RTM-100: Robotic time-lapse microscope — Mark Prainito

RTM-100: Robotic time-lapse microscope In design

An infinity-corrected brightfield microscope with a motorized XYZ stage, LED condenser, and autofocus, designed from first principles.

RTM-100 robotic time-lapse microscope, general arrangement drawing: front and side elevations, plan view, sections through the imaging train and LED condenser, a stage stack-up detail, an isometric view, and the key data table. — A compact upright brightfield microscope designed from first principles rather than adapted from an open-source frame. Every subsystem is mine: a rigid aluminum base and column; a three-axis stepper stage (XY sample stage, Z optical head) on MGN12H rails with Tr8×2 lead screws and anti-backlash nuts; an infinity-corrected imaging train built from an RMS objective, an achromatic tube lens and a Raspberry Pi HQ camera; an LED condenser with the diffuser at the condenser's front focal plane; and a custom Pico 2 + TMC2209 controller board running grblHAL.

Python on a Raspberry Pi 5 handles autofocus, drift-locked time-lapse, and tile scanning with stitching, with subject tracking to follow. It is built for long time-lapses such as crystal growth under crossed polarizers. The general-arrangement drawing is Rev A1 (October 2026); every dimension is still being checked against measured parts before anything is cut.

Optical design
Mechanical design
SolidWorks
Altium
Python
2026

Drawing as SVG Full-resolution PNG

Optics
10×/0.25 plan objective, ∞/180; f = 100 mm tube lens; 5.56× onto the sensor

Sensor
IMX477, 1.55 µm pixels; 1.13 × 0.85 mm field; 0.279 µm per pixel

Resolution
1.34 µm (Rayleigh); depth of field 9.9 µm

Stage
X 50, Y 25, Z 100 mm travel; 0.3125 µm per microstep (Tr8×2, NEMA17 0.9°, 1/16)

Illumination
3 W LED, two aspheres, diffuser at F₂; condenser NA 0.10–0.40

Control
Pico 2, 3× TMC2209, LDD-500L, grblHAL; Raspberry Pi 5 host

Frame
MIC-6 base 300 × 250 × 12.7 mm, 2040 column; ≈5 kg, 300 × 276 × 443 mm

LED condenser layout: the LED on its heatsink, collector asphere L1, the diffuser and aperture disc at the front focal plane of condenser asphere L2, and the sample plane 43 mm above the base, with ray paths for one LED point and one diffuser point. — A compact upright brightfield microscope designed from first principles rather than adapted from an open-source frame. Every subsystem is mine: a rigid aluminum base and column; a three-axis stepper stage (XY sample stage, Z optical head) on MGN12H rails with Tr8×2 lead screws and anti-backlash nuts; an infinity-corrected imaging train built from an RMS objective, an achromatic tube lens and a Raspberry Pi HQ camera; an LED condenser with the diffuser at the condenser's front focal plane; and a custom Pico 2 + TMC2209 controller board running grblHAL.

Python on a Raspberry Pi 5 handles autofocus, drift-locked time-lapse, and tile scanning with stitching, with subject tracking to follow. It is built for long time-lapses such as crystal growth under crossed polarizers. The general-arrangement drawing is Rev A1 (October 2026); every dimension is still being checked against measured parts before anything is cut.

Optical design
Mechanical design
SolidWorks
Altium
Python
2026

Drawing as SVG Full-resolution PNG

Optics
10×/0.25 plan objective, ∞/180; f = 100 mm tube lens; 5.56× onto the sensor

Sensor
IMX477, 1.55 µm pixels; 1.13 × 0.85 mm field; 0.279 µm per pixel

Resolution
1.34 µm (Rayleigh); depth of field 9.9 µm

Stage
X 50, Y 25, Z 100 mm travel; 0.3125 µm per microstep (Tr8×2, NEMA17 0.9°, 1/16)

Illumination
3 W LED, two aspheres, diffuser at F₂; condenser NA 0.10–0.40

Control
Pico 2, 3× TMC2209, LDD-500L, grblHAL; Raspberry Pi 5 host

Frame
MIC-6 base 300 × 250 × 12.7 mm, 2040 column; ≈5 kg, 300 × 276 × 443 mm