The Arduino Internet Gizmo
The Arduino Internet Gizmo is a USB, Arduino, and RFID device for web surfing. The gizmo works by placing an RFID tag on the top of the gizmo. The gizmo reads the RFID tag and sends the tag number via USB to a program running on a PC. The program looks up the tag number and the associated web site and then invokes the default web browser to open a new tab for the web site. The gizmo consists of an Arduino Uno, a Parallax serial RFID tag reader, an assortment of LEDs, and a few other parts packaged inside a ATX power supply case recycled from an old PC. The software components of the gizmo consist of a small program running on the Arduino and a small Python program running on the PC or laptop.
The Arduino Internet Gizmo is fun to use and makes an excellent desk toy and sure beats using a mouse and keyboard to load your favorite web sites.
Step 1: How it works
The second figure and the attached PDF file show the circuit schematic for the Arduino Internet Gizmo. The RFID card reader is connected the Arduino pins 3 and 4. Pin 3 is used for sending the RFID card data to the Arduino and pin 4 is used to enable or disable reading. Arduino pins 6 – 13 are used to control the illumination of the LEDs on top of the gizmo. Arduino pin 5 is used to turn on the red-green-blue LED color changing circuit. Pin 5 connects to an optocoupler that turns the color changing LED circuit on and off. I used the optocoupler circuit rather than connect the color changing LEDs directly to the Arduino because the color changing LEDs draw varying amounts of current as they change color and with five of them, I wasn’t sure what effect that would have on the Arduino, so I felt it was better to use the optocoupler and power the color changing LEDs independently.
Details on how the software works is covered in step 20.
More information on how the RFID card reader works can be found in the data sheet for the Parallax serial RFID card reader.
Step 2: Prepare the case
In this step, we will prepare the case for the Arduino Internet Gizmo. You will need the following for this step:
- Power supply from a PC (I used a non-working ATX power supply)
- Wire cutters
- Goo Gone (or similar solvent to remove adhesive)
- 4 Vinyl bumpers (rubber feet)
Follow these steps to prepare the case:
- Remove the screws holding the power supply case together as shown in the second photo. Save these screws: you’ll need them to put the case back together.
- Remove all of the guts from the power supply as shown in the third photo. You’ll need to remove screws and cuts wires to get everything out. Save the parts for some future project (there’s a wealth of good stuff inside the power supply) or responsibly dispose of the innards as e-waste.
- Remove all the labels and stickers on the outside of the case. I found that my finger nails did the best to scrape them off without scratching the case. Use Goo-Gone or a similar product to remove any remaining adhesive.
- Apply the vinyl bumpers to the bottom of the case (see fourth and fifth photos).
Step 3: Assemble the color changing LED circuit
In this step, we will assemble the color changing LED circuit. This circuit is “on” whenever the Arduino Internet Gizmo is powered on and operational. It’s purpose is decorative and to make the gizmo look cool! You will need the following parts and tools for this step:
- 5 Red-Green-Blue color changing LEDs (You probably won’t find these in your local electronics store. If you search on eBay for “5mm led rainbow rgb” you’ll find them. They cost approximately $13 for 100.)
- 5 100 ohm 1/4 watt resistors (Radio Shack 271-1311)
- 1 4-Pin Lite-On LTV-817 Optocoupler (Jameco part number 878243)
- Screw terminal (Jameco part number 2094485)
- Adafruit Perma-Proto Quarter-Sized Breadboard Printed Circuit Board (part number 589)
- 4 1/4″ Round nylon #4 spacers
- Soldering iron and solder
- Wire strippers and wire cutters
Follow these steps to assemble the circuit:
- Solder the resistors and jumper wires as shown in the first photo. Use the labels for the pins in the photo as a guide to make sure you’re placing everything correctly (note: the numbers 1 to 15 along the top and A to J along the sides)
- Solder the optocoupler as shown in the second photo. The alignment of the chip is critical: the round dot on the chip indicating “pin 1” should be in the lower left hand corner (hole E2)
- Bend the LED wires as shown the third photo.
- Solder three of the LEDs as shown in the fourth and fifth photo. Note that the longer lead on the LED (the positive side) goes in the hole in the same column as the orange wires (6, 10, 14).
- Put two nylon spacers on each of the LEDs leads as shown in the sixth and seventh photos.
- Solder the LEDs to the circuit board as shown in the eighth, ninth, and tenth photos. Note that the longer (positive) LED lead goes into the holes in the same columns as the orange wires (8 and 12).
- Solder the screw terminal to the circuit board as shown in the eleventh photo (note: this photo shows a red and black wire attached the the circuit board – you don’t need to attach anything there in this step – I had those attached so I could test the board).
When powered up, the LEDs will change colors as shown in the last three photos. When enclosed in the case, the color changing LED circuit will look like this:
For more detail: The Arduino Internet Gizmo
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