Fab@Home:Model 1 Cables
From Fab @ Home
Welcome to the Fab@Home Model 1 Cables Page
Here you will learn how to make all of the cables for the Fab@Home Model 1.
Power Supply Cable
The Elpac power supply provides 24 volts DC for the stepper motor amplifier. The Xylotex amplifier board power connection is via screw terminals, while the power supply cable terminates with with a power jack. The connector needs to be removed, and the power cable sheath stripped, and the conductors stripped and tinned.
Cable Extensions for HSI Motors
The HSI Motors come prewired with 12" long leads, colored red, red-white stripe, green, green-white stripe. You will need to extend the prewired leads by soldering on extensions using 4 Conductor Shielded 22awg cable. Each motor requires a slightly different length of extension to allow reach to the amplifier board while allowing enough slack for motion. In the table below, you can find the recommended extension lengths for the X, Y, and Z motors, and for the 1-Syringe Tool motor. Total length is measured from the body of the motor, extension length is the addtional amount of cable required, and is the total length less the 12" long prewired leads on the motors. For details on how to prepare the motor cable extensions, see:
|Model 1 Motor Cable Extension Lengths||(Metric)|
|Motor||Total Length||Extension Length||Total Length||Extension Length|
|X Motor||32 inch||20 inch||81.28 cm||50.8 cm|
|Y Motor||35 inch||23 inch||88.9 cm||58.42 cm|
|Z Motor||25 inch||13 inch||63.5 cm||33.02 cm|
|1-Syringe Tool Motor||52 inch||40 inch||132.08 cm||101.6 cm|
Cables for Limit Switches
The Model 1 design includes 6 limit switches for the chassis motion axes, 2 per axis. The limit switches on the Model 1 provide a signal to the microcontroller when the axes have moved as far as they can. The microcontroller can then stop trying to move that axis, preventing damage to the hardware. You need to make some cables to connect the limit switches to the microcontroller (via the amplifier board). Here you can find the recommended length of cable to make for each switch. You should use the "2 Conductor No Shield 22awg" cable for this purpose. The limit switch simply breaks a circuit, so it does not matter which color of conductor from the cable connects to which pin of the switch. For details on how to prepare the cables, see:
|Limit Switch Cable Lengths||(Metric)|
|Switch Axis Location||Cable Length||Cable Length|
|X Front||31 inch||78.74 cm|
|X Rear||23 inch||58.42 cm|
|Y Left||52 inch||132.08 cm|
|Y Right||52 inch||132.08 cm|
|Z Top||30 inch||76.2 cm|
|Z Bottom||11 inch||27.94 cm|
There are three ribbon cables required for the Model 1. These are:
To prepare these two ribbon cables, proceed as follows:
Step 2:Make an IDC connector on the end of each piece of ribbon cable, as described in the Assembly Tips for IDC Connectors page, and label the cables as IDC26 #1 and #2 - to keep them distinct
Step 4:Referring to the Electronics Schematic, strip and tin the appropriate conductors of the ribbon cables to make the connections between the LPC-H2148 and the Winford DB25 breakout board. Note the orientation of the cables - start counting from the right (which should be the red conductor on grey ribbon) with the connector down and connector pins facing you.
Amplifier Enable Cable
Updated: 14:59, 4 May 2007 (EDT)
Note that amplifier enables require firmware version 3.
Because stepper motors have a constant current running through them during operation, they can become quite hot. The Xylotex amplifier board has an electronic interface which allows an external device to enable/disable the amplifiers on demand, and here we will make a cable which will allow the LPC-H2148 to shut off the amplifier when it is sitting idle.
Step 2:From the extra ribbon cable leftover from above, peel off 2 strands, and cut them to 4" (100mm) in length. You will also need two of the jumpers that you removed from the Xylotex board in Step 1.
Bundling and Routing the Cables
Here you will see some recommendations for protecting, organizing, and routing the various cables of your Fab@Home Model 1. The Model 1 Bill of Materials includes polyester braiding, which is a loosely woven tube of polyester. When squeezed longitudinally, this braiding will expand to many times its relaxed diameters, allowing you fit several cables inside. The braid then relaxes down around the cables, grouping them and protecting them from abrasion. For help with cutting, sealing, and threading cables through braiding, see:
|Braid Lengths, and Cable Bundling||(Metric)|
|Bundle Name||Cables in Bundle||Braid Length (relaxed)||Braid Length (relaxed)|
|X Bundle||X-axis motor cable, X-front limit switch||31 inches||78.74 cm|
|Z Bundle||Z-axis motor cable, Z-top limit switch||30 inch||76.2 cm|
|Y Carriage Bundle||Y-axis motor cable, Y-left and Y-right limit switches||52 inch||132.08 cm|
|1-Syringe Tool||Syringe tool motor||52 inch||132.08 cm|
Note:The above lengths provide the simplest bundling process. If you would like to conserve braid and/or more tightly bundle your cables, you can bundle the X, Y, and Z bundles together in the same braid by passing cables through the wall of the braid at branching points, and cutting shorter pieces to cover the ends past branching points.
The Model 1 Chassis has a number of holes provided for routing the various cables, and also for zip-tying the cables to various points on the carriages and chassis to secure them.
Here you can see the origin of the Y Bundle and 1-Syringe Tool bundle at the Y carriage. The braid for Y Limit Switch cables is secured with zipties right at the cable connectors. A short piece of braid is used to protect one of the limit switch cables until it can form a junction with the full length of braid used for the Y Bundle. Secure the Y Bundle with a ziptie to one of the holes provided in the side plates of the Y-carriage, as shown. The braid for the 1-Syringe Tool bundle should be secured to the back of the 1-Syringe Tool body with a ziptie as shown.
Observe that the 1-Syringe Tool bundle is kept essentially separate from the other bundles. This simplifies changing tools in the case that you are considering working with more than one deposition tool. Note also how the X-Rear Limit Switch Cable enters the XYZ-Combined Bundle near the routing hole in the rear of the machine base. This is a more aggressive bundling scheme in which the X,Y, and Z bundles are packed into the piece of braid used for the X Bundle. This reduces the overall amount of braid required, but adds the complication of more junctions in the braid.
- Buy tools required for assembly
- Choose your style options
- Buy the parts for the Model 1
- Build the cables and subassemblies
- Assemble the subassemblies into the complete Model 1 System
- Program the LPC-H2148 with the Model 1 Firmware
- Install the Fab@Home Model 1 Application
- Commission the Model 1
- Use the Model 1