Christmas gift : 134 Leds Christmas Tree.

26 12 2007

I got a very surprising gift from K. It is a 134 Leds xmas tree and framed nicely with a black photo wood frame!
She worked so hard on soldering 134 leds, Thank you. The kit was bought from local electronic store, should be the same as MK117 sold in this online store:

Here are some photos:



See it in action:

LED Flower Vase

19 12 2007

I want to make something simple, small and elegant for my lover’s birthday. Finally I come up with using 5×7 dot matrix led to make a flower vase, it can be used to display some text messages for her:)


Here are the components:

1. 5×7 dot matrix led
2. Atmel AVR tiny13
3. 2 x 74HC595 shift register with Latch
4. 2 x wooden prototype boards
5. 1 x coin battery holder
6. 1 x CR2032 coin battery (3V)
7. 3 x paper flowers
8. semi-transparent brown mud (from Franc Franc)
9. Switch for turning ON/OFF

I want to make things small, so I put the 5×7 dot matrix led horizontally and used the 5×4 dot matrix font, such that it can nearly display 2 characters at a time. For the MCU part, AVR Atmel tiny13 is a very small MCU, it is quite suitable for this kind of small application. The only problem is that it has limited IO pins, I have to use 2 x 74HC595 chips to extend the output pins, so I can driver 5×7 dot matrix led with only 3 IO pins, i.e. Clock Data, Latch.


Sorry for not posting any circuit digram, as I make it in hurry. After I spend a lots of time soldering the lines linking between the leds and the shift registers, here is the circuit board:


Then, I program the AVR Tiny13 with the STK500, the socket on the prototype board is a DIP socket, so I program the Tiny13 on STK500 and then put it back on the board to test. After several hours, the software is done.

Let’s put all the things together! I really love the effect when putting the led matrix in the transparent mud, the brown color is a good match.


Video demo:

Lastly, don’t forget the packing!


Hope you all may find useful.

Please also check out the notes by bitartist, including schematic & source codes:

2 hours LOVE project.

11 12 2007

I want to make a simple circuit for my lover, so I come up with using four 7-segment LEDs to make the word “L O V E” for her.

List of materials:
1. Four 7-segment LEDs
2. Resistors
3. A wooden prototype board
4. USB cable cord
5. Solder iron
6. Paper Clip
7. A plastic box
8. Red papers

Step 1 – Paint the wooden prototype board in White.

Step 2 – Put the 7 segment LEDs on the board


Step 3 – Solder!

Simply connect the “ON” segment pins to +5V and ground each of segment.

For detail, please check out this website: 7 Segment LEDs


I break the paper clips into three wires and organize them into three parallel lines to ease of soldering. You will see how simple it is. Finally cut of the usb cable and use only the +5v and GND lines. I didn’t have the many resistors around, so I put few of them and test the brightness. You can find the best resistor value yourself.

Step 4 – Power up by USB


Step 5 – Packing it

In order to make it nice enough to put near her computer desk, I put the board into the circular plastic box and put some red papers to it. Hah..looks like a LOVE bomb 🙂


I spent about 2 hours at mid-night to do this project, it is really simple and fun:)