Building An Ethernet Connected RFID Reader

August 26, 2013 by 14 Comments

For the last few years, [Lt_Lemming] was the president of Brisbane’s hackerspace. Until several months ago, access to the local was done using 125KHz RFID tags and an Arduino board with a prototyping shield. As the hackerspace gained members and moved to bigger facilities, [Lt_Lemming] decided to build himself a more compact and advanced platform.

His Simple NetworkAble RFID Controller (SNARC) is a platform which can be connected to an Ethernet network and different RFID readers in order to implement smart access control functionalities. Through hole components were selected so even solder apprentices may assemble it. The PCB was designed using Fritzing, and development can even be done inside the Arduino IDE as ISP and serial headers are available on the board. Finally, an N-channel mosfet controls the door locking mechanism.

The project is open hardware and software, and all the sources can be downloaded from [Lt_Lemming]’s github repo.

Comparing USB To Ethernet Converters: Apple Vs. Knock-off

March 22, 2013 by 4 Comments

usb-ethernet-comparison

[Angus Gratton] recently cracked open a pair of USB to Ethernet converters to see what’s inside. One was an Apple branded device, the other a no-name from eBay. The former rings in at $30, with the latter just $4. This type of comparison is one of our favorites. It’s especially interesting with Apple products as they are known for solid hardware choices and the knock-offs are equally infamous for shoddy imitations.

From the outside both devices look about the same. The internal differences start right away with a whole-board metal shield on the Apple dongle and none on the off-brand. But the hardware inside is actually quite similar. There’s an RJ-45 jack on the left, followed by the Ethernet isolation chip next to it. From there we start to see differences. The off-brand had a blank chip where Apple’s ASIX AX88772ALF USB to Ethernet bridge controller is located. There is also a difference with the clock; Apple is using two crystals with the other using just one.

[via Reddit]

Cheap As Chips Arduino Ethernet Shield

July 10, 2012 by 51 Comments

It’s no secret that Ethernet shields for the Arduino are a little expensive. With the official Ethernet shield selling for about $50 and other options not much cheaper, there’s a lot of room for improvement for Arduinofied Ethernet. [Boris] over at Open Electronics has a solution to this problem: his Ethercard powered by a $3 Ethernet controller.

The Ethercard uses the Microchip ENC28J60, a through-hole Ethernet controller. There isn’t much else on the board apart from an RJ45 jack, caps, resistors, and a cheap buffer chip. This board was designed to be easily produced, and we’re thinking it might be possible to etch this board at home.

There are a few drawbacks to this ENC28J60 Ethernet shield – the official Arduino Ethernet shield has a 10/100 Mbps connection where the Microchip-powered shield is limited to 10 Mbps. Given the reduced cost, ease of assembly, and the fact that it’s pretty hard to saturate a 100Mbps connection with an Arduino this flaw can be easily ignored.

Pretty neat, especially considering how much you can do with an Ethernet connection on your Arduino. Files and code available in the git.

Using The Raspi As An Ethernet Shield

June 24, 2012 by 47 Comments

[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.

Nah, You Don’t Need An Ethernet Module For Your Arduino

June 12, 2012 by 21 Comments

[Andy] needed a cheap Internet connection between a data-gathering Arduino and his home server. An Ethernet shield would suffice, but he couldn’t run CAT5 to the Arduino’s location. Wireless shields are hideously expensive, and after looking over the popular Zigbee modules, [Andy] had a few concerns about range and build complexity.

The obvious solution to this problem was getting a cheap WiFi router, flashing OpenWRT firmware on the device, and piping sensor data through the Arduino’s USB port, through the router, and over a WiFi connection to the server.

[Andy] used a TP-Link TL-WR703N wireless ‘travel router’ available on eBay £15 (~$30 USD when we checked). After flashing the router with OpenWRT, [Andy] had a wireless connection from a remote data-collecting Arduino directly to his server.

Attentive Hack a Day readers will note this is the third ‘wireless router + OpenWRT as a dev board’ build this week (first one, second one) . No, we don’t know what’s going on, or why the collective unconscious of makers around the globe decided to latch onto this type of build so suddenly. OpenWRT is available for hundreds of different routers, and anything that keeps disused routers out of the landfill (with the bonus of doing something useful) is alright in our book, so if you have another similar build, send it in and we’ll get around to it sometime.

Ethernet Over Telephone Wire

April 18, 2012 by 83 Comments

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.

Easy Workout Logging With Ethernet-enabled Exercise Bike

March 3, 2012 by 6 Comments

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.