Turn a timer into a bomb timer

A really simple project to have fun and play cops and thieves. For educational and fun uses only.

To have a bomb timer, you need two things.
1. To get sure that nobody can cut the cables or open the case and check the circuit.
2. You have to trigger a relay when the buzzer beeps in the end of count-down.

1. You put more than two cable connecting the timer and the trigger. This way, nobody can know which cables to cut. You take two cables and connect them in the case, in a way that if the case opens, they disconnect. In the other side of the cables (trigger side) you check the connection of these cables with a relay normally close. If its power is cut off (by cutting the cables or by opening the case) the relay closes and the trigger goes 'boom'.

2. You connect two cables to the buzzer's connections, that is in parallel. When the buzzer beeps, you get a voltage in your cables. You make a flip-flop circuit to avoid close-open-close-open (this happens when beep-beep-beep). Finally you drive a relay from the ff output. Simple but a little tricky too.

The timer is a simple gadget you can find in your local RadioShack shop.

Turn usefull a simple water level alarm

This is how I re-made my $5 water level alarm. (I took it from the Lidl stores, they have good deals and when it comes to electronics, they are first class value for money!) It had a wide paper with two conductive areas where you see the four RCA inputs. It had to be just in the place you wanted to watch the water level. It was not very usable that way. Now, you can watch four zones with four standard RCA cables and have the main module in your "control room". The LEDs indicate which zone is wet and you can turn off the annoying beeper when you see the alert. It will be very useful in a sail boat.




This is the case from the inside. A LED, a resistor, and an RCA input for each channel, where channels are in parallel connection. The jack goes on the board, where the conductive paper was. The original circuit is really simple.

Making a simple oscillator and 555 tester

Well, I made a very stupid thing, I connected a 555 directly to 5Volts, 3Amps! And of course, it burned right away! Just giving it 5Volts is not a guaranty. You can give it even 9Volts, but hey, not more than 500 - 700 mAmps max. The simplest thing you can do, is give it 9Volts from a 9Volt battery. The battery works as a proper power supply: it gives the load only the Amps it pulls to work, so it will not fry a 555...

Anyway, if you want to test your 555 chip to see whether it works fine or it is destroyed, you can easily enough built your own 555 tester which of course is a simple low pulse supply (oscillator). The main idea is here, but I gave it a little push, and made the pulse changeable, I guess this gives me the right to call it "oscillator".

In the pictures you can see the circuit, a photo of it, and the project finished in the box. I decided to connect the battery outside the box, because this way I can be sure that the buttery is OK, so I will have no doubt when a 555 IC does not work.

You can find plenty of free circuit-sites in my links section, and the worth the study every one of them.

Debugging in programming

Well, I've been proud for my fast debugging tricks quite a few years now. The debugging methods are quite known, because you cannot really make a program -except the 'Hello world' one! - unless you can debug. But every programming language has its own way to help you debug the code, additionally to the self contained debugging tools. For example, Flash has got the very very good Debugger which you can enable by Ctrl + Shift + Enter, to run with the movie. The Flash Debugger is quite a good tool. You can see the value of a variable in real time, you can change it, as well as you can change every attribute in every movie clip of the movie. You can see everything the same way, even for a loaded movie into a main's movie object.

The other day I had a conversation with my brother, he is a Biologist, about the way they try to fix a not successful experiment. The main methods they use are really alike to the debugging methods! Of course I cannot explain exactly their methods, but mainly, they

1. Investigate what the output molecule contains and how close its fabric is to the protein which is reflected by the gene they try to decode, or
2. Change the starting point a little bit, that would be the gene I think, to see what molecule will come out as result.

This is a probably very lousy explanation, so I will ask my brother to write and correct me. Although, programmers will easily find the similarities of these methods to the debugging procedure. What do we do?

1. Trace, print, and examine all the outputs and the inner variables of a function or class, to find the exact point of the bug. We compare these values to the ones we expect if the function would work properly.
2. If this doesn't work, we change the algorithm in the function, to see how the output values change, in order to find out where the bug is!


Will come back with more debugging tricks!

How much fun can you have with 5 Euros?

Well, I still cannot believe it! I bought a zip-zap car, two days ago, in order to cannibalize it and take the wheels, rc circuit, steering system, and pager motor, for the needs of making my first indoor rc airplane, which I describe in my relative article "Will it fly?".

I am so sorry for my fly (this is how I named my plane), but I am not going to kill my zip-zap! It is just so fun to play with! I took in with my in the coffee shop, and rolled it between the tables! Everybody loved it, and asking where I got it!

I cleared my table and started a parking competition with my buddies, between two glasses! After a while, I dropped it off the table and the poor zip-zap stopped working... It was the 10th time I drop it.. I was so sorry...

Back in my house I opened at look in it, I was lucky that just the battery was out of place, so I fixed it and worked again! Then, I dropped a little water on the floor, and start playing! It would not stop twisting! I practiced a lot with the counter steering! No grip at all! You should try it, you won't believe how much fun you can buy with 5 euros! You can watch a video of my zip zap drifting!

I will have to buy a second one to build my Fly... I hope I can make the decision to kill it...