Those of you that live in snowier climates will drool over the I-Shovel, a battery powered robot that shovels the snow off your driveway, saving you countless hours of backbreaking labor over the course of a single winter. Its inventors claim that, despite its relatively underpowered motor, it keeps the driveway clear even in heavy snowfall; the trick, apparently, is that the robot constantly monitors the amount of snow on the driveway and springs into action whenever a significant but manageable layer has built up. Unfortunately, the I-Shovel is still a prototype, but with any luck you’ll be able to actually buy one soon. If you’re impatient, of course, you could always try building your own.

[via Toolmonger]

      

There are a ton of digital picture frame tutorials out there. Most are old laptops with crafty case reconfigurations that fit a photo frame profile.

We set out to build a 100% DIY, scratch-built digital picture frame. Our frame has a 12bit color LCD, gigabytes of storage on common, FAT-formatted microSD cards, and you can build it at home. We’ve got the details below.

Concept overview

The bitmap images are stored on common, PC-readable microSD cards. A PIC microcontroller reads the images over a three wire SPI bus. The PIC processes the image data and writes it to a color LCD over a unidirectional, 9bit SPI-like bus. A configuration file on the SD card defines the delay between images.

Hardware

Click for a full size schematic image (PNG). The circuit and PCB are designed using the freeware version of Cadsoft Eagle. All the files for this project are included in the project archive linked at the end of the article.

Microcontroller

We used a Microchip PIC24FJ64GA002 28pin SOIC microcontroller (IC1) in this project. We really like this chip because the peripheral pin select feature lets us put important features on the pins we want; this gives a smaller, simpler, more compact PCB. Each power pin has a 0.1uF bypass capacitor to ground (C1,2). The internal 2.5volt regulator requires a 10uF tantalum capacitor (C12). The chip is programmed through a five pin header, SV1. R1 is a pull-up resistor for the MCLR function on pin 1. Read more about this chip in our PIC24F introduction.

A 32.768kHz crystal (Q1) and two 27pF capacitors (C10,11) provide an oscillator for the real-time clock calendar (RTCC). These parts are optional, the initial firmware doesn’t use them. The RTCC could be used as part of a function that superimposes the current time on the screen. Buttons connected to the programming header could be used to set the time.

SD card

MicroSD cards are completely compatible with regular SD cards, microSD cards can be used in an SD card reader/writer with an adapter. We tested several microSD card holders, and settled on one from SparkFun Electronics. The microSD card requires a bypass capacitor between the power pin and ground (C3). An LED indicates microSD read activity, but its also useful for general debugging (LED1, R2).

Color LCD 128×128 Nokia knock-off

This project is designed around SparkFun’s $20 color LCD panel. The LCD logic runs at 3.3volts and requires a decoupling capacitor (C4). The LED backlight requires a separate 7volt supply, and appears to have an internal current limiter because example designs don’t use external resistors.

The LCD has a separate input for the 3.3volt display supply. Many report noise in the display if this voltage isn’t clean. We used a ferrite bead (L1) and 0.1uF capacitor (C5) to filter the supply, and haven’t experienced any problems. This even worked on a dirty home-etched prototype. The ferrite bead type isn’t important, we used one left over from our tiny web server project.

The small connector is easy to solder on a professional board with a solder mask, but buy several as insurance. SparkFun has a PCB footprint for this part in their Eagle parts library, but the spacing between the pads is smaller than Olimex or BatchPCB will manufacture. We fudged it by decreasing the pad size to get more space between.  Don’t depend on the connector to hold the LCD in place, use tape to hold it down. We used sticky-tack to attach the LCD temporarily.

We prototyped an LCD carrier board prior to sending the final design for manufacture. We recommend against using a ground fill under the connector without a solder mask.

Power supply

A 3.3volt supply, provided by an LD1117S33 (IC2), powers the PIC, microSD card, LCD logic, and LCD display. IC2 requires a 0.1uF bypass capacitor (C6) on the supply side, and a 10uF capacitor (C13) on the output. We used the same tantalum capacitor that we used for the PIC internal regulator.

The LCD backlight is powered by an LM317 adjustable regulator (IC3) configured to 7volts with 240 (R5) and 1100 (R6) ohm resistors. C7 and C8 are 0.1uF bypass capacitors for the LM317.

J1 is a SMD power jack for a common 2.1mm DC barrel plug. C11 is a 10uF electrolytic capacitor that smooths any lag in the supply voltage. C11 has a maximum 16volt input rating, so the supply voltage is best kept under 12volts. 9-12 volts is probably the idea power supply range.

PCB

Click for a full size placement diagram (PNG). L1, C5, and the LCD are on the opposite side. We can’t prototype two-sided boards in mom’s basement, so we sent this design to BatchPCB. Next week we’ll show you how we did it.

Partslist

Part Description IC1 PIC 24FJ64GA002 (SOIC) IC2 LD1117S33 3.3volt regulator (SOT223) IC3 LM317 adjustable regulator (SOT223) U$1 Color LCD 128×128 Nokia knock-off
- Nokia knock-off connector
C1-8 0.1uF capacitor (0805) C10,11 27pF capacitor (0805) C12,13 10uF tantalum capacitor (SMCA) C14 10uF electrolytic capacitor (SMD) L1 ferrite bead (0805) LED1 LED (0805) Q1 32.768kHz crystal R1 2000 ohm resistor (0805) R2 390 ohm resistor (0805) R5 240 ohm resistor (0805) R6 1100 ohm resistor (0805) SD1 microSD card holder J1 2.1mm power jack (SMD) SV1 0.1” male pin header, right angle

Firmware

The firmware is written in C using the free demonstration version of the PIC C30 compiler. Learn all about working with this PIC in our introduction to the PIC 24F series. The firmware is included in the project archive at the end of the article.

FAT12/16/32 disk library

Microchip’s FAT 12/16/32 library gives us easy access to files stored on SD cards. We gave a detailed description of this library in our web server on a business card project. If you’re having trouble reading a card with the library, check that it was formatted in a digital camera or using Panasonic’s SD card formatter.

Nokia 6100 LCD driver

SparkFun has a basic 8bit color driver (ZIP) for the Nokia 6100. We ported it to the PIC, and updated it for the 2byte-per-pixel 12bit color mode. With a small amount of added complexity, the pixel write rate could easily be increased by using a different 12bit mode that delivers two pixels using 3 bytes.

The LCD uses a 9bit protocol, one bit more than most SPI hardware will handle. The first bit tells the LCD whether the next 8bits are data or a command. On the PIC 24F it’s impossible to manually bang in the first bit, and then use the SPI peripheral to send the remaining 8bits. We lose direct control of the pins when hardware SPI is enabled. The data entry has to be completely bit-banged, which dramatically reduces the screen refresh rate.

Reading Bitmaps

There are a ton of bitmap formats.  Windows compatibility keeps everyone using the ancient Windows v3 format. We created two C structs to read the V3 bitmap data.

Offset Bytes Bitmap file header 0 2 Always 0×42 0×4D (hex for BM) 2 4 File size (bytes) 6 2 Reserved, ignored 8 2 Reserved, ignored 10 4 Location in file of the first bitmap data

Bitmap files start with a 14byte file header. The first two bytes are the letters ‘BM’, indicating a bitmap.  If the first two bytes are correct, the firmware loads the information header. The last four bytes indicate the beginning of bitmap data, but the current firmware just assumes it will begin at the end of the headers.

Offset Bytes Bitmap information header 14 4 Length of bitmap information header (40bytes for Windows V3 bitmaps) 18 4 Width (pixels) 22 4 Height (pixels) 26 2 Color planes, always 1 28 2 Color bits per pixel (1, 4, 8, 16, 24 and 32) 30 4 Compression method, we only read uncompressed (type 0) 34 4 Image data length 38 4 Horizontal resolution (pixels per meter) 42 4 Vertical resolution (pixel per meter) 46 4 Number of colors, ignored. 50 4 Number of important colors, ignored.

A Windows V3 bitmap information header is 40bytes long. The firmware verifies that the header length (offset 14) is 40, indicating a V3 bitmap. If the width (132), height (132), color depth (24), and compression (0) all check out, the image data is processed and output to the screen.

Offset Bytes 24bit image bitmap data 54+(3n) 1 pixel n red value 54+(3n+1) 1 pixel n green value 54+(3n+2) 1 pixel n blue value

Bitmap images have uncompressed, 1:1 representations of pixel data stored in three byte sequences.  The data starts at the lower right-hand corner of the image; first the red value, then green and blue. Wikipedia has a complete bitmap walk through.

If the color depth of a bitmap image (24bits) is greater than the LCD can display (12bits), we need to discard the least significant bits of color data. To convert from 24bit color to 12bit color, we just chuck half the color data; an 8bit value of 11110011 is pushed four bits to the right, giving 1111.

Firmware walk-through

• Init PIC, SD, LCD.
• Read config.ini, create if it does not exist.
• Use first character of config.ini to set between image delay.
• Look for images, open next image.
• Read and check bitmap file header for proper format.
• Read and check bitmap information header for version, size, color.
• Read and display each pixel value. Adjust bit depth as needed.
• Delay, then repeat from 4.

Preparing images

To keep this demo simple, the photo frame only displays the most common bitmap format. Images must be sized to 132×132pixels, with 24bit color.

• Open a picture with an image editing program.
• Draw a square selection box over the part of the image you want to use, usually using shift and drag.
• Crop the image.
• Size the image to 132×132pixels.
• Save the image as a windows bitmap, 24bits of color depth.

Other image sizes and formats could be supported with a firmware upgrade (PNG, JPG), especially with a pin-compatible microcontroller upgrade to a giant dsPIC 33F.

Using it

Put images in the root directory of a FAT formatted SD card. Depending on the last device to format the card, it might need to be formatted with a digital camera or the Panasonic SD formatter.

Optional: make a config.ini file with a text editor. Enter a single digit, from 0-9, to set the between picture delay. Save the file. If you don’t create your own config.ini file, one will be created for you with a 1 second delay.

Put the card in the socket, and plug in the digital picture frame. Images will cycle on the screen with the defined delay.

Taking it further

We see a lot of potential in this simple digital picture frame. Many features can be added with a firmware upgrade, some are the basis for future hardware.

• Display other image formats, scale images
• Random fades and wipes
• Display time and date over image, set with buttons connected to programming pins
• Extend the configuration options in config.ini to include longer delays, fade or wipe type
• Use a sub directory for images because there are some file limitations to the root directory of a FAT formatted SD card.
• Add an ethernet connection for networked display updates.

Download: dpf.v1.zip

      

Bug Labs, the company that makes modular electronics that allow you to build your own tech doohickeys quickly and easily, has announced five new modules: BUGprojector, a mini DLP projector developed in conjunction with Texas Instruments, which sounds very much like the tiny DLP projector we posted about last week; BUGsound, an audio processing module with four stereo input/output jacks, a microphone, a speaker, and builtin hardware codecs; BUGbee (802.15.4) and BUGwifi (802.11 and Bluetooth 2.0+EDR), which will let you connect wirelessly with your PAN and WLAN, respectively; and BUG3g GSM, for connecting to (you guessed it) 3G GSM networks. In conjunction with Bug Labs’ existing series of modules, especially the highly versatile BUGvonHippel universal module, you’ll be able to create some pretty kickass gadgets. No word yet on pricing, although Bug Labs expects to ship by the end of Q1 2009.

      

ArtFall allows you to draw on a whiteboard, then have small geometric shapes interact with your drawing like a barrier. Imagine a pachinko machine where you have to draw the pegs in. Not only can you draw barriers, but you can change the direction of gravity with either an iPhone or a Wiimote. The footage also shows some sound interaction as the pieces seem to bounce with the bass from some music. The effect is quite nice and somewhat reminiscent of the whiteboard pong we saw recently.

[thanks eric]

      

The Coby DP-151sx Digital picture frame keychain seems to be ripe for hacking. At roughly $9, you get a screen, and Li-Ion battery. That’s not bad considering a similar screen alone would cost $20 elsewhere even though it runs on a slower serial connection.  While they’ve only put a 3 color pattern on it so far, more can’t be far behind. If you don’t feel like actually tearing it apart, there are some projects that have managed to customize what it displays via the USB connection.

      

[Eric Archer] constructed an analog computer to model the physics of a bouncing ball. The core is a TL074 opamp that does all the integral math. He had no trouble finding descriptions of analog computers, but how to set the initial conditions was rarely covered. The controls include potentiometers to set the initial velocity, force of gravity, and coefficient of restitution (how much energy is lost in the bounce). The output is displayed on an oscilloscope. He mentions that this output could be used in electronic music, citing Aphex Twin’s Bucephalus Bouncing Ball. Watch the video below for a demo of all the features.

      

When several students from the University of Toronto became tired of having multiple remotes lying around, they decided to do something about it. Their solution to this problem came in the form of UIRemote, a universal remote application for the iPhone. The application allows the iPhone to control anything that is normally controlled by an infrared remote, thanks to the use of a custom infrared adapter that plugs into the phone’s headphone port. It’s a technique similar to our iPod remote control from 2004. While the UIRemote application and adapter are still in beta, the students expect to release both things simultaneously sometime within the next two months.

[via Engadget]

      

On the off chance that you want to program a microcontroller to play your games for you, you should check this out. Near Future Laboratories has made a dongle that can allow an Arduino to operate as a PS2 or PS3 controller. You can see the Arduino running a random path generator in Katamari Damacy in the video above. They wanted to see how long it would take to clear a room. It managed to get almost all of them in about 70 minutes, only missing those that you have to cross a narrow bridge for.  Actually, this could be quite useful in allowing people to create alternative input methods. You may recall reading about their early progress back in June 2008.

      

Wired Threat Level has posted an interview with the hacker who recently broke into several high profile twitter accounts, such as Fox News, and Barack Obama. Since we know how much you all love twitter, we thought you might want to learn more about it. Apparently he used a brute force method to get into a member of the support team. The password was “happiness” which was cracked pretty quickly. This might be a good time to review your own strategies to prevent brute force attacks.

      

If you’ve ever been curious what it is like to work at ThinkGeek, check out this video. [John Frazier], a purchasing agent, talks about the history of ThinkGeek as well as what daily work is like. Fairly interesting, but the summary is that it’s just like any other job, with more toys. They probably have to test all the products fairly thoroughly, we know we would.

[thanks Yan]

      

Some of you probably have plans to build your own spaceships, we know we do. Well, the propulsion system can be a bit tricky, especially if you plan on using plasma drives. This breakdown and build of a simple plasma thruster should help you on your way. All you really need is some Argon, a large capacitor bank, and a custom nozzle. You’ve already got most of that right? As usual, be very careful. This is high voltage and very hot.

      

The Cheap Vegetable Gardener sent us his fully automated grow chamber project. In the quest to have fresh strawberries year round, they’ve made some progress in the area of automating their plant care. The whole thing is controlled by a computer that can turn on/off the lights and adjust the temperature. It also takes snapshots and logs the environment conditions so you can chart it all out nicely. The automated watering feature isn’t done yet, but hopefully will be soon.

      

For those unfortunate few of you who don’t already have a plasma cutter sitting around, [jandgse812] is here to help. He walks you through the process of building your own plasma cutter from scratch. Adding up the list of parts brings the total project to roughly $300.  He has included visual diagrams for all the wiring as well as specific part numbers and where to get them. Be careful, this is potentially very dangerous, but also very cool. You may need to get a copy of the mission impossible theme to play whenever you use it. At least, that’s what [jandgse812] recommends. You can see a video of it in action after the break.

      

tircd is an ircd proxy for talking to the Twitter API. It should work with any standard IRC client. After running the Perl script, you authenticate to the IRC server using your Twitter username as your /nick. Join the room #twitter and the /topic will be set to your last update. Any message you type will update Twitter and the room’s topic. All of the people you are following show up in the room as users and post messages as they tweet. If you private message one of them, it will become a direct message on Twitter. Other commands work too: /whois to get a person’s bio, /invite to start following, and /kick to unfollow. The project is brand new and will be added new features in the future like Search API support. Follow @tircd for updates.

      

The GP2Y0D02 is an infrared proximity sensor with a detection field that extends 80cm. This type of sensor can be used to build collision avoidance systems for robots. We’ll demonstrate this sensor using a single resistor and a multimeter.

Sharp GP2Y0D02 fixed 80cm IR proximity detector (Digikey #425-2064-ND, $14.38). Datasheet (PDF).

The GP2Y0D02 requires a 5volt power supply (not shown). A 0.1uF bypass capacitor between power and ground (C1) is a good idea, but we didn’t use it in our demonstration. The open collector output (pin 1) pulls to ground when no object is detected, a 12K pull-up resistor (R1) holds the signal high when an object is detected.

In the demonstration we connected the output of the sensor to a multimeter. When nothing is in front of the sensor, the detector holds the output low (0.40volts). When we put a PCB in front of the sensor, the output changes to high-impedance and the pull-up resistor (R1) holds the signal high (5volts).

Why open collector?

An open collector output doesn’t toggle between high and ground, it toggles between ground and unconnected. The unconnected state, also called high impedance, exerts nothing on the output and allows the signal line to float. This is an undefined state for most microcontrollers that returns rapidly varying values, so we use a resistor (R1) to hold the signal high. The open collector output overcomes the small amount of current flowing through resistor to register the low state. Without this resistor, the output will never reach a proper high state.

Open collector outputs are useful when several sensors need to share the same microcontroller pin. Multiple sensors outputting high to the same microcontroller pin is generally considered a bad practice that can damage parts of a circuit. Multiple open collector outputs, however, can only switch to ground; a single resistor holds the signal high. In the case of multiple GP2Y0D02s, the signal will be high only when all connected sensors detect an object and switch to high impedance state.

Like this post? Check out the parts posts you may have missed.

      

[martiaz] has released an exploit which allows homebrew on the PSP3000. It takes advantage of a vulnerability when loading save games on a game called GripShift. You can see the PSP running unsigned code in the video.

[thanks wraggy]

      

[rog8811] sent in this really cool hack where he used the optics sled from a PS3 as a foundation for a 7 color hand held laser projector. Combining a green laser, a blue ray laser, and a red laser, he is able to produce a variety of color  including white. There are step by step instructions on how to make a multicolored laser. He then goes even further, showing how to integrate this into a hand held projector with pre programmed patterns. You can see some examples of the different colors and patterns in this video.