This Instructable is for anyone who attended my robot building workshop at Kaleidoscope Learning Center (KLC), or has bought one of the Rocket Brand Studios robot kits used in that workshop. It's a really nice pocket-sized programmable robot.
You can use this Instructable to assemble the kit from scratch, or as a reference to repair or modify your completed robot.
The laser cut chassis for the kit was beautifully designed by my good friend Chis at Rocket Brand Studios. However, you could make something similar yourself and use this Instructable as a guide.
Step 1: Getting Started
- (1) PICAXE-08 Motor Driver Board
- Plexiglass chassis parts
- (2) Motors
- (1) 3xAAA Battery Pack
- Plastic Acorn Bolt and Nut (roller thing)
- O-rings for wheels
- Bag of screws and stuff
- One small Phillips head screwdriver
- One small flat head screwdriver
Step 2: Remove Protective Coating
The plexiglass parts for this robot kit have a clear plastic sheet on each side which need to be removed before assembly. You can remove them all now or remove it as you go. Just don't forget to remove it from each side of the parts.
To remove the protective coating, you can use a fingernail (preferably your own) to get an edge started, and then simply peel it back.
Step 3: Attach Motors
Before you begin, note the orientation of the motor and the robot base plate in the second picture. See those dashed lines etched in the plexiglass. This is how you will be attaching the motor. You will use the lines as a guide as you place the motor. You will also use the outer edge of the base plate as a guide. The edge of the motor should line up with the edge of the base plate, as shown.
Note: One the double sided foam tape touches the plexiglass, it is very hard to remove. Take your time and line it up carefully. Second chances are hard to come by.
Once you are confident in how the motor will attach, and which way the motor shaft and wires will face, go ahead and peel back the protective sheet from the double sided tape. You will only peel back the tape from one side of the motor at this time. Be sure to get the correct side.
I find it is easiest to place the motor on the table and carefully lower the base plate on top of it, watching how the edges and etched dashed lines are aligned. Press the motor firmly onto the plate to attach it.
Repeat the process for the second motor, and you should end up with something very much like the last picture. Two motors are attached to the base plate with wires sticking out towards the wider front edge of the base, and the white motor shafts sticking out to the sides.
Step 4: Attach Switches
There are two bumper switches in the kit. One with red wires attached, and one with black. The one with red wires will go on the left side of your robot. The one with the black wires goes on the right. The switches will be positioned as shown in the pictures.
Peel back the protective sheet from the double sided tape and attach the switches to the base plate. Easy peasy, lemon squeezy.
Step 5: Attach the Top Plate
If you haven't already done so, remove the clear protective sheet from both sides of the top plate.
Note the etched lines in the top plate, which you will use to help align the plate onto the motors.
Before you attach the plate, I find it is easiest to route the wires from the switches and motor upwards through the rectangular hole in the top plate.
Now remove the protective sheet from the top of the two motors, carefully line up the top plate over the motors and drop the plate into position. Press the two plates together firmly.
Step 6: Build the Wheels
- One large circle with larger holes
- One large circle with smaller holes
- One smaller circle
Holding the two bolts in place with your fingers, finger tighten two nuts onto the bolts to hold everything in place. Just finger tight.
Now make sure the smaller holes on the one outer circle are nicely centered inside the larger holes on the other outer circle. Then use a Phllips head screwdriver to tighten the bolts. Use your fingers to hold the nuts from spinning as you tighten each bolt.
Repeat this process for the other wheel.
Step 7: Attach the Servo Horn
Your kit includes two little white servo horns. These are used to attach the wheels to the motors. In this step they will be attached to the wheels.
Examine the white servo horn, and you will see that two of the mounting holes have been drilled out to be a little larger than the rest. We will use these two holes to attach the servo horn to the wheels using the pointy screws that have built in washer-like flange on the head.
Use the pictures below to guide you as you attach the servo horn.
Insert a screw through one of the two larger holes of the wheel, and screw it through the flat side of the servo horn into one of the two drilled out mounting holes. As you tighten the screw, it will tend to make the servo horn want to rotate. So just get it started, and then insert the other screw. The second screw will help hold the servo horn in place while you tighten each screw. Tighten the two screws until the flat white side of the servo horn is flush with the side of the wheel.
Now would be a good time to attach the the o-ring to the wheel. Just stretch it over one side and work around until you have it in place as shown in the last two pictures.
Repeat this process for the other wheel.
Step 8: Connect the Wheels
The wheels attach to the motors as shown in the pictures below. The servo horn will fit over the white shaft of the motor. Slide it on completely, as shown in the third picture.
Now use one of the small pointy screws to attach the wheel to the motor through the center mounting hole. Note that it can be a bit tricky to get the screw put in place into the mounting hole correctly. You can either hold the wheel facing up and try to drop the screw in, or you can fit the screw onto the end of the screwdriver and use it to guide the screw into place. Tighten the screw with a Phillips head screwdriver, but just snug it into place. Do not over tighten it.
Repeat for the other wheel.
Step 9: Attach the Rear Slider
Your kit includes a white plastic bolt and acorn nut. Insert the bolt down through the mounting hole at the rear of the bottom plate. Attach the acorn nut from underneath and finger tighten it.
That's it. Easy, right?
Step 10: Attach the Battery Pack
Open the battery pack by sliding the two halves apart. Insert three AAA batteries as shown, and close the battery pack.
NOTE: Make sure the switch of the battery pack is set to OFF. I'll mention this again later. It's important.
Peel away the protective sheet from the double sided foam tape on the bottom of the battery pack. The bottom is the side without the switch on it.
Posiiton the battery pack over the top of the robot so that the switch and wires are to the front of the robot, and there is enough room for the wires that pass up through the top deck. Gently press the battery box into place on the top of the robot.
Step 11: Attach the PICAXE Brain
Now it's time to give our robot its brain.
Peel back the protective sheet from the double sided foam tape on top of the battery pack. Carefully position the PICAXE-08 Motor Driver Board so that the circular jack is facing the rear of the robot. Also be sure that the board does not cover the power switch on the battery pack. Press the board gently into place on top of the battery pack.
NOTE: Double check that the power switch is OFF. In the next step we will start attaching wires. (I told you I'd mention that again.)
Step 12: Connect the Wires
You don't need to solder anything. The PICAXE motor driver board uses screw terminals, which screw down onto the exposed metal ends of the wires to make electrical contact. Use the pictures below as a guide as you make connections.
Find the two wires from the left motor and connect them to the two terminal blocks on the left side of the motor board labeled 0 and 1. Be sure you have the correct motor wires. The red wire should be attached at the rear, to the terminal labeled 1. The black wire attaches to the terminal labeled 0. Use a small flat head screwdriver to tighten the terminal screws onto the pins.
I like to gently tuck the wires out of the way, as shown in third picture.
Attach the wires from the right motor in a similar way, as shown in the forth picture. The red wire should be at the rear, connected to the terminal labeled 2. The black motor wire should connect to the terminal labeled 4.
Now take the two red wires from the left bump switch. Connect them to the two terminals labeled IN3/5. It does not matter which red wire goes into which of the two terminals.
Next take the two black wires from the right bump switch. Connect them to the two terminals labeled IN3. Once again, it does not matter which black wire goes into which of the two terminals.
Next, we are going to connect the power to the motor driver board. First, let me remind you once again to check that the power switch on the battery pack is set to OFF. This is the step where if you do this wrong, bad things can happen, like ruining your nice robot brain. So be careful.
With the power switch safely off, attach the red wire from the battery pack to the screw terminal at the left-rear of the board, labeled V+. This is the positive power connection.
Next, take the black wire from the battery pack and attach it to the screw terminal labeled 0V. This is the negative side of the power connection, also known as ground.
NOTE: I know you are tempted to switch your robot on right now, but wait just a second and read the next step first.
Step 13: Set the Board Jumpers and Power Up!
Your motor driver board is a fully programmable robot brain and dual motor driver. It has a little black jumper on it, which is used to select between RUN and PROG (program) mode. There's a second little black jumper that is used to select whether both input switches are wired to input 3 or if one is wired to input 3 and one is wired to input 5.
If you don't know what any of that means, don't worry about it. Just follow the steps below to set the jumpers for operating your robot.
First, find the RUN/PROG jumper, which is located near the circular plug at the rear of the robot, right next two the little 8-pin integrated circuit chip (that's the robot's brain, by the way). Set the RUN/PROG jumper so that it is across the center pin and the RUN pin, as shown in the first picture.
Next, find the Input 3/5 jumper. This jumper is located just behind the four unused terminal connectors at the front of the motor driver board. It is a bit hard to see the labels. Set the 3/5 jumper so that it is across the center pin and the 5 pin, as shown in the second picture. If you can't make out the picture, the jumper should be set between the left pin and the center pin.
Your jumpers should now be set, and look like the third picture.
OK, you are ready to test your robot. The board came pre-programmed, so just switch on the power. There will be about a two second delay, and then your robot should drive forward. If one of the bumper switches is hit, the robot will stop, back up a bit, and then turn.
Step 14: Further Resources and Programming
Now that you've started, keep learning! Here are some references for you.
- Main PICAXE website.
- Picaxe 08 Motor Driver Board User Manual
- Refer to the PICAXE Manual 1 for info on getting started with PICAXE.
- Refer to the PICAXE Manual 2 for info on BASIC commands.
- Refer to the PICAXE Manual 3 for info on interfacing the PICAXE to external circuits.
Some other great kits and products are available from:
Robot Building Community:
Hey, the robot was pre-programmed, but you can experiment and adapt the program or write your own. Below is a link to some simple code that will work for this robot.
To program the robot, you will need to download and install the PICAXE Programming Editor for your operating system. It's free. Be sure to follow the installation instructions carefully! You will also need a PICAXE USB Download Cable, which you will have to purchase. It is available for purchase from Robot Shop and other find vendors.
Connect your PICAXE USB Download Cable to your computer. Check the instructions on the PICAXE website to be sure you have the drivers installed correctly, and the correct COM port selected. We will not repeat their instructions here.
Be sure Jumper H1 is set to 'PROG'. Connect the other end of the PICAXE USB Download Cable to the circular programming jack on the PICAXE-08 board. Set the robot on something so that its wheels do not touch the ground. Turn the switch on the battery holder to 'ON'.
Use the PICAXE Program Editor to program the robot. After the program is downloaded, turn off the robot using the switch on the battery holder. Disconnect the programming jack. Set Jumper H1 to 'RUN', and set your robot down on the ground.
Turn the robot on, and watch it go! Whenever it bumps into something that contacts one of the two microswitches, it should stop and try to turn to avoid the obstacle.
it is common the the robot may not drive completely straight when moving forward. This is because the two motors may run at slightly different speeds. It is not critical. However, if the robot does not drives backward instead of forward, or if it spins in circles, you need to change something.
You can fix these problems either in hardware by changing how the wires from the motors are connected, or in software, by changing with pins are set to high or low in the program.
If the robot drives backwards instead of forwards, then the motors are BOTH wired backwards, and needs to be changed in either software or hardware.
If the robot spins to the left instead of driving forwards, then the LEFT motor is wired backwards, and needs to be changed in either software or hardware.
If the robot spins to the right instead of driving forwards, then the RIGHT motor is wired backwards, and needs to be changed in either software or hardware.
Don't be upset if your robot misbehaves at first. This is a great learning opportunity!