Joe's Hobby Electronics
  • Joe's Hobby Electronics
    • Electronics Blog

Stepper Motors

17/3/2015

0 Comments

 
I've been neglecting the site and I apologise for that. Work has been really busy, I got suckered into building a website for somebody (actually suckered isn't correct as I volunteered though I didn't know what I was letting myself in for), and I've been working on some custom gizmo orders for people.

That said I've still had time to play in the workshop and I've got some projects to write-up that I think people may be interested in.

This last week I've been consumed with stepper motors. Well to be specific, trying to find some that are fairly small, powerful and cheap which is proving a challenge.

Ebay is awash right now with 5v steppers that are geared - model number is 28BYJ-48 rated at 5v.
I ordered several but I probably should have grabbed just the one first to experiment with.
Now they are nice steppers for the money. However they have a built in gear box that reduces the speed and means their maximum output speed is very limited. The gear box does mean they have a fair amount of torque though.
Picture
28BYJ-48 Available in 5v or 12v models
They would be great for clocks, robotics and even drive motors as long as you don't want your creation to whizz around the place to fast, but for my application much to slow.

However, they weren't a complete waste. Each motor was supplied with a little driver board. Now I don't use stepper motors often, and I've always opted for dedicated driver chips for them. However these driver boards are simply based around a ULN2003 Darlington driver chip. Each IC's contain seven Darlington drivers, rated at around 500ma and up to 50v. They even have the suppression diodes built in and are perfect for driving low current small steppers, motors, bulbs and relays.
It's one of those "why didn't I think of that" type of situations. You simply drive the IC from your CPU, and with four output lines you can drive the stepper in either direction and run in different stepping modes, all for peanuts. These IC's (or one of the many alternate variants) are usually easy to get hold of, and in the case of the ULN2003, you get three spare driver channels for other things as a bonus. I think there is an 8-channel variant which would be useful for a robot with two steppers.

So, whilst it turned unto a useful exercise after all it doesn't solve my current problem.

One solution that I've tried previously is using a modified radio modellers servo motor.
You open the servo and make a change (usually simple) to allow the shaft continuous 360 degree rotation.
However, whilst usually having masses of torque, servo's are rather large, expensive and quite noisy.
There are some micro servos available but they are tricky to modify for full 360 degree rotation.

So, back to searching Ebay.
0 Comments



Leave a Reply.

    Author

    A software and hardware engineer who loves retro computers.

    Archives

    June 2020
    May 2020
    April 2020
    March 2020
    September 2019
    January 2019
    April 2018
    May 2016
    April 2016
    March 2016
    February 2016
    January 2016
    May 2015
    April 2015
    March 2015
    January 2015
    December 2014
    September 2014
    August 2014
    April 2014
    March 2014
    January 2014
    October 2013
    September 2013
    August 2013
    July 2013
    June 2013
    April 2013
    March 2013
    January 2013
    September 2012
    June 2012
    May 2012
    April 2012
    February 2012
    January 2012
    December 2011
    November 2011
    October 2011
    September 2011
    August 2011
    July 2011
    June 2011

    Categories

    All
    18f25k20
    18F25K22
    1-wire
    2114
    2764
    74hc595
    74ls595
    86-0325
    8MHz
    Access Speed
    Acorn
    Acorn System 1
    Alarm
    Aluminium Panel
    Amicus
    Amicus18
    Amicus Basic
    Amplifier
    Antex 1107
    Anti-static Mat
    Arduino
    Assembler
    Backlight
    Bargains
    Basic
    Bat
    Batdetector
    Bat Detector
    Bats
    Bench Audio Amplifier
    Bench Light
    Breadboard
    Bubbler
    Buck
    Bug
    "C"
    Cable
    Cable Gauge
    Cable Wire Size
    Capacitors
    Catalogue
    Clive Maxfield
    Clock
    Clocks
    Common Emitter
    Compiled
    Compiler
    Connector
    CPU
    CPU Simulator
    Crownhill
    Custom Computer
    Custom CPU
    Damage
    Develop
    Diode
    Diptrace
    Double-sided
    Double-Sided PCB
    Dry-joint
    Ds1302
    DS1820
    Ds18b20
    Ebay
    EEPROM
    Electronics And Circuits
    Eprom
    Erase
    Etch
    Evaporator
    Failed Capacitor
    Fake
    Fax Paper
    Ferric Chloride
    Fire Hazzard
    Firmware
    Florescent Tube
    Health And Safety
    Hidden Part Numbers
    High-Voltage
    Hv
    Incubator
    INS8154
    Instruction Set
    Inverter
    Kickstarter
    Lcd
    LM2596
    LM386
    Maxim
    Maximum Current Rating
    Mega
    Mit
    MITx 6.002
    MK4
    Molex
    Mosfet
    NE555
    Nixie
    Nixie Clock
    Npn
    OXO
    Oxo Machine
    Pcb
    Pic
    Pic Basic
    Pickit2
    Pickit3
    Pic Programmer
    Pixy
    Poster
    Pre-amp
    Prices
    Programming
    Project Box
    Project Case
    Project Enclosure
    Psu
    Psu Failure
    Qfn
    RAM
    Rapid Electronics
    Raspberry Pi
    Regulated 5v Psu
    Regulator
    Repair
    Review
    SAD (Segment Address Decoder)
    SCC
    SCC MK4
    Seven Segment Display
    Shift Register
    Silient 700
    Slow Progress
    Smoke
    Smps
    Soldering
    Speed
    Speed Test
    Stepper Motor
    Supression
    Swg
    Switch Box
    Tank
    Tantalum Capacitor
    Temperature
    Temperature Sensor
    Texas Instruments
    Thermometer
    Tic Tac Toe
    Tic-tac-toe
    Timer
    Tools
    Traffic Lights
    Transistor
    Usb
    Uv
    Vbe
    Vcb
    Vce
    W65C02
    Wash
    Weller
    Wirecutters
    Wire Cutters
    Wire Strippers
    Wiring
    Wp3eu
    X2 Capacitor
    X Capacitor
    Y Capacitor

    RSS Feed

© Joe Farr, 2011 - 2020 - Email: HobbyElectronics@kcsl.uk.com