Tim's XY Plotter: Tim's XY Plotter Circuit Boards (V3)

Tim's XY Plotter Circuit Boards

(Current)

These are my Current Circuit boards. I made for my XY Plotter here: Tim's XY Plotter.

I changed and fix a few things. (oh and still not quite as I want)

Some details of my old boards can be found here: My Previous Circuit Boards

To see how I make my own PCB's take a look at my Blog here: Tim's PCB (Plotted Circuit Board).

I am controlling the plotter with an Arduino NANO.

Pins currently used are:

Motors
14 (A0) = Stepper Motor 2 direction
15 (A1) = Stepper Motor 2 step
16 (A2) = Stepper Motor 1 direction
17 (A3) = Stepper Motor 1 step
7 (D7) = Enable Stepper Motors.

The drivers are set to 16 micro steps

Stops
2 (D2) = Y Stop
3 (D3) = X Stop

Tools
10 (D10) = Servo 1
9 (D9) = Servo 2
5 (D5) = Tool Power, PWM, On/Off
4 (D4) = Stepper Motor Direction. Auxiliary Height Control (Z)
20 (D20) = Stepper Motor Step. Auxiliary Height Control (Z)

The Stepper Motor Drivers I am using are:

Pololu DRV8825

There are other drivers that are similar and have a compatible pin configuration.
the Pololu DRV8825 has three pins for setting the Step Mode. (if using a different driver check the order of the pins, I have found the sequence to be reversed on some)

For the Pololu DRV8825, the modes are as follows:

MODE2	MODE1	MODE0	STEP MODE
0	0	0	Full step (2-phase excitation) with 71% current
0	0	1	1/2 step (1-2 phase excitation)
0	1	0	1/4 step (W1-2 phase excitation)
0	1	1	8 microsteps/step
1	0	0	16 microsteps/step
1	0	1	32 microsteps/step
1	1	0	32 microsteps/step
1	1	1	32 microsteps/step

I currently have it set at 16 microsteps/step (100).
This is quite high, its pushing the Arduino NANO near to its limit for speed calculations. (I may set it back to 8 if I find it problematic)

The driver also has a small potentiometer for setting the limit on the amperage to the motors.
Video: setting the current limit on Pololu stepper motor driver carriers

The latest HEX file for my plotter is: Tims_Plotter_05.ino.with_bootloader.hex (old bootloader)

The firmware returns "ok" with carriage return and new line, on acknowledge of a command.
The commands it recognizes followed by a carriage return are:
G00 X<dec.number> Y<dec.number>
G00 F<dec.number>
G01 X<dec.number> Y<dec.number>
G02 X<dec.number> Y<dec.number> I<dec.number> J<dec.number>
G03 X<dec.number> Y<dec.number> I<dec.number> J<dec.number>
G04 P<number>
G90

uses
M03 L<number> as on/down (optional level)
M05 L<number> as off/up (optional level)
M18 motors of
M100 help
R01 as reset to home

The reason I am not using an off the shelf grbl shield. (one could be used with different pin configuration in the firmware)

Is because I want to use the standard (Arduino) interrupt pins.
The reason for wanting the interrupt pins is: Future versions may detect out of bounds moment.

My latest software to send plot files can be found here: Tim's XY Stepper Controller

So the first board is the Controller board. (My current Board)
I have managed to get the latest iteration of my board to a size of 100mm 70mm.
This size of board are quite cheep to buy on eBay.

Getting it to fit on the 100x70mm board, I have not left the USB easily accessible, this is not a problem, as I will be connecting to it via Bluetooth.

I made some extensions on my 3D Printer to support it to the existing brackets.

STL Files:
Mount_L.stl
Mount_R.stl

Main changes to the board:
The new board has a 7805 for powering 5v rail.
The 5 volt and 12 volt pinouts are now better placed.
Added Bluetooth Module Socket.
Added I2C Socket.
Added a clone pinout for my Laser, so it can be left plugged in.

Some of the remaining pins not used by the motors and stops are accessible via Pinouts.

I have created the circuit with fitzing, here is the file: Tim's XY Controller (100x70).fzz

To get every thing to fit the 100mm X 70mm Board I was limited to where the components would go.
There is a slight issue when plugging in a USB cable to the Arduino NANO, the cable to the second board needs to be removed.
This is not much of an issue as I will be using Bluetooth to communicate with the plotter, USB is only needed to program the board.

From The controller board there are two 4 core cables running down to the stepper motors, one left and one right. (800mm approx.)
One 8 core cable drops down to the Second Board.(450mm approx.)

The Second board has an optical sensor for the Y Axis Stop, Pinouts from the cable and an other socket for the cable to continue to the Trolley.

On top of the board is fixed a Shutter for the Y Axis Optical Sensor.

STL File:
New X Stop.stl

One Printed the end of the stop needs to be coated with something that won't let Infrared Light through.
I use a black permanent marker.

I have done a video to show that this is necessary when I was modifying my 3D Printer.

I have created the circuit with fitzing, here is the file: Circuit Board X 003.fzz

From this board, the cable continues on to the Trolley.(approx. 400mm)

The Cable is supported at the mid point.

The next board has an Optical Sensor for the X Axis Stop. It also has Pinouts from the cable, some of which are placed in printed sockets for the Servo Plugs.