jlauer

Hey all, for what it’s worth, I got intrigued by this problem to get ChiliPeppr to do on-the-fly Gcode conversion as you send your job to a 4 pulley system. I did a Google Hangout with Jordan to talk through it. I did a bit more work after the Hangout to figure out the final calculations of a 4 pulley system to calculate the length of wire needed for a 4 pulley system to achieve an XYZ coordinate.

Here’s the code that calculates the length with a sample image of what I’m calculating:

// To achieve a floating/hanging object at a sample position of 6,2,3
var x = 6;
var y = 2;
var z = 3;
		
// what are the positions of each corner for the pulleys so we can calc
var fl_pos = {x:0,y:0,z:10};
var bl_pos = {x:0,y:10,z:10};
var br_pos = {x:10,y:10,z:10};
var fr_pos = {x:10,y:0,z:10};

// convert XYZ cartesion coordinates to XYZA (fl,bl,br,fr) pulley lengths
// fl=front left, bl=back left, br=back right, fr=front right
// Find hypotenuse length for fl,bl,br,fr in xy plane
var fl_xy_hyp = Math.sqrt((x * x) + (y * y));
var bl_xy_hyp = Math.sqrt((x * x) + ((bl_pos.y - y) * (bl_pos.y - y)));
var br_xy_hyp = Math.sqrt(((br_pos.x - x) * (br_pos.x - x)) + ((br_pos.y - y) * (br_pos.y - y)));
var fr_xy_hyp = Math.sqrt(((fr_pos.x - x) * (fr_pos.x - x)) + (Math.abs(fr_pos.y - y) * Math.abs(fr_pos.y - y)));

// Find hypotenuse length for z plane 
var fl_hyp = Math.sqrt((fl_xy_hyp * fl_xy_hyp) + ((fl_pos.z - z) * (fl_pos.z - z)));
var bl_hyp = Math.sqrt((bl_xy_hyp * bl_xy_hyp) + ((bl_pos.z - z) * (bl_pos.z - z)));
var br_hyp = Math.sqrt((br_xy_hyp * br_xy_hyp) + ((br_pos.z - z) * (br_pos.z - z)));
var fr_hyp = Math.sqrt((fr_xy_hyp * fr_xy_hyp) + ((fr_pos.z - z) * (fr_pos.z - z)));

console.log("Pulley len FL:", fl_hyp, "len BL:", bl_hyp, "len BR:", br_hyp, "len FR:", fr_hyp);

Now, if that code is good, you can paste in this entire macro and run it. It will attach to the Gcode send event. Rewrite the gcode to XYZA and you should get your steppers unreeling the correct amount of wire. I mapped X to the front-left pulley, Y to back-left pulley, Z to back-right pulley, and A to front-right pulley. The A would still have to get configured to counter-act the fact that it’s set for angles rather than linear coordinates. I still don’t have that one figured out, but Alden gave some pointers.

// rewrite g-code to 4axis pulley system
var myMacro = {
	init: function() {
		// Uninit previous runs to unsubscribe correctly, i.e.
		// so we don't subscribe 100's of times each time we modify
		// and run this macro
		if (window["myMacro"]) {
			macro.status("This macro was run before. Cleaning up...");
			window["myMacro"].uninit();
		}
		macro.status("Starting watch on pulley rewrite macro");
		// subscribe to JSON send at a higher priority than the default
		// so we can intercept these pubsub's before they go to the TinyG
		// cuz we're going to rewrite them
		chilipeppr.subscribe('/com-chilipeppr-widget-serialport/jsonSend', this, this.onJsonSend, 5);
		// store macro in window object so we have it next time thru
		window["myMacro"] = this;
		
		// get 3d coordinates by asking the 3d viewer to give them to us 
		// we'll get this.obj3d set for us so we can use it later
		this.getXyzCoords();
	},
	uninit: function() {
		macro.status("Uninitting macro.");
		chilipeppr.unsubscribe("/com-chilipeppr-widget-serialport/jsonSend", this.onJsonSend);
	},
	onJsonSend: function(data) {
		console.group('pulley rewrite'); 
		console.log(data);
		
		// if the data is an array, then return immediately because we only want to do a rewrite
		// when jsonSend is individual lines, not when its a multiline array object.
		// this might seem odd why, but chilipeppr sends lines individually at first and does
		// it's own ganging up if user picked "multi-line" mode, so let's not rewrite stuff
		// over and over. just know that if you look for a single line you're safe.
		if (Array.isArray(data)) {
			console.log("data was an array, so returning immediately cuz don't want to modify arrays of jsonData");
			console.groupEnd();
			return;
		}
		
		// extract the line from the ID which is of the form "g45" for line 45
		var line = parseInt(data.Id.replace(/g/, ""));

		// get xyz coords and cleaned up meta data for gcode from the 3d viewer parsed data
		var coord = this.getXyzCoordsForLine(line);
		console.log("xyz coords for line:", line, coord);

		// check if we have a cmd and if it is a G0 or G1, otherwise return
		if ('cmd' in coord.meta.args && coord.meta.args.cmd.match(/g1|g0/i)) {
			console.log("this is a command we want to process. good.");
		} else {
			console.log("This gcode line did not contain a G0 or G1 command, so not rewriting");
			console.groupEnd();
			return;
		}
		
		var cmd = coord.meta.args.cmd;

		// get simple vars for xyz
		var x = coord.end.x;
		var y = coord.end.y;
		var z = coord.end.z;
		
		//var x = 6;
		//var y = 2;
		//var z = 3;
		
		// what are the positions of each corner for the pulleys so we can calc
		var fl_pos = {x:0,y:0,z:10};
		var bl_pos = {x:0,y:10,z:10};
		var br_pos = {x:10,y:10,z:10};
		var fr_pos = {x:10,y:0,z:10};

		// convert XYZ cartesion coordinates to XYZA (fl,bl,br,fr) pulley lengths
		// fl=front left, bl=back left, br=back right, fr=front right
		// Find hypotenuse length for fl,bl,br,fr in xy plane
		var fl_xy_hyp = Math.sqrt((x * x) + (y * y));
		var bl_xy_hyp = Math.sqrt((x * x) + ((bl_pos.y - y) * (bl_pos.y - y)));
		var br_xy_hyp = Math.sqrt(((br_pos.x - x) * (br_pos.x - x)) + ((br_pos.y - y) * (br_pos.y - y)));
		var fr_xy_hyp = Math.sqrt(((fr_pos.x - x) * (fr_pos.x - x)) + (Math.abs(fr_pos.y - y) * Math.abs(fr_pos.y - y)));
		
		// Find hypotenuse length for z plane 
		var fl_hyp = Math.sqrt((fl_xy_hyp * fl_xy_hyp) + ((fl_pos.z - z) * (fl_pos.z - z)));
		var bl_hyp = Math.sqrt((bl_xy_hyp * bl_xy_hyp) + ((bl_pos.z - z) * (bl_pos.z - z)));
		var br_hyp = Math.sqrt((br_xy_hyp * br_xy_hyp) + ((br_pos.z - z) * (br_pos.z - z)));
		var fr_hyp = Math.sqrt((fr_xy_hyp * fr_xy_hyp) + ((fr_pos.z - z) * (fr_pos.z - z)));
		
		console.log("Pulley len FL:", fl_hyp, "len BL:", bl_hyp, "len BR:", br_hyp, "len FR:", fr_hyp);
				
		var gcode = cmd + " X" + fl_hyp + " Y" + bl_hyp + " Z" + br_hyp + " A" + fr_hyp;
		console.log("Final gcode:", gcode);

		// see if there was a feedrate
		if ('f' in coord.meta.args) {
			console.log("there was a feedrate:", coord.meta.args.f);
			gcode += " F" + coord.meta.args.f;
		}
		gcode += "\n";
		
		//republish the gcode command that was intercepted
		var obj = {D: gcode, Id: data.Id};
		// unsubscribe so that we don't get our own rewritten gcode coming back to us
		chilipeppr.unsubscribe('/com-chilipeppr-widget-serialport/jsonSend', this.onJsonSend); 
		// send the gcode off as if nothing really changed, even tho we completely rewrote it
		chilipeppr.publish('/com-chilipeppr-widget-serialport/jsonSend', obj);
		// resubscribe immediately so we can rewrite the next line of gcode
		chilipeppr.subscribe('/com-chilipeppr-widget-serialport/jsonSend', this, this.onJsonSend, 5);
		
		console.groupEnd();
		return false;
	},
	obj3d: null,
	getXyzCoords: function() {
		chilipeppr.subscribe("/com-chilipeppr-widget-3dviewer/recv3dObject", this, this.getXyzCoordsRecv3dObj);
		chilipeppr.publish("/com-chilipeppr-widget-3dviewer/request3dObject", "");
	},
	getXyzCoordsRecv3dObj: function(obj3d) {
		console.log("Got our 3d obj. Line count:", obj3d.userData.lines.length);
		this.obj3d = obj3d;
		// unsub so we don't get anymore callbacks on this
		chilipeppr.unsubscribe("/com-chilipeppr-widget-3dviewer/recv3dObject", this.getXyzCoordsRecv3dObj);
	},
	getXyzCoordsForLine: function(line) {
		console.log("getXyzCoordsForLine. line:", line);
		var ret = { 
			start: {
				index: null, x: null, y: null, z: null
			},
			end: {
				index: null, x: null, y: null, z: null
			},
			meta: null
		};
		var indx = line - 2;
		if (indx < 0) indx = 0;
		ret.start.index = indx;
		ret.start.x = this.obj3d.userData.lines[indx].p2.x;
		ret.start.y = this.obj3d.userData.lines[indx].p2.y;
		ret.start.z = this.obj3d.userData.lines[indx].p2.z;
		indx = line - 1;
		ret.end.index = indx;
		ret.end.x = this.obj3d.userData.lines[indx].p2.x;
		ret.end.y = this.obj3d.userData.lines[indx].p2.y;
		ret.end.z = this.obj3d.userData.lines[indx].p2.z;
		ret.meta = this.obj3d.userData.lines[indx];
		return ret;
	}
}
myMacro.init();

• This reply was modified 10 years, 1 month ago by jlauer.
• This reply was modified 10 years, 1 month ago by jlauer.

Hi inacio,

Want to jump on a Google hangout real quick? I’d like to perhaps give some ideas on how to do this in ChiliPeppr. I think the code will be easier and you’ll gain all the benefits of the 3D viewer and the rest of the community being able to benefit off your work. I could get you started on how to intercept the Gcode and convert to your 4 axis pulley system. I could do it right now if you’re available. I’m jlauer12@gmail.com on Google Hangouts.

-John

Hey Matt,

I do some laser engraving/cutting but use around a 3W diode, so I’m guessing you’re using a 40W CO2 which can cut a lot more stuff. The key trick is using the M3/M5 commands for spindle on/off to instead trigger your laser. There’s also the other trick of controlling an Arduino in parallel to the TinyG movements. This trick additionally uses the Z axis value to decide when to turn the laser on/off instead of M3/M5 (this can create the ability to use more Gcode workflow tools to generate your laser commands). You can see how I’m doing it in the laser soldering video with TinyG. https://www.youtube.com/watch?v=T2h7hagVfnA

If you need super fine toggling of the laser for imprinting images that is a tougher problem as you have to sync the TinyG moves and the laser toggling at a super high rate. I think this could be done by soldering to the “step” pin on the A axis (or other) and setting the TinyG steps/mm to be your toggle setting, i.e. if you want to toggle the laser on/off 1000 times per second and your feedrate is 1mm/sec you can get 1000 on/off’s per mm. Then you have to figure out how to setup the A axis correctly for the correct steps to correspond to your engraving. If this is your approach you could create a widget in ChiliPeppr and a new workspace where you drop-in that widget that intercepts the Gcode, calculates the A axis value, and the rewrites the Gcode.

-John

• This reply was modified 10 years, 1 month ago by jlauer.

Hey James,

I’m in Seattle, so not quite the bay area, but at least same time zone. I’m really early on in thinking through what elements are needed for the Pick and Place project. The part I’m working on right now is a laser solderer. Not sure it’s going to work though. I have the hardware built and now adding a widget to ChiliPeppr to control it. It’s got a PID to control the laser to not overcook the solder using the Melexis MLX90614 infrared heat sensor. I have a USB Microscope mounted to be able to see the process.

So far I don’t need a fiducial for recognition as I already know the location from the PCB Gcode, however I’m keen to see if the fiducial recognition can happen inside ChiliPeppr because it is a fundamental item that will be needed for a lot of things in the future. I have a lot of webcam integration built using WebRTC. The cool thing with WebRTC is you can just grab a frame and then process it as a bitmap to do things like object detection. This blog seems to give a decent rundown on object detection using WebRTC. http://techslides.com/object-detection-with-html5-getusermedia/

-John

Yeah. It’s official. We needed one.

https://groups.google.com/forum/#!forum/chilipeppr

Here’s my suggestion using ChiliPeppr. One of the design goals was to let you bind into multiple serial ports at the same time from CP so you could sync your CNC commands with other hardware (thus a hardware fiddle). So, I would setup an Arduino that reads your sensor on your spindle. Then write a tiny bit of code that just spits out the sensor position every 250ms or perhaps when you request it. Then write a macro in CP that binds into the serial port with your sensor.

chilipeppr.subscribe("/com-chilipeppr-widget-serialport/ws/recv", function(data) {
    if (data.P == "COM4") {
        // this is data from my Arduino sensor
        if (data.D.match(/1000/)) {
            // I'm at 1000rpm, now move Z into aluminum
            chilipeppr.publish("/com-chilipeppr-widget-serialport/send", "G1 Z-2 F100\n");
        }
    }
});

• This reply was modified 10 years, 3 months ago by jlauer.

I will be setting one up this week. We DEFINITELY need a forum for it. Any suggestions on best forum? I’m pretty Google-centric since it’s on Google App Engine and uses a Google login, but Google’s forum is kinda old feeling and Google+ Pages aren’t ideal for a forum either.

Also, released v1.3 of the Serial Port JSON Server last night. It increases performance and reliability of never losing Gcode ever due to buffer overflows.