Introduction: SpokePOV: LED Bike Wheel Images
Tired: A red blinker on your seatpost
Wired: Programmable full-wheel images in any color
Specifications and Features:
- Can be used with road, mountain or BMX wheels!
- 30 LEDs on each side (22 for BMX) x 256 radial pixels
- Runs on 2-3 AA batteries for 10 hours or more, assuming 3000mAh alkalines and 50% image coverage.
- Can run on rechargable NiMH AA's
- Comes with high-brightness red/yellow/green or blue LEDs
- Automatically shuts off after 3 minutes
- wxPython based software runs on any Linux or Windows or Mac with Parallel port or serial port
- Design is all through-hole parts, perfect for a first time kit builder.
- With one spoke, total persistence at 15mph. Two spokes, 10mph. Three spokes, 7mph. (Assuming a mountain bike wheel). Looks cool even if not completely persistant.
- Great for safe riding at night, provides excellent side visibility.
For more information, like how to use the software to update images, visit http://www.ladyada.net/make/spokepov
& check out more cool projects at http://www.ladyada.net/
Step 1: Intro
These instruction assume you purchased the kit or at least the PCB. All parts are through-hole and this should be a very easy project, even for a beginner. Still, if you've never soldered before, this tutorial is really awesome. If you're part of the new streaming-video-generation, this set of soldering mpegs may do you right:
Step 2: Tools
There are a few tools that are required for assembly. None of these tools are included in the kit. If you don't have them, now would be a good time to borrow or purchase them. They are very very handy whenever assembling/fixing/modifying electronic devices! I provide links to buy them, but of course, you should get them whereever is most convenient/inexpensive. Many of these parts are available in a place like Radio Shack or other (higher quality) DIY electronics stores.
Step 3: Parts
All these parts are included in the kit:
1 IC1 ATtiny2323 microcontroller
1 IC1* generic 20 pin socket
1 IC2 25LC080 1kbyte EEPROM
1 IC2* generic 8 pin socket
8 IC3-IC10 74HC595 serial to parallel latch
1 X1 DN6852 hall effect sensor
1 S1 SKQBAKA010 waterproof switch
1 J2 30310-6002HB programming header
4 n/a 12BH092 AA battery clips
1 R1 generic 1/4W 10Kohm 5% resistor
8 RN1-RN8 266-xxx 10-pin bussed resistor network
60 LED1-LED60 high brightness LED's
1 PCB custom silkscreened printed circuit board (PCB)
Step 4: Lets Get Ready to Solder!
Get your bench set up for soldering, and place the PCB in a good board holder
Step 5: Attach Battery Clips - Part 1
Place the 4 battery clips in the top two battery positions, as shown. Tack them in place with solder so that when you turn the board over they wont fall out!
Step 6: Attach Battery Clips - Part 2
Now turn the board over and solder the outer tabs of the clips first and then resolder the inner tabs. Make sure theres plenty of solder: these connections are not just electrical, they're mechanical too!
Step 7: Attach Programming Socket
Put in the programming socket, make sure to align the notch with the picture on the PCB. Now turn the PCB over and hold the socket in place while you solder it in.
Step 8: Attach Microcontroller Socket
Place the large socket as shown. There's a notch in the socket which should line up with the notch in the image of the socket. The notch will help you align the microcontroller chip in properly. Turn the board over and hold the socket in with a finger, tack two corners pins to keep it in place then solder the rest of the pins.
Step 9: Attach Small Socket
Solder in the smaller socket just like the larger one. make sure to orient the notch as shown
Step 10: Attach Latch Chips
Place the 6 top 74HC595 latch chips in the proper spots, making sure to align the notches on the chip with the notches in the pictures. Tack them in place by soldering two corner pins of each one from the top. Then turn the board over and solder all the pins.
Next, do the same with the 2 latches on the reverse side.
Step 11: Attach the LED's
Cut the LEDs from the tape and place the first 30 into the front row. Make sure that the flat side of the LED is aligned with the flat side of the LED shown on the board. Otherwise the LED will not light up. This is a pretty common mistake so work slowly and carefully.
When you place each LED, bend the leads out so that it wont fall out when you turn the board over.
Solder the LEDs and clip the leads, either one at a time or all at once, whichever is easiest for you.
After one side of the board is done, repeat for the other row of LEDs
Step 12: Attach the Resistor Networks
Solder in the 8 9-SIP resistor networks. Make sure you align them correctly: one side of the resistor pack has a dot which corresponds to pin 1 which is marked with an X in the picture on the circuit board.
Step 13: Attach the 10k-ohm Resistor
Place the one 10K resistor. Bend the leads like with the LEDs and solder it in, then clip the leads off.
Step 14: Attach Button
Place the button, which will snap into place. Solder it in.
Step 15: Attach the Sensor
Bend the sensor so that the face points out as shown. Since the sensor has to stick out but has short leads, solder it from the top, making sure that the leads don't stick too far through on the other side. See the picture to the left.
Step 16: Plug in Microcontroller Chip and EEPROM Chip
Put the microcontroller in the large socket so that the notches match up. The sensor can 'lean' on the microcontroller. If you want, you can use a bit of glue to support it.
Flip the board over and place the EEPROM in the smaller socket so that the notches line up. You're done!
Step 17: Test
Now that you're done assembling it, you can test the board to make sure its functioning. Put two good AA batteries into the clips. Whenever the microcontroller gets notice of a 'hard reset' it goes through a little test routine where it lights up all the LEDs in order. If none of the LEDs are lighting up, go back and check to see if you put in any latches, batteries or the microcontroller in backwards. If just a few LEDs arent lighting up, check if they're in backwards.
Step 18: Hacking - Animations
Animations! Have a pacmac chomp while you ride...Download the animation-supported software, and make sure you have upgraded the EEPROM to hold more images. I suggest either a 2K EEPROM (25C16P-1.8) for 2 images, or 4K (25C32P-1.8) for 4 images. You can buy these from Mouser for a few dollars a piece. You can't use just 3 frames (well, you could but the code doesnt support it). Then upload the images to seperate banks. Note that the software can't (yet) tell how big the EEPROM is so if you only have 2 image banks, bank #3 will be the same as #1 and #4 is really #2. Then set the number of rotations to display each image, just like any other variable. OK you're ready to rock.
Step 19: Hacking - More Colors
Wow look at all the pretty colors! The standard kit uses 2 batteries, which will work with red, orange and yellow LED's. If you want to use green, blue, white or purple LED's you will need to add a third battery. To do that, purchase 2 more battery clips from Mouser. Before you solder them in, you have to cut a trace. I thought I'd be all smart and put a note on the PCB about which trace to cut but I put it on the wrong side of the board. If you hold it up to a bright light you'll see the trace, or use this handy guide:
Step 20: Install
Attach the spokepov to your bike wheel with zipties as shown.
After it is attached, place the magnet on the frame as shown. The magnet must line up with the sensor on the PCB, it may take some fiddling with the sensor and magnet to get them in range. The range on the sensor is 1-2 centimeters.
If you are attaching more than one SpokePOV on your wheel, make sure they are lined up at an equal distance from the rim, use a ruler.
Step 21: Build and Connect the Programming Dongle
Instructions for building the programming dongle are at http://www.ladyada.net/make/spokepov
it should be a breeze in comparison. (Note that in this image, R1 and R4 are swapped, don't make that mistake!)
Now connect it up!
Step 22: Run the Image Design & Download Software
You can import images as .bmp files, then do a little touchup before writing the image to the spokepov. For more detailed instructions on how to run the software visit http://www.ladyada.net/make/spokepov