Tuesday, December 31, 2013

Bird Alarm Clock

Who likes waking up to the sound of alarm bells?

From my experiences with different alarm clocks, I found that something that gradually gets louder wakes you up more patiently, comfortably, and fully than a sudden burst of obnoxious noise.

For example, for years I have used an alarm clock with the bells and hammer: every morning I would wake up still half asleep and extremely pissed.

I'm sure many people have this Ikea alarm clock...

Today, I use my cell phone to gradually play "Wake Up Everybody" louder. I usually wake up more invigorated and inspired... because of the song.

If you haven't caught on these are not my pictures... but this is my phone. I recommend it.

Usually when I do not wake up, my parents have to (thanks mom and dad).
So as a Holiday/ Anniversary gift, I decided to make an alarm clock, using my Ikea alarm clock and an old toy.

How I went about doing this is almost the same way I went about with my 555 mouse or my Phaser

Basically, you take some pre-built hardware and you use it's trigger for something else. I love this sort of work: it requires little programming, and its often cheaper and less time consuming because it involves cheap mass manufactured hardware that can be bought for pocket change, instead of expensive microcontrollers and raw parts.

I will proceed in talking about this project. Sorry, I did not take pictures.

1) open up the alarm clock. There should be a gearbox and three tabs on the PCB sticking out of the gearbox.
These three pads are Vcc (From battery pack, usually red wire is connected to it), GND (from battery pack, usually black wire), and some other pad with another color wire connected to it.

The third pad is connected to the motor of the alarm clock, if you trace it.
What happens is that when the alarm clock hits the time when it must activate, it grounds that third pad to connect the motor to ground and let electricity flow from cathode (-) to anode (+).

So, instead of grounding the motor, I would ground a robotic bird

2) open up whatever toy you want to activate when the alarm clock is grounded. Connect two wires to the battery pack: Vcc and GND.

Connect Vcc to whatever Vcc needs to be powered by, and the GND of the toy to the third pad on the alarm clock.

This is the basic concept of what's going on.
I had a voltage regulator in there to handle some Vcc issues... that was not the main circuit.
In essence, this circuit requires no components, just some rewiring.

okay where is the arduino stuff

For you arduino folks out there playing with multiplexing and H-Bridges, this might teach you an important concept.
Look at this instructables for example.

Also, read this for some understanding: Constants
You will further understand how microcontroller pins work.

Keso, the author of this instructables, connects the end of LEDs to other I/O pins.
He turns on one I/O pin and turns off the other I/O pin to turn on one LED. What he is actually doing when he turns of an I/O pin is grounding it, letting current flow.

Using this method, Keso was able to implement 6 LEDs when he only had 5 I/O pins.

Using this method, you could also make a low voltage motor turn both directions without an H-bridge. Simply connect one lead of each motor to an I/O pin, and write one pin 1, the other 0, and depending on whether the pins are 1,0 or 0,1, the motor will turn different directions.

I don't often see this method implemented, but to get the word out, it can do amazing things.

I hope that nugget of information helps.

Sunday, December 22, 2013

Aluminum PCB Attempt (1)

Making PCBs at home is awesome.
Feel the power of making a professional-looking circuit board at home with these amazing chemicals that eat copper.

Pretty rad.
Sadly, not everyone can get their hands on etchant, or photosensitive boards, or any of that fancy stuff. As always, I investigated a cheaper way to make PCBs. I'm not talking about that 3D printing stuff or the conductive ink pens (those things are not cheap to begin with).

I'm talking real lyfe.

Okay. So the objective of this was to make a PCB that could use any substrate. That means I could implement a circuit on any surface: wood, glass, plastic, curved surfaces, paper, maybe even clothing!
Before we continue on how I did this, we must first understand how PCBs work.

Basically, a sheet of copper is pasted on top of an insulative substrate: usually phenolic or fiberglass, or flexible plastic. Printed Circuit Boards are much more sophisticated today, with multiple layers. These layers are connected through vias. Like elevators, they are conductive holes that transport electrons.

Here are some pictures from the internet:

As you can see, each trace is like a wire, a road to move electrons.

PCBs can get crazy, with layers of different types of conductors. A solder mask is that green thing that prevents the PCB from oxidation or shorts.


Now that you get the point of how these PCBs work, people usually make PCBs at home by etching away copper from a copper-clad board to get traces.
You could look at my post on VU meters evolution to get an idea of how I do it at home.

So, it seems like PCB manufacturing at home is limited to copper boards on phenolic/fiberglass surfaces.
Instead of using copper sheets (because they were not cheap), I used aluminum foil as the conductor. Instead of using fiberglass/phenolic, I used whatever I felt like. The following is my attempt on aluminum PCBs.

I decided for attempt 1 that I was going to use a plastic sheet

For this first attempt I was going to use SMD parts, so I do not have to drill holes (the DIP parts will be bent into SMD).

Sanded out

Just programming the chip

I really had no photosensitive aluminum foil, so I would use the toner transfer method.

I cut out one piece.

Taped it to aluminum foil. The back of the foil has a piece of tape to keep it flat.

Then I ironed it. The tape melted, which was bad...

The toner stayed intact with the foil, but the end product wasn't flat.

Use crazy-glue to glue it onto the plastic

Bath in water to remove the paper

It did not glue on too well... there were air gaps and wrinkles

dangerous chemicals.

crack a window.

two parts hydrogen peroxide

one part hydrochloric acid

It should etch the aluminum pretty well.

You will start to notice that the etchant gets in the cracks...

It etched away at traces from below.

So this time, I would glue the aluminum onto a flat surface first.

Then I drew silly patterns on it with a circuit-writer pen (an oil based ink pen, it's a Sharpie in essence).

I put it in.

Working well!

Then the ink started dissolving...

It didn't come out too well...

Conclusion from attempt 1:
You must always put the substrate on the foil first to ensure an airtight bond that will not allow any etchant in between.
This means that you cannot use a substrate that melts under a clothing iron, because...

Conclusion from attempt 2:
Oil based ink does not last too well in our etchant.

This PCB attempt could have been successful, if I were using glass, for example.

However, I was not using glass. In the end, this was pretty much a failure. The goal was to use any substrate. I am currently limited to substrates that do not melt under a clothing iron.

This gives me a nugget of information for my next attempt though, which is good, so I got that going for me.