# Circuit design

1. May 12, 2005

### Serj

Is there a program for designing circuit boards that does not require knowledge of circuits? Were you can just specify what you want the circuit to do and the program designs the circuit board for you.

2. May 13, 2005

### egsmith

How would you specify what the circuit should do with no knowledge of circuits? Or put another way, what should the input to this program look like?

3. May 13, 2005

### Serj

It's hard to explain so i'll just give you a scenario.
You want a chip to run an electric motor for 10 rotations then stop. There is a small generater hooked up to the motor that produces a certain number of volts when the motor turns one rotaion. You tell the program you want current to flow through wires leading out of the chip (to the motor) until the chip receives a certain ammount of current (from the generator). Then the computer designs the chip.

4. May 13, 2005

### Cliff_J

Generators don't work like that, they are not water pumps.

If you want 10 revolutions you could implement a cam on the shaft and a microswitch that would feed into a 4017 decade counter and have it stop the output. The output could be controlled by a simple 555 chip. The output could be controled by a simple transistor. A couple small caps and resistors and you have a circuit that would work with a tiny motor for $1. There are countless other ways to do it too. Understanding how to design the circuit is part of the fun. If its a neat project you should be able to find someone in an EE program at a local university who would be willing to help out. 5. May 13, 2005 ### Serj than you, and yes it would be fun. But I'm only one person and it would take a very long time to design a more complex chip. That's why I was really hoping there would be a program for it. 6. May 13, 2005 ### chroot Staff Emeritus 1) You're never going to be designing chips on a hobbyist budget. Integrated circuits are fantastically expensive when you're only making one or two units. 2) There are no computer programs which can understand input as vague as your description. If you cannot design the circuit, you will need a sentient engineer to design it for you. 3) Your completed circuit will most likely be composed of a number of commercially-available chips wired together. - Warren 7. May 13, 2005 ### Serj what is the easiest program for designing circuits? 8. May 13, 2005 ### chroot Staff Emeritus Your brain is the principal instrument for designing circuits. For a circuit as simple as yours, there's no reason to use a computer program at all. It would take you longer to learn to use a CAD program than to just design the circuit by hand. First, you'll need to find integrated circuits which do various jobs (like the 555, which is a timer), and read their datasheets to understand how they work. Then, you'll have to put a circuit together on a breadboard and see if it works. Honestly, if you're looking for a magic bullet which will allow you to design circuits without ever learning any electronics -- good luck. There's a reason it takes years to become an electrical engineer, and there's no shortcut. What you're asking is similar to saying "I'd like to be a virtuoso on the violin, but I really don't like practicing. Can anyone give me a violin that just plays itself?" - Warren 9. May 14, 2005 ### Serj That was just an example. I want to make cicruits far more complicated. Which is why I need a fancy program to help me do it. What does CAD do?Can it do some of the calcuations for me?or atleast make the task easier? They do have player pianos. 10. May 14, 2005 ### sepulker The absolutely EASIEST approach to your problem (for you) is to buy a BASIC Stamp Programming Kit manufactured by Parallax. This is basically a standardized and simplified microcontroller interface intended for educational and hobbyist uses. There is an entire chapter devoted to exactly what you are talking about; i.e. motor controllers. Infact, rotating a motor is as easy as typing in "Rotate Motor 10 times". Middle-schoolers can use them. The kits go for about$80 and are even available at Radioshack.

11. May 14, 2005

### chroot

Staff Emeritus
CAD (computer-aided design) programs help the designer by automatically checking for design errors, by making errors easier to see and correct, and by doing all the drudgery of drawing thousands of lines from device to device.

The programs don't help you design, however, they simply help you implement a design. You actually need more knowledge of circuits to use a sophisticated CAD program than you do to just design one by hand. They are not "automatic design" tools in any respect.

To give you an example, CAD programs will help you implement a circuit using a 555 timer IC. They will not, however, allow you to design with one without even knowing what one is.

The kind of electronics you're talking about designing are well within the grasp of a hobbyist with only a modicum of electronics knowledge. You really ought to just learn some electronics.

- Warren

12. May 14, 2005

### Gokul43201

Staff Emeritus
You can do reasonable simluations using something like SPICE. But you will need a good grasp of the concepts first.

13. May 14, 2005

### chroot

Staff Emeritus
SPICE is a fine simulator, but it won't design anything for you -- the best it will do is help you refine a design. If you don't know what a 555 timer is, it's not going to suggest one for you.

- Warren