But does your simulation work when you apply a logic high or low to the port pin, by means of, say a switch?

When you connected a voltmeter to the output of the LDR, what readings did you get when...

You don't need a ADC. Put the LDR in series with a resistor of about 10K and connect the output of the LDR to a port pin. When the Laser shines on the LDR, its resistance will be much lower than 10K...

You've explained what you need to do, but you haven't asked a question.
An LDR in a voltage divider would replace the switch, if your code works for a switch, it will work with a LDR. But it's not...

And your question?

If you were interested in those topics, you'd come up with a project yourself. Actually you'd think up of a number of projects. You'd be spoiled for choice of projects if you were interested. You...

Do people learn to play a musical instrument because they want to be paid off? Learning the skill itself is the pay off. If that isn't enough, I'd suggest learning something else.

There isn't anything special about programmers that work for TV broadcasting companies. Yes, they write the programs in the same languages. If you turn on the news and see a bar chart, it may have...

The phototransistor is just a switch, the output is either the positive supply or ground. You could program a microcontroller to read the outputs and send serial data to the PC's serial port.

The...

If it's just a proof of concept project, and you're not going to be near a car park. Then IR is fine.

That's all that's needed for the sensor. The IR LED is on constantly. The output is taken from the collector of the phototransistor, which acts as a switch. When an object blocks the IR light, the...

Since that detects any sort of motion then takes pictures, you would need to look at the pictures to be sure if there was a car in the bay.
In a project like this, you would also need sensors that...

To send the data from the sensors to a PC. Isn't that what you want to do?

An IR LED and IR phototransistor will do for the car detection.
http://home.cogeco.ca/~rpaisley4/ATDetLong.GIF

You can look on http://www.ftdichip.com/ for creating a parallel or serial to USB...

An old book but this is the electronics bible.
http://www.amazon.com/Art-Electronics-Paul-Horowitz/dp/0521370957

Less advanced, but useful and easy to learn are all of Floyd's books....

What I posted is a segment of code from putchar.c which you can find in the lib folder.
printf won't work the way you posted because TI needs to be set before calling printf. You usually set TI...

Depends how printf is implemented in your compiler. In Keil, TI must
be set before printf is called. The is because of how putchar is implemented (which is called by printf.)

while (!TI);
TI =...

As long pins 2 and 3 are tied together, it will work.

Attach a female DB9 connector onto your male to female RS-232 cable.
Get the solder type, not PCB type. Then solder wires to it and tie pin 2 and pin 3 together.

Those seem to be range sensors though that output a voltage corresponding to the distance of the IR led?
You can get detectors with a digital output. Like the TSOP1738.

You could go with ten IR LEDS and ten IR phototransistors and use this simple circuit.
http://www.reconnsworld.com/ir_ultrasonic/basicirdetectemit.gif
The output is high when an object blocks the...

Which I did because there's no reason I can see to use more than one IR receiver attached to a single device.

And build a IR detector out of discrete components? What kind of silly idea is that?...

What the hell are you talking about. I said it's probable you don't need more than one receiver, not what he does and doesn't need. I don't know, that's why I am effectively asking.
It's just food...

You probably don't need lots of IR sensors. You probably only need one and send different data to it. If you want to interface to the PC though its serial port, it's easiest to use a microcontroller...

If you can send data, why would you think you couldn't send the name or contents of a text file? If there's more text than there is RAM available, the answer is no though.

After you run your program, check the state of the port pins with LPT to confirm it isn't working.
http://neil.fraser.name/software/lpt/
If not, there's also Userport. ...

XP won't allow access to the port. Install GiveIO, and it will.
http://sourceforge.net/project/showfiles.php?group_id=46487&package_id=77441&release_id=150767

Just use a GSM modem for receiving text messages. You can get one with a serial port.

Learning assembly helps you understand how the hardware works.
On certain platforms, learning how the hardware works is necessary to program the hardware, in any language.
Learning the hardware...

This looks like C not C++, so look into creating structs.

Which would you rather call out over the phone, a long string of binary numbers or a short string of hexadecimal numbers?

You need a hex editor as mentioned, like
http://www.softcircuits.com/cygnus/fe/
You just convert the hexadecimal bytes to binary in your head.

Python is nice and easy to learn, but it's powerful. This is a beginner's tutorial and teaches you how to make Pong by lesson 8, which you probably won't find possible in another language....

You don't see them because "1" and "0" are just the symbols we have given to binary numbers. We could have called them "alphas" and "betas" or anything else instead. Asking what a 1 or 0 is ...

An EXE file is a Windows file. Your assembler should output a binary file, which would probably need to be converted to an Intel Hex file, the standard for burning to EPROMs, depending on where the...

You can download the uVision IDE with an evaluation compiler that's limited to 2K of object code. If it's the c51 compiler you want, that should be good for a couple hundred lines of code.

The first step is using a search engine and typing "Turbo C graphics".
Next you could enter "How to draw Mickey Mouse".

Then if necessary, use a forum to post code and ask a question as to why...

http://lazyfoo.net/SDL_tutorials/lesson20/index.php

Writing FNAME in the program will be the same as writing 9EH.

int i;
int *p;

p = &i; // p holds the address of i

*p = 10;
The last assignment says take the value in p, go to that address and put 10 there.
Therefore, i now holds 10.

To prove that...

Have a microcontroller generate the PWM.
You can communicate with the microcontroller using the PC.