Using the Raspi as an Ethernet shield

[Alexandre] wanted to set up a web-based temperature logger with his Arduino, but found the Arduino Ethernet shield a little finicky. Since his Raspberry pi was just delivered, he figured he could use the Raspi as an Ethernet shield with just a little bit of coding.

After [Alexandre] set up his Arduino to send a thermocouple through the USB, the only thing left to do was to add node.js to the Raspi’s Debian installation. Every five minutes, the Arduino wakes up, takes a temperature reading, and sends it over to the Raspberry pi. From there, it’s easy parse the Arduino’s JSON output and serve it up on the web.

In the end, [Alexandre] successfully set up his Raspberry pi as an Ethernet shield to serve a web page displaying the current temperature (don’t F5 that link, btw). One interesting thing we have to point out is the cost of setting up this online temperature logger: the Arduino Ethernet shield sells for $45 USD, while the Raspberry pi is available for $35. Yes, it’s actually less expensive to use a Raspberry pi as an Ethernet shield than the current Arduino offerings. There you have it, just in case you were still on the fence about this whole Raspi thing.

Hackaday Links: April 29, 2012

More old computers on FPGAs!

[Andy] loves his Memotech MTX computer. It’s an oldie with a Z80 running at 4MHz; the perfect target for an FPGA port. The ReMemotech has everything the old one has – cassette interface and all – and can run up to six times faster than the original.

Also found in 10-forward

If you’re going to build a jukebox, why not go all out? Here’s a touch screen jukeboxwith an LCARS skin. Yep, the same interface found on Star Trek: The Next Generation.

New desktop wallpaper for you

[McMonster] found a great pair of blog posts (1, 2) showing what ancient ICs look like without their casing. Since these were CERDIP packages (two ceramic plates glued together) they were exceptionally easy to take apart leaving the entire chip intact. Pages are in Polish, but there’s a Google Translate button on the sidebar

Cheap and easy Arduino wi-fi

Quick quiz: what’s the easiest way to get data onto an Arduino wirelessly? XBees? GSM modules? Nope, just get a wireless router and an Ethernet shield. The Ethernet module only cost [Doss] $20, and we’re sure Hackaday readers have a spare wireless router around somewhere.

Chiptunes! Chiptunes I say!

[mdmoose29] has been working on making a custom SNES cartridge for a dubstep artist (tell us more, [moose]…). In his search for programming tools, he found theSNES Game Maker. We tried it out for a bit and it’s still a very unrefined beta. Still, making SNES programming easier is awesome.

You people are awesome. Here’s six things for a links post.

[Valentin] made a night vision monocular from an old VHS camcorder, a small spy camera, and a handful of infrared LEDs. Here’s a video of [Valentin]‘s build in action.

CoolBot keeps your laser cutter from overheating

[Charles] wrote in to share the project he just built for the London Hackerspace. He calls it CoolBot, and as the name indicates it’s responsible for keeping the laser cutter from overheating.

At its heart the system is a water pump. It uses a plastic storage container as a reservoir, with an outfeed from the laser tube coming in the top of the lid. [Charles] mounted a temperature sensor using a 3D printed part to anchor it in the center of the return stream. An Arduino clone uses this sensor, as well as ambient room temperature and laser tube temperature sensors to decide when to switch on the cooling pump. As with any hackerspace add-on, this wouldn’t be complete without Internet connectivity so he included an Ethernet shield in the project box. Speaking of, that box uses panel-mount connectors to keep dust and water away from the electronics. But the lid of the controller box also includes a character LCD for quick reference.

Don’t miss [Charles'] explanation of the system in the video after the break.

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Ethernet over telephone wire

When [Bobo1on1] upgraded his Internet connection from ADSL to Fiber he ran into an issue of actually getting that speed to his desktop computer though his LAN setup. Before he had been using a telephone extension wire which ran from where the DSL entered the house, through a splitter, to his computer where the modem was located. Now that the router used by the fiber system is located at teh entry point, he has no easy way to run Ethernet cable to his computer room. Wifi is predictably slower than the 50mbit WAN connection, and he was unable to use the telephone cable as Ethernet directly.

The solution turns out to be a pair of TP-Link home plug adapters. These are designed to use your home’s mains wiring for data transfer. But [Bob] rigged it up so that they can push 224 mbits/sec over the telephone wire. Since you can’t run mains voltage through the telephone wire he had to hack a method to separate power for the devices from the data I/O. This was done with an external power supply and some passive components for filtering. The drawback is that this is half-duplex so up/down communications cannot happen at the same time.

Twittertape machine keeps track of your social media stock.

During the gilded age, oil magnates, entrepreneurs, and robber barons would have a ticker tape machine in their study. This machine would print stock and commodity prices and chart these men’s assets climbing higher and higher. A lot has changed in 100 years, as now [Adam] can be kept apprised of what @KimKardashian, @BarackObama and @stephenfry ate for breakfast with his Twittertape machine.

Interestingly, [Adam]‘s build didn’t start off as a tarnished lump of 100-year-old brass; he built his beautiful ticker machine out of old clock movements he picked up on eBay. Even though the shiny part of the build only holds the roll of paper, it’s still a wonderful build. Right now the machine is connected to Ethernet, but he’s planning on adding WiFi and a few batteries for a completely wireless build.

Unlike the other ticker tape machine we saw this week, [Adam] did away with the loud clashing of gears and solenoids found in 100-year-old ticker machines. This ticker machine prints on cash register receipt paper and a very small thermal printer in the base. Although [Adam]‘s build doesn’t sound like two robots trading blows, there’s no ink needed and no danger of the letter wheel becoming misaligned and misspelling everything.

Check out [Adam]‘s build in action after the break.

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Easy workout logging with Ethernet-enabled exercise bike

It will be easy to keep your exercise routine on track if you don’t have to do anything at all to log your workouts. [Reefab] developed this add-on hardware for his exercise bike that automatically logs his workout on the Internet.

He’s using RunKeeper to store and display the workout data. They offer a token-based API which [Reefab] implemented in his Arduino sketch. The hardware to grab data from the exercise bike is quite simple to set up. A rare-earth magnet was added to the fly-wheel with a reed switch positioned next it in order to measure the number and speed of rotations. This is exactly how a consumer bicycle computer works, needing just one accurate measurement corresponding to how far the bike travels with each revolution of that wheel.

In addition to the networked-logging feature [Reefab] included a character display so you can follow your speed and distance data during the workout.

Display Twitter on an Arduino

If you ever wanted your name out on the Internet, now is your time to shine. [Chris] hooked up an Arduino to the Internet and is streaming the results of combing through Twitter live to the entire world.

The SocialBot9000, as [Chris] calls his build, is an Arduino Uno connected to an Ethernet shield and an LCD character display. The firmware uses the Twitter API to search for recent posts containing the phrase, ‘socialbot9000.’ A PHP script on the Arduino does all the heavy lifting and with the great Bildr tutorial on getting the Ethernet shield up and running, [Chris] was off to the races.

Because it’s extremely doubtful that everyone on the Internet could manage typing a message into Twitter that would be correctly parsed by the SocialBot9000, [Chris] put a small form up on the build log that will correctly generate the message and take you to your Twitter account for posting. After all that was done, [Chris] decided to have some fun and set up a live feed from a camera in front of the LCD display for the world to watch.