Cheap Hall effect sensor endstop

thingiverse

Improve your Solidoodle printer by using cheap Hall effect sensors as magnetic endstops. These sensors are very accurate, wear-free and easy to replace with mechanical switches. Unlike the Hall-O, they trigger on a fixed magnetic field strength and can't be calibrated. They cost just 20 cents per piece. John used A3144 temperature-resistant sensors, but OHN3019 were chosen for availability and price. Both types have an integrated voltage regulator and can be driven with 4.5-24V, allowing direct attachment to the endstop connector of the sanguinololu without additional logic. The only downside is hysteresis, which causes the sensor to remain triggered after being activated until a specific distance is reached. Print a replacement part in Sketchup 8 for your Solidoodle 2's mechanical endstops with 2 layers and 0.3 infill, as there should be no force on this part. To install magnetic endstops, follow these steps: 1) Print the replacement part; 2) choose supply voltage on solder pads at the back of the sanguinololu; 3) change firmware parameter '_ENDSTOPS_INVERTING' to true for the axis being modified; 4) solder three 35cm wires to sensor pins; 5) reuse endstop connector and insert new wires; 6) connect wires to sensor according to pinout; 7) test with Pronterface and a magnet; 8) glue sensor into part and install with matching magnet; 9) carefully test again. Always be cautious during testing, as damage may occur if the endstop doesn't react properly. Links to relevant sources are provided in the instructions. Note: The author is not responsible for any losses, damages or liabilities resulting from using this part.