Gadget design, robotics, hacks, DIY technology and more.

Hypothetical situation: Let’s suppose tomorrow is your friend’s birthday and you forgot to get him/her a present. Also, let’s assume you have no money whatsoever, all nearby stores are closed and he/she doesn’t like things that come from the garbage.

What to do?
(a) You don’t give him any present at all (second best option).
(b) You make a gift yourself (best option).
(c) You go into exile.

I chose “b”. Below, instruction on how to make a quick and nice puzzle.

Materials

• 19 big nails
• a piece of wood

Tools

• hammer
• sand paper
• sanding machine (particularly useful, but optional)
• glue
• drill
• jig saw

In order to build a nice puzzle that will…well puzzle your friend for a while, especially if he/she is an engineering student, do as follows:

1. Cut a large piece of wood that will become the main board
2. Cut a small block that will stand and the nail stand.
3. Glue them together so they look nice and the nail stand is not in the way
4. Drill holes of equal depth on the small wood block so 18 nails can stand separately in each hole
5. Plant a nail in the middle of the board and make sure it is nice and vertical.
6. If you have some printable labels you can print the game instruction and stick them on an empty spot on the wood board. Make sure you sand everything well before applying the labels.
7. It should look like the picture below.

Game Instructions: Put all 18 nails on the central nail. The resulting structure should be stable.
This means they should all be placed so that they only touch the central nail’s head and maybe each other.

Game Solution: You can find the puzzle solution here.

Now enjoy your new puzzle. _

I polished up the code for my Arduino POV display and I think it is now ready to be shown to the world!

The source code for the POV display can be downloaded here.

The parameters in the code can be changed in order to display other images besides of the default arrows.

Data

The displayed image is stored in the data string. Each drawing is divided in frames (i.e. one frame for each letter of a word) and each frame is divided in columns. The image to be displayed must be encoded into 1s (ON) and 0s (OFF) and each value must be stored in the data string in the order illustrated below.

The duration of each column (i.e. how much time they stay ON), the spacing between frames and the spacing between images are set respectively by the integers timer1, timer2 and timer3. Keep in mind that their values depend on the rotation speed.

Finally, the number of frames and their length is set respectively by frame_num and frame_len.

Arrow (>):

• timer1: 3
• timer2: 15
• timer3: 0
• data: {1,0,0,0,0,1, 1,1,0,0,1,1, 0,1,1,1,1,0, 0,0,1,1,0,0}
• frame_len: 4
• frame_num: 1

“Alan” (my brother’s name):

• timer1: 3
• timer2: 15
• timer3: 13
• data: {1,1,1,1,1,1, 1,0,0,1,0,0, 1,0,0,1,0,0, 1,1,1,1,1,1, 1,1,1,1,1,1, 0,0,0,0,0,1, 0,0,0,0,0,1, 0,0,0,0,0,1, 1,1,1,1,1,1, 1,0,0,1,0,0, 1,0,0,1,0,0, 1,1,1,1,1,1, 1,1,1,1,1,1, 0,1,1,0,0,0, 0,0,0,1,1,0, 1,1,1,1,1,1}
• frame_len: 4
• frame_num: 4

Sinewave (or girly flower):

• timer1: 3
• timer2: 3
• timer3: 0
• data: {0,0,1,0,0,0, 0,1,0,0,0,0, 1,0,0,0,0,0, 1,0,0,0,0,0, 0,1,0,0,0,0, 0,0,1,0,0,0, 0,0,0,1,0,0, 0,0,0,0,1,0, 0,0,0,0,0,1, 0,0,0,0,0,1, 0,0,0,0,1,0, 0,0,0,1,0,0}
• frame_len: 12
• frame_num: 1

E = MC^2:

• timer1: 2
• timer2: 10
• timer3: 22
• data: {1,1,1,1,1,1, 1,0,0,1,0,1, 1,0,0,1,0,1, 1,0,0,1,0,1, 1,0,0,1,0,1, 0,0,0,1,0,1, 0,0,0,1,0,1, 0,0,0,1,0,1, 0,0,0,1,0,1, 0,0,0,1,0,1, 1,1,1,1,1,1, 0,1,0,0,0,0, 0,0,1,0,0,0, 0,1,0,0,0,0, 1,1,1,1,1,1, 0,1,1,1,1,0, 1,0,0,0,0,1, 1,0,0,0,0,1, 1,0,0,0,0,1, 0,1,0,0,1,0, 0,1,0,0,1,0, 1,0,0,1,1,0, 1,0,1,0,1,0, 0,1,0,0,1,0, 0,0,0,0,0,0}
• frame_len: 5
• frame_num: 5

The Arduino software is good and works very well under Linux. Nevertheless, it doesn’t create a menu item when installed and it can be tricky to create one for those who are not very used to Linux (like me).

In order to add a KDE menu launcher for the Arduino software, open the KDE Menu Editor, create a new item and put

cd /opt/arduino-0007/; ./arduino

in the Command field. Also, make sure that Run in terminal is checked and replace /opt/arduino-0007/ by your own installation path.

I’m sure there are thousands of other ways of doing this (including many than only require a few commands in the terminal) but at least this ways is pretty simple and and can be done without knowing that much about Linux.