Extensible LED Beam
Do you get tired of that hundreds of LED doing the same thing over and over again? Turn on together, turn off together and flash together?
Or, if you know basic programming of micro controller, how many LED can you control with I/Os?
In this instructable, with the help of 74HC595, you would know how to form a standard section of 8 LEDs, which can be extented limitless. And it only takes 4 I/Os.
Not only on/off control to individual LED, but also brightness control on single LED can be carried out.
animation video of 2 Sections (16 LEDs):
Step 1: Make the Base Board of a Single Section
Make the base board with a 80 x 40 perforated PC board.
Dimension matters. because not only the distance between LEDs in one section should be equal, but also the leds between section need to be distanced equaly, 1000mil.
Tip: When cutting off the board, you do not have to cut it through, cut groove on bothe sides, and bend it with a plier. It would take off easily.
Step 2: Put the LEDs & Resistors On
There are several tricks to solder component on the board.
Step 1: Learn the layout drawing. The actual layout will be exactly processed by it.
Step 2: solder the LEDs
Tip: Only solder one pin at first. Push the LED head with your thumb, and at the same time, meld the tin by the electronic iron. In this way, you can solider the LED attached to board tightly. And then you could solider the other pin.
Step 3: solder the 100 ohms Resistors. Most of LED is 3.3v, In this case, Because the power supply is USB / 5v, resistor is needed to protect the led from over loading.
Tip: Assumping you got your solder pen in your right hand, pick the tiny SOP 100 ohms resistor with tweezers in your left hand. Meld the tin on the second pin of the LED, and push one end of the resistor into it. Then Take the solder pen away and the tin solided. That is it.
SOP resistor is much compressed than tradtional big resisitor. If the resistor is gone or fly away, do not even take a try to find it. :)
Material list (to make a single section):
a. Perforated PC board x 1
b. Soldering Tin
c. DIP 74HC595N x 1
d. a 16 pin IC holder for 74HC595N
e. LED (3.3v) x 8
f. SOP 100ohms Resistor x 8
g. Straight Pin: 6pin x 3, 2pin x 1
h. L Pin: 6 pin x 1
i. 6 pin Rainbow wire (length: 8 inch)x 1
j. DoPund head cap for Rainbow wire: 5pin x 2, 1pin x 2
k. jumper wire.
l: jumper head cap x 6
Step 3: Solder the Pins
Put the pins on both ends of the boards
Tip: Do not solder all the pins one by one at once. Just solder the ones on both ends at first. As what we did in soldering the LEDs, meld one end and push, meld another end and push. Do this 1 or 2 rounds, the pin set would be attached to the board tightly. And then you could solder the pins in between.
When soldering the 2 rows on the right end of the board, make the connection after all the pins are welded. To build the connection is basically like melding a little extra bit of tin between the dots. With your solder pen touching the dots around, accidently or not, the tin will be melded together and a bridge would be built. It would required a little practise. However, it is a basic trick for exprienced solder players.
Tip: When do the pushing in soldering the pin, put on some protection on your thumbs. THE PINS ARE VERY HOT!
Step 4: Solder the Jumper Wire & the IC Holder
Step 1: There are 2 sections of jumper wire are needed in current design. (red lines in the drawing)
The shorter one is more tricky, as it needs to get around the pins and IC holder.
Tip: you could use the cut PC board to do the measuring.
Step 2: Solder the IC holder (16pin)
Tip: You could introduce tape to hold the IC holder for you. As same as what we did before, solder the 2 pins on the diagonal ends, meld them one after another while pushing to make it attached tightly to the board. And then solder the rest pins.
Step 5: Weld by Soldering
It may seems like a waste of soldering tin. But it is most orangized way to do the connection on a perforated PC board. If there are too many bridges hanging in the middle of sky, it always look like a mess. and if one is broken, it is hard to identify where.
Tip: Meld some tin on each plate on the path, one by one. Then connect every 2 of them, then complete the whole wire.
If the line is long, do not connect it to the component at first. Because it needs one or two minutes for the whole line to cool down. If the component is connected, the heat will be conducted to the parts, causing it burn. The pins, PC holder does not care the heat as much as the LEDs, resistors, capacitors, microcontrollers that are compared vulnerable.
After all the wires are laid. check it with your multimeter according to the drawing. If there is any short-circuit case, check it with your lamp, to find it out.
Building wires by soldering tin is tougher than soldering parts on, but it is still basic skill.
Look at my finished board, It is beautiful, isn't it?
You may insisit that jumper line can connect the IC with the LEDs. I agree. I just want a nice layout and organized looking.
Step 6: Make the Connector, Plug the IC & Buildup the Rainbow
Put another 6pin set aside to the one that is already there. You could use a little fast glue to solid it. And then turn over and build the connection with extra tin.
Rainbow wire is introduced to make the connection between the pins on both ends, in order to extend bus to the following sections.
Auction: Make sure 74HC595N is pluged in the right direction. Regarding the rainbow wires, all the pins are parallel, except one, the blue one in the picture. becasue the IC in the next section get data from the preious IC, but not from the bus.
Congratulations. A section is completed.
Step 7: Connection!
There is not much to play with only one section. Try to make more.
Connection between them is simple. you can easily connect them by jumper heads. you would need 6 of them to make a connection.
In my pictures, you may feel confused that the LED are not on the same line. It is because the other one is of an older design, which is not uniform. It would not be a problem for you.
Step 8: Program & Have Fun
The core of each section is a very classic IC: 74HC595, which is widely used and easy to find. It is a 8-bit serial-in/serial or parallel-out shift register with output latches; 3-state. You can drive it easily with 89C51 MCU, Arduino, Netduino or other micro controller system, with basic programming skill. Google it, you would find plenty solutions.
The rainbow lines are the bus, including GND, VCC, SH(CP), ST(CP), OE and Data, all you need to control a series of 74HC595.
Check them with the datasheet.
In my LED beam, I have successfully make animation of the police vehicles, breathing, meteors. I believe you could do better than I did.:)
Good luck and Have fun.