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Genesis V0.5 Documentation

A project log for FarmBot - Open-Source CNC Farming

FarmBot is an open-source CNC farming machine and software package built for small scale, hyper local, DIY food production.

Rory AronsonRory Aronson 07/18/2015 at 17:070 Comments

Genesis V0.5 exhibits the following changes from Genesis V4

Contents

Tracks

Tracks Change LogTracks RenderingsTracks PhotosTracks Bill of Materials
Part NameDescriptionQuantitySourceCost/UnitTotal Cost
Vertical PostsCan be aluminum extrusions, wood posts, or other supporting infrastructure6---
Track Joining Plates3mm thick aluminum plates to join Track Extrusions to Vertical Posts6Self Manufactured~$1~$6
FastenersFor attaching the Track Joining Plates to the Vertical Posts. Could be wood screws, machine screws with tee nuts, etc.12Various Sources~$0.10~$1.20
M5x8mm ScrewsM5 machine screws, 8mm length, 0.8 thread pitch, low-profile 3mm hex heads8OpenBuilds$4.50/25 pieces$4.50
Tee NutsFor attaching M5 screws to OpenBuilds aluminum extrusions8OpenBuilds$4.95/25 pieces$4.95
Track Extrusions20x40mm, 1.5m length V-Slot Aluminum Extrusions4OpenBuilds$19.50$78.00
Tracks Assembly Instructions
  1. Setup the Posts
    1. Depending on where you are installing your FarmBot will change what material and how you might setup your Track Posts. You might use 2x4s of wood, or aluminum extrusions, or existing infrastructure. The posts might attach to a wooden raised bed, or be set in the ground or in small foundations. The choice is up to you how you set this up.
    2. Install short (100-500mm) vertical posts for one of the tracks. Attach or secure the posts however you like, though it is critical to ensure that the posts will not significantly move once installed. Space the posts 1500mm apart, center to center unless you are using shorter track lengths, in which case space the posts that far apart. Ensure the posts are aligned properly and the same height. You may want to use a level to ensure this.
    3. If you are setting up multiple track sections (more than 1500mm in total length), it is best to install the end posts first and tie a guide string in between these two posts to ensure your tracks are installed in a straight line.
    4. Depending on the width of your FarmBot, space the second Track's posts the appropriate distance away from the first Track's. It is critical that the distance between the two sets is consistent, if it is not, there will be unnecessary forces placed on the Gantry and Tracks.
  2. Attach the Track Plates
    1. The track plates should be screwed onto the inside of the posts using the appropriate fasteners: 8mm M5 screws and tee nuts if the posts are aluminum extrusions, standard wood screws if attaching onto wood posts. The top of the posts should NOT be flush with the top of the plates. Rather, the top of the posts should come up to cover only half of the plates.
Tracks Issues and Proposed Solutions

Gantry

Gantry Change LogGantry RenderingsGantry PhotosGantry Bill of Materials
Part NameDescriptionQuantitySourceCost/UnitTotal Cost
Vertical Columns500mm long 20x40mm V-Slot aluminum extrusions2OpenBuilds$6.50$13.00
Gantry Plates3mm thick aluminum or acrylic plates to attach the Track wheels to the Vertical Columns2Self Manufactured with a Laser Cutter, CNC Router, or WaterJet Cutter~$5.00~$10.00
Solid V Wheel KitsEach assembly includes one 25mm M5 screw, one locknut, two bearings, one precision shim, and one solid delrin v-wheel.8OpenBuids$3.95$31.60
1/4 inch Eccentric SpacersFor adjusting the distance between the V-wheels2OpenBuilds$2.00$4.00
Main Beam1.5m long 20x40mm V-Slot aluminum extrusion for spanning the width between the tracks1OpenBuilds$19.50$19.50
Gantry Corner Brackets3mm thick aluminum plates to attach the vertical columns to the main beam2Self Manufactured with a Laser Cutter, CNC Router, or WaterJet Cutter~$5.00~$10.00
Gantry Motor Mount3mm thick aluminum plate to attach the gantry motor to the vertical column1Self Manufactured with a Laser Cutter, CNC Router, or WaterJet Cutter~$5.00~$5.00
NEMA 17 Stepper MotorDual, 5mm shafts with integrated rotary encoder on back side. Used for moving the gantry along the tracks1Unknown~$30.00~$30.00
8mm M3 ScrewsFor attaching the stepper motor to the mounting plate4Pack of 25 from OpenBuilds$2.00$2.00
5mm to 5mm Flex CouplingFor attaching the stepper motor to the drive shaft1Adafruit$4.95$4.95
5mm staineless steel rod1.5m in length1unknown~$20~$20
Drive Shaft Bearing Plate3mm thick aluminum plate to hold the drive shaft's bearing1Self Manufactured with a Laser Cutter, CNC Router, or WaterJet Cutter~$5.00~$5.00
Drive Shaft Bearing16mm OD, 5mm ID, 5mm thickness1OpenBuilds$1.00$1.00
Drive Shaft Lock Collars5mm ID, they capture the drive shaft bearing in place2OpenBuilds$0.90$1.80
Motor Housing3D printed1Self manufactured or ordered from Shapeways~15.00$15.00
Total CostAll components of the Gantry-Various-~$172.85
Gantry Assembly InstructionsAssemble the Gantry Plates

Gather and lay out all of the parts. You will need: 2 Gantry Plates, 8 solid V-wheel kits, and 2 eccentric spacers. It is best to lay out the gantry plates as a mirror image of each other and attach all of the wheel kits facing towards you to ensure you end up with both a left facing and a right facing assembly!

Attach the three solid V-wheel assemblies with normal spacers onto each plate. The order of parts is: Screw head, Plate, Spacer, Wheel Assembly, Lock-nut. Use a 3mm allen wrench and a 8mm crescent wrench to tighten the assemblies. Use a moderate amount of torque.

Attach the single solid V-wheel assembly with the eccentric spacer onto each plate. The eccentric spacer fits into the largest hole on the plate. You should now have two Gantry plates with 4 V-wheel assemblies on each.

Attach the Gantry Plate Assemblies to the Gantry Columns using 4 8mm M5 screws and tee nuts for each assembly. Make sure that the column is attached to the same side of the Gantry Plate as the V-wheel assemblies. It is easiest to partially screw together all of the screws and tee nuts, slide in the extrusion, and then tighten all of the screws at once.

Assemble the Gantry Main Beam

Attach the two corner brackets at either end using 2 8mm M5 screws and tee nuts for each bracket. Make sure both of the brackets are in the same orientation and on the same side of the extrusion.

Lightly screw together 5 sets of 25mm M5 screws and tee nuts and slide them onto the Gantry Main Beam. Evenly distribute them across the beam and then tighten them into place.

Attach the Column Assemblies to the Main Beam Assembly

Using two 8mm M5 screws on each side. Make sure that the V-wheels are facing outward and both of the plates are attached to same side of the Main Beam, and facing in the same direction.

Attach Gantry to TracksFeed and Secure BeltsGantry Issues and Proposed Solutions

Cross-Slide

Cross-Slide Change LogCross-Slide RenderingsCross-Slide PhotosCross-Slide Issues and Proposed Solutions

Z-Axis

Z-Axis Change LogZ-Axis RenderingsZ-Axis PhotosZ-Axis Assembly Instructions

Partially screw 2 8mm M5 screws and tee nuts into the motor mounting bracket. Route the Stepper Motor's cable through the bracket and attach the motor to the bracket with 4 8mm M3 screws.

Z-Axis Issues and Proposed Solutions

Universal Tool Mount

The Universal Tool Mount (UTM) allows FarmBot Genesis to automatically switch tool is on the z-axis depending on the operation needing to be completed. The UTM is ncessary because it is not feasible to have all tools mounted on the z-axis at one time for several reasons:

  1. This would be very heavy and create more stresses on all components, as well as necessitate a larger z-axis motor.
  2. Most tools need to be the "lowest" thing on the z-axis in order to work. Having multiple tools competing for the lowest position (ex: a temperature probe and a seed injector) would not be ideal and may not work at all. The use of individual tool raising and lowering mechanisms, or a turret style mechanism would be complex, heavy, bulky, and limited in the number of tools it could support.
  3. The Z-Axis's size must be kept to a minimum in order for it to have minimal impact on the plants, especially when there is not very much space between them.

The UTM is a single 3D printed component that mounts to the Z-Axis aluminum extrusion using two M5 screws and tee nuts. It features 3 strong neodymium ring magnets to magnetically hold tools in place via washers or other magnets placed in the same configuration on the Tool. The magnets double as the keying system to ensure that tools are properly oriented in the UTM. The magnets also function as the passage ways for water, liquid amendments (eg: fertilizer), and vacuum or compressed air to pass through from the UTM (and the rest of FarmBot) to the Tool. In addition, the UTM has 4 spring loaded screws that make electrical connections with Tools. Two are for power (GND and +5V), and two are for data (0 to +5V).

Universal Tool Mount Change Log

There are many changes from the V4 UTM design including the following. For a video overview of the design, click here.

There are two versions of the Universal Tool Mount this time around. Both are functionally the same, one is simply optimized for the Fused Deposition Modeling (FDM) 3D printing process while the other is optimized for Stereolithography or Selective Laser Sintering (SLS). The major change is that the FDM version is much bulkier so that no support material is needed. This means that the part takes a long time to print, but it requires very little to no manual cleanup once done printing.

The SLS version is significantly smaller in volume, allowing to be printed with less material, thereby saving on time and cost. However, these printers are generally more expensive and not as widely available to the public as FDM printers are such as RepRaps.

Therefore both versions have great merit and will are made available for download. Make sure to select the correct model before printing depending on the process you choose or have access to!

A note about Tools, Power, and Data

Tim Evers and Rory Aronson had a lengthy discussion in email regarding how to handle communication between the tools and the Arduino/RAMPS board. This discussion can be seen on the Universal Tool Mount page. The summary:

FDM Universal Tool Mount RenderingsFDM VersionSLS VersionUniversal Tool Mount PhotosFDM Version

Note: In these photos, there are M3 screws in the mount. I did not have the M5 screws on hand at the time of taking the photo, thought he mount is designed for M5 screws.

SLS VersionUniversal Tool Mount Issues and Proposed Solutions

Electronics

V5 hardware integrates Rotary Encoders onto the back of each of the stepper motors. This is important to ensure that FarmBot always knows where it is in the circumstances when it has been inadvertently moved (by kids or pets) or it tries to move but is prevented from doing so due to some obstruction (rocks, branches, kids, pets). Unfortunately, there are no readily accessible add-on rotary encoders from popular sites like Adafruit or Sparkfun (as of September 2014), however, there are a handful of companies who do produce small, add-on encoders that mount nicely to the back panel of the stepper motor and hook onto a second shaft coming from the motor. The encoders modeled in the renderings below are based on those offered by Schneider Electric.

Electronics RenderingsElectronics PhotosElectronics Issues and Proposed Solutions

Seed Injector

Seed Injector RenderingsSeed Injector Photos

Nutrient Dispenser

Nutrient Dispenser Photos

Manufacturing Files

All of the plates can be CNC routed, laser cut, or waterjet cut. The motor housings, Universal Tool Mount, and Tools can be 3D printed. .STL and .DXF files for manufacturing can be downloaded here.

3D CAD Files

FarmBot Genesis V5 was designed natively in SolidWorks 2014. Using SolidWorks 2014 or a newer version will provide the most seamless experience if you are interested in viewing or modifying the 3D part files. For those without access to SolidWorks, we have converted the files to other commonly used file formats.

All file formats can be downloaded here.

Discussions