Automic LED
Description
Design of a microscope capable of positioning and moving along the XYZ axes, using high-accuracy motion transmission systems. The microscope is equipped with an LED light source of different wavelengths, The microscope is illuminated axially by a surface-mounted LED, which contains different colours, including red, green, blue, white, violet and yellow. The LED is powered by a variable voltage source from a pulse-width modulation (PWM) signal to analogue voltage converter. The PWM signal is supplied by the PCA9685 controller, which has 16 control outputs and communicates with the NVIDIA Jetson Orin Nano board via I2C through port 2. This multi-colour LED system was replicated in the observation base of the system, where the sample is placed. The system incorporates six distinct individual controls for each of the three 6-colour LED units. The two missing lines, in addition to the supplementary controls incorporated into the device – such as the light inside the machine and the endstops sensors – are managed and interpreted by an Arduino Nano development board. This board communicates with the NVIDIA Jetson Orin Nano board via I2C through port 1. The control app has been programmed in Python 3 and is supported by the Jetson Orin Nano artificial intelligence card. In order to construct and implement this work, the traction and motion system was modelled in 3D program Fusion 360, incorporating both commercial components and bespoke designs, which were then processed using a resin 3D printer Photon Mono 2. Subsequently, the equipment was electronically instrumented using TMC2209 stepper motor driver to control traction.
Files
Steps to reproduce
The core of the machine is constituted by the 3-axis linear motion system. The system performs the longitudinal movement on the X-axis based on a 12 mm diameter, 4-wire steel rod, structured as a ball screw, with a ball nut SFU1204 on which the carriages MGN12 slide on 12 mm steel rods. The shaft has been engineered with precision to accommodate the respective EK and EF mountings, in this case designated as EK10 and EF10, respectively. The longitudinal X-axis comprises two replicas of this arrangement. The fixing system is constituted of a 6 mm-thick aluminium plate that has been pre-machined to accommodate the EF and EK ball screw mount with standard sheet metal threading. The perforations in the plate were produced by means of a fibre laser. The motion motors are NEMA 17 stepper motors, which are powered by 12 volts of direct current. The motor shaft and spindle are supported by a standard flexible single shaft coupling, which is notable for its absence of a wedge and the presence of a grub screw. The motor is supported on a resin structure designed exclusively for this device, which is printed in resin with a 4k monochrome MSLA printer. For the Y-axis drive, a resin-printed, mountable structure was utilised on the ball nut of the X-axis drive spindle, which is mounted on two sliding load carriages MGN12, sliding along 12C linear guide. The guide was fastened to the mounting plate in a manner that ensured both its tightness and parallelism, with the objective of preventing fractures and deflections of the carriages. The material selected for this project was 6061 aluminium. The material has a Young's modulus of 69 GPa and a density of 2.7 g/cm3. The thickness of 4.8 mm was deemed sufficient to meet the mechanical loading demands, in addition to fulfilling mounting requirements. The maximum load that can be estimated is 8.75 kilograms in total, with tensile forces of less than 37 N. Lateral movement of the optical system in the Y-axis is achieved by means of traction provided by a 4-thread acme T8 threaded rod with an anti-backlashing nut system mounted in the centre of a sliding axis, consisting of two 12 mm steel rods. The guides permit the movement of the commercially available cast aluminium element via linear bearings at each end. This element is responsible for supporting the optical system of the cylindrical microscope, which is specifically selected for this application. It provides adequate support for the microscope, which is equipped with three objectives of 5, 10 and 20x, in addition to a 12-megapixel C-mount camera. The rod is coupled to a NEMA 17 stepper motor, the function of which is to provide the drive. For the Z-axis drive, a NEMA 17 stepper motor was utilised, which was coupled to an 8 mm steel rod sliding system attached to the Y-axis aluminium element. This configuration enabled the microscope objectives to be zoomed in. The mechanism functions through utilisation of a T8 acme threaded road, comprising four threads.
Institutions
- Tecnológico Nacional de MéxicoMexico City, Mexico City