Multi wire cutting machine

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Bernique
Posts: 2
Joined: Mon Oct 07, 2024 3:40 pm

Multi wire cutting machine

Post by Bernique »

Hello,

hope I'm in the right section for posting... sorry if not!
this post is going to be a little long, but I'm trying to give the full context to get sharp answers if possible :mrgreen:

For personnal use to assit me while producing small PCBs, I'm trying to develop a wire cutting machine with the following rough specifications:
  • can handle 4 different wires as a standard (wires size is centered around 22AWG and maybe smaller diameter)
  • has trim capabilities, almost at one end of the wire (and only pre-cutting on the other hand)
  • can retreive predifined programs on a µSD card
  • has an OLED screen for communication
  • as well as a rotary encoder to navigate through the interface and the functions
In order to do so, I've planned to use the following devices:
  • 5 Nema stepper motors and DRV8825 drivers to feed wires and move the cutting head from one location to the other
  • one MG996R servo to cut and trim wires
  • one OLED screen (the usual SSD1306), based on I2C protocol,
  • one rotary encoder
  • and the most important here: an STM32F407VET6 µC to control all of the above
So far all is fine.

As wiring all of those devices sounds like a huge spagghetti dish, I decided to use a commercial 3DPrint board to avoid wiring between the µC and the DRV drivers for example and then finally save space and time.
I finally end up buying a Makerbase MKS Robin Nano v3.1 which should have all necessay connectors to match my devices with a minimal form factor. It is built around an STM32F407VET6 µC.
In fact, only the I2C interface needs some little work to be ready (an EEPROM is connected to the µC using I2C, so I can use those pins to connect my OLED screen with minimal soldering work around ;-)


What I have done so far?
Before jumping in a complete assembly, I'm trying to establish clear communication between the STM32 on the board and all my devices separately.

I can blink a led connected on PB2 for example. Good start!
Stepper motor are also running fine connected on the dedicated sockets (just 4 wires from the board to the motor, it's perfect!)

Concerning the servo, I was not able to run any librairy with success (I've been testin 3 different ones if I remember correctly)... various error type, mainly dependencies as far as I could understand it. I also tried to run it by full hardware control through the registeries, but could not control it as I wished. I finally end up with controlling the servo in µ second and delay fonction to simulated 50Hz and up time for the angle, understanding that this will stuck the program during running phase which is not an issue in my application (nothing else is suposed to move during cutting phases!)
); Acceptable let's say!

Where I'm now stuck is the I2C for OLED control. I've been reading many different post around the subject, but could not find any solution simple enough to run my screen as easily as if it was with a UNO or ESP32 board.

So comes my first question: does any of your have a good link to achieve OLED control with cool librairy so I can design and drive my screen for interface purpose?

thx for reading me so far... and hope to read you :D
STM32ardui
Posts: 142
Joined: Mon May 06, 2024 1:46 pm
Answers: 1
Location: Germany

Re: Multi wire cutting machine

Post by STM32ardui »

Bernique wrote: Wed Oct 23, 2024 9:05 pm Where I'm now stuck is the I2C for OLED control. I've been reading many different post around the subject, but could not find any solution simple enough to run my screen as easily as if it was with a UNO or ESP32 board.
If you're using ArduinoIDE and STM32duino, methods of graphic libraries should be the same for ArduinoUNO, ESP32 or STM32. Of course you have to learn how to draw graphic elements or text in different size. So that may be not cool or easy. You're staying rather vague, no information, which library you used and why it is difficult etc.
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