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72 – Cricket Robot Documentation 

 
 

Horn Assembly Parts:  
Horn, Rivet from 
Servo kit, 2-56 x 3/8” 
screw, and original 
horn screw. 

Centering the Servos 

Your servos are now electrically connected and you have a battery connection. When the 
controller is turned on, it will center each servo to its middle position. You have no 
mechanical connection between the motors and the legs so the motors will turn without 
moving anything. This allows the motors to be centered in the correct position before we 
install the control arms that will move the legs. If the motors are not centered before the 
mechanical connection is made, the legs might be forced into a bad position possibly 
damaging the robot. 
 
Turn on your controller using the switch next to the batteries and the controller will center 
the servos, make a beep, and then pause for a couple of seconds. During that pause, turn 
off the robot. If you miss the pause; just turn the controller off and then on again. When 
you hear the first sound, turn the switch off. This procedure allows us to center the servo 
shafts to the correct position before attaching the servo horns which will be used to move 
the control arms.  
 

Installing the Servo Horns 

Inside the accessories package for the Hitec 311 servos are extra horns. Horns are the 
plastic pieces that screw onto the servo shaft. We will not be using the default horn which 
comes attached to the servo. Locate the horn and pieces shown in the photo below. Two 
of the horns have an extra-large hole drilled in the end spot and the third horn has an 
extra-large hole in the third spot. The ones with the hole in the end are the right and left 
horns and the other is the center horn. Each horn has a serrated and a smooth side.  
 
The accessories package also has four rivets which are normally used for mounting the 
servo. We will be using one rivet as a bearing point for each horn. On the right and left 
horns, place a rivet through the 2-56 x 3/8” machine screw and screw it into the first hole 
on the serrated side of the horn. On the center horn, place a rivet through the 2-56 x 3/8” 
machine screw and screw it into the third hole on the non-serrated side of the horn. 
 

 

 

Summary of Contents for Arduino Walking Robot

Page 1: ...Revision 1 0B Copyright 2015 Cricket Robot Documentation...

Page 2: ...ance 11 Random Noises 11 Flashing LED Eyes 11 Remote Control 11 PLAYING WITH CRICKET 12 ABOUT CRICKET S HARDWARE 13 Chassis 13 Legs 13 Servo Motors 13 Arduino Controller 14 Batteries 15 Speaker and So...

Page 3: ...ts 42 Assemble the Leg Control Arms 46 Assemble the Sonar Bracket 47 ABS Parts of Chassis are Now Complete 51 Installing the Servos into the Chassis 52 Installing Cricket s Legs 54 Installing the Leg...

Page 4: ...uires just the standard Arduino Environment and a USB down load cable Description Cricket is a six legged walking robot He uses three motors to make the six legs walk in a tri gate fashion Tri gate me...

Page 5: ...n away from the obstruction and keep wandering around Cricket will continue to walk around until his battery becomes weak You can tell the battery is weak when the robot starts to act erratically Repl...

Page 6: ...operation code Use the following instructions for your remote These instructions are also on the battery door of your remote If you have an older remote the code may be different but the instructions...

Page 7: ...can purchase SparkFun part number DEV 9716 or any similar 6 pin Arduino programming module https www sparkfun com products 9716 The Cricket program can be edited in the Arduino environment and the Ard...

Page 8: ...8 Cricket Robot Documentation Top View...

Page 9: ...9 Cricket Robot Documentation Bottom View...

Page 10: ...10 Cricket Robot Documentation Front View...

Page 11: ...eps scans the area in front of him for the best direction and then continues moving forward in the best direction If either the feelers are bumped Cricket will also do a sonar survey of what is in fro...

Page 12: ...control steer Cricket through an obstacle course Try the programming experiments in the manual Cricket Programming After you tried the above think about ways that you would improve your Cricket You co...

Page 13: ...et uses three servo motors for walking and one for the Sonar These motors are hobby servo motors used for model airplanes and cars Each motor has three wires that supply 6 volts red ground black and t...

Page 14: ...ront left of the circuit board allows the Basic programs to be downloaded into the Arduino There is a small speaker for sounds and LEDs that can be blinked The battery pack powers the Arduino directly...

Page 15: ...this ability using a small speaker to generate many different sound effects I would be an interesting experiment to modify some of the Sound commands in the Cricket program and see how it affects Cric...

Page 16: ...et stuck For this reason Cricket has long feelers much like a real cricket has These feelers are connected to small switches which turn on when the feeler is pushed The Arduino controller checks the s...

Page 17: ...ill need to use a USB Serial programming module that plugs into the header just above the Digital I O This module is an Arduino standard is inexpensive and can be purchased from multiple sources Spark...

Page 18: ...nd install it using their instructions The SparkFun USB Serial module DEV 09716 will be recognized with the Arduino drivers Once you have the Arduino software installed connect the SparkFun or similar...

Page 19: ...ou have previously downloaded Note if the Arduino Software loads in the wrong language you can change it in the preferences dialog See the Arduino Software IDE page for details Open the blink Example...

Page 20: ...e serial ports To find out you can disconnect your Arduino board and re open the menu the entry that disappears should be the Arduino board Reconnect the board and select that serial port Upload the p...

Page 21: ...e troubleshooting suggestions You have programmed Cricket with a Sketch that only blinks the pin 13 LED If you would like to restore Cricket to his full operation select the Cricket program from your...

Page 22: ...n center the motors after mounting them in the chassis The Cricket Arduino Controller uses a printed circuit board PC Board The PC board has four surface mount components that have been soldered in pl...

Page 23: ...rt designations and outlines of the parts Be sure to note any parts that have a polarity or keyed direction before you install them The instructions will mention if a part has a polarity or direction...

Page 24: ...ation Parts Layout Use this diagram to help you to locate where the parts are installed Follow each of the steps to complete your controller All controller parts are listed in the parts table PC Board...

Page 25: ...small sign Install the resistors which each have a series of colored bands to indicate their value Bend the leads of each resistor so that they form legs which drop into the holes on the board You ca...

Page 26: ...just drop in and there is no polarity Solder the leads from the back of the board and clip the excess lead length Install the two 22 pf capacitors which both have the same marking of 220 No lead bendi...

Page 27: ...notch on the PC Board designation towards large 0 25 hole Solder 2 corner pins and then make sure the socket is flush to the board Solder the remaining 28 pins Install IR1 which is IR Remote Control S...

Page 28: ...the on the part so that it lines up with the hole labeled with a There is no marking on this part Solder and then clip the excess lead length Install transistor Q1 making sure the rounded side matches...

Page 29: ...he board and then solder the other pin Connectors for Digital Analog and ICSP are three pin headers which were broken from a long strips found in your kit Carefully install and solder each connector S...

Page 30: ...s 3 pin connectors in the locations pointed to in the arrow Leave these connectors off We will just solder a jumper at those locations rather than using a connector Qty Location Description 2 L1 L2 Ri...

Page 31: ...he board and then solder the remaining 3 leads The photo below shows 3 pin connectors in the locations pointed to by the arrows Leave these connectors off We will just solder a jumper at those locatio...

Page 32: ...s of your Arduino IC by bending them against a table top until they are perpendicular Do this on both sides Insert the Arduino IC into the U1 socket noting that the notch is facing the large 0 25 hole...

Page 33: ...asy and goes quickly Just follow the rest of this section to build your Cricket Chassis The following diagram shows all of the plastic chassis parts for your Cricket Robot Each part is labeled with a...

Page 34: ...d cut it off later with the Xacto knife If you try to wipe it it will smear Cricket s chassis is laser cut so the corners and notches are sharp If you would like to have an extra nice job a little bit...

Page 35: ...the pivots all the way into the notch Slide one 6 32 x 5 8 screws through the pivot hole to make sure the holes line up This is very important so that the legs move smoothly You may optionally Clamp...

Page 36: ...obot Documentation Attach the rubber feet part S to each of the 6 legs including the center legs part D Cut the bellow material T into 6 parts with 7 segments each using an Xacto knife or single edge...

Page 37: ...ellows are cosmetic They give the legs the appearance of having hydraulic cylinders If you don t like them they may be left off or attached in a different spot All 6 legs complete with rubber foot pad...

Page 38: ...surfaces Use 2 nails provided to line up the leg beam stack File off ridges so that the stack of 3 parts fit together flat File both sides of G and one side of each F part Make sure that you apply gl...

Page 39: ...se the supplied nails to align the center beam while clamping it The nails are discarded later after the glue dries You may use spring clamps to clamp the center beam OR you may use masking tape to ho...

Page 40: ...side surface is smooth using sandpaper the file or the Xacto knife and that the beam fits snuggly in the notch on the chassis body Once you have checked the dry fit apply glue to the inner surface San...

Page 41: ...at the surfaces mate The chassis body is completely symmetrical so the beam can be installed on either side Whichever side you install it on becomes the bottom of the Cricket Robot Use masking tape or...

Page 42: ...ridge off and try dry fitting them into the matching notches on the body A IMPORTANT The motor mounts H must be installed on the same side of the body A as the center beam F G was installed on When y...

Page 43: ...h of the three motor mounts H Left Motor Mount Center Motor Mount Right Motor Mount Make sure each of the three mounts H are perpendicular to the chassis body You may tape or clamp them if you like bu...

Page 44: ...File or sand the ridge off and dry fit them into the matching notches on the body A before gluing them IMPORTANT The motor mounts N must be installed on the opposite side of the body A as the center b...

Page 45: ...45 Cricket Robot Documentation Installing the PCB mounts N 4 PCB mounts N installed Note that they are on the opposite side of the body from the motor mounts...

Page 46: ...will not fit on the arm use a file or sandpaper to lightly fit the parts The two leg control arms are mirror images for right and left sides The retainer is attached to one side with the small round c...

Page 47: ...trips Do not apply glue to the inner notch which is where the servo horn will ride This shows the Left Control Arm with keyhole facing down Hole Left Control Arm Left Control Arm Right Control Arm Thi...

Page 48: ...ket The Sonar mount bracket is made up of parts L and M The upright L has a tab that must fit into a slot on the base M Check the fit and if it is tight remove the ridge using a file or sandpaper Chec...

Page 49: ...40 x 3 8 flathead screw These parts are shown in the photo below The Completed Sonar Bracket 4 40 flathead Adapter R star washer spacer Push the flat head screw through the countersunk side of adapter...

Page 50: ...50 Cricket Robot Documentation Completed Sonar Servo Linkage Attach the post to the Sonar Servo horn using two 0 x 3 16 flathead sheet metal screws Tighten the screws with a 1 Phillips screw driver...

Page 51: ...f the ABS assembly You should have the completed body legs control arms and Sonar Bracket The photo also shows a center control arm right side which did not require any gluing Let everything dry befor...

Page 52: ...body of the servo and its connector A black indelible ink pen works well These labels stand for right left and center and are important because we will setup the servos based on their position on the...

Page 53: ...ervo the same way with the shaft and wire towards the front of the robot Insert the center servo with the shaft to the left side of the robot as shown Use only 2 screws because this servo will be remo...

Page 54: ...he opening at the front of the robot The shaft should face the center of the robot as shown Mount the sonar servo with the 2 screws from the supplied HS 55 accessories inside the box using a 1 Phillip...

Page 55: ...ion Verify your servo installation against these photos Route all servo wires through the left access hole in the body as shown Your servo wires should be loosely routed as shown Later we will neaten...

Page 56: ...screwdriver tighten the 6 32 self locking nut onto the screw from the bottom of the robot Tighten all the way until the screw will not turn anymore and then loosen one half turn Make sure the legs mov...

Page 57: ...ng a 6 32 x 5 8 screw through the center beam and the leg The screw head should be closest to the right and left servos Tighten all the way until the screw will not turn anymore and then loosen one ha...

Page 58: ...round keyhole pointing down as shown Insert the machine screw through the arm and into the hole in the leg The screw will self tap itself into the plastic Tighten the screw all the way and then pack...

Page 59: ...bot Documentation Your leg control arm on the left side should look like this Note the round keyhole pointing down Your leg control arm on the right side should look like this Note the round keyhole p...

Page 60: ...leg control arm E is installed on the front of two posts coming up from the center legs D with the round Keyhole facing down as shown Add two 4 40 x screws through the center leg control arm as shown...

Page 61: ...stalled Make sure all the legs move freely and loosen or tighten the leg screws as needed Secure the center control arm E to the center legs as shown using two 4 40 x Screws and 4 40 Self Locking Nuts...

Page 62: ...f the robot towards the back with rubbing alcohol or water Let it dry Attach two strips of double sided tape to the back of the battery holder by removing one side of the protective paper Only one tap...

Page 63: ...de of the double sided tape and press the battery holder into place The battery holder should be placed all the way up to the center brace and centered between the servo control arms There should be a...

Page 64: ...wn Installing it face down may seem wrong but the chassis acts as a sound board with the sound exiting the rear of the speaker Glue the speaker by holding it firmly in place and putting three drops of...

Page 65: ...bend the end of the feeler into a tiny loop if you don t want to use the bead Slide a supplied glass bead onto the feeler Add a small drop of the supplied glue or Crazy Glue to the end of the wire and...

Page 66: ...h the feelers to the control board The little nubs on the feeler switch actuators P must face the switch button Tighten the screw with a 1 Phillips screw driver and pliers until tight and then back of...

Page 67: ...bend the two feelers away from each other so there is about to between them Next take a pair of pliers with the Cricket controller lying on a table and bend the feelers about 1 from the switch actuato...

Page 68: ...shown Carefully slide the controller over the sonar post When it is resting on the four PCB mounts carefully push down on it until it snaps into place Connect the speaker to the connector labeled SPK...

Page 69: ...o the numbers on the connectors along the left side of the robot The yellow wire faces in towards the center of the robot THIS IS IMPORTANT The photo at the left shows the correct orientation for each...

Page 70: ...nal closest to the center of the board The Black wire goes to the terminal labeled GND which is the center terminal Be sure you have these connections correct so that you don t damage your controller...

Page 71: ...for the first time verify that you have connected the motors and battery as shown below Red Battery Black Battery No Connect 9 Right Servo 10 Left Servo 11 Center Servo 12 Sonar Servo SPK speaker wire...

Page 72: ...ound turn the switch off This procedure allows us to center the servo shafts to the correct position before attaching the servo horns which will be used to move the control arms Installing the Servo H...

Page 73: ...on the right and left sides make sure the slot they ride in is free of glue or plastic flash Check that the screw and rivet ride smoothly in the slot Right and left horns Serrated side up Center horn...

Page 74: ...pick the closest position to vertical Be very careful to not move the servo shafts as you install each of the adapters If you think you may have moved the shaft turn on the controller to center the sh...

Page 75: ...is in position add the horn The serrations should be facing in and mesh with serrations on the adapter which keep it from sliding around Line up the bottom edge of the horn with the adapter and screw...

Page 76: ...ation Install all four screws to retain the center servo motor Check that your robot center motor installation looks like the photo at the left The rivet bearing point should be poking through the cen...

Page 77: ...nd use wire ties to hold them in place If you would like you can turn your robot on and let him walk a bit If you hear any binding in the motors you can remove the horns and repeat the centering proce...

Page 78: ...nhead screws You will need to slightly tip the module to install it in the bracket The screws are at diagonal positions Note The photo shows the sonar post and screws which we already installed on the...

Page 79: ...e with the ribbed side facing as shown Place the flat washer on the screw and push it through the hole in the sonar bracket Add the external star washer and then the internal star washer Note The exte...

Page 80: ...ervo post and tighten it with a 1 Phillips screwdriver Try to hold the post from turning so that the servo maintains it center position Note Later if you find that the sonar module does not face strai...

Page 81: ...place Neaten up the four servo wires by removing the slack by pushing them through the hole in the chassis Use one of the supplied wire ties to retain the four servo wires from moving around Allow a l...

Page 82: ...ner on the side of the center servo by peeling the backing off and pressing it into place Route the right and left servo wires through the wire retainer Make sure there is some slack so that the wires...

Page 83: ...into a neat bundle and tuck it between the sonar and center servos Use two more wire ties to retain the wire bundle in place Note There is a small amount of slack one the right and left servo wires t...

Page 84: ...m the top Make sure your wires are not hanging out The legs should center as shown when turned on and the sonar should be facing forward From the side the right and left motor horns should be vertical...

Page 85: ...forward and the feelers should look like the photo From the bottom the center servo horn should be vertical and the wires should be out of the way of moving servo horns Your feelers should extend in...

Page 86: ...rom the bottom of the sonar module and bend through a graceful loop into its connector on the controller This bend allows for movement of the wire as the sonar module turns right and left Recheck that...

Page 87: ...something in the way he should back up scan with the sonar and pick a way around the object Cricket will make random sounds while walking around If you have problems with your Cricket refer to the tr...

Page 88: ...ote Doesn t Work If the remote fails to work it may need to be reset Press and release the TV button See the section on reprogramming your remote Legs Not Working If any of Crickets legs appear to not...

Page 89: ...erious problem has occurred Sound is not very loud or non existent Check the speaker wiring and that the speaker is tightly glued to the chassis If you can t figure the problem out contact us Replacem...

Page 90: ...90 Cricket Robot Documentation Appendix A Schematics...

Page 91: ...91 Cricket Robot Documentation...

Page 92: ...92 Cricket Robot Documentation Appendix B Parts List...

Page 93: ...93 Cricket Robot Documentation...

Page 94: ...94 Cricket Robot Documentation Appendix C PC Board Layout All Layers Parts Layout...

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