VM801P43A-BK + GIFT - BRIDGETEK PTE LTD

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Gripper Kit (#28202) for Boe-Bot or ActivityBot Robots

The Gripper Kit

This kit allows your Parallax Boe-Bot (#28132 & #28832) or ActivityBot

(#32500) robot to pick up objects. Note: robots are sold separately. This kit

is not compatible with the Shield-Bot for Arduino (#130-35000 & #32335).

Before getting started, take an inventory of the parts in your kit. Use Fig #1

to identify each part to the parts list. Once you have inventoried your kit,

proceed to Step #1.

Parts List

Item Qty Description

1 (1) hinge mount

2 (1) dowel pin

3 (2) linkage plate

4 (4) Gripper link

5 (8) #4 x 1” spacer

6 (2) Gripper plate

7 (8) 4-40 x 1.25” screw

8 (15) 4-40 hex nut

9 (1) spring

10 (2) control arm

11 (1) Parallax Standard Servo

12 (1) actuator rod

13 (2) Brass E-Z Connector

14 (8) foam tape

15 (9) 4-40 x 1/4” screw

16 (2) servo bracket

17 (4) 4-40 x 3/8" screw

18 (2) 4-40 lock-nut (not shown)

19 (4) #4 x 1.25” standoff

(not shown)

Fig #1

Recommended Tools

• Pliers

• Phillips #2 point screwdriver

• Small flat-blade screwdriver

• A sharp-tipped hobby knife,

such as an X-Acto® knife

-OR-

A hand drill with 5/64″ bit

WARNING!

DO NOT use electric

screwdrivers with this kit. Please

assemble using hand tools only

to avoid damaging your Gripper.

Step #1: Spacers

Item Qty Description

4 (2) Gripper link

5 (2) #4 x 1" spacer

• The Gripper Links have an angled port ion on top.

Insert spacers into the larg e plastic holes near the

lower side of the angled portion.

• Use Fig #2 as a guide to install the spacers. When

done, the pieces will appear as shown in Fig #3.

Fig #2

Fig #3

Step #2: Gripper Links

Item Qty Description

6 (1) Gripper plate

7 (2) 4-40 x 1.25" pan head screw

8 (2) 4-40 Hex Nut

• Match the angled portions on top of the plastic links to

the angles on top of the Gripper as shown in Fig #5.

• Move links and spacers into the Gripper plate, then

secure with 4-40 screws and nuts as shown in Fig #4.

• Tighten securely.

• Before continuing, double check your work to ensure

that the pieces are angled as in Fig #5.

Fig #4

Fig #5

Step # 3: Foam Tape

Item Qty Description

14 (4) foam tape

• Cut four pieces of foam tape, each 2 inches long.

• Apply foam tape to the Gripper plate as shown in

Fig #7.

This completes the left-side Gripper sub-assembly.

Fig #6

Fig #7

Step # 4: Second Gripper Sub-assembly

Item Qty Description

4 (2) Gripper link

5 (2) #4 x 1" spacer

6 (1) Gripper plate

7 (2) 4-40 x 1.25" pan head screw

8 (2) 4-40 hex nut

14 (4) foam tape

• Repeat Steps #1 through #3 to build the right-side

Gripper sub-assembly in a similar fashion.

• Be sure the angled portions of the links match with the

Grippers face to face. Position the pieces exactly as

they appear in Fig #8.

• Double check your work, then proceed to Step #5.

Fig #8

Step #5: Linkage Plates

Item Qty Description

3 (2) link age plat e

5 (4) #4 x 1" spacer

7 (4) 4-40 x 1.25" pan head screw

8 (4) 4-40 hex nut

• Position the upper and lower linkage plates a bo ve and

below the Gripper links as shown in Fig #9. The top

linkage plate’s hi nge tabs s hou ld curl down, and the

bottom linkage plate’s tabs curl up.

• Insert a spacer into each Gripper link, and secure the

link between the top and bottom linkage plates with

1.25” screws and nuts Fig #9.

• When all four plastic links are installed, tighten

securely.

• Double check your work against Fig #10 . Note again

that the hinge tabs on the bottom linkage plate curl

up, while hinge tabs on top plate curl down.

Fig #9

Fig #10

Step # 6: Control Arms

Item Qty Description

10 (2) control arm

15 (4) 4-40 x ¼" pan head screw

• Attach control arms with 4-40 x ¼" screws as shown

in Fig #11.

• Final assembly must match Fig #12. Double check

your work, then proceed to Step #7.

Fig #11

Fig #12

Step # 7: E-Z Connectors

Item Qty Description

13 (2) Brass 0.072 E-Z Connector set

• Insert a brass E/Z Connector into the end of each

control arm and secure with washers. Plier s m a y be

needed to seat the black snap-washers. Save the set-

screws for a later step.

• Check your work ; your final assembly should match

Fig #13.

Fig #13

Step #8: Install Gripper Hinge Plate

Item Qty Description

1 (1) hinge mount

15 (3) 4-40 x ¼" pan head screw

8 (3) 4-40 hex nut

Note: Remounting the wheels (and, if using the ActivityBot,

the wheel encoders) “axle-forward” moves the axle closer to

the front of the chassis. This helps prevent your robot from

tipping forward when it picks up objects.

• Remove the wheels and un-mount the servos,

keeping the screws and nuts. Turn the servos over

and re-position them so their axles are closer to the

front of the chassis.

• If using the ActivityBot, unscrew and detach each

encoder sensor from its bracket. Turn around each

bracket and re-attach each encoder sensor so the

lenses are repositioned over the servo axles, see

Fig #16A on the next page.

• Re-mount the servos with original screws and nuts.

• Attach the hinge mount to the front of the chassis

with 4-40 x ¼" screws and nuts as shown in

Fig #14 and Fig #15.

• Double chec k your work against Fig #16 A/B.

Fig #14 – Top View

Fig #15 – Bottom View

Fig #16A – ActivityBot, Axle and Encoder Forward Fig #16B - Boe-Bot , Axles Forward

Step # 9: Position G r ipper on Robot

Item Qty Description

(1) Gripper assembly

(1) Boe-Bot or ActivityBot robot, assembled

• Remove one wheel to allow for dowel pin installation in

the next step, Step #10.

• Position the Gripper assembly onto the hinge mount as

shown in Fig #17 below.

• Place the top hinge tabs over the tabs on the hinge

mount so the top of the Gripper st ays on the hinge

mount.

Fig #17

Step #10: Insert Dowel Pin

Item Qty Description

2 (1) dowel pin

• Insert dowel pin.

• If dowel pin slips in very easily, use nee dle nose plier s

to slightly crimp the center of the hinge plate.

• Replace whee l.

Fig #18

Fig #19

Step # 11: Drill Servo Horn

Item Qty Description

(11) (1) servo horn

• Use Fig #20 as a guide. The servo horn needs to

have one of the outside holes enlarged. Using a 5/64”

drill bit, Ph il lip s -tip screwdriver, or hobby knife, gently

enlarge the hole slightly. When using a knife, carve

from each side to keep the hole even.

• Test the hole size by inserting the actuator rod

through the hole.

• Com pare your work to Fig #21 then proceed to

Step #12.

Note: The pictures in the remaining steps show only one

servo horn arm for clarity.

Fig #20

Fig #21

Step #12: Servo Brackets

Item Qty Description

16 (2) servo brackets

17 (4) 4-40 x 3/8" pan head screw

8 (4) 4-40 hex nut

11 (1) Parallax Standard Servo

• Attach servo brackets to servo with 4-40 screws and

nuts. Make sure the metal brackets are placed below

the plastic servo tabs as shown in Fig #22.

• The final assembly should match Fig #23. Double

check your work, then proceed to Step #13.

Note: Only one arm of the servo horn is shown for clarity.

Fig #22

Fig #23

B

Drill

5/64″

Ream

Hole

Larger

or

Step #13: Bend Actuator Rod

Item Qty Description

12 (1) actuator rod

• Using the needle nose pliers, bend actuator rod at

mid-point. Then bend as shown in Fig #24.

Fig #24

Step #14: Install Actuator Rod

Item Qty Description

12 (1) actuator rod

11 (1) Parallax Standard Servo

• Thread bent rod through servo horn as shown in

Fig #25.

Fig #25

Step #15: Install Spring

Item Qty Description

9 (1) spring

• Squeeze spring between the Gripper and the

mounting bracket.

• Position the spring to fit over tabs as shown in

Fig #26 below.

Fig #26

Step #16: Fasten Servo to Chassis

Item Qty Description

19 (2) #4 1.25” standoff

15 (2) 4-40 x ¼" pan head screw

6 (2) 4-40 hex nut

18 (2) lock nut

• Remove the battery pack.

• Insert the actuator rods into the control horns on the

Gripper.

• Fasten the servo brackets to the servo as shown,

using the hex nuts.

• Fasten the servo brackets to the top slots in the

chassis using the lock nuts. You may need to

temporarily remove the battery pack during this step.

Make sure to position the servo shaft on the right as

shown in Fig #27.

• Re-install the battery pack, and replace the

development board support standoffs (A) with the

1.25” standoffs in this kit.

• When finished, carefully com par e your robot to

Fig #28 to make sure everything is correct.

Fig #27

Fig #28

A

Step #17: Plug in Servo

• Boe-Bot: Make sure your servo port power jumper is

set to 5V.

• Plug the gripper servo in to the P14 port, making sure

the black wire is closest to the breadboard.

• ActivityBot: Set the servo port power jumper for

P16/P17 to 5V.

• Plug the gripper servo into the P16 port, making sure

the black wire is closest to the breadboard.

Rev B

Black

Red

X4 X5

15 14 13 12

Ri ght Wheel Servo

Left Wheel Servo

Gripper Servo

X3 Vdd Vss

Vin

Fig #29A – for Boe-Bot Fig #29B – for ActivityBot

Step #18: Fasten Actuator Rod

Item Qty Description

13 (2) Set-screws for E/Z connector

• Locate the set-screws set aside from Step #7.

• Insert the ends of the actuator rod about 1/4 inch into

the E/Z holes in the sides of the brass E/Z connectors

• Lock the actuator rods in place using the set-screws

(see arrow in Fig #30).

Fig #30

Step #19: Adjust Servo Horn Position

' For Boe-Bot robot

' {$STAMP BS2}

' {$PBASIC 2.5}

DO

PULSOUT 14, 250

PAUSE 20

LOOP

// For ActivityBot robot

#include "simpletools.h"

#include "abdrive.h"

#include "servo.h"

int main()

{ while(1)

{

servo_angle(16, 0);

}

• Remove the screw from the servo horn and pull the

servo horn off the servo.

• T ype in the program for your robot (Boe-Bot or

ActivityBot), at left.

• Turn the switch to Position 2 and run t he pr ogr am.

The splined servo shaft will rotate to the clockwise end

of the servo’s range.

• Now replace the servo horn as shown in Fig #31

below. Align the servo horn 90 degrees to the servo

body, pointing towards the chassis.

• Replace the servo screw and gently tighten.

Fig #31

Step #20: Final Gripper Adjustment

' For Boe-Bot robot

' {$STAMP BS2}

' {$PBASIC 2.5}

DO

PULSOUT 14, 1250

PAUSE 20

LOOP

// For ActivityBot robot

#include "simpletools.h"

#include "abdrive.h"

#include "servo.h"

int main()

{ while(1)

{

servo_angle(16, 1800);

}

• Edit your program to match the listing at left for your

robot.

• Turn the switch to Position 2 and download the

program.

• The servo shaft will move the Gripper to the closed

position.

• Loosen the set screws in the E/Z connectors and

adjust the rods so the Gripper is fully closed and

slightly raised off the surface.

• Re-tighten the set screws securely

Your Gripper is now ready to lift:

• Objects up to 2 in. (5 cm) wide

• Up to 4 oz (113 grams) without counterweight

• Up to 14 ounces (397 grams) with counterweight (not

included)

• Please note that these measurements are

approximate; individual Gripper performance may vary

with battery charge, servo performance, and actuator

rod adjustment.

Revision History: Version 4.0 adds support for ActivityBot robot.