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Sharp GP2Y0D810Z0F Digital Distance Sensor 10cm

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I always prefer buying sensors if the application is something important.
Homemade sensors always have problems of reliability and accuracy.

The one i got from Pololu were with the board, and it is quite stable, however as the minimum range is pretty large, i didnt find use for these,But these are definitely good for the particular range applications.
I would love to see the schematic.

Thanks a lot!

Heres the schematic with part numbers and values for a simple IR emitter/ detector.

Again, this works reliably well ranging from 0.5V at 30cm to 4.75V at 1cm distance in a dim ambient light. In normal room light conditions it starts at just over 1V up to 4.75V

The IR emittor in this example is always on, the datasheet suggests it can be used with a smaller resistor (works out at 40ohm) for short bursts, 22ms if i remember right, but im going to test it as an always on LED with an 80ohm resistor too to make it brighter and increasing the overall range.

I predict that sunlight would disable this sensor.
In fact, I predict that certain floodlights would disable it too.
You could probably also point a remote control at it and confuse it.
The sensors you pay for (like the Sharp ones) use better modulation than simple "flood it with light" to get a little better sensitivity. Not that they are great, but they get rid of the first order of problems.

Not to knock your circuit at all -- if it actually solves the problem you have, then a cheap solution is great engineering! Just be aware of what problems it /doesn't/ solve, before you try to rely on it and something has an accident...

Im going to be a bit pedantic here, not to be argumentative but so people who are interested in making their own sensors arent put off trying them...

 First of all, yes sunlight does disable this sensor somewhat just the same as it affects Sharp sensors (they also suffer oversaturation, just like the eyes in your head become oversaturated in bright sunlight) Thats the reason Im doing tests with different resistor values and also intend to repeat the tests with the detector in a photodarlington setup so I can minimize oversaturation while maximizing the light I want.

 Sure floodlights also produce oversaturation issues, but the phototransistor is sensitive to light around the 850nm range, so floodlighting would have to include light of this range to make a significant difference. Floodlighting at the right range would also provide oversaturation on Sharp sensors.

 TV remotes can interfere, but this can be solved if needed by modulating the light which would be a software based solution (one which I intend to use if i need to in a way that i can switch modulation on or off if its needed to conserve runtime when its not). Just as tv remotes interfere with sensors, firing modulated light at the right frequency towards a Sharp sensor will also provide false feedback.. Thats why you should be careful when using more than one sharp sensor at once since they interfere with their own modulation. Making them yourself you can decide if you need to give each sensor its own independant modulation or not removing this problem entirely.

 I also plan on running software based high pass spike filters on multiple samples to further increase reliability.

 Sharp sensors also suffer from random spikes (there are many examples of them being connected to oscilloscopes to demonstrate it) for this reason I would suggest that people using them learn how to make software based high pass spike filters in order to be safe against them.

 Im not slating Sharp sensors, in fact i recommend their use and also have 2 of them in use at the minute, but they are tailored towards a generic audience and solve most light sensor issues in a generic way, but that means if you want to use them for something more specific then you are limited to the output they provide.

 There are problems that affect all sensors, which a premade device like a Sharp sensor can solve to provide an easy to use sensor with a degree of reliability, but you can also do the same for yourself and make something that is just as if not more reliable for your application - it is important to understand what those issues are in order to be able to address them. Making them yourself can allow you to do more in software too, such as background light cancelling and the such by being able to independantly control the emitter. Build in reliability algo's so you can decide whether that particular sensor input is reliable or not and do something else if not..

 Im going to be using 8 sensors of this type - Sharp sensors would no doubt interfere with each other rendering them unreliable and an over expensive solution as well as getting the satisfaction of knowing that I made em myself. :D

Duane Degn:
paulstreats, I'm betting you've seen this before, but I thought I'd post a link just in case you or someone else hadn't.


They are little smt IR source and detector in one package. I believe they are commonly used in line following circuits.

SparkFun sells a couple of breakout boards for the sensor.

The Sharp sensors sure seem like overkill for a line follower. I'd think they'd be better used for object or drop off detection.


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