Project in progress
Heavy Duty Automatic Wire Cutter

Heavy Duty Automatic Wire Cutter © MIT

An arduino controlled automatic wire cutter capable of cutting steel cable

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Components and supplies

16x2 LCD
3x4 Membrane keypad
5V Relay
11026 02
Jumper wires (generic)
1 Pack should suffice, I only used 17 wires
24v power supply aqrbg7y5vc
OpenBuilds 24V/14.6A Power Supply
This build isn't very power hungry so a smaller 24V power supply should do. (2 amps and up to be safe)
MA860 microstep driver
Stepper motor
I did not buy the stepper motor I used. It was provided to me, so I do not know exactly what model it is unfortunately. But if you want to cut steel cable that comes in large rolls it will need to be fairly powerful. My one had a 5:1 gear ratio
Festo MSFG-24/42-50/60 24V DC solenoid
Festo VL/O-3-1/4 Valve

Necessary tools and machines

Pro dmm box 600  26129.1449785766.500.659
Digilent Mastech MS8217 Autorange Digital Multimeter
Any multimeter will do for this! I only needed to check for continuity and take a couple voltage readings.
Absolutely crucial for bending things, grabbing things, holding things or picking out hard to reach nosehairs.
Side Cutters
Absolutely crucial for stripping or cutting wires.

Apps and online services

About this project


My name is Simon Robinson, at the time of writing this I am a 3rd year engineering student at Stellenbosch University, and this is my first arduino project submission. I hope you enjoy!

This project was a request from FirstPro Engineering, they had lots of steel cable that they had to manually cut and it was taking lots of time to do so. They contacted me to see if I could build them an automated system to do it for them. They would handle the heavy duty pneumatic side, all I had to do was handle the automation. This is what I came up with.

This project was surprisingly simple. It only makes use of GPIO pins and 2 I2C pins on an arduino nano, nothing too fancy. It uses a stepper motor, its driver, a keypad, an LCD, and a relay to switch on a solenoid valve. I started this project with little to no knowledge on how any of these components worked. All I had was my knowledge gained from my engineering degree so far, which was mainly how to solder, how to debug and how to program, and here I am with an almost complete build! This has been an invaluable learning experience that has helped me gain knowledge that will no doubt be useful in the future.


The system allows you to navigate a menu and input your desired length of cable and your desired amount using the keypad and LCD. You are then given the choice to begin cutting. Once cutting begins the arduino uses information given about the system in code (such as the feeder wheel radius, and required steps per revolution on the stepper motor) to calculate how many loops it has to execute to feed the correct amount of wire through.

Then the feeding begins by sending signals to the stepper motor driver to drive the stepper motor one step at a time. (That's a lot of steps in one sentence!) Once feeding stops the arduino opens a relay which sends 24 volts to a solenoid which opens a pneumatic valve. The pneumatic valve drives a piston and blade to cut the wire. It then closes the relay and resets the piston and blade, and we now have one piece of wire! It repeats this process until the desired amount of wires is cut.

As of now I have only completed the backbone of the system. Every piece works together the way it should, however the motor is not connected to a feeder or wire yet, and the valve is not connected to a piston or air compressor, so though the system works, it won't be cutting any wire just yet. This is a work in progress and more pictures will follow as the separate components get put into their respective places!

Here are some photos and a video of the build process:

The keypad was connected to pins 1-8 of the arduino as shown.

Next the LCD was connected. SCL->SCL and SDA->SDA. The expansion board makes finding the respective pins a breeze.

Next the microstep driver was connected to the arduino. PUL+ and DIR+ were connected to pins 9 and 10 respectively and their negative counterparts were connected to ground.

Next I connected up the stepper motor. I did not know which wires were connected to which coils at first, so I simply used a multi-meter to check for continuity and quickly found the wire pairs for each coil. After some trial and error with the wiring I found that the setup shown gave me the desired direction on the motor. I have read online that some stepper motors have specific wiring configurations to operate properly, with people saying they experience drops in speed or changes in direction when wires were connected the wrong way. I did not experience this with the motor I am using. It seemed to maintain a constant speed no matter what way I connected the wire pairs. The only thing that changed was the direction of the motor.

Next I grabbed a 5V relay and soldered some jumpers onto it. Believe it or not, finding the right relay for this job was more difficult than I expected for someone who had no knowledge of relays before this. It took me 3 tries before I figured out what relay I needed. I had previously been working with a 24V relay thinking that meant it could handle a 24V load, when in actual fact it meant it needed 24V to operate the switch. Next I had tried to use a 5V solid state relay that was only rated for AC loads. (My solenoid is 24V DC), finally I came to the correct relay, a 5V relay rated for 30V DC loads. Perfect!

I quickly connected up the relay board with VCC and GND going to 5V and ground on the arduino and IN going to pin 12. It was then time for the final step. Connect up the solenoid valve to the 24V power supply and the relay and run the software!

The (almost) completed product!

If you would like to recreate this project I have attached a wiring diagram for you to use as well as a link to my code. Feel free to use it! Just give me a shout out if you do :)

That's it for now! Hopefully I will update with some more pictures and videos when the rest of the machine get's done! Stay tuned until then, and if you have any suggestions on how to improve this post at all please feel free to leave a comment! This is my first time posting this sort of thing and I welcome any constructive advice!


Arduino Wire cutter Code
This is the git repository for the code that I wrote for this project. It is written in C.


Wiring diagram
A diagram that will show you how to connect up every component in the system to get it to run properly
Wire cutter pinout zaozhcqht8



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