Let's Make Robots!

My Big-Base Robot

Follows things with certain colors, shapes, etc.
Bill-O-Materials.xls19.5 KB

I have posted many ideas for robots, but this will be my second on this website.


It is a Butler Robot. It will have a 12v Mini Fridge onboard, with a springed DC Solenoid wired to a Max232 chip, to the USB of a local laptop. An onboard wireless camera will be linked to its radio receiver connected to a TV Tuner (RCA inputs) to the USB of a computer. The computer will be running image/video processing software to detect and follow distinct blobs of color, shape, etc.



The final designs with some calculations for finding the inertia of the entire robot. Really to figure out the stress placed on the wood.

(I went with 3/4" plywood) Eventually I will paint it white.



Plan rendered in Google Sketchup, obviously not drawn to scale



The two 12v 24AH batteries



Closer look



Sabertooth 2x25 Motor driver, very strong and reccommended by me! Capable of 25A load per channel, and 50A fully



The robot head next to my 1st place baseball trophy

When I received the head from this toy:


 I gutted it. Of course it didnt look as nice as the model picture. I took out the leds inside as they were not bright enough, and added my own red ones for the eyes and blue leds for the headlights above (where the red and blue panels are, I took them off) 



The hefty motors

~from a Jazzy 1100 Wheelchair




Edit #1:



 L brackets



Caster not screwed in, because I need to first see if the wheelchair motors will have clearence, and everything would be flat. Yes I know thats alot of brackets, extra sturdiness! :)








 Vertical slab thingy, I needed four of these guys










I do not thinki it is going to hold at all


Future alterations:

  • Use XBee Modules... to make it go wireless 
  • Upgrade Batteries to 72AH

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Thx a lot...precious informations!

Ok, this seems too good to be true...

Using your "track a color" software, could the laptop then send out (very) simple serial  data based on your X/Y numbers? Now, I have to admit that I am a picaxe guy, not a real programmer/coder/ computer guy, but it seems that if your tracking software could simply spit out (2) variables, X and Y, it would be a piece of cake to have the picaxe control the motors to keep that object "in frame" and thus be driving to it. 

This seems to simple to be true. I NEED as much information as you can give me on this one... Hell, I simply can not believe we couldn't come up with a "you code something that will talk to a picaxe" for me and I "weld a proper chassis" for you!


I wish someone would make me a chassis... this crap has buggin' me for a while. Well it is close to what you said with the two planes. It uses a center of gravity variable I arbitrarily chose 85 pixels x 85 pixels as the size the bot should try to maintain (this equates to a couple inches from the object). Doing so will require forward and backwards movement based on the relative size of me or the previously determined center of gravity variable. Steering involves rotating the robot from right to left and moving the camera from up to down.

To create these movement commands I added an SSC (serial servo controllers, the bot uses electronic speed controls compatible with PWM signals created by the SSC) to move the robot. The SSC module communicates to the SSC board via serial commands.

The SSC module will send two variables to the SSC board that range from 0 to 255 with 0 meaning reverse, 127.5 neutral and 255 full forward. The bot have two wheelchair motors that control the left and right wheels independently (differential drive). Which is convient since it can rotate in one spot. There is one more servo that controls the tilt of the camera that also ranges from 0 to 255 with 220 meaning the camera is pointed about straight. Then I wrote a code intertwined with the, center of gravity variable into motor commands from 0 to 255 for each motor and for the tilt servo.

This last code was in VisualBasic.

TheVB script first grabs our size variable, center of gravity and compares it with what size we'd like to maintain in view (I chose 85 perviously). If the object is too big it moves backwards by a relative amount or if the object is smaller than it moves forwards. However, it is needed to change the relative amounts for the right and left motors to ensure that we can rotate towards the the object as appropriately.

The left and right motors, also use the SSC module similar to the tilt feature.


impressive, why is the camera illegal/ where can i get one
2.1 GHz is reserved for the military/government, I might not even stick with wireless. I picked up a 30 fps wired webcam, maybe use that
You can get angle-iron from the hardware store. 1"x1"x1/8" thick will work. You can cut it with a hack saw, drill with regular bits and use bolts to bolt it to the frame. In terms of wood --nothing wrong with it. Your cabinets are wood and hold a hundred pounds of dishes!
You may have to remove or notch around that 90 degree pin thing sticking up out of the top of the motors...
so you suggest that i stay with completely wood? I think I want to make a rectangular base with the motors, and caster out of the metal I was talking about though, do you know where i can get this?
The 90 degree pin is a gear release, twisted one way, the gears engage the motor, twisted another way, the wheels are loose so you can push the robot (wheelchair) when the battery or whatever else fails.

I hope this is understandable. Basically, you are removing the 4 allen key bolts at the top of the motor unit and replacing them with the same but much longer. In the little devider boxes at the hardware store (where all the specialty screws are) you can find little steel tube spacers. Find some that fit over the allen key bolts. This will allow a space above the motor units so all the stuff sticking up will clear the little shelf you are going to build above. The shelf is just 3 pieces of pine, 2 triangles and a "shelf". Pre-drill and zip these together with wood glue and drywall screws 1 5/8" or 2" (PREDRILL!!). You might even want to add a washer on top of the tube spaces so they don't crush themselves into the soft pine. 

This should do it --Super simple with no special tools. Also, You have to get some triangle corners on the main box!!! As weight is applied to the motors, the top edges are going to get smashed together!