circuit

I have been playing around with BEAM robotics and I have found answers to a lot of my questions but this one still persists. Why does there have to be a pull-up resistor? Can`t I interpret the signal without it? My first guess is that if Vin is smaller than Vref then V+ at the top of the pull-up circuit will be grounded through the op-amp so that Vo is grounded as well. In the other case, electricity flows through Vo and I can use the signal to activate a transistor.

Hey everyone. So, I just finished my first robot in a few years, my first being 2 1/2 years ago. This one is a lot more complicated in terms of hardware since I made my own boards and all, and have 5 ICs in one circuit. I'm done with programming and everything runs well but there's one ongoing problem with my Sharp IR GP2D120 sensor.

Hi y'all, just joined LMR, fantastic site, lovin' it already . . .

I am a bit of a beginner to robotics, I mean I can program and all that, and make these things, but I know not how or why they work.

One thing I have been wondering is about capacitors:

When designing a circuit, how does one know where to place capacitors, or why to have them, or how they function in that position?

With this circuit in particular (from here: http://letsmakerobots.com/node/2074), why the caps?

those two in the top-right, why do they both need to be there?

Hi everybody. I have an idea for some wierd stuff (I don't want to say what it is untill it works), but I don't know how to make it and I don't know how to google it.

I need a circuit that uses one DC power source, and a capacitator, and it can't have any switches, it has to work all the time the power is conected. It needs to charge the capacitator and when it's full send all the electricity it to the "Parts"/electronics. But "Parts"/electronics shouldnt get any power while capacitator is charging.

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?

I had an idea tonight that is either inspired... or stupid. Please help me determine which. ; j

I was thinking about using one of my new Picaxe-08 processors for a project. They only have 5 I/O ports, three of which can be either an input or an output. However, for my project, I wanted to be able to control two motors and two sensors. Since traditional dual H-Bridge designs would require four processor outputs to control two motors with forward and reverse, that would leave only one I/O port left. Boo hoo.

Does anyone know how to set up one of these things:

I can't seem to get it working.

Someone made a quick "tutorial" on LMR but I just don't get it.

I found a diagram here that just doesn't make sense. The wire colors are all messed up.

Then I found this:

A place for the discussion TofuRobot brought up regarding other electronic projects. Instead of being lost to the shoutbox nether regions,here's a screenshot of the beginning.

Personally, I think tip/walkthrough would be the right place for stuff that can also apply to robotics. Non-robotics (like the carduino example) would go in a blog.

Ok, to make sure I would not mess up I got a little help reading the circuit from Instructables. After following this word for word, I found that my circuit simply did not work, and when I touched the transistor it was extremely hot.

Here is what I put together following the instructions:

[Honestly, that's the best photo I got.]

Hello guys. I'm creating a RF controlled 2.5kg sumo bot. I'm a mechanical engg. student and so don't have much knowledge in electronics.

Basically I need to create a 10Amp motor driver for driving 2 12V dc motors,10A each using relays.
Buttons on remote control:

      1
2           3
      4

1-Move Forward
2-Rotate Anticlockwise
3-Rotate Clockwise
4-Reverse


I'm planning to use these schematics for radio controlling

Nerd TV done right. Two people in their respective "labs" video chatting live for all to watch. Recorded shows on Vimeo.

Impresive geek biographies for the both of them.

click

Like many here, I were in need of a bit of amplification of a weak signal. This signal had "low impedance", I suppose. The supplied circuit diagram shows two different ways of meeting my need.

The left circuit uses a NPN transistor. The right hand circuit uses a PNP transistor. I chose the one with PNP. Quite "arbitrarily". The BP103B is also known as FA300.

I have a fairly strong background in code development, but I would like to build a stronger knowledge in curcuit design. I can read a datasheet and learn how to hook up a certain component, but when it comes to using a specific component for a use other than it is designed for I lack the knowledge to know when to use a capacitor, flyback diodes, etc.

I'm not positive this is the right place to post this.  Admins please move it if I'm asking in the wrong place.

I have a circuit digram but i cannot understand it. can anyone help me explain?

Pjnai123