Let's Make Robots!

Guard II

Waits, listens, looks and shoots

21 January 2009

Guard II is now up and running. I'll try to make a video in the next few days but it's time consuming.

This is a stationary bot that listens and "looks" for targets. When it finds one it shoots a ball at them.

Overall, this has worked well for me. It came together quickly, and unlike Guard, the design of both the bot and its program are my own. The ultrasonic problem was a simple fix in the end, but the nxt-g interface made it hard to spot. I hadn't created a control link between the sensor block and the fire/don't fire decision block.

I am finding that the ultrasonic module only gives a reasonable reading off a hard surface that's pretty much at 90 degrees to the sensor, and along a very narrow beam. Soft or angled surfaces won't register.

With a stationary bot, the range of its "weapon" is now more obvious, and it's not as good as I hoped. I'll need to see if this can be improved with higher gearing or another design change.

31 January 2009

Finally got some video up. I'm entering Guard into the Cat-Splat Challenge (someone has to enter), I think it meets the criteria. I had to lower the ultrasonic sensor so that it could see its "victim"! The higher gearing didn't work - the motor doesn't have the torque todrive the gear-train.

I could also enter the video for "show your feet on LMR".

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Got fed up with Guard's tangled legs, so built a stationary version with extra sensors.

Ultrasonics aren't working reliably yet. Pic and video to come.

Are maybe going to make a RobotC program if you like or why not try your own, anyway it's good training for both of us.

 /Emil Hemdal (SWE)

@Emil: I may try RobotC at some point, but not right now because there's only so much time in a day and:

  1. I have a job, kids and a time-consuming non-robot project that all have priority
  2. Once Guard is complete with video I'll break it down again as there are a couple of other nxt projects that I really want to try out
  3. I kinda like working within the limits of nxt-g
  4. I have a PIC based robot project sitting on my desk that I also want to progress with, and it's going to involve another learning curve or two



/Emil Hemdal (SWE)

I'm calling "Shoes!"

Who else is in this club? I challenge everyone to provide links here.... Not to your own videos, mind you! That would suck the fun out.

You want someone else to video my shoes? Or do you want to suck my shoes? Too many biers my friend.

BTW I hear that the statue of a golden shoe errected in memory of the journalist who threw his shoe at Dubyah Bush recently has been taken down. I'm amazed they managed to get a statue up so soon. It'd take at least ten years here.


Showing a foot does not count when the shoe blocks the shot. Crocs, perhaps, but not socks.

I would not like to be hit in the head with a shoe made of gold!

he got mousey a couple of times. :)

It looks really good now.

/Emil Hemdal (SWE)

Whaha awesome