Differential infrared z probe

thingiverse

This is a modified version of David Crockers differential infrared Z probe. I uploaded the Eagle source files, allowing you to customize them as needed. In addition, I have included the Gerber files in a zip file, which I sent to Elecrow for manufacturing the PCB (they offer affordable rates, with two-sided PCBs available for just one dollar). If you're interested in ordering this PCB from Elecrow, please use my referral link: http://www.elecrow.com/referral-program/MTgxNjBqMnQ=/. I made several changes to the original design. I replaced the SMD IR diodes with regular ones, as they can be obtained at a low cost. The diodes are also mounted in a shroud, ensuring proper positioning and minimizing the impact of the wider opening angle. Furthermore, I exchanged the large capacitor for a ceramic SMD one. Please note that this PCB is not compatible with David Crockers IR board in terms of dimensions, so I designed a custom mount for it. However, I don't have an E3DV6 mount or similar, as my printer is a replicator. Here's the BOM: * 1 x SMD Resistor 3.3kohm 1206 * 2 x SMD Resistor 3kohm 1206 * 1 x SMD Resistor 1kohm 1206 * 1 x SMD Resistor 866ohm 1206 * 1 x SMD Resistor 330ohm 1206 * 1 x SMD Capacitor 22uF 1206 * 1 x SMD Capacitor 100nF 1206 * 1 x SMD Capacitor 1nF 1206 * 1 x SMD Inductance 1uH 1206 * 1 x SMD LED Red 1206 * 1 x Attiny25-20su * 2 x Infrared LED (SFH4550 or a 3mm IR diode, available in pairs with photodiodes on Aliexpress) * 1 x Photodiode (the original spec uses a phototransistor; simply add a transistor to the diode if necessary) * 1 x PCB (manufacture it at Elecrow or mill it yourself) Notes: * The photo diode in the schematic must be reversed, and the printed + and - symbols on the PCB need to be reversed as well. * The SFH4550 IR diodes have a small opening angle, but any cheap IR diode with the shroud can be used. The shroud only fits 3mm diodes; if you're using the SFH4550, you'll need to modify it. * Angles of the diodes are 56 and 45 degrees, calculated for optimal precision. Trigger height is 4mm. Unfortunately, I don't have images of the printed part. You can find the firmware for programming the Attiny here: https://github.com/dc42/OrmerodSensorBoard/tree/master/Firmware/Mini-differential-IR/V1.2 I'd like to extend my gratitude to David Crockers for his Omerod design: https://miscsolutions.wordpress.com/mini-height-sensor-board/. PS: You might want to consider replacing the 1206 parts with smaller ones, allowing you to make the PCB smaller and matching it with the Crockers board dimensions.