Author Topic: tension regulator, decoupling capacitator and arduino 5v pin  (Read 1423 times)

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Offline MeckelBotTopic starter

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hello all.

im making a line follower, but then i got excited and started getting in some sensors (nothing fancy, individually they all work perfectly) but when assembling everything together, i had a few questions:

First of all: Do i need a tension regulator? I have 2 DC motors, 2 piezo elements, 1 IR sensor, and 3 LDRs. I believe the only thing that could spike are the motors, but they have an independent energy supply, which is controlled by the control circuit with a transistor. Ive read I should use some small capacitators to increase de life of the motors. how many farads? the motors run best at 7v i think, but ive tried with 3v and it looks good enough. dont know whats the load current.

then i read about decoupling capacitators, which make sense. where do i put them? the 2 piezo elements, the IR and the LDRs will all be connected the same way, i think: 5v-resistor-analog pin-sensor-gnd . A friend studying electrical engineering told me it would be unwise to try and calculate where should i put them, because if my limited knowledge and time to finish this.

and so i though about something: can i connect everything to the 5v pin? if not, what can i do to keep everything controlled?

thanks  :)

Offline waltr

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Re: tension regulator, decoupling capacitator and arduino 5v pin
« Reply #1 on: May 29, 2011, 07:47:55 AM »
The short answer to using de-coupling caps is:
One cap should be put on each device (IC) and close to the devices power and ground pins. 0.1uF is a common value to use.

Does your line-follower work? Does all the addition sensors work?

Offline MeckelBotTopic starter

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Re: tension regulator, decoupling capacitator and arduino 5v pin
« Reply #2 on: May 29, 2011, 11:20:08 AM »
thank you for the capacitators advice.

well, i can get 2 to work, but then it gets messy and they all connect to each other because of the ground and 5v pin.

what i was thinking of doing was something like this (I hope i did not make any mistake, i did it with the breadboard view, and then exported the scheme):

all the sensors end up connected because they share 2 pins. ir sensor and piezo had no problems, but when i try connecting the ldr, one of the others starts misbehaving. my goal is to connect 3 ldr, 1 ir sensor, and 1 piezo.


EDIT:   So, after some research and testing, i have concluded that i seriously need those capacitators. with an ldr and the piezo connected, even if the piezo is connected to the analog pin, the ldr still accounts for 95% of the variation. will 0.1 uf be enough?

I was also advised to use 4.7 on the piezo, but if the ldr is the one changing the value, then my piezo doesnt really create that much tension change, right? (I dont have a multimeter to check it out).

I guess for now, thats my problem. Huge, huge interference between sensors, which i hope is the "noise" and will be solved with the capacitators

« Last Edit: May 29, 2011, 01:30:59 PM by MeckelBot »


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