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Topic: hi all i need a help (Read 4437 times) previous topic - next topic

zamir89

im trying to drive this 5v 2a stepper motor using tip 122 transistor ....after the connection the motor drive but the torque is not high enough as i can easily stop it using my hand....the resistor im using is 0.4ohm should i use 1Kohm as in this diagram so the motor will operate at high torque?

raschemmel

What is the motor supply  ? (hint: arduino +5V is not a correct answer to this question)

ALSO - PLEASE STATE YOUR KNOWLEDGE OR EXPERIENCE WITH ELECTRONICS.
Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,<br />DS18B20s,74c922,nRF24L01, RS232, SD card, RC fixed wing, quadcopter

Robin2

Is that a 5-wire or 6-wire stepper?

If it is a 6-wire stepper just ignore the two centre wires (keep them separate from each other and everything else) and treat the motor as a 4-wire bipolar stepper. Then just get a proper stepper motor driver board and save yourself a lot of trouble. I would get a 3amp driver board to give a bit of headroom.

The main shortcoming with your design is that you can't use high voltages because you have no current limiting circuitry to prevent overloading the motor.

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

Grumpy_Mike

Quote
the resistor im using is 0.4ohm

You sure of that!
That would mean you are overloading the arduino output pins. It won't affect the motor but it might fry your arduino. Stick with 1K.

raschemmel

@Robin,
Here we go again...

@OP,
Can you  post a vendor link or datasheet for your motor ?
Where is your code ?
What is your motor power supply ?
Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,<br />DS18B20s,74c922,nRF24L01, RS232, SD card, RC fixed wing, quadcopter

MarkT


im trying to drive this 5v 2a stepper motor using tip 122 transistor ....after the connection the motor drive but the torque is not high enough as i can easily stop it using my hand....the resistor im using is 0.4ohm should i use 1Kohm as in this diagram so the motor will operate at high torque?


The diodes are in the wrong place, they go anode to collector, cathode to +ve motor
supply.  You have possibly blown something.

You'll need ~6.5V supply to get to about 5V to the motor, since darlingtons drop lots
of voltage at high current.  And enough amps in the power supply.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

raschemmel

#6
May 16, 2014, 12:58 am Last Edit: May 16, 2014, 01:37 am by raschemmel Reason: 1
Do you know how to test the TIP122? (put the diods across the motor windings as suggested. cathode to +Vmotor , anode to Collector)
Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,<br />DS18B20s,74c922,nRF24L01, RS232, SD card, RC fixed wing, quadcopter

zamir89

err..im using a standard 5v 2amps adapter...u guys mean the diodes connection are wrong?

Grumpy_Mike

Yes they should be between the collector and the motor supply.

zamir89

humm thanks all i think this is the limit this motor can go....if i use a higher supply it may damage the coils

Robin2


humm thanks all i think this is the limit this motor can go....if i use a higher supply it may damage the coils


Did you read Reply #2?

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

zamir89

hmm buying a proper driver...nah i already owned a big easy driver i decided to make own driver

raschemmel

Did you measure the resistor Mike asked you about ? Is it really 0.4 ohms ?
You never posted your code. You never posted a photo of your circuit. You never posted any measurements for the TIP122s.
I really don't see how you can draw any conclusions on your own, considering the circuit was miswired to begin with, the resistor value you claim to be using doesn't match the schematic you posted, and we still haven't seen your code.
Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,<br />DS18B20s,74c922,nRF24L01, RS232, SD card, RC fixed wing, quadcopter

Robin2


hmm buying a proper driver...nah i already owned a big easy driver i decided to make own driver


Then I will happily leave you to your masochism.

Would you mind going back to your original post and changing the title to something more meangingful so that I know to avoid it.

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

MarkT

Absolutely, subject lines are there to identify the subject of the posting so those with
the right expertise can find relevant threads to contribute to.  We can all work out
someone posting here is wanting help with an Arduino project!
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

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