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2009 Robot Games

May 3rd, 2009
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The 2009 Robot Games are now done!

Yours truly came in second in the Minesweeper event, and missed out the top 3 slots in both Mini Sumo and Line Follower.

Was a great time and looking forward to next year’s already!

Videos have been posted; both on Facebook, and the WCRS Website.

Home Learning

January 29th, 2009
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Or what I have been doing for the last 3 months.

I’ll tell the story with pictures:img_0009

The box behind the little motor is a test tool I made initially to test servos. In the hobby store, these kinds of testers sell for about $100. Not only did this one only cost a grand total of $50, but it does much much more than just a motor tester. Simply hook to USB and reprogram it to do whatever you need it to.

So far, this is what I have programmed into it:

  • LCD Tester
  • Servo Tester – 5 points
  • Servo Tester – continuously variable
  • Voltmeter – 0 to 5 volts
  • LED tester
  • Power Supply

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Joule Thief. Excellent little piece. Takes dead batteries and pumps up the voltage to drive a nice and bright white LED. We have it in our bathroom as it makes a great nightlight using our old, would have been thrown out batteries.


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Technically my first robot, although he has gone through 3 revisions already. Right now I have a mechanical engineer helping me to produce a commercial grade chassis for it. He currently navigates rooms with basic obstacle avoidance. This last rev added a tilt to the distance sensor so that he may scan in 3D. Future upgrades with the new chassis coming include the ability to mount a WIFI camera and view images seen from his vantage point remotely.


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I had received a handy board and decided to push what I could do with it. He is functional, avoids obstacles and races along until he encounters an object at which time he can slam on the brakes. Functional accelerometer meant to check for crash angles. Ultimately the handy board could not provide enough resolution nor processing speed to keep pace with this particular RC frame, so what was learning from him will be applied towards my treaded robot.



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This is Meowchi. He made it into a rev 2 and was a functional line follower that was created by hacking another robot platform’s motherboard. It was more of a proof of concept and worked well, but ultimately his motors gave their life to our new electrically controlled blinds in our bedroom.


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This is my mini sumo. Although fucntional and works fine, it turns out he’s a little wimpy for competition. (Only because for some reason they won’t let me compete with 10 year olds, even though I am at the beginner level.) I’ll have to either beef him up or tear him apart and rebuild him ala the Six Million Dollar Man. (We have the technology)

Merry Christmas!

December 24th, 2008
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‘Twas the night before Christmas, and all through the house,
Not a creature was stirring, except my robotic mouse.

The Atmels were hung by the chimney with care,
In hopes that St Nick, could debug them in pairs.

The children were nestled all snug in their beds,
While versions of “C” code scrolled through their heads.

And mamma in her ‘kerchief, and I in my cap,
Snuggled in bed, downloaded code samples to adapt.

.. That’s as far as I got.

Happy hacking holidays!

Futuba S3004 Mod

November 5th, 2008
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This is my Strip Down and continous rotation mod to the Futuba S3004. Right now PM Hobby sells these here in Calgary for about $18.

Specs as listed at robotshop:

Specifications :
Single ball bearing on output shaft
Precise tight fit throughout the geartrain
Being standard size and lightweight, it fits many applications.
Three pole motor
Speed: 0.19 sec/60o at 6V
Torque: 4.1 Kg-cm (57oz-in) at 6V
Standard “J”-type connector with ~5″ of wire
Nylon gears

Start by removing the horn, flipping the servo over and removing the bottom 4 screws.

Have a quick look at the gears layout and note locations for later. A snapshot with a digital camera always helps if you have a short memory :) I usually place the gears right above where I am working in the proper order.

Have a look where the output shaft (the one with the bearing) was. You’ll see a shaft sticking through the hole with 2 flat sides. This is the feedback potentiometer. Unlike the S148, this servo’s output gear is completely molded so there is no plate to remove. Instead we must decide on a different plan of attack. If you have the room, you could simply desolder the potentiometer and mount it outside the case for easy trim adjust.

Since I prefer to leave the case looking stock, I’ll cut the potentiometer’s shaft so that it will no longer turn with the output gear. Carefully extract the board to gain access. This is a bit tricky as the potentiometer is soldered last onto the board, and is held into the case with 2 clips molded into the shell.

Once the shaft is snipped, reassemble the board into the shell. It took a bit for me to finess the pot properly back inside.. I had to push it into place from the bottom with a screwdriver so that it would clip back in. I also filed a bit of a slot in it so that I could adjust the trim. Remember to also cut the stop bar on the output shaft.

Quick test with my servo tester – all is good. 90 stops the motor completely, and forward/reverse are both working perfectly. All in All Took about 1/2 hour including taking pictures. I think future mods should take ~ 20 minutes. I also think I can skip removing the board and just cut the potentiometer shaft flush with the casing. will be a touch harder to set the pot, but will drastically cut down mod time.

Quick Build

September 28th, 2008
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More pictures and info to come.. just a teaser of a quick project I’m throwing together this week.

Arduino Temperature Display

August 18th, 2008
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This was more of a proof of concept, a “I can do it” sort of project. I had purchased the LM35 so long ago with plans to use it with a PicMicro.

I had purchased a couple of the Freeduino SB boards from Solarbotics, and found that I liked the quick/rapid prototyping it offers. Its my first experience with the Arduinos, and apart from limited availability of the microcontroller, and an incorrect capacitor on the power supply, I’ve been pleasantly surprised.

I actually desoldered the capacitor out of the circuit to regain full voltage control of the board, and for future ones I’ll also have to desolder the vreg, since I prefer to use a switchmode and I’ll bypass some of the board control with my switch to save battery power.

LM35 is hooked up into Analog 0, and the reference is set to internal, which switches the 5V reference to 1.1V. Measured with my DMM, it was closer to 1.043 and that is so close to the magic 1.024 number that the raw value is closer to the true reading from the LM35.

The LCD is the SLCD162 MeLabs LCD Display, which I also picked up from Solarbotics.

The LM35 is taped to an old northbridge heatsink, which provides a closer “In Air” reading.

I’ll be tearing apart this circuit to use the microcontroller in another project, but at least it will have some memory resting here on the site.

Sketch

LED Tester

August 17th, 2008
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While I was working for a manufacturing company, we would occasionaly go through our scrap parts from the machines, and at times would find hundreds of LEDs. They could be saved and used on the next run, but we had two issues:

1. What color was the LED?

2. Polarity on the surface mounts?

This tester was made to make my personal life easier. Output is limited and pulsed at a 50% duty rate. Power is delivered to a set of multimeter leads that were lying around the shop. A PIC12F675 was programmed for the 50% duty.

There are two modes in the tester, with a bicolor LED to indicate which mode is active. The pic reads the switch position and is configured to reset on change. Green indicates red lead = positve and black lead = negative. Red indicates not polarity sensitive. In this mode, the pic swaps the positive and negative continuously so that the LED will illuminate regardless of polarity. This let me sort through the hundreds of LEDs quickly, placing each color in its own container, and then determining polarity later, during the production runs.

Overall, a very simple design. The PIC12F675 is socketed to allow program updates. (Never needed any) The battery here is the same one I built it with, which is now over 6 years ago. Although I don’t comb through hundreds of surface mount LEDs, the tester is still handy. The pushbutton switch is wired directly to the 7805 vreg, and I didn’t require any bulky capacitors in the circuit, since we’re dealing with pure DC.

Most of the parts were scavenged from scrap units we had at the time. The container is an old toothpick canister. Hot glue and tie-wraps were my best friends on this build. The blue wire we had at the shop for repairing damaged PCBs.

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