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farmbots:farmbot-hammerhead

This is the project page for the farmbot I am constructing. It is an indoor farmbot measuring 1.25mx0.5m by about 0.4m. Hammerhead was the first name that came into my head at the time, don't judge me. Current status: Building X

Design Overview

This section presents the general design of the farmbot.

FarmBot Hammerhead is a XYZ cartesian robot built using Aluminium extrusion and wheels as rails, and steppers motors and belts as actuators. The design is heavily based on FarmBot Genesis and my own laziness.

Design patterns

This is a table of design problems, justifications and solutions employed. Minimise effects of vibrations Spring washers are used with fasteners on all structural components (brackets, mounts, gantry) Excessive stepper vibrations/over-current Use a stepper driver which has a max-current setting Wheels binding when bolted to gantry Do not over-tighten, use M5 flat washer between bearings inside wheel Not enough clearance between gantry and rail to attach belt Space the wheels out more using an additional nut.

Bill of materials

M5 Pan head fasteners 1cm 20-50 M5 Pan Head fasteners 4cm 10-20 M5 Pan Head fasteners 2cm 10-20 M5 Nut 40-70 M5 Flat washers 20-50 M5 Spring washers 40-60 V-slot Aluminium extrusion x1M 2 V-slot Aluminium extrusion x25cm 2 V-slot Aluminium extrusion x50cm 3 3mm acrylic idler mount plate (custom) 2 3mm acrylic stepper mount plate (custom) 2 3mm acrylic X-gantry plate (custom) 2 40t GT2 pulley 3 V-slot wheels 16 GT2 idler 2 GT2 Belt 2mm pitch 6mm width 10m roll Twist/cable/belt ties 4 NEMA17 stepper motors 4 3d printed right angle bracket 4

Present status

Under Construction. I am still waiting on parts and building as I go. Currently built a single X slide.

Build

X slide Current status: Almost completed, awaiting 40 tooth pulley

Brackets and motor mount are 3mm laser cut acrylic, the DXF files were from FarmBot Genesis. I use the L bracket designed as part of FarmBot Genesis as a crude but highly effective idler mount. The 20 tooth pulley is too small for the belt to clear the tracks (see pictures) so I will be upgrading to a 40 tooth pulley. Come on, that heatshrink idler literally redefines the phase 'dodgey as fuck'.

Resources

The idler and the motor mount plate .DXF files can be downloaded here.

farmbots/farmbot-hammerhead.txt · Last modified: 2016/10/12 06:36 by roryaronson