Let's Make Robots!

sharp IR sensor for beginner robot

alrighty, so i'm about 80% done the robot detailed on the 'start here' page. however, i have NO idea what on earth to connect the sharp IR sensor to. the tutorial mentions anything labeled v or g, and analogue input one.. which area is the analogue input? also, in the picture, the sensor appears to be connected to something not labeled with any of these. and how do you go around connecting the unused inputs to v? it says there should be three unused in the tutorial, but if i was to hook it up where it seems to be in the picture, i'd have four unused inputs. if they even are inputs.

..i'm a little confused about this all, hah. assistance would be greatly appreciated :)

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I hope this will help:


Looking forward to seeing your robot! :D 

/ Fritsl

ooooh, that is extremely helpful.

one last fuzzy area - how should i go around connecting the unused outputs to v?

Uhhh, no.

Don't connect any unused anything to V. Some say you should connect unused inputs to Ground (through a resistor) but I don't think anyone does this (unless the board is set up this way as a default). Just hook up your motors and servo and such --Just leave the other pins be.


Good luck, dude  

www.rocketbrandcustom.com baby!!

"Weather you use the ribbons or “my method” of connecting the Sharp IR, you should also connect the 3 remaining analogue input to V."


so i don't actually need to do this...? 

Yes, yes, do it, boy :)

These are analouge inputs, they are supposed to be connected to V! If you do so, but with some kind of risistor between, you get the value of the resistor - but it is of course perfectly fine to not add a resistor - it is the same as "turning the nob all the way to one end", it is how it is supposed to be!

Chris is talking about something else :) 

/ Fritsl

Reason is: There are 4 analogue inputs. But this is not the finest measuring equipment in the world, and so the returned value tends to be more or less the sum of the others if they are left to hang.

You will also see strange readings on the pins not connected if only one is connected directly or through a resistor - to V.

If you for some reason would like, you might also add a resistor instead of connecting directly to V. That will give you another result on these.. but that would be a strange thing to do :)

Main thing is that if one is used, it tends to be a mess if the others are left hanging. And strange readings are not nice :).. AND I assure you that the analogue inputs are ment to be connected to V or less than V. That is the point with these!

Try not doing as I wrote in the walk through, and you will get strange readings.. possibly! Then do as I write, connect the remaining hanging to V, and you will get rock steady readings all the sudden! 

/ Fritsl

does it matter which v i connect them to? should they all be connected to the same one?

You can actually have 2 V's, but I assume you only have one (is only using one power supply)

If you only use one (battery-pack, not two), then all V's are the same, just as all G's are the same. It is connected to itself all over in your circuit.
Should you - though I assume not - have more than one power supply, you can use any as well, as long as the V you use has not got more voltage than "V1" (the one your chip is running on)
So.. If you follow the "First robot"-project, there will be a direct connection between all V's everywhere on your board, and up to your power supply. You can use any, or make branches from one etc, it does not matter :) V goes to unused analogue in!

/ Fritsl