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  • Author Author: Former Member
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Arduino: Find the greatest value

Former Member

Dear element14 members,

 

     I am doing a science fair project where I am taking 10 readings from a photo-resistor and trying to take the greatest value to do something else. Is there a simpler code than making a lot of  if statements? .....or maybe an IC or something?

 

Thanks In Advance,

 

Blockman301

  • in reply to Former Member

    Hi Nehemiah,

    For this, you don't need to store all 10 readings, just create 2 variables - one to store the maximum sensor READING and one for the corresponding servo POSITION, then as you take each reading, decide if the new sensor reading is larger than your previous maximum. If the new reading is larger than the old maximum READING, store the new reading as your maximum READING and store its position as your maximal POSITION. After the 10th reading simply send your second servo to the maximal servo POSITION.

    Doug

  • Here is what I am doing. I have a photo resistor on a servo. Every 5 minutes I want the servo to move to 10 different positions and take 10 readings. Then I want it to take the greatest of the readings and move a different servo to the positions of the greatest reading.

     

    Thanks in advance,

    Nehemiah Branson

  • Hi Nehemiah,

    For a software solution you could use a "For" loop.

    Cycle through all 10 readings - if the next reading is greater than the max reading, replace the max reading with this new value.

    Doug

  • Hi Nehemiah,

    What is the timing of your 10 readings?

    You might be able to use a "peak-hold" circuit to retain the maximum analog voltage and just sample it once.

    There are lots of example circuits on the net - the simplest uses just a diode and capacitor and maybe a resistor.

    For higher accuracy you can add a dual op-amp to eliminate the voltage drop across the diode.

    If you describe the requirement in more detail, the optimal solution description can also be more detailed.

    Doug