%load all the FEMM functions. the folder with all the M files for FEMM should have already been added to path 
addpath('c:\\femm42\\mfiles');
openfemm;

function make_round_turn(x, y, radius, material, circuit)
	x1 = x - radius;
	x2 = x + radius; 
	y1 = y; 
	y2 = y; 

	mi_drawarc(x1, y1, x2, y2, 180, 10);
	mi_addarc(x2, y2, x1, y1, 180, 10);

	mi_addblocklabel(x,y);
	mi_selectlabel(x,y);
	%comment out first for automeshing
	mi_setblockprop(material, 1, 0, circuit, 0, 0, 1); 
	%mi_setblockprop(material, 0, 10E-3, circuit, 0, 0, 1);
	mi_clearselected;
endfunction

function make_rectangle(x, y, w, h, material, circuit)
	x1 = x - w/2;
	y1 = y - h/2;
	x2 = x + w/2;
	y2 = y - h/2;
	x3 = x + w/2;
	y3 = y + h/2;
	x4 = x - w/2;
	y4 = y + h/2;

	mi_drawpolygon([x1,y1;x2,y2;x3,y3;x4,y4])

	mi_addblocklabel(x,y);
	mi_selectlabel(x,y);
	%comment out first for automeshing
	mi_setblockprop(material, 1, 0, circuit, 0, 0, 1); 
	%mi_setblockprop(material, 0, 10E-3, circuit, 0, 0, 1);
	mi_clearselected;
endfunction

% materials 
copper_conductivity = 58.0;

%parameters. All dimentions in mm 
w_trace = 1; % width trace 
h_trace = 0.035; %thickness of 1oz copper
h_pcb = 1.6; % 0.2mm prepreg 
freq = 0;
probe_offset = 0.05; % distance from probe tip to wire

%constants 
i_wire = 1;
%sensor_offset = 1.6; %offset of from sensor to end of probe tip
sensor_offset = 0.5;
probe_sensitivity_H = 0.8; %volts/gauss
probe_sensitivity_L = 0.2; 
probe_max_G = 6.0; % max field strength for sensor saturation

trace_widths = [0.05 : 0.05 : 3]
field_strengths = []
for w_trace = trace_widths

	%create new document 
	% "0 for a magnetics problem, 1 for an electrostatics problem, 2 for a heat flow problem, or 3 for a current flow problem"
	newdocument(0);

	% Define the problem type.  Magnetostatic; Units of mm; Axisymmetric; 
	% Precision of 10^(-8) for the linear solver; a placeholder of 0 for 
	% the depth dimension, and an angle constraint of 30 degrees

	%(freq,units,type,precision,depth,minangle,(acsolver))
	mi_probdef(freq, 'millimeters', 'planar', 1.e-8, 100, 30);

	%define materials and circuits 

	mi_addmaterial('Air', 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0);
	mi_addmaterial('Copper', 1, 1, 0, 0, copper_conductivity, 0, 0, 1, 0, 0, 0);

	mi_addcircprop('iwire', i_wire, 1);
	mi_addcircprop('iwireN', -1*i_wire, 1);

	%air 
	mi_addblocklabel(0, -2);
	mi_selectlabel(0,-2);
	% (’blockname’, automesh, meshsize, ’incircuit’, magdir, group, turns) 
	mi_setblockprop('Air', 1, 0, '<None>', 0, 0, 0);
	mi_clearselected

	% top trace
	make_rectangle(0, h_pcb/2 + h_trace/2, w_trace, h_trace, 'Copper', 'iwire');
	% return path
	make_rectangle(0, -h_pcb/2- h_trace/2, max(w_trace * 20, 20 * h_pcb), h_trace, 'Copper', 'iwireN');


	%boundary condition 
	mi_makeABC(5, max(w_trace * 20, 50), 0,0, 0);
	mi_saveas('trace.fem');

	% mesh 
	smartmesh(1);
	mi_createmesh();


	%run simulation 
	mi_analyze();
	mi_loadsolution();

	%obtain B field

	measuredB = abs(mo_getb(0,(h_pcb/2 + probe_offset + sensor_offset))(1));
	measuredG = measuredB ./ 1E-4; % convert tesla to gauss
	current_sensitivity_H = measuredG * probe_sensitivity_H;
	current_sensitivity_L = measuredG * probe_sensitivity_L;

	probe_max_current = probe_max_G ./ measuredG;
	disp("Field Strength:");
	disp(measuredG);
	disp("Sensitivity High Gain:");
	disp(current_sensitivity_H);
	disp("Sensitivity Low Gain:");
	disp(current_sensitivity_L);
	disp("Max Current:");
	disp(probe_max_current);

	field_strengths = [field_strengths measuredG]
	mi_close();
endfor

export_data = [trace_widths;field_strengths]';  % '
csvwrite("trace_fields.csv", export_data )