Alphabot Build Instructions

[robothut]

I need a place to start compiling the build instructions for the AlphaBot project. So hold off adding any posts to this thread until I get done with the basic instructions. Then you can all post all you want with questions and comments and that way I can go back to my instructions posts and make changes and addtions so that in the end anyone that reads this post will see the instruction first and other replys after. Like say it will take some time so be patient.

There will be more information here than you will need to build the robot. I will include information about how some parts are made that you will not have to deal with but you might find interesting.

Here is a basic order for assembling the robot. I will cover each topic in detail.

1 Paint the metal and resin parts

2 Assemble the motor gear box and drive linkage.

3 Detail the body front part.

4 Screw the back and side parts together.

5 Build the flasher switches.

6 Install the switches and antenna mount part.

7 Assemble Arms and arm linkage.

8 Install Motor gear box and pin walk pivot plate.

9 wire up Motor, lights, switches and remote power cable.

10 Install Horn

11 Install antenna sprocket and chain.

12 Lube linkage.

13 Screw on body front

14 Install feet.

15 Built remote control unit.

[robothut]

Painting the Aluminum parts. If you want to leave the robot a natural aluminum color skip this step.

Of the 6 aluminum parts you will need to paint 4 of them. The front the back the side and the inside leg part. If you plan to use spray paint make sure to clean and prep the metal first. Wipe the metal down with some lacquer thinner or paint thinner to remove any oil and drit from the metal. Next use a self etching spray primer other wise your paint may not stick well to the aluminum. Now you can spray the metal any color you want. You may want the screws to match the body color if so then take a old piece of cardboard and poke 58 holes in it with a nail or knife. Place 58 of the little #2 self taping sheet metal screws in the holes. Now you can paint the screws if you want them painted. Here is a picture of the self etching primer and some pictures of AlphaBots with non painte screws and then with painted screws. Sometimes seeing helps one decide what looks best.

Now if you decide to Powder coat the parts everything stays the same except you do not need to put on the self etching primer. You will not want to powder coat the screws as the powder coat will be to much of a build up on the threads and the slots in the tiny screw heads. So if the screws need to match the powder coated parts then you will have to find a close color match in spray paint just for the screws.

[robothut]

Painting the resin parts.There are 7 resin parts, 6 of them will need to be painted. The resin part that does not require paint would be the antenna / eye mount part inside the robot. Before you can paint the resin part you will need to do some clean up work on it. In a attempt to save money simple gravity feed rubber molds will be used to make these resin parts. So if you want a perfect looking part you will need to do some sanding and maybe some filling. The resin will sand very easly, first go at it with some 220 grit, then when it all looks even sand abit with some 330 or 400 grit. Next primer the part and lightly sand again then paint. You don't have to use spray paint, you may find that useing water base hobby paints work even better. The Bellows in the arms assemblies are not resin but they can be painted if the origional black color is not to your likeing. Try useing the Krylon Fusion type paint on them, most other paints will not stick to the plastic bellows very well. Inside the bellows you will have a 1 inch wood dowel for support, the end of the wood dowel where the claw screws on will need to be painted. Wood will take a few coats to seal first then sand and paint.

Here are some pictures of the resin molds used to make the test parts. They are simple gavity feed molds.

Ever wonder what resin looks like before during and after its been mixed and poured in a mold.

Ever wonder how I drill the screw holes in the resin feet so they can pivet? Not yet you haven't but once you build a bot you will. So heres the secrete. I made a small drill bit that would fit into a right angle screw driver device that I chuck in the drill press, then I use a aluminum template to make sure the I drill the screw hole in exactly the right place.

[robothut]

Assembling the motor / gearbox.Here is what you will see when you open the box. and here is what you will see when you open the bag. and if you open the little bag with the gears in it you will see this. Notice that one of the large white gears has a hole in it. This is so you can tell it apart from the other two large white gears.

[robothut]

The instruction sheet will show you how to assemble the gear box in 3 different speeds. We need to assemble for low speed as it has the most power. So find one of the two gear shaft pins and feed it threw the motor houseing and then the large white gear with the hole then one of the other large white gears. Next take the other gear shaft pin and put it threw the motor housing and place the last large white gear and the small tube spacer on it.. The motor will need the pinion gear pressed on make sure you press the little gear all the way on the shaft, back to the motor with just a small space left so the gear does not rub on the motor. If you do not get the gear pressed back all the way it will not engage the proper gear. Now you can snap the motor down in place in the metal frame but first if you put just a dab of goop glue on the back bottom of the motor it will keep the motor from ever popping out of the frame on its own, you know like if you were to ship the robot to a friend and the shipper bounces the bot around and the motor pops out and when the robot gets there it does not work.

[robothut]

Next we add the output shaft assembly. Open the little bag of screws and hardware. We will use the drive shaft with the treaded ends, th other drive shaft will not be used, also not used will be the 2 self tapping screws and the little washer. So slide the threaded drive shaft into the metal frame, besure to place the brass gear on the shaft as shown then push the shaft threw the other end of the frame. You can place the small hex set screw in the brass gear at this time if you like useing the included hex wrentch. You will be adjusting this later so do not over tighten the set screw at this time. Next slide on the chain sprocket "place it in the postion shown in the picture with long nipple faceing the end of the drive shaft" and place nuts on both ends of the threaded output shaft. Tighten the two nuts as much as possible, we do not want these to work lose later as this would cause problems. This picture shows the set screw hex wrentch and the drive shast assembly screwed on to the main gear box. It is screwed to the main gear box useing a short screw and a ling screw provided in the hardware bag.

[robothut]

What we need to do next is add some crank mechanics so we can connect the walking and arm swinging mechanics. Rather than spend big bucks haveing a laser cut metal crank made I decided to use standard RC Servo parts for this, they are cheep and can be had from many different sources. Also by useing a 4 post type "called a Cross" we can use the 4 legs "posts" to control simple switches for the lights and horn. We will be able to use these to program the order that lights and beeps happen by cutting off some of the legs / posts. Before we can intall the servo Cross part we need to drill and tap each part for a 4-40 thread. Tap and drill sets are cheep (2 or 3 bucks at any hardware store) so if the kit form of this robot does not come pre drilled and taped this how to do it. Drill the tap hole on one of the 4 legs of the cross as close to the center hub as possible. Then use the tap to tap in the threads to this hole you just drilled. A power screw driver works well for this as they trun at a slower speed. The reson we are taping in new holes close to the hub center and not useing some of the excisting holes in the Cross legs is that we need to limit the travel of the linkage and we can use the extra power we will save by having less travel. OK so you have drilled and taped a 4-40 thread hole in one leg of each Cross part right.

Now we will place them on the drive shaft. You will find they fit tight in fact to can thread them on the shaft. Make sure you place the Cross part with the long nipple part facing in towards the gear box. We want the long nipple part to go over the nut that you already tightened on the shaft. Next we will add a second nut to the drive shaft. This will push the cross in and over the inside nut even more. You will need to use needle nose tpye plyers to hold on to this nut and tighten it all the way, it will be pulling into the cross as well and can be hard to get ahold of but stick to it and tighten it all up good. Now its time to do the same on the other end of the drive shaft but now make sure that when you tighten everything up that the hole that you drilled in the cross parts are opposite each other, we need it set so that when one linkage is pushing the other is pulling. The two cross parts on the drive shaft can be placed on a table top to hold them in perfect aligment as you tighten up the last nut. There is a extra little drive shaft sticking out the front that we will not be useing so snip or cut this off. Also once the nuts on the drive shafts are tight you can snip or cut off the extra threaded shaft.

[robothut]

Now is a good time to check that the motor gear box is operating correctly. Sometimes some of the plastic gears bind if the metal gearbox frame is a bit tight. So if you have a battery laying around and some wire just shoot the motor a volt or two and see how it sounds. It should sound consistant, if you here radical changes in sound then something is probably binding abit. Also you can normaly tell just by feeling the plastic gears, they should all have just alittle free end play, if they do not then gentaly push back on the metal frame part that the motor front goes into, the same part that the plastic gears shafts go threw.

Now is a good time to glue the plastic sprocket in place on the drive shaft. Just push the gear in toward the gearbox, apply alittle GOOP glue to the shaft out near the end and rotate and slide sprocket out to the end of the drive shaft. Put a little goop glue on the shaft on the gear box side of the sprocket now and rotate and push the sprocket into the goop, then work it back out to the end of the shaft and let it dry.

Now is a great time to glue the GRILL lamp in place. Yes we could make a fancy laser cut holder for the lamp or even a resin holder but it would just add to the cost of the project. Use a little GOOP GLUE to secure the 3.8 volt lamp to the top of the motor. Make sure that the brass base of the lamp does not contact the metal of the motor. You will see that it is easy for the lamp to glue to the motor by contacting the glass part of the lamp and the plastic end part of the motor. If the lamp ever needs to be replace you will find that you can easly remove it and glue in a new one.

We will now make the drive linkage for the walking and the arm moving. I use .081 brass rod for the linkage with small electrical crimp type connector eyelets. The two leg walk units need to be 3 & 5/8 long from center of eyelet too end of brass rod. I have found that the dollart store electrical eyelets fit the brass rod best. Solder the eyelet and brass rod connection. You can use a high wattage soldering pencil or a mini tourch, a mini tourch is alot faster. Next made the two arm linkage parts they will be 1 & 5/8 long from center hole to center hole of the eyelets. Not that the eyelets face opposite each other. Also there will be a joggle bend added to one end of each unit to help with alignment. Be sure to solder the eyelet to brass connections.

You can now put one leg linkage and one arm linkage on each of the drive shaft cranks useing a 4-40 screw and a plastic spacer provided. Do not tighten the screw down you want the linkage units to be free to move with out binding. A small dab of goop glue on the end of the 4-40 screw that stick threw the crank will keep it from working lose or tighting up. Just a dab of lube on the linkage / screw connection will help in free operation as well.

[robothut]

The body front paint should be dry by now so why not put on the nose, the eye jell diffuser and the Grill tanslucent artwork. The nose you can see just slips in to the slots, then bend the metal on the back side and add alittle goop if you want to realy keep that nose from moving around. Now the story of the nose goes like this. We were going to have the nose laser cut and bent at the metal shop like the other metal parts, but because its so small and hard to handel on the laser cutter and the metal bending machine the cost per nose was going to be almost $10 buck! So what is happeing now is the artwork for the nose can be held to thin alluminum and the part can be cut out with scissors, the nose can be bent by hand useing something with a thin straight edge like a knife or better yet a putty knife. There you just save $10 bucks. Make sure you paint the nose the right nose color before you put it on.

The eye jell just requires that you place a small amount of goop around the eye hloes on the inside of the front then stick the jell into it. Leave the dull side of the jell to the inside of the robot shinny side visible threw the eye holes. The Grill artwork is a decal that is placed on a piece of clear plastic so just place some goop glue around the edges of the translucent grill part and watch from the front as you place the parts together so you can line up the artwork with the metal grill cutouts. set the assembly aside to dry. This picture does not show the eye jell, sorry I did not take a picture at that point.

[robothut]

Time to do some screwing around. Get the back part , the main side part the inside leg part and the bag of #2 screws. Screw the parts together! We are haveing some fun now! Yes I know the parts should be painted in these pictures but I did not know what color you were going to go with so use your imagination.

[robothut]

Building Flasher switches. Switches in toy robots are normal very crude. So lets go with that. We will use some 1/4 inch wide 2.5 inch long supper thin brass sheeting. Now if the inside of your robot has no paint on it then you can use the body as part of the swtich but if your inside body has some paint on it (over spray) then don't bother trying to clean it off just add a second contact for best results. Basicly we are going to wrap a piece of cardboard around the end of the brass contact to insulate it from the robot, the brass will be glued with goop inside the cardboard and the cardboard will be glued to the inside of the robot. Origionaly I was going to screw the switches in useing the mounting screws that also hold the motor gear box in place but things change and now the switches will be glued in place. We will make 2 sets of switches one will be controled by the right drive shaft crank and the other by the left drive shaft crank. One switch will control the flashing of the GRILL display (the lamp we just glued to the top of the motor) and by a magic electrical trick "that I will share with you" that same switch will make the eye LEDs light when ever the GRILL lamp is OFF. The other switch will be for the horn. You can set your robot up any way you want but what I have done on mine is have the GRILL and Eyes alternatly flash 3 times per robot walk cycle and the horn beep once per walk cycle. The horn honks when the GRILL lamp is not lit as the grill lamp sucks over 200 ma of power, no reason to have the grill lamp the horn and the motor all fighting for power at the same time when you can program the order of things just by snipping of some of those fingers off the drive shaft crank we talked about earlyer. But back to the switch we have the thin brass glued inside the cardboard case and because my robots have powder coat over spray on the inside I have added a second brass or it could be tin strip to the bottom of the assembly. This added bottom contact can be any type metal as sit does not have to bend or spring around it just lays there as a clean contact for the thin brass part to contact when the drive shaft crank pushed on it. See how I bent alittle of the brass over at the one end of the assembly. That is so you can solder a wire there. The also note how I bent the brass, this will make it a normaly OPEN type switch and will be come a CLOSED circuit when the drive shaft crank fingers push on it. The botom metal strip I made a contrasting metal so you could tell it was seperate. It becomes the common conection for the swtich, again if you robot has a clean metal inside then you realy do not have to add this strip but why not so we are all doing the same thing. I think from now on if I refer to COMMON ground or negative that means the frame of the robot when the robot is walking forward. Or Positive that again means when the robot is walking forward as all votages reverse when the robot reverses. Its not important to know that now but it might be helpful later. Here is a simple line schematic that shows a typical simple light switch in a toy . Then below it is the same switch and lamp being used to alternatly light up 2 LEDs. Basicly the lamp requires over 200 ma of current to light up but the LEDs need less than 20 ma to light up so by placeing the LEDs acoss the switch the Lamp will not light as the leds can only pass on 20 ma or less but the ressistance of that 200 ma lamp is very low so the Leds will light up. This same "Jedi "impedance trick is used in many space toys that have alternating lights but only one simple switch. In the case of the old toys that do this there are no LEDs just lamps so what they do is the switch controls 2 lamps wired in parallel and the third lamp goes across the switch, so the third lamp will light when ever the switch is open and go out when the switch closes to turn on the first two lamps. Very cool. One of my favorite old school tricks used in space toys mainly from china. Origionaly this how the AlphaBot worked, the 2 eyes were lamps controled by the switch and the GRILL lamp was across the switch and came on when the Eyes were OFF. I had to drop the eye lamps as the current was just to much with all the lights and motors and horn actions. Thank God for LEDs.

[robothut]

I find that I can not go back and edit the posts so will start a thread with build instructions.