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tri
09-06-2004, 11:11 AM
hai guys,
i jyst wanted to know is there any readymade stuff for range finding
,i checked out some transducers which would cost $35, i want some
cheaper ones,
plz let me know if u guys know something of that sort

vikas
09-06-2004, 02:35 PM
Sonar sensors are availible in india also well last one i hear comone was offering them from about Rs 700 thats good enough if you dont want to build your own

Pulkit_gaur
09-06-2004, 03:43 PM
Hey ,
U can use IR for range finding.
Sharp's GP series IR range sensors give output directly in digital format.
and regrding U-Sonic you can make a simple PIC 16f84 based range calculator which can give u range measurements from 3 cm to 100 cm with 1 cm acuracy.

Thanx and regards
-
Pulkit

mexx
09-07-2004, 01:37 AM
hiii pulkit

do u think those GP2DI2 distance measuring sensors are available here in india??if so do let us know ..where and how to get those!! :)

vikas
09-07-2004, 06:44 AM
HEllo

well the Sharp's GP series IR range sensors are good but there is availibility is not that easy . And thats why i did not recommend them . IT your know of a place where you can buy them ( and the cost ) let us know :) .

09-07-2004, 08:40 AM
Sharps IR sensor range is limited to 12 cm,that was what i read last time
But they are rugged enough.and pretty accrate.

Sonars rather ultrasonics are good for long ranges.I have done one,but just gave a ping and received a ping back.I still have to load the math on the F84a.
here's a link:
http://www.leang.com/robotics/info/articles/minison/minison.html

Sonar transducers come for Rs 350 a pair in Bombay.Remeber u have to have access to tuning equipment[an oscilloscope/sig generator] if u plan to make ur own sonar set.]

If u have any old polaroid sensors lying around,u can rip of the sonar range module right off. Google for "polaroid sonar"

happy_99 ahd got the gp12 sensors from acroname.Maybe he can help u with the prices.

ice
//gerry

Pulkit_gaur
09-07-2004, 08:48 AM
Well Ice ,
The schematic given on this site is technically incorrect and it is just an idea , because if u notice the gain at the first stage has a value of 10000 which is impractical to realise in a high impedance ckt. with out appropriate pre-amplifier , author must have used a concatenated series ampl. here to achieve this gain , so in practical system this ckt. will fail or will give absurd signals.

thanks and regards
-
Pulkit

tri
09-07-2004, 02:25 PM
vikas can u be plz more specific about who is 0ffering as i need it urgently within 2 to 3 days

vikas
09-07-2004, 03:08 PM
Well i am not offering an sensors i was just quoting a price which i heard from one of my friends who was using it .

ice
09-07-2004, 08:12 PM
Pulkit,
Thanks for the info.The circuit used to give spurious outputs,but rarely.

The range was limited.but good enough for obstacle avoidance,but difficult for ranging.I'll try it out again,this time i'll load the math in the F84.
It'll be good if u can suggest us a few circuits.
Thanks again.
gerry

Pulkit_gaur
09-07-2004, 10:02 PM
HI ice ,

Well to give u a circuit it will take a day or two , actually the given system has other basic flaw as they are using wrong value of components to lock the PLL at the desired freq. check out the formula and put the value,actually u don't need a PLL to work there .The modules are tightly tuned at a freeq of 38-42 Khz band so they do the filtering by themselves.
There is no need for that PLL part.

Thanks and regards
-
Pulkit

ice
09-07-2004, 10:54 PM
the modules i bought had no ratings on them...but i think ur right..they were made for the 40Khz freq..They are from murata.

i don't think the circuit would have worked without the PLL.The PLl vaues are designed for a 40Khz detection freq.
I myself was transmitiing a 40Khz tuned Ping.

Without the ratings [transducer],thePLL was the safest way to go

bye,
ice
//gerry

happy_99
09-07-2004, 11:18 PM
hiii pulkit

do u think those GP2DI2 distance measuring sensors are available here in india??if so do let us know ..where and how to get those!! :)

I brought 2 nos. of GP2D12 from Acroname. It cost me < Rs.1500/- including shipping. ($11.5x2 + $7 for shipping) I asked them to send it through normal airmail parcel, as it's the cheapest of all. It took abt 4weeks for the stuff to reach here.

REgds

happy_99

ice
09-08-2004, 09:11 AM
I did some searching,u don't need a PLL if the moduls are tuned to the same frequency.Just the pream and the amp
bye,
ice
//gerry

ingenium
09-09-2004, 04:02 PM
hi,
can u give me the address where u got the sensors? can u tell me in a bit detail? any site etc offering the info...

ingenium
09-09-2004, 04:03 PM
hi,
can u give me the address where u got the sensors? can u tell me in a bit detail? any site etc offering the info...

happy_99
09-09-2004, 10:58 PM
hi,
can u give me the address where u got the sensors? can u tell me in a bit detail? any site etc offering the info...

Check here

www.acroname.com
Email: sales@acroname.com

Part: Sharp GP2D12 IR Ranging Sensor

The sensor uses IR rays to determine the range to the object. Output is anlogue voltage proportional to the distance. Range is from 10cm-80cm for the above mentioned part.

Regds

happy_99

siddharthvaidya
10-08-2005, 08:08 AM
Hey can you give me the url from where you ordered this sensor in rs.1500.

ice
10-08-2005, 03:54 PM
Here
http://www.acroname.com/robotics/parts/R48-IR12.html

If you are buying from these guys,you would like to order in bulk,ask the forum if anyone needs these sensors.

They sometimes give educational discounts and also when buying in bulk.