Assembly Instructions v1.0¶

• Assembly Instructions v1.0
  • • Mechanical System
      • Motor Mount
      • Motor Mount Bracket
      • Main Structure
      • Final Assembly
    • Data Acquisition (DAQ) System
      • MAX31855 Thermocouple Amplifier Breakout Board
      • Force Sensing Resistor (FSR) cable system
      • Arduino ProtoShield

Mechanical System¶

The assembly of the Mechanical System consists of four main sub-assemblies (shown in Figure 1 below):

1. The motor mount (a modified Estes D & E Engine Mount Kit)
2. The motor mount bracket
3. The main structure
4. The back plate

Figure 1 - Shepard Mechanical Components

Notes

• Be sure to cut out the parts listed in CutList tab of the BOM
• Add notes about the glues we use

Motor Mount¶

Assembly of the motor mount follows the instructions supplied with the Estes D & E Engine Mount Kit with a few small exceptions which are required to accomodate the t-connector (MM06) used to vent the ejection charge)

1. Take the mount tube (MM01) and mark one end as the front [where the motor will be inserted] and the other as the rear [where the t-connector (MM06) will be attached]
2. Test fit the t-connector (MM06) in the mount tube (MM01) by inserting it approximately 1/4" into the mount tube (MM01) and then remove it; the fit will be tight, and may even require a slight stretching of the mount tube (MM01)
3. Make a mark 1/4" from one end of the red engine block (MM04)
4. Cut the red engine block (MM04) at the 1/4" line from the previous step, keeping the larger section as the final engine block (see Figure 2)
   Figure 2 - Modified Engine Block (top) vs Original Engine Block (bottom)
   
5. Follow Step 1 in the Estes D & E Engine Mount Kit instructions
   1. Step 1.A - Make a mark on the mount tube (MM01) 1" from the rear and 5/8" from the front [this second mark should be offset along the circumference of the mount tube (MM01) slightly]
   2. Step 1.B - Cut a 1/8" wide slit at the mark 1" from the rear of the mount tube (MM01); insert the engine hook (MM05) into the slit (see Figure 3)
      Figure 3 - Engine hook inserted into mount tube
      
   3. Step 1.C - Apply wood glue to the outside of engine block (MM06) and the inside of the inside of the rear section of the mount tube (MM01) making sure to completely coat the inside of the mount tube (MM01) up to where the engine hook (MM05) is inserted; Slide the engine block (MM06) into the rear of the mount tube (MM01) until it rests agains the engine hook (MM05); be sure to smooth any excess glue in the mount tube (MM01) to create a smooth water tight surface (see Figure 4)
      Figure 4 - Engine block inserted into mount tube
      
6. Follow Step 2 in the Estes D & E Engine Mount Kit instructions - Apply a bead of wood glue around the mount tube (MM01) just to the rear of the mark 5/8" from the front and then slide the engine retainer ring (MM02) onto the the mount tube (MM01) from the front of the mount tube (MM01) until the engine retainer ring (MM02) is just past the 5/8" mark (see Figure 5)
   Figure 5 - Engine retainer ring mounted
   
7. Allow the assembly to dry overnight
8. Apply a bead of multi-surface glue to the edge of the base end of the t-connector (MM06)
9. Insert the t-connector (MM06) into the rear of the mount tube (MM01) (see Figure 6)
   Figure 6 - Completed motor mount
   
10. Allow the motor mount to dry over night

Motor Mount Bracket¶

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Main Structure¶

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Final Assembly¶

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Data Acquisition (DAQ) System¶

The assembly of the DAQ system consists of three main sub-assemblies:

1. MAX31855 Thermocouple Amplifier Breakout Board
2. Force Sensing Resistor (FSR) cable system
3. Arduino ProtoShield

MAX31855 Thermocouple Amplifier Breakout Board¶

• The only assembly required for the MAX31855 breakout board is to solder the header pins and terminal block onto the board. Once this is done the breakout board can be soldered to the Arduino Protoshield.

Force Sensing Resistor (FSR) cable system¶

• The FSR came with male pins, which complicated assembly somewhat. It would be simpler to buy the version of the FSR with a female connector and make your cable fit that configuration. As it was, female D-SUB connectors that were on hand were used to connect the FSR to the CAT 5e cable that was used between the FSR and the ProtoShield. The pins were crimped on to two of the leads of the CAT 5e cable so that the female ends could receive the male pins of the FSR. The reason crimping was used instead of soldering for the pins is that it's very easy to melt the FSR's substrate, thus making the FSR useless, or at least severely altering its operation.

Arduino ProtoShield¶

Components were soldered onto the ProtoShield in the configuration shown in the images below. Note that in the bottom view, the ProtoShield has been flipped vertically towards the bottom of the picture. This allows you to orient yourself so that you can follow the traces. For higher resolution images to aid in assembly, check the Shepard_v1.0_DAQ_Assembly_Images.zip file here

Figure 1 - Top View of the ProtoShield

1. The MAX 31855 breakout board has the correct header pin spacing to fit the holes on the ProtoShield, so it was inserted directly. Note that the capacitor that is included with the K type thermocouple when purchased is being used. The thermocouple's reading had too much noise in it otherwise.
2. The red and green wires used were breadboard prototyping jumpers from Radio Shack. Left over Ethernet cable wires can be used as well.
3. The resistor was soldered directly to the ProtoShield, but care should be taken that the leads of the resistor do not short any of the connections on the board.
4. A 14 pin DIP socket was used for the TLV2374 for multiple reasons including prevention of overheating of the IC during soldering, and ease of replacement in the event of damage due to a wiring mistake.
5. A smaller screw terminal block for the FSR leads (left side) would have ideal, but the larger block pictured was all that was available at the time of assembly. The pins are spaced more widely on the block and thus the positioning was dictated by the spacing of the holes on the ProtoShield.
6. Notice that even though the two green jumper wires disappear under the MAX 31855 breakout board in the image, they have been labeled with what pins they go from/to.

Figure 2 - Bottom View of the ProtoShield

1. If you view the high resolution version of this image from the Shepard_v1.0_DAQ_Assembly_Images.zip file here , you'll notice that several solder bridges have been made to connect different points. Use the schematic diagram found in the Shepard_v1.0_DAQ.zip file here to give you a more complete view of what's being bridged.
2. The solder bridges are made by laying short lengths of stripped solid wire against the pins (or in the holes) and then soldering them.
3. Figure 3 labels what the corresponding top side connections are for most of the solder joints.

Figure 3 - Bottom View of ProtoShield With Landmark Connections

1. The solder positions where the green and white/green wires are coming off the board is the location of the Force Sensing Resistor (FSR) screw terminal.