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Sunday, July 11, 2010

Robot Working... Sort of...

    Well, I blew a lot of time soldering my proto board this weekend.  I learned a lot.  First of all, I really stink at soldering!  I spent some time reviewing my board.  I now have a design for a proto board that will reduce the amount of jumpers I need to solder.  I'm going to buy one of the Radio Shack boards that have some holes connected.  I ordered a slew of female header pins, some chip sockets, etc from Sparkfun.  The result should be a board with two 18 pin sockets, a piezo speaker, a 5 V regulator, and some additional headers.  I'll have 2 2-pin header with 0.1 uF caps for the motor drivers to cancel noise.  I'll have 2 3-pin headers for signal positive and ground.  This board should be able to be reused for multiple projects.  The idea is to have everything connected to female jumpers.  That way, I can just stick wires in where I need them.  Any project specific parts can be either soldered in or I'll add jumpers.  The other nice thing about female jumpers is that I reduce the risk of frying parts.
    I ran into quite a few challenges this weekend.  Other than soldering wires to the wrong spots, I also had a few mechanical failures.  I ordered 2 geared motors from Solarbotics.  Right after I soldered 22 gauge solid wires to them, one of the leads snapped.  It sheared so close to the join that there was no hope of a fix.  Aaaagh!  I dropped back and punted.  I pulled the motors out and replaced them with the only spares I had: two 3 Volt motors with gear teeth from Radio Shack.  When I tested them on my breadboard, they wreaked havoc.  They put a ton of noise on the line.  I put 0.1 uF caps across their positive and negative leads to cancel the noise. 
    Once I got the rest of the problems worked out, I hooked it all up and went for a test ride.  The code worked great.  The only problem was the switch from 6 Volt motors to 3 Volt.  When the robot decided to turn, it peeled out, doing doughnuts!  I need to gear the turn delay time Waaaaaaaaay down. 
    I see that I can upload images here.  I'll take images of the final code when I get it and upload that.  Once I build my good proto board, I'll upload images of that, too.  I downloaded a freeware version of Eagle CAD.  I think I should be able to use that to generate a good schematic.  I am just getting familiar with it.  TAFN!

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