![]() ![]() Given the prop has a bucket of I/O pins (man I love the prop) I don't see then need to use shift registers, but current 'best practice' might mean I should. What is the current 'best thinking' on how to drive multiple leds with the ability to PWM? (a search of the site gives a host of methods) – we’re going to attach a resistor to the anode (+) of each LED.So as part of our first project together, my daughter wants to help build a word clock ( ). ![]() Keep in mind that up to 31 LEDs will be lit at once (“IT IS TWENTY FIVE MINUTES PAST ELEVEN”), so if you drive each LED at 20mA you will need a 620mA power supply – this is part of the reason why I planned for 10mA a piece.įirst, trim one lead of each resistor leaving about 3-5mm (see photo 1). I chose to use 1Kohm resistors and drive the LEDs at 10mA (half their rated current), but you might want to use 470ohm or smaller depending on your power supply and LEDs. We need to attach a resistor to each LED to limit the current that flows through it. Now comes the repetitive task of soldering all 98 LEDs and resistors. (Edit 8/1/10: Added a better description of the construction paper border and more Step 3: Soldering LEDs Also, put a piece of black electrical tape behind each of the non-used spacer letters to make sure no stray light gets through. Tape this on the inside (back) of the letter mask to help diffuse the LED light and make the letters a dim gray when not illuminated. Now, cut out a square piece of the black garbage bag big enough to cover all of the letters. Tape the transparencies to the back of the border (photo 6). Use a utility knife to cut out the inner square leaving a 0.5″ paper border (photo 5). Mark lines 0.5″ in from each side forming an 8″x8″ square (photo 4). Cut a piece of construction paper to be 9″x9″. Therefore you need to cut a piece of construction paper to form a border and fill the gap – it also adds a nice touch of color. Note: the viewable area of the Ikea frame is 8.5″ square, but unfortunately you can’t print all the way to the edge of the transparency. Align the letters of the two layers and tape the layers together with double-sided tape on the top and bottom black regions – see photos 2 and 3. Depending on how dark your ink is you may need more or fewer layers to get an opaque black.Ĭut off the clear parts of the transparency so only the black square is left. ![]() ![]() The ink wasn’t quite black enough to completely block out light, so I printed 2 of them and stacked them. Since there’s a lot of black ink, I had my transparencies printed at Staples for something like 50 cents a piece. I thought of several different ways to make the letters, such as silk-screening on the back of the glass, or having a custom black sticker made, but eventually I settled on printing black onto transparencies – see the attached PDF file. The key to making the clock look nice was making the glossy black letter mask. Optionally a breadboard is useful for prototyping the circuit Step 2: The black letter mask Total cost: around $44 (using standalone ATMega168) or $67 (if you buy a full Arduino) Arduino Tutorial Online Courses Video Trainingĩ8 white LEDs – $7-10 (buy in bulk on ebay)ġ Arduino (or an ATMega168/ATMega328 and extra hardware – 5V regulator, crystal, etc) – $7 (for standalone chip and extra hardware) or $30 for arduino USB boardģ HCF4094 shift registers – $1.44 at Digikeyġ Barrel-plug connector – $0.38 at DigikeyĢ Buttons – scavenged from old electronicsġ 6V or 7V DC wall wart – scavenged from old electronics, or ~$4 onlineġ sheet colored paper (used for a hint of color around the border)ġ 9″ square piece of cardboard (used to hold LEDs in place)ġ cereal box (cut up to make light baffles – see step 3)Ģ printed transparencies (see attached pdf on step 2) – $1ġ protoboard for microcontroller, driver ICs, etc.Arduino Nano Projects List in PDF offline downloadable.Android based arduino Projects List Download PDF.esp8266 arduino projects list in pdf offline downloadable.Arduino Proteus Projects List for Download.Arduino UNO Projects List in PDF offline downloadable.Arduino Mega 2560 projects list in PDF offline downloadable.Arduino Complete Projects List PDF Downloadable.Huge List of tutorials & Components based resources. ![]()
0 Comments
Leave a Reply. |