I,The Curious Engineer,cordially invite you to witness the holy matrimony of ARM and 8051.
All this while,I was majorly involved with writing the code, that the hardware of my project was left untouched.
Now that I have reached the first milestone in my project (the program is now successfully able to solve the cross!!) ,my attention moved on to the hardware.
The initial design was of three arms, two of which are fixed (one on the left and right) and one on the bottom that is retractable.Two of my teammates took on the task of designing the arms, but a couple of weeks ago,at the college workshop, one of them got a very deep and unfortunate cut on his finger while trying to bend the sheet metal, tightly gripped to the vice.
This incident made us reconsider the use of three arms and consider if use of six arms would be better.
In the latter, we plan to connect the shaft of the stepper motor to the center of each side of the cube.
This eliminates the need of building the retracting fingers mechanism and hence, avoid further injuries.
The reason for preferring stepper motors over servo motors are
1. Steppers have high torque( mine are 4-kg/cm each.)
2. Stepper motors are very precise. Servo motors have a ± 1° offset angle.
3. Stepper cost < Servo cost. (Not true every time, but this time, since I bought the parts in bulk.)
4. Servo motors with 360° are unavailable.180° is the maximum.
A fresh piece of a stepper motor is very expensive. So, it is advisable to buy the steppers that have been scrapped from old broken down machinery, to keep the costs low.
(Works for me every time.)
The six steppers that I now have are all 5 wire, Unipolar motors with a step angle of 1.8°.
To drive these motors, ULN2003A IC's are being made use of.
The ULN's are a package of 7 Darlington pairs array with each capable of delivering a maximum current of 500ma.
Herein lies the problem!!
The ULN2003's are all 5V logic based IC's and the FRDM-KL25Z is 3.3V logic based.
One solution would be to use a 3v to 5v converter.The converters however are expensive (150 rupees).
The solution I want to use is to use a AT89S52 chip coupled with the FRDM board.
The output of the FRDM board is read in by the AT89S52 and correspondingly outputs the same to the ULN2003A.
FRDM(3.3V) ---> AT89S52(5V) ---> ULN2003A ---> Stepper motor
All this while,I was majorly involved with writing the code, that the hardware of my project was left untouched.
Now that I have reached the first milestone in my project (the program is now successfully able to solve the cross!!) ,my attention moved on to the hardware.
The initial design was of three arms, two of which are fixed (one on the left and right) and one on the bottom that is retractable.Two of my teammates took on the task of designing the arms, but a couple of weeks ago,at the college workshop, one of them got a very deep and unfortunate cut on his finger while trying to bend the sheet metal, tightly gripped to the vice.
This incident made us reconsider the use of three arms and consider if use of six arms would be better.
In the latter, we plan to connect the shaft of the stepper motor to the center of each side of the cube.
This eliminates the need of building the retracting fingers mechanism and hence, avoid further injuries.
The reason for preferring stepper motors over servo motors are
1. Steppers have high torque( mine are 4-kg/cm each.)
2. Stepper motors are very precise. Servo motors have a ± 1° offset angle.
3. Stepper cost < Servo cost. (Not true every time, but this time, since I bought the parts in bulk.)
4. Servo motors with 360° are unavailable.180° is the maximum.
A fresh piece of a stepper motor is very expensive. So, it is advisable to buy the steppers that have been scrapped from old broken down machinery, to keep the costs low.
(Works for me every time.)
The six steppers that I now have are all 5 wire, Unipolar motors with a step angle of 1.8°.
To drive these motors, ULN2003A IC's are being made use of.
The ULN's are a package of 7 Darlington pairs array with each capable of delivering a maximum current of 500ma.
Herein lies the problem!!
The ULN2003's are all 5V logic based IC's and the FRDM-KL25Z is 3.3V logic based.
One solution would be to use a 3v to 5v converter.The converters however are expensive (150 rupees).
The solution I want to use is to use a AT89S52 chip coupled with the FRDM board.
The output of the FRDM board is read in by the AT89S52 and correspondingly outputs the same to the ULN2003A.
FRDM(3.3V) ---> AT89S52(5V) ---> ULN2003A ---> Stepper motor
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