Sensors: MAX31820

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MAX31820 is a cheaper replacement for the DS18B20 1-Wire (TM) temperature probe.

The DS18B20 was originally manufactured by Dallas Semiconductor. Maxim bought Dallas Semi and continues to manufacture the 1-Wire line of temperature sensors with the MAX31820.

The main differences between the DS18B20 and the MAX31820 are:

  1. Power supply range (DS18B20 is 3 - 5 VDC, MAX31820 is 3.3 VDC).
  2. Temperature accuracy range (MAX31820 is as accurate but over a narrower temperature range).
  3. Price (the MAX31820 is about half the price of the DS18B20).
  4. Counterfeits (the DS18B20 is counterfeited by Russian and Chinese companies).

  • Two MAX31820s installed in a probe designed to slip between two frames


  • SCAD script to print the probes:
union() {
   translate([2.5,143.7,.4]) rotate ([0,0,15]) cube([1,4,3.6]); 
   translate([4.9,143.9,.4]) rotate ([0,0,-15]) cube([1,4,3.6]); 
   translate([1.45,147.5,.4]) cube([1,4,3.6]); 
   difference() {
           translate([.2,0,0]) cube([8,160,4]);
           translate([4.5,160,0]) scale([1,1,2]) rotate ([90,0,0]) cylinder(2,10,10, $fn=180);
           translate([-1.8,141,0]) cube([12,19,4]);
           translate([6.25,135,0]) rotate ([0,0,-17]) cube([2,7,4]);
           translate([.2,134.4,0]) rotate ([0,0,17]) cube([2,7,4]);       
      translate([1.2,5,.5]) cube([1.4,150,2]);
      translate([3.5,5,.5]) cube([1.4,150,2]);
      translate([5.8,5,.5]) cube([1.4,150,2]);
      translate([.2,144,.5]) cube([1.4,9,2]);
      translate([6.8,144,.5]) cube([1.4,9,2]);
      translate([1.2,2,.5]) cube([6,8,10]);
      translate([1.2,2,2.4]) cube([6,9,10]);
      translate([1.2,14,2.4]) cube([6,7,10]);    
      translate([1.2,132,.5]) cube([6,8,10]);
      translate([1.2,131,2.4]) cube([6,10,10]);
      translate([-.7,144,.5]) cube([10,11,10]);
      translate([-.7,144,2.4]) cube([10,6,10]);    
      translate([4.25,161,2])  rotate ([90,0,0]) cylinder(12,1.8,1.8, $fn=180);
      translate([-10,145,-30]) cube([30,30,30]);