Let's Make Robots!

Our robot project journal

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Hi, Jim. Welcome to LMR.

I took a quick look at your site, and it seems you have posted quite a bit of material on your project. Good stuff. I hope you and your grandsons will post on LMR when you have updates so we know to come check out your work.

I look forward to seeing more, and hope to see you around on LMR. It's a great place for inspiration, getting and giving help, or just exchanging ideas.

We're very excited about joining LMR and will post soon. We typically work on "Homer" every weekend and then update our journal by Sunday evening. We'll also try to post on LMR at the same time.

Thanks again,


My gandsons and I are making really good progress on our robot project named "Homer" as documented on our journal at appiphania.com. This past week we had a really interesting challenge calibrating our port and starboard IR sensors and thought we'd share our experience.

We're using a Sharp IR model GP2YOA21YK. This is a 10 to 80 cm model that we purchased from Robotshop. These are amazing little sensors.... not just an IR transmitter /reciever but a very sophistocated complete range processing unit. As an example; they can detect and measure distance to a flat black object, very low reflectivity with no problem.

The best overall description of and how to use these awesome little guys is at:  http://www.acroname.com/robotics/info/articles/sharp/sharp.html

The most significant thing to know is that the output voltage is non-linear and needs to be lineralized for object distance measurment. The next is that the voltage output under 10cm falls rapidly which will cause significant response errors if not compensated for.  You can check out my journal at Appiphania.com to see how we resolved the linearity issue.



Yeah, those Sharp sensors have been used quite a bit on this site. Thanks for sharing. It sounds like Homer is coming along nicely.