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  1. ;D then i think its better for me to go to the microcontroller section. i have feeling this topic wont stop here :) you helped me a lot...thank you
  2. Hello recently im doing the software part...is it ok to put my software problems here or should i open a new topic ? thank you :)
  3. well i was thinking about using the analog output since its straight forward, but then i found out its reversed all over. about the PWM...do i have to use microcontroller to make it work as i want? is there's other way i could use to deal with PWM instead of software implementation ? thank you
  4. hello again recently im facing s problem in the Ultrasonic sensor that im using, the ultrasonic im using is LV-Maxsonar-EZ1, its a great sensor that can give different types of outputs like Analog and digital outputs. here's the datasheet of the sensor: http://www.wrighthobbies.net/datasheets/MaxSonar-EZ1-Datasheet.pdf the problem that im facing is that the analog output of this sensor is proportional to the distance of obstacle detected...which means when the object is at 3m distance the value (lets say) 3V, and at 0.5m the value is 0.4V. i want it to be inversely proportional to the distance, in order for the vibrator (which is connected to the output of the sensor) vibrates strongly when an abject comes near by instead of the opposite. any idea how to overcome this problem ?
  5. im very sorry..i think i used the wrong equation...ok R1= 3.3k R2= 2.2k i went through the datasheet...well im not that good at reading datasheets...i get really confused. but i guess ur point is the motor can't be connected directly to LM393 without motor drive. rit ? i hope you dont get angry or bored of me, im under real stress these days. thank you
  6. for R2...i did get 1.6V from this equation...but the thing is the nearest resistance value that can be found in market is 4k7 (i guess) thats why i wrote R≈4.7k. regarding RL...well i think its the load thats going to b connected (i.e. motor) Rv is represents that input device. rit ?
  7. alright...i went through all websites. ok lets say i choose this simple comparator : and lets say i want the comparator to trigger ON when the input reaches almost 2V. the equation used is Vref = (R2 /R1+R2) * Vcc substitute Vref=2V , Vcc=5V R1=3R2/7, lets say R1= 10K R2≈4.7k am i still on the safe side ? RL i couldnt find the way to get its value, same as Rv. my main question...if i have a lets say IR sensor connected directly to this comparator, and i want it to trigger when i have 2V coming from it, where it should be connected exactly, cuz from the graph above the Vin is pointing to the Rv.
  8. thank you well the deadline for the whole project is after 4 months, plus i have other subjects and projects so i cant concentrate on this one alone although its the most important. i found my circuit in one of ur links...calculating the resistances values right now. thank you again
  9. can you please show what is the suitable circuit of a comparator that triggers on when the voltage reach lets say 2V ? power source is 5V, using LM324 or anything better. thank you
  10. thank you...small note: the battery type is LiPo (Lithium polymer) not Li-ion :)
  11. sorry but how did you know (or assume ) that the battery should not be charged at a current higher than 400mA ? the instruction didn't mention that....here are the instruction given: # Do prevent the battery output from short circuit. # Do use battery with specified equipment. # Do not get into a microwave or heated place or a pressure-container or the place where generates static electricity. # Do use the specified charger and observe charging requirement (under 1C). # Do not connect input circuit with external power source directly. # Do not mix other types of battery in when using. # When the battery is in use or during charge, do not reverse connect. # Do not disassemble or reconstruct battery. # Do not put sharp objects together with the battery. # Do not use or charge the battery with conspicuous damage. # Keep the battery away from babies. # If skin or cloth is smeared with liquid from the battery, flush with fresh water. # Do not use a battery near fire, including the disused battery. thanks again....
  12. hi again I want to use a LiPo battery for my recent project as its cheap and efficient. the problem is the battery that i found has the following specifications: 7.4V, 800mA, 10 cell and the LiPo charger i found have the following specifications: 7.4V, 600mA, 2 cell as you can see, the charger is for 2 cell battery, i dont know if it can be used for the given battery (10 cell ) what i know is the time that normal battery takes to get charged is calculated by divide the capacity of the battery by the charge rate of the charger, then increase the amount of time by about 20% to allow for a certain amount of inefficiency, but im still not sure about charging a 10 cell battery with a 2 cell charger ! these are the pictures for the battery and the charger: please guide me thank you
  13. if i put a series resistor...the resistor will be damaged due to the exceeded power dissipation i guess, correct me if im wrong plz. any way this is the circuit im using: thank you
  14. Hi every1 its a simple question actually, i wan to build an IR sensor which works on a power source of 5V, 10mA...the problem is my power source is 5V,1A which might damage the IR TX & RX, so i need to reduce the current. i tried to connect parallel resistor ( in Crocodile) but the power dissipation keep blowing the resistor and LED up (LED is just an example). if i changed the parallel resistor power dissipation (size) from 2W to other larger value...would it help me overcome the problem ? i know that this question might be little bit under-level question...but sometimes simple questions force u to ask :) thanks for helping
  15. ok...i'll start working on the amplification circuit soon...and i'll upload a picture of circuit im constructing...note that i need the output of the amp ( the input is connected to the ultrasonic sensor) to be giving a variable voltage starting from 0 to 5 or 7 volt depending on the distance of the obstacle. hope to get advices and help from everyone who read this topic. thank you
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