# voltage

## Servo powering problem

Hi guys, me and my friend have built an arduino controlled Quadruped "mantis" robot.

## Variable Voltage

Can anybody please recommend a variable voltage regulator that I can purchase to test out variable voltages when building an electromagnet?

## How do I connect a 5V sensor to a 3.3V input

Hi

I am using a IR sensor (photo transistor) that was ripped out of a ball mouse and I am running it at 5V, but I need to connect it to a Raspberry Pi which runs at 3.3V (at least the IO-pins are).

I can place a 3.3V regulator before the sensor and adjust the pull down resistors, or use a zener diode to limit the output, but I was wondering wheter my currecnt setup will be safe to use.

Sorry for the poor quality drawing by the way.

## How to power different voltage motors from same power source?

I am taking the "There are no stupid questions" comment to heart here.

I am hoping to power DC motors and servo motors from the same power source. The problem is, the servos want 6V and my DC motors are rated for 1.5-3V. A nice simple solution like a potential divider won't work, since each motor has a non-constant resistance, and a voltage regulator would be hideously inefficient. Adding a separate battery pack seems a silly idea, especially given the Arduino will have one of its own as well.

## QRD1114 Resistor Values

Hi all,

I'm using a QRD1114 sensor for a line-follower. Datasheet: http://www.fairchildsemi.com/ds/QR/QRD1114.pdf

Im hooking it up with this schematic:

However, I'm unsure how the value for the 10K resistor was calculated? It's acting as a potential divider, right?

For the LED im guessing that the value of 220 was taken from doing:

R=(Input Voltage - Max Forward Voltage)/(Optimum forward current)

## log. voltage

Hi, in my new robot I am using ATmega644, but I need hepl with log. votage. In AVR Studio I set PB7 out and set log 1, but when I measure voltage between PB7 and GND, multimeter shows 0.8 - 1.1 V. Had anybody same problem? But it is not only PB7.  The 0.8 - 1.1 V are on all ports. When I put atmega in to breadboard everything is OK.

I have connected LCD to PORTB and PB7 is controlled backlight. When PB7=1 then backlight on but when I measure voltage on PB7, multimerer shows 0.8 Volts.

## IR LEDs and transistors voltage

Anyone knows the voltage and currents for these devices? There seems to be ABSOLUTELY no information. I bought them from yourduino.com because I told myself I could figure it out but I now highly doubt this. *facepalm*

http://arduino-direct.com/sunshop/index.php?l=product_detail&p=210

http://arduino-direct.com/sunshop/index.php?l=product_detail&p=217

## Can a 3,4V solar panel charge a 3,6V NiMH battery pack?

Can a 3,4V (open circuit voltage) solar panel charge a 3,6V NiMH battery pack?

## How Much Voltage Should I Use

I'm working on a small robot that will be using 2 continuous rotation servos that each require 6v to operate. Now my question is should I hook both up to a single 6v power source OR hook both up to a 12v power source OR hook each servo to its own 6v power source? Hope someone can help me, thanks!

## constant 4.5 V supply using batteries?

how may i get a constant power supply of 4.5 Volt

using batteries?

## Moisture sensor.(Just another DIY)

Moisture sensor for your garden...so it measures moisture...
Headphone plug turned moisture sensor. For a little while now I've been looking at how to do a diy moisture sensor that I could use for my garden project. There … Read more

## How did you cope with the Arduino Mini 5V

The Arduino Mini and a bunch of other electronics require a 5V power source. The only way I can achieve that using standart batteries (AA, AAA) would be to use a power regulator (preferrably a low-dropout power regulator which I can't find on robotshop). So how do you suggest I get my 5V? It doesn't need to work with standart batteries - as long as the solution is cheap. What other online store would be good for a low-dropout voltage regulator?

P.S.: This website is awesome!

## Measuring voltage with an Arduino

I was wondering if I could measure battery voltage simply by hooking the battery's + to an analog Arduino pin so that my robot can know when it's low on power. From what i've understood, a battery of 1.5 volts is dead when it outputs 1.4 volts (gonna do some research about this). I guess I can apply this approximation to different voltages battery. The only problem is that, if I want to use a battery with voltage superior to 5v (Arduino analog pins set 5v as a maximum), how do I divide the voltage? Again, I guess I'll need op-amps to do that and voltage dividers, but what do I exactly do?

## Run 12V stepper with 5V??? [SOLVED]

Hey guys I have a quick question. I've never used a stepper motor before, but I have one that will fit my new robot nicely. It is a 12V motor kinda like the one below

I don't have a 12V power supply right now, only a 5V. I want to know if this motor works before I go and buy a new battery. Does anyone know if it will even work with 5V? I just need it to move just enough to let me know it works, then I'll go get a battery.

## 5V and 3V together

Hello!

I'm building a board that needs both 3v and 5v as it has some components working on 3v and others on 5v. Now what is the best to do in this case? I am not sure, i've analyzed some of the options but i really do not know the advantages/disadvantages of each:

- have a 5V regulator and a 3V regulator with the input connected to the 5v reg's output (could be done, the 3v reg is low dropout)

- have a 5V reg and some diodes to output 3V (or a voltage divider with resistors)

- have a 5v reg and a 3v reg with both inputs connected to the v+ on the battery

## My first robot..........

So I've decided to build my first robot which not the LMR "start here" one (that one is going to be my second one) and im using this circuit- http://costaricabeam.solarbotics.net/Circuits/Vores/555%20Photovore.png . I've tried about 10 different designs for the body but its just not working. When i cover the left photocell with my hand and the other one is exposed to light the speed of the motors is the same and same with the right photocell. has anyone tried the circuit? did it work?

## Windshield wiper motors, have you tried'em?

Have any of you experimented with windshield wiper motors? I know they've been used in budget robotwars fighters. I just need to get an idea what kind of strength they have (with the original gearbox).
Will it be able to pull 20 Kg vwith a 20 cm diameter wheel mounted directly to the output shaft? what abot 50 Kg? -or a 100?

Let's say I have a motor control circuit that's too small. It could be the motor output of a Picaxe, the adafruit motorshield for arduino or a the innards of an old RC toy. The main thing is that it has two output wires, both capable of delivering positive and negative to make a motor turn both ways.

What if you want to use a bigger motor that needs more power? Below are three circuit diagrams

## Arduino voltage regulator and other questions.

Hello, I have a few questions I hope somebody or several people can answer :)

## RC power for my picaxe

I'm using RC ESC's to drive the motors in my current robot project. These speed controllers has a built in power regulator (called a BEC) that is meant to power your RC receiver. I've measured and the voltage produced is a steady 5.03 Volts.

Can any of you think of a reason why I couldn't or shouldn't use this as power source for my Picaxe 28x1 ?

Can't seem to insert hyperlinks with Opera browser on my old iMac, so here are a link if you wanna read more about RC ESCs or BECs

http://en.wikipedia.org/wiki/Electronic_speed_controller

## LED's

When using an LED formation, with a picaxe and added sensors, servos, and motors that is powered by four AA batteries, does that change what the source voltage for the LED formation would be? And would it be possible to add this LED formation to the start here bot at one of the output pins so you could control the blinking of several LEDS instead of one at a time. Or if there is a better way to accomplish this could you please enlighten me?

## 5v voltage regulation.

Is there a simple thingy that I can hook up to any voltage higher than 5V (within reasonable range) and always get 5volt out?

## Capacitor's voltage rating

Hi guys.

Do you know what the voltage rating on capacitors is? My idea is that the voltage rating is just the maximum voltage it can take before the blue smoke comes out, but i'm not sure.

thank you :)

## Voltage Regulators

Price: \$1.2 USD

Collected by 8 members
5V Regulators Being stupid I can never find out how much resistor and what do i know I would need to get my 7,2V Racing pack battery to turn in to nice 5V that my … Read more

## Power to the motors..?

I am building "Slaughter of Lego" these days.. But I have a problem feeding the motors enough voltage. Without building a complicated H-bridge, and without burning Servos.

It is a dual core mothafukka, wait and see ;)