Saturday, March 21, 2015

Lesson 67 - Modding Switches

Today I got a shipment of electronics. Me and my little girl were both excited to open a bunch of envelopes to see what's inside; we have been waiting for some more Arduinos and mechanical switches for our upcoming Electronic Instrument. She immediately recognized the Arduinos, of which I was kinda proud.

The switches were a disappointment though. Colorful and all, but unfortunately of the "latching" type, meaning a switch that stays down when you press it, and comes back up when you press it again. And that just won't do if you're planning to build a keyboard for a musical instrument, will it?

So, we started "modding" the switches be removing certain parts from inside. We had 15 switches to mod in total so there was some real work to do! You'd thing this would be tedious and boring for a 6-year old girl? Nope, not at all. Even the 3-year old helped the best she can. In the end, I was the only one (not counting the 3-year old in) unable to open the plastic casing of a switch without breaking it. 

So the 6-year old can now mod a switch without any adult help, and does it better than me... And here they are, all 15 switched, modded by willing child labor!

Then we did some design on how the instrument would look like.

Next up: woodwork. We need to build a casing for our thingie. And maybe we need to visit the local "recycling center" to scavenge some parts, including a little speaker element. The Hartke element might be a bit too heavy-duty for our use case, weighing 1 kg or so. You can see it in the picture too. Quite a monster, ain't she?

Friday, March 6, 2015

Soldering school

Today her older cousins were visiting. She organized a Soldering School where she explained how to solder and had them all do some basic soldering. Was fun.

Thursday, March 5, 2015

Solder On!

Yesterday she was sick and I got to spend the whole day at home with her. Guess what we did? Well, she slept and watched Netflix while I was working. For a while. But when she got her energy back, guess what she wanted to do. Solder. So we did some serious soldering. Behold the METAL HORSE!

And today, I asked her to do her violin homework. Guess what she wanted to do. Solder. So solder we did. She soldered a resistor on the perfboard perfectly!

Sunday, March 1, 2015

Lesson 66 - Solder Star

Yesterday she asked me if we could now build the magical electric instrument together. The one we discussed in Lesson 65. I said yes.

So we started by recapping on our previous work with electricity. She struggled with terms (voltage etc) but with some help, she was quickly able to construct a circuit that will light up a led with 3.3 volts from the Arduino. And she remembered that you cannot use 5 volts for that. 

Soon we were about to start connecting the speaker element to the board. Whoa! One of the wires soldered to the speaker had gone missing. We concluded that we're gonna have to solder it back. Now this speaker element is heavy-duty and has a magnet so powerful that when it gets stuck to a piece of metal, she can barely drag it free with all her might. Now imagine using a soldering iron on that. It'll do its best to draw the burning-hot iron to the speaker element. So we decided I'll do the soldering but she'll get to practice soldering after that. She helped me by keeping the wire in place with her steady little hands while I applied solder.

After fixing the speaker I let her do some free practice with the soldering iron, under my supervision, of course. She started by almost burning the power line of the soldering iron. After I showed her the burn-marks on the plastic cover, she took good care not to repeat that mistake again. Here are some of here works.

A stickman and a star that is. She wanted to keep on soldering but it was almost bedtime so we had to stop for now. Was fun! I think need a better soldering iron though. Mine's a 5 dollar one from the Internet.

Monday, February 23, 2015

Lesson 65 - Arduino

Yesterday we took a look at electronics and Arduinos. We discussed what electricity is and what voltage roughly means. We tinkered with some wires, leds and resistors to see that you have to make a circuit from the 5 Volt output of the Arduino into GND which stands for ground and is 0 Volts. We draw a lot of stuff on the paper to illustrate how our circuits worked.

It was fun to use the 5 Volt and 3.3 Volt outputs of Arduino to run some motors (voltage affects run speed!) and then leds (you cannot feed 5 volts to a led or you'll break it!).

She got really excited and told me she wants to build a robot that moves and talks. I used my consulting skills to talk this down to a single blinking led. We almost got that far in the end.

So, from a talking robot down to a single lit led we went. But we had fun all the way.

Today I build a simple instrument with a push button and a potentiometer for controlling output frequency. The speaker is actually the tweeter part of my 350W Hartke Bass Combo that got spectacularly destroyed on the stage some 20 years ago.

And that was super fun to play with. We agreed to build an electric piano-like keyboard instrument together. I think that's a really nice exercise really, as there's electronics, coding and even mechanics / woodwork involved. I'm planning to make casing out of wood. Let's see if we can do this...

Friday, February 20, 2015

Lesson 64 - Back To Turtle

Every now and then she asks for a computer lesson. Today that happened again and there we went. After a brief discussion we decided to try Turtle Roy again. It had been a while since the last time, but she remembered at least some of the basic stuff. She laid out grandiose plans of what she wants to achieve today and I told her it involves recursive algorithms. We decided to start with basics and try to draw a rectangle first.

After some practice, we started formulating the one-liner. Meanwhile, here little sister


And then I got my computer back.

After discussing how the algorithm should be constructed, she started editing it inline. I taught her one of my coding tricks.

"Always type both opening and closing parentheses first and then add content between"

Maybe this is the lesson she'll always remember and will teach it to her own children later. After some editing, she had this.

    r 4 (s [fd 121, rt 90])

It draws a perfect rectangle! Now it was time to give a name to this algorithm and move to the next steps. Her patience was running out though. So we saved the work to continue later...

    save "neliö"

Nothing new this time really. But we had a good time and maybe we'll get to some new stuff next time, if we continue the saved program.

Sunday, January 25, 2015

Lesson 63 - Raspberry

A Raspberry Pi came from the mail and has been lying on the kitchen table for a while. 

It's essentially a little, dirt-cheap computer that can run Linux and has HDMI output, LAN connector and a couple of USBs. The interesting part for me is that you can easily plug in a Wifi adapter and you can use the GPIO pins to control electronics like LEDs and motors. And when I say motors I mean ROBOTS. Autonomous, Internet-connected ROBOTS.

I guess I was nibbling this skeletal little computer when my daughter asked me to have a "computer lesson" again. We discussed the Raspberry a little, but then went to draw the computer on a whiteboard. This is what it became. 

It's 95% drawn and written by her.

We started from CPU and its central role as the part that runs her programs. Then to RAM from where the CPU reads its instructions. And then, what do you think happens to the stuff in RAM when you unplug the power cords (drawn in the diagram). Her answer was funny, but I unfortunately forgot it already. Then we went on to persistent storage, or "hard disk", display, keyboards, USB connectors and stuff. She enjoyed drawing a lot!

Then we took a look at the Raspberry that looked like this.

All the parts are neatly exposed on this computer, ain't they! We identified the parts in her diagram that were currently missing in the Raspberry and marked them with red magnets. Then we added an SD card as the "hard drive" of the computer.

I installed a Wifi dongle (took me a while, I admit), created her an user accound. Later I told her that even though we don't yet have a keyboard and a display for the Raspberry, she can use it via network. She was quite enthusiastic to try it so we logged in using SSH using her own computer.

Once there, we decided to create a file using vim (which I pre-installed of course). As usually it took quite a while to select a suitable name for this new file, especially when she had to negotiate it with her baby sister. Eventually she kinda pulled rank and decided to name the file after herself. The naming debate had exhausted her though and she quit before even starting to think about what the file should contain.

Fun day! I especially recommend the drawing part. Afterwards I wrote a little Python program that blinks a led. Maybe we'll create a Raspberry robot soon. I have motors and stuff you know.