First off I’d like to say if you aren’t entirely clear on this topic once we are done, I would recommend e-mailing me and also downloading Fritzing here, moving on…
You know how to solder, you generally know what the basic components do, and now its time to make a prototype of your project in order to make sure it works and you haven’t overlooked anything. But wait, what is this thing in front of you? That my good friend is a breadboard, a solderless breadboard to be exact, and here is everything you need to know about it:
NOTE: Whatever you do, DON’T PUT THE PINS OF AN INTEGRATED CIRCUIT ALL ON ONE SIDE OF THE BOARD! I know it might fit but it will break because you could potentially short your VCC to Ground which is not good. PUT THEM IN THE MIDDLE! (Yes, this is coming from experience)
What we will mainly be working tonight is the exalted (cue angelic chorus) 555 timer IC. The 555 timer is a nifty little piece of silicon that, you guessed it, times, well pulses actually. You can set the frequency of this pulse that it spits out. This can be used for a whole manner of things: making sound, lighting leds, driving clock signals (maybe), and a lot more.
Now this is why we’ve asked you to bring your laptops because we aren’t going to provide you with the pinout of the 555 timer, you will need to look that up on its datasheet. “Wait, datasheet, what is that?” GLAD YOU ASKED! The datasheet is a document that explains pretty much everything you need to know regarding the specific integrated circuit. All you need to do is google the IC and should find it lickity-split! You can find the
Since this workshop is less on the 555 timer specifically and more on breadboarding, I’m not going to delve too deep into the pinout of the 555 timer, all i’m going to say is power goes in the VCC pin, the ground wire goes to GND, the OUT wire is the output signal, and the RESET pin is active-low, so that means you need to pull it high to turn it off which may be a little confusing.
A lot of the circuits we have set up for tonight are from this website.
NOTE: The 555 timers we have can take a voltage up to 15V but the 74HC595 can only take an input voltage of up to 7V, which is obviously more than our battery. In order to step that down for the 74HC595, you can do a simple resistor divider to 5 volts which looks like this:
where R1 is 1000 ohms and R2 is 1250 ohms. Remember, if you can’t make 1250 or 1k, you can put two resistors in series and the total resistance is both of them added together like so:
In prototyping with limited amount of resources, you need to get creative.
Alright, that is really all the information you may need to get started, so grab a 555 timer, a breadboard, and get started.