Go Down

Topic: How to control hundreds stepper motors with one arduino uno? (Read 5940 times) previous topic - next topic

peefour

Hi,

we have a big lockers cabinet (hundreds of locks) in our sporting hall. I want to modernise it by making the locks electronic, and control their access via one central keypad, powered by an arduino uno.

I want to replace the mechanic lock mechanisms by stepping motors. Access to each locker is provided through a central keypad. When a user types his secret code, his locker will open.

I want to do this with an arduino uno, but I am puzzled by how to steer so many steppers (as they have many wires).

I want to use stepper BYJ-48

1a) what to use: multiplexers, shift registers, something else?
1b) what IC to use (with most outputs, lowest cost, enough power, ec.)
1c) how to chain them to achieve hundreds outputs?

2) does every stepper needs its own driver IC (ULN2003AN)?

Thanks!

 

jremington


Isaac96

Hundreds of steppers? How much current do they draw? The Adafruit Motor Shield v2.3 can control 2 steppers at 13.5 volts and is apparently capable of 1A. You should check the Adafruit website to be absolutely sure.
EDIT: The shields can be daisy-chained together.
Do not PM me for help. I will delete immediately.
CONNECT THE GROUNDS!

After Tuesday, even the calendar goes W T F

peefour

they don't have to be steppers, dc motors with gear are also good (maybe even better?)

Isaac96

The Adafruit Motor Shield v2.3 can handle 4 DC motors. The official Arduino Motor Shield can handle 2.
I am not sure about others.
Do not PM me for help. I will delete immediately.
CONNECT THE GROUNDS!

After Tuesday, even the calendar goes W T F

mudassir9999

You've to make your own Stepper motor PCB driver board, in which you need to attach  a lot,lot of drivers ICs ,attach bunch of basic electronic items, then by using I2C or SPI you can control the motors.

TomGeorge

Hi,
You could use the electric automotive door lock units. some are now rack and motor type.
Use an array, say 4 x 25 in  each bank.
You will only be actuating one at a time so power requirements won't be astronomical.
This has been done many times before so it is not impossible.

Tom.... :)
A tourist parks up in Queensland use this method as their locker system, for you to store your gear for the days visit.

http://www.gearbest.com/car-gadgets/pp_143912.html?currency=AUD&gclid=CNKgwrr07MUCFUxwvAod4JcAFg

http://www.ebay.com.au/bhp/car-door-locks

http://www.jaycar.com.au/Automotive-%26-Mobile-Security/Car-Electronic-Access-%26-Accessories/Keyless-Access/Slave-Door-Lock-Actuator/p/LR8813
Everything runs on smoke, let the smoke out, it stops running....

peefour

all thanks for answering!
As mentioned before it does not have to be a stepper motor, it can be also a dc motor, servo, or something else. Only important requirement is that it needs to be low power (is powered by batteries that need to last min 1 year)

@TomGeorge & @mudassir9999: can you please give more details on how to do this?

thanks dudes!!


Isaac96

Door lock units? You could use solenoids. They only take 1 pin each and you could use ULN2001 Darlingtons and 74HC595 shift registers to get unlimited outputs from 3 pins.
Do not PM me for help. I will delete immediately.
CONNECT THE GROUNDS!

After Tuesday, even the calendar goes W T F

CrossRoads

Or TPIC6A595, shift register & with 500mA output current sink.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

mudassir9999

If you're using DC Geared Motor then L293D H-Bridge Motor driver Chip is a better option, This chip can control upto 2 DC motors so you will need 50 of them,These are cheap and abundantly available.

Now these Ics can be controlled by using a PWM or Just by using HIGH and LOW functions..

You'll need many pins to control that number of Motors.So,Arduino Mega has many GPIO pins,You can use it

Just give it a try with 2 motors first, Later work on all 100 motors and send data using I2C to Each

Here is the INSTRUCTABLE guide of controlling the two DC motors with L293Dchip

click here.


Meanwhile i would also prefer to use solenoids..

TomGeorge

Hi,

Quote
Only important requirement is that it needs to be low power (is powered by batteries that need to last min 1 year)
Why does the battery have to last a year, can't you power it of a power pack?

Tom.... :)
Everything runs on smoke, let the smoke out, it stops running....

CrossRoads

Quote
Only important requirement is that it needs to be low power (is powered by batteries that need to last min 1 year)
That is going to need a pretty high capacity battery.

Imagine the solenoid locks the cabinet in the unpowered state.
User walks to central location, enters the locker number, enters his security number, his (spring-loaded?) door pops open, and he walks over. When done, he pushes the door closed.
The central station could be designed to be in sleep mode most of the time, powering down the solenoid drive circuit and display until a key is pressed to wake it up.

Small solenoid examples
http://www.ledex.com/miniature-solenoids/miniature-solenoids.html
This brochure shows the Power (voltage x current) needed for various models
http://www.ledex.com/pdf/Ledex_Shortform.pdf
Say you had model that needed 5W, so 5V-1A, and it needed to retract for 1 second to allow the door to pop open. Then you'd need 500mA from a 5V battery for every opening.
"Hundreds of locks", okay, say 300.
Each one opening 2 time a day for say 180 times a year, every other day on average.
500mA x 1 second x 2 x 300 locks x 180 days = 54000mAS, x 1min/60S x 1Hr/60min = 15AH battery.
So you might get by with a 6V motorcycle battery for a year, depending on how much self-discharge it had.  If the system is in a hall tho, why not just power the system from wall power, with say a 4 hour battery backup system for the occasional outage?

I imagine the door would have a part that would push into a recess (like a regular hallway door) so it could be pushed close when the solenoid was extended.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

MarkT

For low power use you need to be able to power everything down when not active.  Use an actuator that only
needs power to move (not to hold position), obviously.  A small leadscrew actuator or geared down DC
motor (for rotary lock).  Probably need microswitches to detect end-stops.

Try looking on AliBaba / AliExpress for an existing unit that might be affordable?
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

peefour

Hi Guys,

Thanks all for your excellent answers.
I am new to actuators (motors, solenoids, etc.), so sorry for my dumb questions.

@MarkT: I never heard of leadscrew actuators, thanks for mentioning. Do they consume less power than solenoids?

@crossroads: this is indeed the scenario I want. The lockers are meant for outside use, where there is no power supply.

0) I want even to go futher then sleep mode, and use a key of the keypad to power up the whole circuit. The arduino should power off the itself and the whole circuit after unlocking the door. Is this feasable?

My first idea was indeed to use solenoids, but i read that they require more power than motors.
1) Is this true?

That's why I was investgating using motors (dc/gear, step, servo, etc.).

2) I think steppers and servos need constantly to be powered, and thus the idle-current can drain the battery? Is this true? What about the idle-current of solenoids?


3) I have another use case, where I want to lock a suitcase (for equipment), that will be opened and closed 10x a day for 360 days/year. The lock and arduino circuit will be powered by 4 AAA batteries, and needs to work for min 1 year.
using Mr. Crossroads equation:
500mA*1s*10times*360days=1800mAs x 1h/3600s=500mAh=0.5Ahis (this is a bit more than 4 strong AAA batteries: 4*1200mAh=0.48Ah).
The problem is that I still need to power the arduino from this 4 batteries, which will not suffice.
Is a a solenoid also in this case the best option?

4) which type of actuator is the most economical (cheapest, incl. extra circuitry when needed) to use, in these cases?

Thanks guys !!



Go Up