-48-With-Drive-Test-Module-Board-ULN2003-5-Line-4-Phase-/170781372685?pt=LH_DefaultDomain_0&hash=item27c35cf10d#ht_3433wt_1398
Elsewhere, anyone know where to find a hub to fit this shaft?
Amanda
I cannot resist...
Somehow these prices are falling faster than a gallon is gas is rising!
http://www.ebay.com/itm/5V-Stepper-Motor-28BYJ-48-With-Drive-Test-Module-Board-ULN2003-5-Line-4-Phase-/170781372685
http://www.ebay.com/itm/1pcs-Ultrasonic-Module-HC-SR04-Distance-Measuring-Transducer-Sensor-for-Arduino-/261009210866
I've always stayed clear of steppers, cuz they're a pain and need so many I/O lines to control them. But it's a challenge and it should go straight without encoders. Plus, I have this BS2 from a Mystery Bag that yearns to control a robot... 8 lines for two motors leaves 8 free lines for sensors. Not too bad. I'll probably make it processor-swappable.
You previously convinced me to buy four of those and haven't used them all up yet!
I have a plan for a cheap robot that involves hobby plywood, one ultrasonic sensor, two stepper motors, and a microcontroller. I've got plenty of the later to chose from as I have one unused Prop proto board, a BS2 from the mystery bad, and one that shall not be named.
The steppers seem to have dropped another penny since yesterday!!! Perhaps we should wait till they pay us to take them off their hands. ;-)
@
http://www.ebay.com/itm/5V-Stepper-Motor-28BYJ-48-With-Drive-Test-Module-Board-ULN2003-5-Line-4-Phase-/271033518283?pt=LH_DefaultDomain_0&hash=item3f1adb48cb
Worth $2.50, yeah, maybe, but I doubt I'll stock them as regular stock. The ones I bought will likely hit the Bargain Bin soon to wash them out.
Jeff
less than 3USD delivered! amazing. And in cute transparent blue plastic
cases...I just love see through enclosures. Comes with all the little attachments
for the shaft too.
Also translucent blue!
Just experimenting with the different modes of driving...... the LEDs are 'brill' for debugging .....YAY
http://www.goldmine-elec-products.com/prodinfo.asp?number=G16267
You must be slipping. If you are going to stock up on the sonar modules why over pay?? You can now get them for under $2 each if you buy 10.
http://www.ebay.com/itm/270752285926
Who you talking to?
Here's a Pre-Shot of the simple construction...
X axis has resolution circa 5000 steps.
Y programming is still to be finished.
The encoder wheels i am not to sure about ..need to be attached etcetc
.....just needed some form of feedback to constrain the playing field.....
You mean .......like this......numnumnum
[video=youtube_share;VIjAjfS8yWY]
OkOk the drive wheels need to be tightened ..... even so the tracking is mm perfect .....
The Parallax "P" you see in the video i over-wrote 5 times to check ....indeed its very accurate....
The Steppers are not the fastest, however with the set up you see in the video i am getting circa 5000 step on X axis and circa 4000 on the Y (good enough for me)......
http://ijprojects.blogspot.com/2012/06/etch-sketch-turned-temperature-data.html
Next on the cards is to hijack some CNC graphics and work_out how to extract and "Prop A Sketch" them.
BTW :- i bought another 4 steppers :-) i could not resist ..... i have found out that the pin headers will plug straight into my RBBB propeller board ie the board forms a chassis and with wheels attached makes for a quick robot.
I'll get to this Etch a Sketch when I can. So many cool projects, so little time! I'm working up a cool little stepper demo board you'll see here soon.
Fabulous work, Bro. I'm a fan of the Gareth channel. Now where's that Like button?
.
I cooked up a chassis with 2 steppers back to back - a pingpong ball and a UV Led strapped under the axle.
Software simple drives and draws a box with 89.9(ish) degree corners onto a sheet of UV sensitive vinyl.
I am gobsmacked how well they are tracking :-)
The units I recived have 5-12v silk screened on the board by a 4 pin header. There's a + and a - by two pins, and a jumper on the other two pins.
Since I order the 5 volt units, I stuck my 5 volts + and - to htese pins and it works. Wheee!
But what about 12 volts? Will connecting 12v to these pins fry the little beggar?
Can I switch the jumper and connect 12 volts to the next set of pins?
Is the voltage jumper more to do with the resistors for the LEDS, or are there different 5 volts and 12 volt ul2003 chips?
The resistors on the 5 volt drivers I have look like yellow purple brown so I think they are 470 ohms.