Introduction: RocketBot Robot (Picaxe)
Rocket Brand Studios Homepage
Rocket Brand Studios Picaxe Bot Page (Tutorials and Test Code)
You will need:
- Soldering iron
- Pliers and dikes (Diagonal cutters --little snippy things)
- Small Screwdrivers
- Hobby Knife (X-acto)
- Masking tape
Step 1: Let's Get Started (Soldering)
Ok, let's get started...
First off, this kit will require soldering and you shouldn't be intimidated by this. Soldering is an incredibly easy skill to learn and there are about 6 million tutorials out there. If you are unfamiliar with soldering, now might be a good time to hit the Googles or the YouTubes and find yourself a tutorial or walk-through. One particular tutorial I like is enclosed below:
Step 2: Assembly 1
Let's start by opening up your kit and removing the bag with all the electronic parts in it. These little parts have a terrible habit of rolling off your desk and getting lost forever. Use a small cookie sheet or shallow dish to keep them all together. Also grab the main board, it will probably be toward the bottom of the box. I personally use a cheap set of "helping hands" to hold the board while I solder, but this is not required. At this point, all you really need is a way to hold the board stable while working with it, some good light and your soldering iron.
Step 3: Assembly 2
We will start with the easy stuff, the resistors. There are a total of 8 on the board, we will be installing 6 and these guys can go in any direction.
- (2) 330 ohm resistors in the front corner
- (2) 330 ohm resistors on sorta the left side of the board
- (1) 10k resistor in the back
- (1) 22k resistor in the back
Solder them in and trim the leads.
Do not install the (2) 4.7K resistors at this time.
The 4.7k resistors are what are known as "pull-up" resistors and are needed if you chose to use the I2c functions of the Picaxe chip. Specifically, they are for the optional line-follow kit. You don't need to know what any of that means, just set the 2 resistors aside in your toolbox and remember where they are. You may need them later as your robot knowledge grows.
Step 4: Assembly 3
Headphone Jack (Sync Connector)
The Picaxe chip uses a headphone jack to connect to the computer (to zap your programs in). We will now install this connector but first, it will need a tiny bit of modification.
Find the headphone jack itself and look at the bottom (with the pins). At the front, you will notice (4) tiny nubs of plastic. There is supposed to be only 2 so we will have to remove a couple. With your hobby knife, slice off the first 2 little nubs. If you end up accidentally removing all 4, no worries, the connector will still work just fine.
Now that you have those 2 guys removed, the connector will sit nice and flush to the board. Insert it, tape it down with a bit of masking tape and solder away. Solder all 5 pins.
There is no need to trim any of the pins after soldering.
Step 5: Assembly 4
There are 2 LED's on the board to indicate power is on for either the brain and/or the motors. I found these very cool square LED's and started using them for my robots. They look great (and even better when on!) but alas, the legs are just a tad bit too wide to fit through the holes on my board. I have taken the liberty to trim off the wide part of the legs thus allowing them to fit my boards, but in doing so I also eliminated the thing that told you which leg was which. --The legs were different lengths to determine + and -. To remedy this, I have placed a small black mark on the LEDs in your kit. This black dot indicates negative.
Grab your board and look at the spot for the 2 LED's. It is up front, next to the 330 and 4.7k resistors. If you look closely at the LED symbol, you will notice it is round with one flat side. This flat side is negative.
The black dot on the underside of your LED's should go to the flat side of the LED symbol on the board. To be more clear, the pin with the black dot on the LED will go through the hole with the SQUARE pad.
Double check yourself, solder them in and trim the legs.
Step 6: Assembly 5
I See Sockets (and a female header)
The IC sockets are next on the list. We are not going to solder our little robot brain or motor driver chip in directly. Using the little sockets will allow you to easily swap out a chip and will protect the chip from being cooked from the soldering process. Each of these sockets include a small notch at the top. This is wicked important. Line up the notch on the socket with the notch in the symbol printed on the board.
It is best to keep these guys flat to the board so I suggest a small piece of masking tape to hold them down while soldering. Also, I suggest soldering only one leg (toward the center of the chip) to start. Solder this one leg then carefully remove your tape (without pulling up on the socket). Now you can place your finger on the socket, press it down and reheat that one leg you soldered. The solder will remelt and the socket will be pushed flush with your finger. Remove the heat, and count to 5 slowly before removing your finger. Take a quick look and be sure it is nice and tidy.
When you are happy with the placement, double check the notch (they should point to the front of the robot) and solder all the pins. Repeat this process with the other socket.
You may follow this same procedure to also install the 21-pin female header. Again, solder just one pin, reheat and adjust and then solder it solid. Be it sits flush as well as 90 degrees to the board. This header strip can go either direction.
There is no need to trim any of the legs on the sockets or the header after soldering. Do not install the chips at this time.
Step 7: Assembly 6
Gotta Lotta Pins
We have a few pins to solder in here and I am not going to lie to you, there is simply no good way of holding these silly things while soldering. I personally use the same method as was used on the IC sockets and female header --solder one pin, straighten, solder them all. A wee bit of patience is needed to get and keep them straight when taping them down and the tape should only touch the very tips of the pins. After you get the one center pin soldered and start the finger-on-top-reheat-straighten process, be aware not to have your finger on the particular pin you are soldering (it's going to get hot, duh!) Also note, that some of the pins will go on the top of the board and some on the bottom. If you look closely at the board, you will notice that each part has an outline around where it goes. This outline will appear on either the top or bottom of the bottom of the board depending on where the part goes. It is very easy to get a rhythm going and solder the wrong thing on the wrong side so take you time, study the pictures and do it right the first time.
Let's get going. Find the strip of straight pins. The pins must be snapped apart into the lengths we need. The pins snap apart quite easily with some small pliers and your fingertips. We will need:
* (1) 3-pin header toward the front of the robot (Bottom) Solder this guy first
* (2) 3-pin headers toward the front of the robot (Top)
* (2) 2-pin headers on the bottom of the board near the "Motor" labels (Bottom)
* (1) 10-pin bent header on the bottom with the pins pointing backward
Be patient, get creative and do whatcha gotta do to get these guys in. Double check the pictures and be sure things are going to the correct side.
Solder them all in. There is no need to trim any of the pins.
Step 8: Assembly 7
Woo Hoo! Motors!
Now we're getting to the good stuff. Grab these parts from the kit:
* (2) Motors
* (2) Little metal brackets
* (2) #4 x 1/2" Screws
* (4) 2-56 x 1/4" Bolts
* (4) 2-56 Nuts
* (4) 2-56 Washers
* (2) Red and Black wires (with the little connectors on the ends)
* (2) Capacitors (they will probably be brown with wider legs than what you used on the board)
Start by screwing the brackets to the motors with the #4 screws. You will need a right and left so be sure they are mirror images of each other. Note: The screw goes through the SECOND hole from the edge. It is slightly larger and goes all the way through the motor. Just go for snug here, you will strip the plastic if you go too tight.
Place the motor on the board (as shown in the picture --the one with my finger holding the wire) as a dry-fit. Do not screw it down at this time. Plug in one of your red and black motor leads and hold it as it appears in the picture. Make a nice little loop and make note where it goes past the contacts on the back of the motor. If in doubt, leave it a bit long. Go ahead and cut the wire to this length. Repeat this process for the other side.
With your hobby knife, split the 2 wires apart at the end without the connector. Be sure you cut DIRECTLY down the middle and that you don't nick either wire. Split it about 3/4" down from the end. Now, with your strippers or very carefully with your hobby knife, strip about 1/4" of wire from the end of each wire exposing the copper wire inside. Do not cut into this copper wire. With your finger tips, twist each of these wires so all the strands are nice and tight together.
Now hold up your capacitors up to the motor connections. Bend the legs outward (as shown in picture) and trim them so the ends will just reach the motor leads. Take the wires we prepared earlier and twist the copper end of the red wire on one leg and the black wire to the other leg. --Again, bunch of pictures below.
We need to "tin" the wires and motor connections. Place the wires so they hang off the edge of your desk and tape them down. With your soldering iron and solder, solder the exposed tips of each wire soldering them to the caps. It should go pretty quick, and you want it to as to not melt the insulation of the wires. Repeat this with the terminals on the motors, just a thin, quick layer of solder on each connection.
No go ahead and solder the wires to the motors. This will be the same as soldering any other connection, place the wire on the connection, tape it or do whatever you need to keep it there, and solder away. It does not matter which wire goes where or that the motors match. Note the picture here so the wires stick out the right way from the motor.
Plug 'em in and screw 'em down! Use (2) of the 2-56 nuts and bolts for each mount and snug them up. No need to go "red face tight" here, just good and snug is all you need. The washers go ON THE TOP of the board, under the head of the screws. Plug the connector into the pins labeled "Motor". It does not matter which way you plug it in, just be sure that your wire has that nice little loop in it and is tidy. Do both motors now.
Step 9: Assembly 8
This step might seem a bit out of order, but it needs to be done now. The reason we held off on this step until now is to be sure the motors were installed first and thus, that the battery pack would fit between them.
Grab the battery pack and clip off the wires at about 2" long. (See picture). Strip and tin the ends, the same way you had done with leads for the motors. Remove the backing off the (2) strips of double-stick tape on the back and stick 'er down.
Note: The wires MUST be on the side near the "Batt" label on the board.
At this point, you can work a neat loop in the wires an stick the stripped, tinned ends through the (2) holes labeled "+" and "-" on the board.
IT COULD NOT BE MORE IMPORTANT THAT THE RED WIRE GO THROUGH THE HOLE MARKED "+" AND THE BLACK THROUGH THE HOLE MARKED "-". Don't screw this one up.
Solder them from the top side of the board and trim the ends.
Step 10: Assembly 9
Stick the wheels on. Do not just push them on. Instead, squeeze them on, pushing against the back of the motor. See picture. Stick 'em on and secure with the little screw (included with the wheels).
Step 11: Assembly 10
I'm not going to lie to you here, the tailwheel assembly is going to be a wee bit tricky. The brackets and wheels were selected because they A) look cool and B) are very practical on a robot like this. They are super-adjustable, roll and rotate effortlessly and one can remove the wheels easily to remove any carpet fuzzies or dog hair that may have gotten wrapped around. I live in a household with 2 big Black Labs so dog hair is a huge ongoing issue.
Don't freak when you see all the little parts, we're going to get through this. I have taken the liberty of making a video to walk you through this step. Watch it now.
(Note: In the video I think I say, "2 extra collars in the bag of screws" I meant to say, "4 extra collars")
- You must put a small notch (with your hobby knife) in the plastic bracket to allow the allen key of the top collar to rotate fully.
- Any and all adjusting (re-bending of the axle wires) must be done with the wires REMOVED from the plastic bracket. Note the picture with my finger pointing to one wheel that is a bit high. This wheel can be adjusted by moving the collars up and down and/or bending the wire into a steeper or more shallow angle. You may also do this to adjust the wheels to be 90 degrees to your table, etc. Again, do not try to bend the wires while still attached to the robot, you will break the plastic bracket.
- Do not bend anything without pliers! If you do, you will get sloppy, round bends and the brackets will not work.
- Don't over tighten the allen key screws in the collars, snug is all you need.
- Be patient with this step, study all the pictures, work slowly.
- If you screw anything up, you can email me to buy a replacement part --or-- you can get this bracket from any hobby shop that sells RC planes. The bracket is a Dubro DUB375.
Step 12: Optional Parts
Why are there places on the board that have no parts?
You may have noticed that there are a few parts laid out on the board that you do not have parts for. Don't worry, they were not forgotten. Instead, these are for the purpose of "future-proofing" in that they will allow you to expand some of the capability of the robot in the future as your skills grow. One such area is on the front of the robot and appears to be 2 rows of holes right next to each other. These are for the optional line-follow kit (which may or may not be available at the time you are reading this).
Check http://www.rocketbrandstudios.com/projects-and-info for availability and for more info
The other spot of concern is near the back close to the 6-pin header. These (3) components are part of the 3.3v kit available at the link above. Your robot is a 5v device but some of the doo-dads you may want to connect to it could run at 3.3v instead. The best example of this would be an X-bee. X-bee's are little devices that can transmit and receive data wirelessly and they work at 3.3v --5v will cook them. If you purchased the 3.3v kit, you may install it now. If not, you may skip this step. Please note, the 3.3v kit can be installed at any time.
Step 13: Assembly 11
Switches are my switches
Go ahead and install the (2) main power switches. They can only go one way. These switches will be well, switched, and need to be very secure. Solder all three legs of both switches on both the top and bottom of the board. I have found that a regular clothes pin works great to hold these guys tight to the board as you solder them in.
The legs on the switches are pretty short, but trim them anyway. --No reason not to be neat and tidy here.
Step 14: Assembly 12
Servo and Sharp Sensor
This is a fun step. We're going to have something that sorta looks like a robot after this.
Grab the servo, the nifty plexiglass bracket, the Sharp distance sensor and the red/black/white wire as well as the little black plastic connector (it will look just like the one that is on the end of the servo).
The servo goes first, it simply fits in the notch at the front of the robot and gets attached with (2) 2-56 bolts and nuts --no washers. Note that the notch is not centered, this is because the output shaft on the servo is not centered. Place the servo so the output shaft at the top is inline with the center line of the robot. Bolt it down --remember, just snug. The servo plugs into the 3-pin header on the BOTTOM of the board labeled "D11" and the brown wire MUST be closest to the edge of the board. If you look closely, the pins on the board are labeled "- + S" which is, Negative Positive Signal ---> Brown Red Orange. With one of the zipties, make a nice bundle with the extra length of wire and zippy-zip it together. Clip off the extra ziptie sticking out.
We can now prepare the pigtail wire for the Sharp sensor. It has a white connector on one end and (3) bare connectors on the other end. These (3) connectors will snap into the small plastic housing (the one that looks like the one on the servo). Now, these need to go in the right way or they will not "click" in. Look closely at the pictures included as there is no good way (via text) to describe it. Each one will slide in and the gentle "click" tells you it is in far enough. The wires MUST be in this order: White/Red/Black --or-- Black/Red/White. You may now plug the white connector into the Sharp sensor itself. It will only go one way.
Sharp Distance Sensor Bracket
The bracket that holds the Sharp sensor should be pretty self-explanatory, but there is one modification to the servo horn you must do. If you look in the baggie of parts that came with the servo, you will find 3 "horns" --the little white things that attach to the top of the servo. Grab the one that is "double sided" but not the one with the 2 little extra "ears". (see pictures) The plexiglass bracket was designed to fit this servo horn however, the holes in the horn are not quite big enough. Feel free to use a fancy-schmancy drill and drill bit to make them bigger --or-- you can do what I do, just ream out the holes a bit with your hobby knife. The holes used are the second ones from the ends. If you hold it up to the plexi bracket, you will see which ones to use. When you are done, you may screw the plexiglass bracket to the servo horn, the Sharp sensor to the bracket and place it on the robot. Do not install the center screw yet. --We have no idea if the servo is centered or not. When you have finished the construction, one of the first things we will do is center the servo at which point we can install that screw.
Step 15: Assembly 13
Don't actually put bread on it
This step is quite satisfying. Grab the little black breadboard from your parts kit. (I have no idea why they call these things "breadboards"). Peel off the backing, be sure it is straight and stick 'er down.
You only get one shot at this, Skippy --Take a deep breath and don't screw it up!
Step 16: Assembly 14
If I only had a brain (and a motor driver for that matter)
Oh, are we getting close here! Grabs your brains, my friend...
You will find a little black piece of foam rubber with (2) chips stuck into it. The larger of the 2 is the Picaxe brain and the smaller one is the motor driver. We will be installing these now.
One thing you may notice is that the legs of these chips will seem too wide to fit in our sockets. They are (all chips come like this) and we need to bend them in. DO NOT TRY TO DO THIS BY HAND! Instead (as shown in the picture) use the table top to bend the legs all at the same time. It is pretty easy to screw this one up so go slowly and carefully. It is also easy to accidentally bend the opposite side you are working on so be aware as to where your fingers are when you do this. Be gentle, be patient. Repeat this process with both the Arduino brain and also the motor driver chip.
At this point, you can press them into their respective sockets. Do not push against the robot itself, instead, put your hand against the underside of the board to support it when pressing them in. Also, note the notch at the top of each chip. The notch in the chip MUST match the notch in the socket.
Step 17: Assembly 15
What is this extra capacitor I have?
If you noticed, there is a big 'ol cap included in your kit. What is this thing? Well, I have noticed through testing that when the motors or servo are run very hard or say, the line-follow sensor board is plugged in, there can be A) electrical noise or B)sudden (bursts) drains of power. This, on occasion, has caused a reset from our microcontroller. The big 'ol cap is a small insurance policy to be sure your robot runs without a problem.
Bottom line: If your robot is acting a bit "funky" (especially intermittently) and your batteries are fully charged, add this capacitor. The side with the "-" sign goes to ground, the other pin goes to VIN. See the picture.
Step 18: Diggida-Done!
Good Job! You did it! Hooray!
I tell you what, buddy --You gots yourselfs a robot, there. Feels good, huh?
Before we go any further, you need to inspect your work carefully. Check each and every solder joint. We are looking for any bad joints but more importantly, we are looking for solder "bridges". A bridge is when the solder from one joint has "bridged" itself to the connection next to it. This is bad. If you find any of these guys, it is usually easy enough to simply re-heat the joint and with the tip of the iron, "encourage" the solder to go back to its home. If you end up with a globby-McGloberson of solder somewhere, you can pick up a roll of desoldering braid from Radio Shack or an online supplier. Follow the instructions, it will make quick work of any extra solder that is not where it should be.
Checking for solder bridges can not be omitted. Check everything carefully.
You can go ahead and add your batteries now if you would like. Use only (4)aaa RECHARGEABLE batteries. This is incredibly important. Alkaline batteries put out a slightly higher voltage than rechargeable do and that slightly higher voltage (when 4 batteries are put together) will add up to a voltage higher than what the chip(s) were designed for. The (4) rechargeables should put out around 4.5 volts, just under the max 5v that the chip allows which will be just right.
Plug 'em in and flip your switches on. One LED should come on with each switch. If they don't, STOP, turn the switches off and remove the batteries. Go back through the steps and check your work. It is probably something as simple as putting the LED's in backward, but it could also be a solder bridge, as described above, or many other things. If you are super-stuck, don't hesitate to check on the website for help or contact me directly. Links below.
Rocket Brand Studios Homepage
Assuming all is right in the world, you can move on to programming this guy and getting to the fun stuff.
For more info, the instruction manual, code and projects to get started, test code, videos, walk-throughs and more please visit:
Rocket Brand Studios Picaxe Bot Page (Tutorials and Test Code)