Author Topic: Sharp IR in Australia  (Read 3327 times)

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Offline BubblesTopic starter

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Sharp IR in Australia
« on: January 10, 2008, 05:49:07 AM »
I've been doing a bit of researching lately and have decided upon buying a microcontroller board to start some projects with. The only problem i am having at the moment is that i cannot for the life of me find a range finder in Australia!  >:( Does anybody know of a store which has a basing in Australia that will have a sharp IR range finder? I have looked at some which do not have a shop/warehouse in Aus however i would really like to find something from within Australia so that i will not have to pay for so much shipping.

Offline robonoob

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Re: Sharp IR in Australia
« Reply #1 on: January 10, 2008, 02:10:53 PM »
I've been doing a bit of researching lately and have decided upon buying a microcontroller board to start some projects with. The only problem i am having at the moment is that i cannot for the life of me find a range finder in Australia!  >:( Does anybody know of a store which has a basing in Australia that will have a sharp IR range finder? I have looked at some which do not have a shop/warehouse in Aus however i would really like to find something from within Australia so that i will not have to pay for so much shipping.
sorry, i cant help you with your problem directly but i think that if money isn't an issue then u could use sonar instead... if u are building a wall avoiding robot or smthing then this would be better imo

Offline Admin

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Re: Sharp IR in Australia
« Reply #2 on: January 10, 2008, 03:40:25 PM »
hmmmm I don't think there will be a store that sells any . . . is shipping from singapore cheap for you? there are a few online robot stores based there if you google it . . .

Offline SmAsH

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Re: Sharp IR in Australia
« Reply #3 on: January 10, 2008, 05:25:49 PM »
yea i got smae problem spipping like 9$ us... sigh oh well ill just stick to photocells
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paulstreats

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Re: Sharp IR in Australia
« Reply #4 on: January 10, 2008, 07:07:40 PM »
Quote
yea i got smae problem spipping like 9$ us... sigh oh well ill just stick to photocells

please please please...... Save up the money for for one.

It really is worth it. Photocells have nothing to replace a ranging device

Offline BubblesTopic starter

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Re: Sharp IR in Australia
« Reply #5 on: January 10, 2008, 07:17:59 PM »
hmmmm I don't think there will be a store that sells any . . . is shipping from singapore cheap for you? there are a few online robot stores based there if you google it . . .

OK, thanks i will check that out.

Actually, does anybody know an alternative to using a sharp ir range finder when all i won't to accomplish is obstacle avoidance?

Offline robonoob

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Re: Sharp IR in Australia
« Reply #6 on: January 11, 2008, 07:05:59 AM »
quote myself above: sorry, i cant help you with your problem directly but i think that if money isn't an issue then u could use sonar instead... if u are building a wall avoiding robot or smthing then this would be better imo

so i would use sonar.

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Re: Sharp IR in Australia
« Reply #7 on: January 11, 2008, 08:12:51 AM »
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Actually, does anybody know an alternative to using a sharp ir range finder when all i won't to accomplish is obstacle avoidance?
Well, you can use two photoresistors seperated by ~2 inches.
http://www.societyofrobots.com/schematics_photoresistor.shtml
Then get a really bright low angle green LED (~15 deg, 4000 candela+), and put it right next to only one of your photoresistors.

Light will shoot out from the LED, bounce off of close objects, reflect back, then only hit the closer photoresistor.

Subtract one photoresistor ADC value from the other and that will be the range to the object.

Why use a second photoresistor? Its a method to cancel out ambient light.

Offline SmAsH

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Re: Sharp IR in Australia
« Reply #8 on: January 11, 2008, 04:32:02 PM »
oh geez thx a lot admin...ill try it now if that fails ill buy an ir range finder ;D
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Offline BubblesTopic starter

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Re: Sharp IR in Australia
« Reply #9 on: January 11, 2008, 11:53:49 PM »
Quote
Actually, does anybody know an alternative to using a sharp ir range finder when all i won't to accomplish is obstacle avoidance?
Well, you can use two photoresistors seperated by ~2 inches.
http://www.societyofrobots.com/schematics_photoresistor.shtml
Then get a really bright low angle green LED (~15 deg, 4000 candela+), and put it right next to only one of your photoresistors.

Light will shoot out from the LED, bounce off of close objects, reflect back, then only hit the closer photoresistor.

Subtract one photoresistor ADC value from the other and that will be the range to the object.

Why use a second photoresistor? Its a method to cancel out ambient light.

Thanks alot for that! I will definitely try it out ;D . What do you think about placing another photoresistor on the other side and averaging out the two side ones and using that value to minus from the central one so that it won't be as susceptible to something like a lamp on one side of the bot?

Offline SmAsH

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Re: Sharp IR in Australia
« Reply #10 on: January 12, 2008, 04:43:39 AM »
um... admin could you show me how to make the circuit...im really noobish and cant find it on the web.. :-\
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Offline Admin

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Re: Sharp IR in Australia
« Reply #11 on: January 12, 2008, 10:18:31 PM »

Offline SmAsH

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Re: Sharp IR in Australia
« Reply #12 on: January 12, 2008, 11:36:44 PM »
oh soz im really blind  :D
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