Good beginner projects?

[A]

I'm planning to build a fume extractor with an old PC fan. Do you guys have any good projects for a beginner?

[rstofer]

What interests you?

There are classic projects such as blinking an LED with a 555 timer.  It's interesting to breadboard and there's a wee bit of calculating involved if you don't simply copy a project.  Even if you do copy a project, you can go back and rework the timing calculations.  They're pretty easy...

A transistor inverter, perhaps connected to the 555 project where the transistor actually controls the LED.  This will take a transistor (2N3904 or 2N2222A), two resistors and an LED.  If you are running at 5V, for example, the base resistor can be pretty much any value but 1K seems good.  You will calculate the LED ballast resistor based on the V_f of the LED (look in datasheet), the desired current, I_f (again, from the datasheet) and the operating voltage.  R = (V_supply-V_f) / I_f.  This ignores a bit of voltage drop across the transistor.  It's an experiment worth doing because this kind of thing comes up all the time.

There are a lot of experiments you can do without having anything more sophisticated than a DMM and, at this level, even a cheap DMM (like $5) will be adequate.  Later on, you will need to upgrade.  You can use an old 5V wall wart as a power supply.  Even an old cell phone charger should work well.

If you're into microcontrollers, or you want to be, anything Arduino will be educational.  Projects are all over the place.  The first project will be just like those above:  blink an LED...

[ZeTeX]

A bench power supply based by the LM350 / LM317 / LT3080/3 / Any good power regulator, as we only want constant-voltage and not constant-current.
The most expensive parts for this kind of project is the heatsink, case, and transformer. for the best performance and quality its best to use a good linear 50Hz or 60Hz transformer and not AC-DC switch-mode adapter.

[james_s]

I built a lot of power supplies starting out. It's one of the easier projects and a very useful one too. You can salvage most of the parts you need from discarded equipment and appliances.

[t1d]

Expanding on the PSU suggestions, any electronic tool would be a good start and build your tool kit...  A simple ESD (Electro-Static Discharge) circuit would be super easy...

It can be made from a 1/2"x1/2" square of copper clad board, a strap to hold the board against your wrist, some insulated wire, a round wire terminal and a 1M Ohm resistor. Cut the wire, anywhere, and solder the resistor to each of the two pieces. Solder the board to one end of the new cable. Attach the wire terminal to the other end of the cable.

The terminal is attached to earth ground. Remove a single face plate screw from either a wall plug, or light switch, place the wire terminal on the screw and screw it back in.

The copper pad is held against your bare skin, on the bottom side of your wrist, with the strap. Wear the wrist band/board when you are working on sensitive components...

That would give you something to practice soldering on and be useful... But, the real meat is in finding out why you might need it and why a 1M Ohm resistor is required... I will leave that to you...

If you think that you will be working with controllers, like the Arduino, or Raspberry Pi, you might want to build a TTL Logic Probe... It is also simple to build and would introduce you to comparators...  I built this one: http://www.neufeld.newton.ks.us/electronics/?p=31

I also suggest checking out the YouTube video series that NASA made on soldering...

[vk3yedotcom]

I build a lot of radio stuff. But once in a while I'll build a 'silly' project. 

Like this drone machine.



A good conversation piece and fun for kids of all ages.

It's very simple and not expensive - provided you can get cheap potentiometers. 

[tggzzz]

Traffic light controller.
- get colour sequence right for one direction, small LEDs
- get relative times right
- for both directions
- add pedestrian crossing request button
- for large LEDs
Do it in an arduino and in pure hardware without software.

If you make a PSU, use it in anger on another circuit and find you have made a mistake, then two circuits will be destroyed. One of the reasons 60s/70s power supplies had such poor reputations was because often their design was assigned to the most inexperienced engineers.

[SingedFingers]

Agreed. I used a motorcycle battery as my first power supply. When your circuit has caught fire a couple of times you learn that you need current limiting.

[james_s]

With the advent of the 78xx and LM317 regulator ICs, building a simple linear power supply got a lot harder to screw up. Certainly you'd want to test it on something non-critical first but for powering the sort of simple beginner projects it's not likely to have much risk. I never had any serious issues arise from the ones I built.

[SingedFingers]

They can still kick out an amp or so. My second supply was an LM723/2N3055 with four switchable current limits (50mA, 100mA, 500mA, 1A) and variable voltage. That was far safer but could destroy TTL logic on the 50mA limit still.

[ez24]

http://tronclub.com/

check out YT on them



https://youtu.be/5SFnZIZa_ZI?t=341

[3db]

Agreed. I used a motorcycle battery as my first power supply. When your circuit has caught fire a couple of times you learn that you need current limiting.

So that's where you got the singed fingers . 

[SingedFingers]

Maybe