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--- granular_gripper [2019/07/25 14:54] – [Parts List and Sources] yuhanghe
+++ granular_gripper [2019/07/29 16:22] (current) – [Final Words] yuhanghe
@@ Line 37: / Line 37: @@
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-To complete this tutorial, you'll need the following items included in this BOM. Some common electrical components, such as prototype board, resistors, and diode that are common for circuit do not have vendors and price listed. To power the compact ejector, a 24 V power supply unit is required. In addition, access to 3D printer is required for this construction.
+To complete this tutorial, you'll need the following items included in this BOM. Some common electrical components, such as prototype board, resistors, and diode that are common for circuit do not have vendors and price listed. To power the compact ejector, a 24 V power supply unit is required. In addition, access to 3D printer is required for this construction. Medium grind coffee grounds was used as the granular material during the construction. To attach the pneumatic fitting on the gripper assembly, a 1/4 in NPT Tap is required.
-Here is the {{:yuhang:gripper:gripper_bom.xlsx| Gripper BOM}}
+Here is the {{:yuhang:gripper:gripper_bom1.xlsx| Gripper BOM}}
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 ==== Construction ====
-This section gives step-by-step instructions along with photos to <fill in the blank>. (If a circuit-building tutorial:) A schematic to construct <fill in the blank> is shown here <add image>. <Add hyperlink to PDF of schematic> is the Acrobat file of the same schematic.
+This section gives step-by-step instructions along with photos to build the granular gripper.
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@@ Line 50: / Line 50: @@
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-<Add photos to make step easier to understand>
+Use 3D printer to manufacture the gripper assembly. The STL 3D models for the gripper assembly can be assessed [[https://drive.google.com/drive/folders/1jMvreFaVj8BmygcOD4aEDI1hRS7eOVnZ?usp=sharing|here]]. For the gripper assembly to function properly, the component gripper_mount must be air tight. To achieve air tight print with 3D printer with PLA filament, you can follow this tutorial [[https://www.instructables.com/id/3D-Printing-Make-Water-Tight-and-Air-Tight-Contain/|3D Printing: Make Water Tight and Air Tight Containers]], which requires printing the model at 100% fill. If there is leak in the 3D printed part, you can try repair the leak with epoxy resin coating or a seal spray like [[https://www.amazon.com/Flex-Seal-Rubber-Sealant-Coating/dp/B07JNLJ2BX/ref=sr_1_3_sspa?keywords=flex+seal&qid=1564093321&s=gateway&sr=8-3-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyRzI3S1AzU09QTFRLJmVuY3J5cHRlZElkPUEwMjIwODkwRjU0QUlINjhTWDNQJmVuY3J5cHRlZEFkSWQ9QTA5NDI2NzcxSlI2RjQ4WktNRUI2JndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==|Flex Seal]]. The following pictures show the gripper assembly that need to be printed.
+{{ :yuhang:gripper:gripper_base.png?300 |}}
+{{ :yuhang:gripper:gripper_mount.png?300 |}}
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@@ Line 56: / Line 58: @@
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-<Additional steps like **Step 3**, **Step 4**, etc>
+Fill the inside of 24 inch balloon with medium coffee grounds. Suggest using a funnel to make the process easier. You may need to blow some air into the balloon for the coffee grounds to settle inside the balloon. Fill the balloon almost completely with coffee ground without stretching balloon's membrane.
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-==== Programming ====
+**Step 3**
-A link to the source code can be found <provide URL to your code, probably saved in this DASL Wiki>.
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-The goal of the code is <brief explanation>.  It works in the following way
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-----
+Cut a circular piece from the dust mask and glue it to the bottom opening in the gripper mount as shown.
-<!- Insert a snippet of your code here.  Try to keep to less than 0.5 page long -->
+{{ :yuhang:gripper:filter.jpg?300 |}}
-----
+The dust mask will act as the filter to keep the coffee grounds inside the balloon during vacuuming.
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-The snippet above serves to <fill in the blank>. It does this by <fill in the blank>.
+**Step 4**
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-----
+\\
-<!- Insert another snippet of your code here.  Try to keep to less than 0.5 page long -->
+Use the 1/4 in NPT tap to create threads on 7/16 in hole on the side of the gripper mount. Wrap some pipe thread tape on the thread of 1/4 in NPT push-to-connect fitting and screw the fitting into the tapped hole.
-----
+{{ :yuhang:gripper:npt_fitting.jpg?300 |}}
-Next, the code does <fill in the blank>.  It does this by <fill in the blank>.
+\\
-<!-- Keep entering snippets of code and descriptions until you've given enough for a reader to understand how it works -->
+**Step 5**
+\\
+\\
+Cut the neck of the balloon to half. Thread the neck of the balloon through the opening in the gripper base. Stretch the entrance of the balloon before placing the bottom opening of gripper mount over the base to seal the balloon. Use screws to assemble the gripper base and mount together.
+\\
+**Step 6**
+\\
+\\
+Attach the G1/8 push-to-connect fittings to the compact ejector. Use the pipe thread tape to ensure that the system is airtight.
+{{ :yuhang:gripper:ejector_fitting.jpg?300 |}}
+The port #1 is the compressed air source and port #2 is the vacuum/blow off output.
+\\
+**Step 7**
+\\
+\\
+Attach the 1/4 in NPT push-to-connect fitting to the 1/4 in NPT quick connect female fitting. Attach the quick connect to the quick connect port on the air compressor.
+{{ :yuhang:gripper:quick_connect.jpg?300 |}}
+\\
+**Step 8**
+\\
+\\
+Use the 1/4 in pneumatic tubing to connect the air compressor to the compact ejector and the granular gripper to the compact ejector.
+{{ :yuhang:gripper:pneumatic_tubing.jpg?300 |}}
+On the air compressor, use the regulator to adjust the compressed air output to 4 bar.
+\\
+**Step 9**
+\\
+\\
+Connect the M12 5 pin cable to the compact ejector. The detail of the wiring and circuit is outlined in the next section.
+==== Circuit ====
+The complete manual for the compact ejector can be found on Schalmz's [[https://pimmedia.schmalz.com/Dokumente/Bedienungsanleitung/10/1002/100202/10020204111/BAL_10.02.02.04111_en-EN_02.pdf|website]]. The instruction on this site only offers rough guide, please refer to the manual for more details on how to properly wire and use the compact ejector.
+The following diagram shows the function of each pin on compact ejector's M12 5 pin port and their corresponding wire colors when the cable is connected to the port.
+{{ :yuhang:gripper:m12_5pin.png |}}
+The following table shows the electrical parameter of the compact ejector. The expect voltage input is 24V. For the normally closed (NC), PNP ejector, the current consumption is 70 mA. The input signal voltage is 15 to 24V and current is 5 mA.
+{{ :yuhang:gripper:electrical_parameter.png |}}
+The following figure shows the circuit diagram for the gripper system. The Arduino is used to receive command from a computer. The digital signal from Arduino is used as the base for transistors to switch on and off the 24 V input signal for vacuum and blow off.
+{{ :yuhang:gripper:circuit.png |}}
+The following figure shows the actual circuit implemented with Arduino and a prototype board.
+{{ :yuhang:gripper:circuitp.jpg |}}
+==== Programming ====
+A link to the source code can be found {{:yuhang:gripper:vacuum_control1.zip| Arduino Code}}
+\\
+<code cpp | Switch.ino>
+  String input; // for incoming serial data
+  int command;
+  bool vac = false; //Switch condition for vacuum
+  bool blow = false; //Switch condition for blow off
+  bool off = true; //Switch condition for off
+void setup() {
+  Serial.begin(9600); // opens serial port, sets data rate to 9600 bps
+  pinMode(8, OUTPUT); //Assign port 8 and 9 as digital output
+  pinMode(9, OUTPUT);
+  digitalWrite(9, HIGH);
+  digitalWrite(8, HIGH);
+}
+void loop() {
+  // send data only when you receive data:
+  if (Serial.available() > 0) {
+    // read the incoming string:
+    input = Serial.readString();
+    // read input data from the serial monitor
+    command = input.toInt();
+    // enter a command of 1 to turn on and off vac
+      if (command == 1) {
+        vac = !vac;
+      }
+    // enter a command of 3 to turn on and off blow off
+      if (command == 3) {
+        blow = !blow;
+      }
+      /*Serial.print("vac: ");
+      Serial.println(vac);
+      Serial.print("blow: ");
+      Serial.println(blow);
+      Serial.print("off: ");
+      Serial.println(off);*/
+    if (vac && blow || !vac && !blow) {
+      vac = false;
+      blow = false;
+      Serial.println("off");
+      // due to circuit design, a HIGH digital output corresponds to off for the ejector signal
+      digitalWrite(9, HIGH);
+      digitalWrite(8, HIGH);
+    }
+    else if (blow) {
+      Serial.println("blow on");
+      // digital pin 8 is connected to blow off
+      digitalWrite(8, LOW);
+      digitalWrite(9, HIGH);
+      delay(300);
+      digitalWrite(8, HIGH);
+      blow = false;
+      vac = false;
+      Serial.println("off");
+    }
+    else if (vac) {
+      Serial.println("vacuum on");
+      // digital pin 9 is connected to vacuum
+      digitalWrite(9, LOW);
+      digitalWrite(8, HIGH);
+    }
+  }
+}
+</code>
+The command for the ejector controller is entered through Serial Monitor on the Arduino IDE accessed through the Tools menu on the top of IDE.
+Enter 1 in the command line to turn on vacuum.
+{{ :yuhang:gripper:vacuum_on.png |}}
+Enter 3 in the command line for a short blow off.
+{{ :yuhang:gripper:blow_off.png |}}
 //
 //
 ==== Final Words ====
-This tutorial's objective was to <fill in the blank>. Complete <choose: construction details, source code and program descriptions> for <fill in the blank>. Once the concepts were conveyed the reader could <fill in the blank>.
+This tutorial's objective was to demonstrate the process of building the granular gripper.
-\\
-\\
-Speculating future work derived from this tutorial, includes <fill in the blank>. In the big picture, the problem of <fill in the blank> can be solved with this tutorial.
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-For questions, clarifications, etc, Email: <paul.oh@unlv.edu>
+For questions, clarifications, etc, Email: <hey6@unlv.nevada.edu>