basic electronics question

[Dist]

Recently one of my OU courses has been teaching me about microcontrollers, ICs, that sort of thing, and ive found it very interesting so i have been thinking about trying to pick up an off the shelf microcontroler along with the programing tools, and some other parts, to possibly make myself a simple electronic game from the knowledge i have learned, like a mastermind game or somthing similar.

The only problem is, my course was a ICT course so it didnt deal with some of the more basic electronical stuff such as power supply. What i want to know is, how complicated is it to regulate the power to microcontrollers and other things, like LEDs? does it require a lot of parts or knowledge? or is it something simple i can do with a battery and a couple off cheap off the shelf parts?

 

[iviv]

Isn't that what resistors are for?

 

[monkeyspank]

capacitors

 

[PhillyDee]

Wouldnt worry about building a power supply, find the voltage you need, and then buy a multi-power plug adaper. LED's need roughly 3-5v (Depends on the LED, check before you connect them up!). I know some electronics, but all basic stuff. Couldnt design anything more complex than small control circuits, and ive never done that since school/college.

 

[Dist]

Isn't that what resistors are for?

my course didnt deal with any information about resistors, or anything to do with how to correctly change battery voltage into the voltage used by the microcontroler or LEDs.

capacitors

1 word replys are not helpfull, if you do not have a proper response to my question then please do not reply at all.

 

[iviv]

Probably easiest to get one of those simple 9v battery thingies that clips on top of it. It'll have a red and black lead. Maybe get a test PCB thing. Don't know the proper name for them, but its plastic, and has several holes. Let you easily test PCB layouts without having to worry about soldering stuff or anything. There are some PC programs that can do this too, but they aren't free.

As for what value resistors, its been too long since I did tech, so I can't help with that.

 

[Haggisman]

The test circuit thingy is called a breadboard!

I used to do some messing around with circuits when I was 15-16, but forgotten most of it now =/

 

[r0undb0y]

All you need to know is what the recommended current and voltage for the LED is and the voltage you are using, then you can work out the resistance needed.

(Vs - Vf) / I

eg
main supply 5v (Vs)
LED Voltage 2v (Vf)
LED current 20mA (I)

(5-2)/0.02 = 150 Ohms resistor required.
If it does not match with a standard value use the closed higher value. In this case probably 180 Ohms.

There are many examples on the web.

For supply regulation if you wish to build it yourself you could google "LM7805 voltage regulator"

Hope this helps..

 

[Flukester]

first find out what supply voltage you need for the microcontroller in question, i don't know about current ones as been out of electronics for years but I'd assume 2ish - 5v...

you need a nice steady voltage for a digital chip (like a PIC microcontroller), so I'd say go the 9v batt route then use a regulator to give a nice 5v rail (like a 7805)... real easy to use, 9v in, ground pin, 5v out.... also then have a 1000uF cap on the 5v rail to keep things nice and smooth, though doesn't really need it or anything else as your from a pure dc supply anyway with no rippple at all.

take above with pinch of salt as im very rusty

 

[iviv]

The test circuit thingy is called a breadboard!

Aah! That's the one! Its all coming back now.

 

[Flukester]

The test circuit thingy is called a breadboard!

I used to do some messing around with circuits when I was 15-16, but forgotten most of it now =/

or use 'stripboard / veroboard' for a quick and dirty PCB replacement

 

[megatron]

IIRC there is a mag called practical electronics and it has examples of electronic circuits. If you can follow the circuit diagram then you can put it on breadboard and it should do what its supposed to do.

 

[Flukester]

All you need to know is what the recommended current and voltage for the LED is and the voltage you are using, then you can work out the resistance needed.

(Vs - Vf) / I

eg
main supply 5v (Vs)
LED Voltage 2v (Vf)
LED current 20mA (I)

(5-2)/0.02 = 150 Ohms resistor required.
If it does not match with a standard value use the closed higher value. In this case probably 180 Ohms.


Hope this helps..

or just be a real lazy slob and buy a LED with built in current limiting resistor for the voltage you are regulating to

 

[mangobreeder]

<cencored> is your friend go there buy a cheap kit for kids and get to grips with the basics

 

[Dist]

Map lin s is your friend go there buy a cheap kit for kids and get to grips with the basics

i know of that site, it is where i plan to buy the parts from. I suggest you remove that from your post though, as it is counted as a competitor. Even if you split it up into multiple words (the mods are not fooled by such simple trickery )

 

[Jotun]

first find out what supply voltage you need for the microcontroller in question, i don't know about current ones as been out of electronics for years but I'd assume 2ish - 5v...

you need a nice steady voltage for a digital chip (like a PIC microcontroller), so I'd say go the 9v batt route then use a regulator to give a nice 5v rail (like a 7805)... real easy to use, 9v in, ground pin, 5v out.... also then have a 1000uF cap on the 5v rail to keep things nice and smooth, though doesn't really need it or anything else as your from a pure dc supply anyway with no rippple at all.

take above with pinch of salt as im very rusty

What you said is right but I think it'd be easier to use 3 1.5V AA batteries for the power source, as that saves messing with regulators, and in my experience with microchips they will work over a range of voltages, as you said 2-5V was the range for the chips I used, however they would go down to 1.6 to 1.7V depending on the chip. It will probabaly also recommend a coupling capacitor value as well, I've found 0.1uF worked best with the chips I was programming.

If the OP posts the chip used it'd help as we can see what power it needs. Also depending on how you are going to be programming it, a lot of the programmers come with a test board as well. Also depending on what chip you are getting, you may want to order 5 or 10, as you will break legs or put it in the wrong way round if you are moving the chip round in and out of chip holders.

 

[megatron]

Also depending on what chip you are getting, you may want to order 5 or 10, as you will break legs or put it in the wrong way round if you are moving the chip round in and out of chip holders.

You can by a socket for ICs which saves breaking the ICs legs.

 

[mangobreeder]

i know of that site, it is where i plan to buy the parts from. I suggest you remove that from your post though, as it is counted as a competitor. Even if you split it up into multiple words (the mods are not fooled by such simple trickery )

how the hell are they consider a competitor, they sell garbage. No-one rivals OCUK.

p.s the "trickery" was not intentional

 

[sniffy]

Can I recommend the PICAXE micro-controller? I used it in my A2 Electronics class and it's an excellent introduction into this area of electronics. You program the chip with BASIC and you can do some pretty cool things with them. My project was a wireless environmental monitor. You could basically monitor temperature and so on in an environment via a computer.

 

[p4radox]

Can I recommend the PICAXE micro-controller? I used it in my A2 Electronics class and it's an excellent introduction into this area of electronics. You program the chip with BASIC and you can do some pretty cool things with them. My project was a wireless environmental monitor. You could basically monitor temperature and so on in an environment via a computer.

Yup. PICs are awesome. A mate of mine has some pretty advanced know-how and is making his own laser quest system using just PIC chips.