149Views8Replies

Author Options:

would a non-light working motion sensor be worth making? Answered

for my year nine project ( i am currently Year Eight (yes i am english, years rather than grades) ) in DT we will be making ping pong ball launchers. my idea to add a bit of uniqueness to it was to make an automated turret. i did think of making a normal light  detecting one but wanted to investigate this instead. my idea is to use a 555 timer chip to create an ossilating signal braodcatsing a few metres then a sensor tuned to the same frequency. then if a body was to enter within the signal range the signal would change and the sensor could detect this change and through an arduino could fire the turret. i just wanted your opinions on weather or not it would work.

8 Replies

user
steveastroukBest Answer (author)2011-03-14

You don't need a processor to do this, you're making a proximity detector. There are all sorts of methods - a classic is to make an oscillator, with an antenna connected to a capacitor in the oscillator, approaching the antenna shifts the frequency, off goes the detector.

Select as Best AnswerUndo Best Answer

user
MadScientist101 (author)2011-03-16

I am on the gifted and telented regester so i tend to have keep up the good work.
1 i have tied the ultra sonics and feel the range is not enough
2 others will be human operated so i wanted mine to stand out and stand alone
but thanks any way, i shall look into the floor pads. :)

Select as Best AnswerUndo Best Answer

user

I hope that's not G+T for spelling and grammar.....

Select as Best AnswerUndo Best Answer

user
ARJOON (author)2011-03-14

it will work but why nonlight

Select as Best AnswerUndo Best Answer

user
MadScientist101 (author)ARJOON2011-03-15

i just wanted to see weather or not it would work and how it compares to a normal ir sensor

Select as Best AnswerUndo Best Answer

user

Its difficult to get directionality with proximity sensors.

Select as Best AnswerUndo Best Answer

user

true but i kinda had the idea of mounting the broad casting and recieving antennas as coils on ferrite cores. and then aim the cores to focus the signal into one area.
thanks

Select as Best AnswerUndo Best Answer

user
rickharris (author)2011-03-15

Your FAr exceeding the needs of the yr 9 curriculum - This in itself isn't a bad thing provided:

a) you will be able to finish what you start
b) your teaching staff can support what you want to do. If they don't show full interest and excitement then there is probably a good reason.

Personally i would go for one of the following as I think you have more chance of success:
a) A circle of pressure switches on the floor - turn towards the one that is activated - You may have made something like this with aluminium foil and card.
b) A Picaxe 08 microprocessor and ultra sonic detector mounded on a servo to scan the area ( more expensive).
c) A PIR detector - the interface may be an issue.
d) Remote operation of a ping pong "gun turret" using servos, you can never beat the human operator!

You don't say what your time table, budget or skill level is so real advice is hard to gauge.

In the UK even if it doesn't work out provided you analyse your problems correctly and suggest improvements you should get 80 or 90% of the marks.

Select as Best AnswerUndo Best Answer