Custom Electronics
July 29, 2013 11:04AM
Ok, i have been working on building a "differant" 3d printer for a while now (like 4 years). I am to the point of no return now. its killing me that i havent finished it yet. I am kind of glad i didnt, in terms of new electronics and stuff. this is going to be a long read sorry.

Here is what i have:
36" dia. table. x + y axis are controled by 48vdc pancake motors. belt to an acme threded rod, with an 1000count encoder on the end. 2 thompson rods per axis. i polished the rods, and greased the bearings. its extreamly smooth. i am still designing the z axis.

The Servo Motor, has a driver hooked up, that takes 5v pwm signal with a direction pin. so its not step/dir. its speed/dir. the encoder is giving feedback to an Arduino DUE, working good up to 1000rpm (going to push to 3000rpm once i get motor driver working).

Each axis also has 3 limit switches, 1 on each end and a third that gets pressed on both ends. (alowing me to have a single interupt for both ends. before i upgraded)

I started to write softwere that incorperates a PID loop. When i give the Arduino DUE a set point it will go to that point with little overshoot. but i do not want to have to use an Arduino DUE on every Axis, that will get to be expencive. I also dont want to have to write code to convert G-Code to setpoints. So i dont know what to do. I have hardwere set for x and y. but i dont have any softwere.

My question is what softwere could i use to interface with my Servo motors and encoders. or should i continue on my custom softwere? When working on my custom softwere, what should i include?
Re: Custom Electronics
August 01, 2013 07:49AM
I would suggest that you find a low cost microcontroller that's capable of running your PID loop. It shouldn't take much. You can probably use one of these with no trouble. They even come in SOIC which is much easier to solder than QFP. If you write the software for the PID microcontroller so that its inputs are "step" and "direction," you can use an existing controller and firmware with no modifications, except slotting in your driver and motor instead of a stepper driver.
Re: Custom Electronics
December 24, 2013 09:53PM
Quote
jchalo99
My question is what softwere could i use to interface with my Servo motors and encoders. or should i continue on my custom softwere? When working on my custom softwere, what should i include?

With some effort, you can probably use LinuxCNC to control everything.
Re: Custom Electronics
December 28, 2013 07:25AM
Quote
Annirak
I would suggest that you find a low cost microcontroller that's capable of running your PID loop. It shouldn't take much. You can probably use one of these with no trouble. They even come in SOIC which is much easier to solder than QFP. If you write the software for the PID microcontroller so that its inputs are "step" and "direction," you can use an existing controller and firmware with no modifications, except slotting in your driver and motor instead of a stepper driver.

Just a FYI for anyone happening to read old posts... TI have dropped their LM3 line completely, i.e. all their Cortex M3 parts. The new line is based on Cortex M4. It seems the LM3 line was too buggy and expensive to fix, so they dropped it. This has made a lot of people unhappy, apparently TI have done this sort of thing before.

Anyway, there are plenty of other manufacturers of Cortex M3 parts to choose from. I think Atmel, NXP and ST have good parts. I don't know about SOIC, but NXP have a DIP part.


What is Open Source?
What is Open Source Hardware?
Open Source in a nutshell: the Four Freedoms
CC BY-NC is not an Open Source license
Sorry, only registered users may post in this forum.

Click here to login