Completed Python Logic Circuit Simulator

Project website

Logic gates are interesting, with a few of them you can create circuits with fairly complex functions. Most of the time, the function of the circuit is anything but obvious from just looking at it. For example, consider this one:
That's an adder. You set the inputs A and B to True or False ( 1 or 0), and the circuit will perform a binary addition where S will give you the sum of the two, and C_out the carry bit. The carry bit can then be fed into another full adder at C_in, and you'll also have two more inputs. This can be expanded to any size one wishes.
All currently functioning computers rely on such gates. Most likely, millions and millions of them are in your cellphone.

If you're at least a little familiar with formal logic, more specifically logical connections such as "and", "or", "nor", "xor" (="exclusive or") and so on, the way these circuits work will probably make sense to you very quickly.

I've written a few posts recently about a logic gate simulator I am writing in Python, pyGates. I won't say I finished it, because there are still a few bugs that come up every now and then, but it's far enough along for others to use. Here's a screenshot of what it currently looks like:


You can create new gates by simply dragging them from the left side of the screen, and destroy them by simply dragging them back there. This is actually the only part where I still get bugs every now and then, sometimes cables don't get destroyed properly, but I'll work on fixing this. For now, you can usually work around that by manually deleting the cable - detaching it from the other gate it is connected to, and clicking into empty space.

The website for the project, a zip file with everything you need and the raw source code is located at my website here: http://home.in.tum.de/~dowling/pyGates/.

Project Ideas

Doing is the best way to learn, and since learning is what we're here for, let's do some stuff. I've had a number of different ideas for projects recently and not so recently, so to offer you some inspirations and perhaps for me to see if any of these still make sense when you see them typed out, I've compiled a little list of them. (Some of these are actually projects I've already started working on)

• "Multiplayer" Paint. Basically, this would be like a chat program that lets two (or more?) people draw on the same canvas as one would in mspaint. I would implement this in C++, just because I want to learn more about it (and graphics / network programming) but also because most people don't have Python interpreters with pygame on their machine. It might be time for something different :)
• Javascript multiplayer Paint! Use a JS canvas for client side, and save the changes to canvas stored server side (maybe use php, or node.js for serverside scripting?) Then, everyone who visits the page can draw on it for everyone else to see. Obvious downsides of this however are the fact that this is still the internet, and I suspect sooner or later (sooner) it will meet a similar fate tot that of Chatroulette
  
• A 3-4 DoF Robotic arm. It doesn't have to be a very good one either, just to keep costs down. Forward and inverse kinematics are pretty interesting, and this would be a good way to learn and practice both. Servos can be picked up pretty cheaply as well, and the whole thing could be run from an Arduino - the only real difficulty in this would be the mechanical parts, I have no good way of making them properly. I got this idea from...
  
• .. building a hexapod. 3DoF would be minimum for each leg to be able tog et decently smooth motion, the problem is that this would be a rather costly product (for me, at least)
• A simple webcrawler. I don't know what you would use it for, but my ideas were perhaps a Reddit bot (find/keep track of reposts, produce statistics based on comments, find most used pun of the day, etc.), or a Wikipedia crawler (create a graph of pagelinks, those are always neat)
• On a similar note, implementing a graphing layout algorithm - finding a good layout for graphs (graph meaning a set of nodes connected by edges) automatically. There are different ways to implement this, the spring model seems like the simplest: each edge is like a spring that pulls two connected nodes together, or pushes them apart based on their distance from each other. One could also base the pushing/pulling force on the "weight" of each node (weight could be number of incoming edges, for example)
• implement quantitative stock trading algorithms. This is something I personally find really interesting, though I haven't worked on it much. Wikipedia has a nice page about the different algorithms that are used today. A technical problem that needs to be solved first is getting a decent sample of historical data for a given stock, as this is very often necessary for such algorithms.

Of course these all aren't new ideas, but I've found that I usually have good ideas while working on something else, and these are just inspirations for you anyway. Potentially all of these are good for learning something new!