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Building a Gripper for Your OpenROV

User-Contributed Guide

User-Contributed Guide

This guide is not managed by the site's staff.

  • Author: patrick121
  • Time estimate: 30 - 45 minutes
  • Difficulty: Moderate

Edit Step 1 How to Build an OpenROV Gripper  ¶ 

Image 1/3: This link contains the CAD files, the laser cutting files, and a parts list.  https://github.com/patrick121/OpenROV-Gripper Image 2/3: This link contains the CAD files, the laser cutting files, and a parts list.  https://github.com/patrick121/OpenROV-Gripper Image 3/3: This link contains the CAD files, the laser cutting files, and a parts list.  https://github.com/patrick121/OpenROV-Gripper

Edit Step 1 How to Build an OpenROV Gripper  ¶ 

Edit Step 2 Gluing Base  ¶ 

Image 1/3: You want the two square cutouts on the outer circle to be on the right side and  the one square cutouts in the inner circle to be facing vertical. Image 2/3: Next put the  six round tabs  into the six square holes so that they face upwards. Acrylic glue these in place. Image 3/3: Your gripper arms will be mounted to these tabs that you just made.

Edit Step 2 Gluing Base  ¶ 

  • Start by taking the base of the gripper and aligning it to face you like in the picture.

  • You want the two square cutouts on the outer circle to be on the right side and the one square cutouts in the inner circle to be facing vertical.

  • Next put the six round tabs into the six square holes so that they face upwards. Acrylic glue these in place.

  • Your gripper arms will be mounted to these tabs that you just made.

Edit Step 3 Adding Left Servo Support  ¶ 

Image 1/3: It should face the opposite way that the front tabs face Image 2/3: Acrylic glue this piece in place. Make sure it is perpendicular to the base. Image 3/3: Acrylic glue this piece in place. Make sure it is perpendicular to the base.

Edit Step 3 Adding Left Servo Support  ¶ 

  • Place the L bracket into the bottom grove of base.

  • It should face the opposite way that the front tabs face

  • Acrylic glue this piece in place. Make sure it is perpendicular to the base.

Edit Step 4 Adding Bottom Servo Support  ¶ 

Image 1/3: On the backside of the base you'll see a square rectangle for a notch in the L bracket to fit into. Image 2/3: Slip these notches into each other and acrylic glue it all in place. Image 3/3: You want the L bracket to be at a 90 degree angle from the bottom support bracket

Edit Step 4 Adding Bottom Servo Support  ¶ 

  • Take the bottom servo bracket and slide the front notch of it into the bottom notch of the servo base.

  • On the backside of the base you'll see a square rectangle for a notch in the L bracket to fit into.

  • Slip these notches into each other and acrylic glue it all in place.

  • You want the L bracket to be at a 90 degree angle from the bottom support bracket

Edit Step 5 Adding Servo Triangle  ¶ 

Image 1/3: Acrylic glue it in place. Image 2/3: Acrylic glue it in place. Image 3/3: Acrylic glue it in place.

Edit Step 5 Adding Servo Triangle  ¶ 

  • Mount the servo triangle like shown in the right servo bracket.

  • Acrylic glue it in place.

Edit Step 6 Attaching Right Servo Support Bracket  ¶ 

Image 1/3: Make sure that the side with the hole in the middle of it is lined up to the side with the support triangle. Image 2/3: Insert the bracket and gently snap it into place so that all of the notch and holes line up. Image 3/3: Acrylic glue this piece into place.

Edit Step 6 Attaching Right Servo Support Bracket  ¶ 

  • Align the right bracket so that it is perpendicular to the base.

  • Make sure that the side with the hole in the middle of it is lined up to the side with the support triangle.

  • Insert the bracket and gently snap it into place so that all of the notch and holes line up.

  • Acrylic glue this piece into place.

  • Congrats, that was the last acrylic gluing step.

Edit Step 7 Making the Servo Horn  ¶ 

Image 1/2: CAUTION: Wear safety goggles. These little bits of plastic tend to fly off at high speeds. Image 2/2: CAUTION: Wear safety goggles. These little bits of plastic tend to fly off at high speeds.

Edit Step 7 Making the Servo Horn  ¶ 

  • Take the servo horn and cut off one side of it.

  • CAUTION: Wear safety goggles. These little bits of plastic tend to fly off at high speeds.

Edit Step 8 Making the Servo Horn  ¶ 

Image 1/3: Drill through the top hole in the servo horn Image 2/3: Make sure to wear safety goggles when doing this step. Image 3/3: Make sure to wear safety goggles when doing this step.

Edit Step 8 Making the Servo Horn  ¶ 

  • Next grab a 5/64 drill bit and drill.

  • Drill through the top hole in the servo horn

  • Make sure to wear safety goggles when doing this step.

Edit Step 9 Securing the Zipties  ¶ 

Image 1/3: Tighten it so that it rest in the notch at the base of the gripper. Image 2/3: Repeat this process with all three gripper arms. Image 3/3: Double check that the cable tie it is fully tightened on all of these. You do not want any loose cable ties.

Edit Step 9 Securing the Zipties  ¶ 

  • Thread the beaded ziptie through the smaller hole at the base of the gripper.

  • Tighten it so that it rest in the notch at the base of the gripper.

  • Repeat this process with all three gripper arms.

  • Double check that the cable tie it is fully tightened on all of these. You do not want any loose cable ties.

Edit Step 10 Securing the Zipties  ¶ 

Image 1/1: Tighten it till taught

Edit Step 10 Securing the Zipties  ¶ 

  • Thread the beaded ziptie through the hole that you drilled in the servo horn.

  • Tighten it till taught

Edit Step 11 Cutting the Zipties  ¶ 

Image 1/2: If you look at the ziptie you'll see that it has beads spaced long it. Image 2/2: Count out seven on these beads starting from 1 at the base.

Edit Step 11 Cutting the Zipties  ¶ 

  • On this part you have to be very precise.

  • If you look at the ziptie you'll see that it has beads spaced long it.

  • Count out seven on these beads starting from 1 at the base.

  • Cut the ziptie after the 7th bead

  • Repeat this step for the other zipties

Edit Step 12 Cutting the Heatshrink  ¶ 

Image 1/3: Place the heatshrink onto the ziptie which is attached to the  servo horn. Image 2/3: Place the heatshrink onto the ziptie which is attached to the  servo horn. Image 3/3: Place the heatshrink onto the ziptie which is attached to the  servo horn.

Edit Step 12 Cutting the Heatshrink  ¶ 

  • Cut 5mm of the 1/8" adhesive lined heatshrink.

  • Place the heatshrink onto the ziptie which is attached to the servo horn.

Edit Step 13 Attaching the Horn and the Gripper Arms Together  ¶ 

Image 1/3: Pick up the three gripper arms in one hand and bunch the zipties together so that all of the ziptie ends come together at one point Image 2/3: Next pickup the servo horn ziptie, make sure that the loose heatshrink is still on it. Image 3/3: Place the end of the servo horn ziptie a couple of beads down from the ends of the gripper arms zipties.

Edit Step 13 Attaching the Horn and the Gripper Arms Together  ¶ 

  • This step is the hardest in the build and requires you to be very precise.

  • Pick up the three gripper arms in one hand and bunch the zipties together so that all of the ziptie ends come together at one point

  • Next pickup the servo horn ziptie, make sure that the loose heatshrink is still on it.

  • Place the end of the servo horn ziptie a couple of beads down from the ends of the gripper arms zipties.

  • Slide the heatshrink down from the servo horn so that it covers the four overlapped zipties.

  • You know that you have done this correctly when you can count four beads from the edge of the shrinkwrap to the base of the ziptie. If it is not four beads then you should redo this step.

  • What this step does is start to make it so that the beads of the servo horn and the beads of the gripper arms overlap to form a strong joint that can be pulled on

Edit Step 14 Attaching the Horn and the Gripper Arms Together  ¶ 

Image 1/1: Be careful not to heat it up too much for you can melt the zipties

Edit Step 14 Attaching the Horn and the Gripper Arms Together  ¶ 

  • Turn your heat gun to a low setting and gently heat up the heatshrink.

  • Be careful not to heat it up too much for you can melt the zipties

  • After using the heatgun, be careful not to jostle the cable ties until the heatshrink has fully cooled. This may take a couple of minutes.

Edit Step 15 Marking the Springs  ¶ 

Image 1/3: Put a sharpie mark at 7mm from the top of the spring loop Image 2/3: Its important to make sure that you have spring aligned like in the picture with the bottom leg on the group on the ruler side. Otherwise you could end up bending the wrong legs of the spring. Image 3/3: Its important to make sure that you have spring aligned like in the picture with the bottom leg on the group on the ruler side. Otherwise you could end up bending the wrong legs of the spring.

Edit Step 15 Marking the Springs  ¶ 

  • Place each spring next to a ruler as shown.

  • Put a sharpie mark at 7mm from the top of the spring loop

  • Its important to make sure that you have spring aligned like in the picture with the bottom leg on the group on the ruler side. Otherwise you could end up bending the wrong legs of the spring.

Edit Step 16 Bending the Springs  ¶ 

Image 1/3: Repeat this with all three springs. Image 2/3: Repeat this with all three springs. Image 3/3: Repeat this with all three springs.

Edit Step 16 Bending the Springs  ¶ 

  • Bend the spring 90° at the sharpie mark like in the pictures.

  • Repeat this with all three springs.

Edit Step 17 Final Assembly  ¶ 

Image 1/3: Thread the nylon machine screw through the tabs and the gripper arm Image 2/3: Insert the bent end of the spring into the small upper hole in each gripper arm and thread the nylon screw through the larger hole in the middle of the spring Image 3/3: Secure the end of each arm with a nylon nut.

Edit Step 17 Final Assembly  ¶ 

  • Put the gripper arms in each of the slots that you made from gluing in the tabs.

  • Thread the nylon machine screw through the tabs and the gripper arm

  • Insert the bent end of the spring into the small upper hole in each gripper arm and thread the nylon screw through the larger hole in the middle of the spring

  • Secure the end of each arm with a nylon nut.

  • Be careful not to torque these nuts down too much. Otherwise, your arm won't be able to move

Edit Step 18 Final Assembly  ¶ 

Image 1/1: The arms should all actuate together and should move relatively easily.

Edit Step 18 Final Assembly  ¶ 

  • Now give your gripper a couple of pulls from the servo horn

  • The arms should all actuate together and should move relatively easily.

  • If it does not move easily try loosening the nuts holding the screws on

Edit Step 19 Attaching the Servo  ¶ 

Image 1/2: You want the bottom lip of the servo to go behind  the top notch in the acrylic (boxed  in red) Image 2/2: You want the bottom lip of the servo to go behind  the top notch in the acrylic (boxed  in red)

Edit Step 19 Attaching the Servo  ¶ 

  • Insert the servo at an angle into the mount.

  • You want the bottom lip of the servo to go behind the top notch in the acrylic (boxed in red)

Edit Step 20 Attaching the Servo  ¶ 

Image 1/2: Make sure to slide the filler screw underneath the front support as you slide the servo downwards. Image 2/2: The filler screw is in  red, the front support is in green.

Edit Step 20 Attaching the Servo  ¶ 

  • Next slide the servo down a little.

  • Make sure to slide the filler screw underneath the front support as you slide the servo downwards.

  • The filler screw is in red, the front support is in green.

Edit Step 21 Attaching the Servo  ¶ 

Image 1/1:

Edit Step 21 Attaching the Servo  ¶ 

  • Slide the servo down all the way so that it locks into place.

Edit Step 22 Configuring the Servo for Your OpenROV 2.8  ¶ 

Image 1/1: All you  have to do is solder the  red servo lead to the OpenROV's  white with red stripe external wire, the black servo lead to the OpenROV's  white with black stripe external wire, and the yellow servo lead to the OpenROV's  white with yellow stripe external wire.

Edit Step 22 Configuring the Servo for Your OpenROV 2.8  ¶ 

  • If you have an OpenROV 2.8 (serial number 2400 and above) hooking up the servo is super easy.

  • All you have to do is solder the red servo lead to the OpenROV's white with red stripe external wire, the black servo lead to the OpenROV's white with black stripe external wire, and the yellow servo lead to the OpenROV's white with yellow stripe external wire.

  • Then in the OpenROV cockpit under the settings tab, click plugins to enable/disable, then click enable external servo.

  • You can now skip to step 30.<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<,<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Edit Step 23 Configuring the Servo for Your OpenROV 2.7  ¶ 

Image 1/3: To start free the external wires from the wiring harness by cutting the ziptie that holds them in  place. Image 2/3: Next snip the heat shrink off of the ends. Image 3/3: Finally, pull them through the top vent in the shell so that you have better access to them.

Edit Step 23 Configuring the Servo for Your OpenROV 2.7  ¶ 

  • If you have an OpenROV 2.7 (serial number 1600 - 2399 ) hooking up the servo requires slightly more work.

  • To start free the external wires from the wiring harness by cutting the ziptie that holds them in place.

  • Next snip the heat shrink off of the ends.

  • Finally, pull them through the top vent in the shell so that you have better access to them.

Edit Step 24 Configuring the Servo for Your OpenROV 2.7  ¶ 

Image 1/1:

Edit Step 24 Configuring the Servo for Your OpenROV 2.7  ¶ 

  • Strip about 5mm off of the end of each external wire.

Edit Step 25 Configuring the Servo for Your OpenROV 2.7  ¶ 

Image 1/1: Remove your electronics from your E-tube.

Edit Step 25 Configuring the Servo for Your OpenROV 2.7  ¶ 

  • Next you need to find out which external wire goes to which solder pad.

  • Remove your electronics from your E-tube.

  • I you look at the DB25 connector you will see six silver solder pads next to it.

Edit Step 26 Configuring the Servo for Your OpenROV 2.7  ¶ 

Image 1/3: Test that this is correct by touching the meter contacts together. Image 2/3: Boxed in red, the meter contacts are touched together. The meter is near 0. Image 3/3: Boxed in  green, the meter contacts are not touched together. The meter is not near 0.

Edit Step 26 Configuring the Servo for Your OpenROV 2.7  ¶ 

  • Pull out a meter and set it to measure resistance (looks for the ohm symbol Ω)

  • Test that this is correct by touching the meter contacts together.

  • Boxed in red, the meter contacts are touched together. The meter is near 0.

  • Boxed in green, the meter contacts are not touched together. The meter is not near 0.

Edit Step 27 Configuring the Servo for Your OpenROV 2.7  ¶ 

Image 1/2: If your meter is not near zero then attach the meter contact to a different external wire. Image 2/2: If your meter is near 0, then attach a piece of tape  to the external wire labeled TP23

Edit Step 27 Configuring the Servo for Your OpenROV 2.7  ¶ 

  • Put one the contacts of the meter on the TP23 pad, then put the other meter contact on one of the wires that you stripped.

  • If your meter is not near zero then attach the meter contact to a different external wire.

  • If your meter is near 0, then attach a piece of tape to the external wire labeled TP23

  • Repeat this process for the TP24 and TP25 pads.

  • In total you should have three wires labeled TP23, TP24, and TP25 which correspond to to the TP23, TP24, and TP25 solder pads.

Edit Step 28 Configuring the Servo for Your OpenROV 2.7  ¶ 

Image 1/3: Cut 6 2cm long tubes of adhesive lines heat shrink Image 2/3: Cut 6 2cm long tubes of adhesive lines heat shrink Image 3/3: Cut 6 2cm long tubes of adhesive lines heat shrink

Edit Step 28 Configuring the Servo for Your OpenROV 2.7  ¶ 

  • Strip the servo wires and the labeled external wires.

  • Cut 6 2cm long tubes of adhesive lines heat shrink

Edit Step 29 Configuring the Servo for Your OpenROV 2.7  ¶ 

Image 1/1: Solder and shrinkwrap the TP24 cable to the red servo wire

Edit Step 29 Configuring the Servo for Your OpenROV 2.7  ¶ 

  • Solder and shrinkwrap the TP23 cable to the yellow servo wire

  • Solder and shrinkwrap the TP24 cable to the red servo wire

  • Solder and shrinkwrap the TP25 cable to the black servo wire

Edit Step 30 Configuring the Servo for Your OpenROV 2.7  ¶ 

Image 1/1:

Edit Step 30 Configuring the Servo for Your OpenROV 2.7  ¶ 

  • Put the other three pieces of shrinkwrap on the remaining non soldered to external wires and shrink it down over the ends.

Edit Step 31 Configuring the Servo for Your OpenROV 2.7  ¶ 

Image 1/1:

Edit Step 31 Configuring the Servo for Your OpenROV 2.7  ¶ 

  • Cut your 3 pin Servo connector to a length of 11 cm.

Edit Step 32 Configuring the Servo for Your OpenROV 2.7  ¶ 

Image 1/1:

Edit Step 32 Configuring the Servo for Your OpenROV 2.7  ¶ 

  • Strip about 3mm off of the end of the servo connector.

Edit Step 33 Configuring the Servo for Your OpenROV 2.7  ¶ 

Image 1/2: This will make it easier to attach the servo connector to the board Image 2/2: This will make it easier to attach the servo connector to the board

Edit Step 33 Configuring the Servo for Your OpenROV 2.7  ¶ 

  • Next put a little blob of solder of the TP23, TP24, and TP25 pad

  • This will make it easier to attach the servo connector to the board

Edit Step 34 Configuring the Servo for Your OpenROV 2.7  ¶ 

Image 1/3: Image 2/3: Image 3/3:

Edit Step 34 Configuring the Servo for Your OpenROV 2.7  ¶ 

  • Solder the white wire to the TP23, the red wire to the TP24 and the black wire to the TP25 solder pads

Edit Step 35  ¶ 

Image 1/2: Image 2/2:

Edit Step 35  ¶ 

  • Plug the servo connector into the the 3 pin connector on the controller board labeled D9 with the black wire on the outside.

Edit Step 36 Configuring the Servo for Your OpenROV 2.7  ¶ 

Image 1/1: Follow this instruction set to upgrade your software. http://openrov.dozuki.com/Guide/Update+Software+Image+From+SD+Card/90

Edit Step 36 Configuring the Servo for Your OpenROV 2.7  ¶ 

  • You need to upgrade your OpenROV software to the latest version so that you can operate the servo from the OpenROV cockpit.

  • Follow this instruction set to upgrade your software. Update Software Image From SD Card

Edit Step 37 Mounting the Gripper Arm  ¶ 

Image 1/3: To do this grab a pair of pliers and a paper towel which is folded over itself several times. Image 2/3: Put this folded paper towel between the threaded rod and  the pliers so that it protects the threads while having pressure on the threaded rod. Image 3/3: Unscrew the four lock nuts and remove the threaded rods

Edit Step 37 Mounting the Gripper Arm  ¶ 

  • Remove the threaded rods from the bottom of the ROV

  • To do this grab a pair of pliers and a paper towel which is folded over itself several times.

  • Put this folded paper towel between the threaded rod and the pliers so that it protects the threads while having pressure on the threaded rod.

  • Unscrew the four lock nuts and remove the threaded rods

Edit Step 38 Mounting the Gripper Arm  ¶ 

Image 1/2: On the other rod, move the jam nut  towards the center. Image 2/2: On the other rod, move the jam nut  towards the center.

Edit Step 38 Mounting the Gripper Arm  ¶ 

  • On one of the rods remove the jam nuts on one side .

  • On the other rod, move the jam nut towards the center.

Edit Step 39 Mounting the Gripper Arm  ¶ 

Image 1/2: Thread the threaded rod with only one nut on it through the back mounting hole in the gripper Image 2/2: In the red square you can see the rod with the center nut threaded through the front gripper hole

Edit Step 39 Mounting the Gripper Arm  ¶ 

  • Thread the threaded rod with two nuts on it through the front hole in the gripper.

  • Thread the threaded rod with only one nut on it through the back mounting hole in the gripper

  • In the red square you can see the rod with the center nut threaded through the front gripper hole

  • I did not include the servo mounted inside of the gripper in the following steps to make visualizing this process easier

Edit Step 40 Mounting the Gripper Arm  ¶ 

Image 1/3: Thread two nuts onto the front rod Image 2/3: screw one of these nut until it sandwiches the 6mm piece of acrylic Image 3/3: screw the other nut about 2cm inwards

Edit Step 40 Mounting the Gripper Arm  ¶ 

  • Thread another nut about two centimeters deep onto the back threaded rod

  • Thread two nuts onto the front rod

  • screw one of these nut until it sandwiches the 6mm piece of acrylic

  • screw the other nut about 2cm inwards

Edit Step 41 Mounting the Gripper Arm  ¶ 

Image 1/3: Do this by inserting the threaded rods into the front two holes. Image 2/3: Make sure that the  E-chassis is still slotted into its holes  in the side of the external frame. Image 3/3: Re-attach  the M5 lock nuts on each side of the threaded rods by using the technique of pliers and a paper towel

Edit Step 41 Mounting the Gripper Arm  ¶ 

  • Next we need to re-attach the threaded rods to the frame

  • Do this by inserting the threaded rods into the front two holes.

  • Make sure that the E-chassis is still slotted into its holes in the side of the external frame.

  • Re-attach the M5 lock nuts on each side of the threaded rods by using the technique of pliers and a paper towel

Edit Step 42 Mounting the Gripper Arm  ¶ 

Image 1/1: Now go pick up some cool stuff!

Edit Step 42 Mounting the Gripper Arm  ¶ 

  • Finally, route the wires for the servo so that they are out of the way of the motors

  • Now go pick up some cool stuff!

You're Done!

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