Looking for some help.

Trying to draw some vector shapes. I make sure I set the point to home, upload machine spec, and then draw vector. When started via SD card, the motors set to home, servo starts going up and down, with no motor action. What gives? Take a look at my txt file below.

This has happened on other vector drawings, but sometimes I get it to work. Not sure what I am doing wrong here.

Please help!

Thanks in advance!

Hi, i have the same problem with my polargraph sd v2. Have you found any solution to your problem? Best, Simon

@simon - Did you put a home command at the start of the queue you're trying to plot from the SD card? If you've previously uploaded the machine specs, the machine knows where home is, but needs to be told it's at home at the beginning of the drawing.

You only need to upload the machine specs once, and the info will be stored when you power down. At the start of each drawing, however, whether sent from the SD card or the controller, you need to physically put your gondola at the home point (the coordinate you told the machine when you uploaded the specs) and then tell the machine it's there, at home, by sending a "SET HOME" command (otherwise, it doesn't have any idea where the gondola is).

When you're preparing a queue for the SD card, with the queue paused, the first thing you do is hit the SET HOME button and the command will be added to the queue. Then you hit the RENDER PIXELS button to add your drawing commands.

When you start a drawing from SD, you put the gondola in the home position, and select your queue. When it starts, the first thing you should hear are the motors do a little wiggle, which tells you the home command you put at the top of the queue has been executed.

Just want to note that simon is right that the machine doesn't ever store the home point. What "set home" actually does is send a pen position (distance from left sprocket, distance from right sprocket) to the machine, and uses the home point position setting in the controller to generate that position.

Aha, yes that's almost exactly right, and everything that starts with machine.* is a parameter that defines the physical machine:

machine.height
machine.motors.accel
machine.motors.maxSpeed
machine.motors.mmPerRev
machine.motors.stepsPerRev
machine.penlift.down
machine.penlift.up
machine.step.multiplier
machine.width

All of the above are saved on the machine's EEPROM, and are non-volatile, and will survive resets and power-offs. They are sent as part of the "upload machine spec" sequence of commands.

BUT, the only other machine property is machine.pen.size, which is also sent during "upload machine spec", but it IS volatile, and will be reset to a default (0.8 I think) when the arduino starts. There _was_ a really good reason for this not to be saved in EEPROM as well, but I can't remember it now...

What that means is if you're doing something that uses pen width (ie a pixel render style), then you need to always add a "set pen width" to your command queue too.

The home point is considered a feature of the controller app

controller.homepoint.x
controller.homepoint.y

in the same way that the page, the frame or the artwork is. Syntactic sugar!