Tag Archives: wifi

App note: Using Vishay infrared receivers in a Wi-Fi environment

via Dangerous Prototypes

an_vishay_usinginfraredreceiversinwifi

2.4Ghz and 5 Ghz Wi-fi signals can sometimes affect IR receivers, here’s Vishay’s app note about them. Link here (PDF)

In recent years, Wi-Fi connectivity has penetrated most consumer electronic devices used for media reproduction. New TVs, satellite receiver and cable boxes, and streaming devices are more often than not built with Wi-Fi capabilities at multiple frequencies: 2.4 GHz and 5 GHz. Most of these appliances continue to support an infrared (IR)-based remote control link, often even when the device also supports a newer RF-based remote control.
IR remote control receivers are built with highly sensitive wideband input stages and are able to detect signals near the noise level of their circuitry. In noisy environments, such as with both low- and high-frequency electromagnetic interference (EMI), the receiver may be noise-triggered, typically manifesting itself in the form of spurious pulses at its output. Most Vishay IR receiver packages are designed with metal shields to effectively guard the receiver against low-frequency EMI. However, these metal shields have not proven entirely satisfactory against high-frequency EMI in the GHz range used for Wi-Fi.

PiBakery – foolproof custom Raspbian setup

via Raspberry Pi

Everybody loves cake, right? Cakes have layers. Mmm…. cake! We’re sure you’re also love PiBakery, a brand new way to bake Raspberry Pi images, which makes creating a custom image a… piece of cake.

blocks-on-workspace

PiBakery was created by David Ferguson. He’s a talented 17-year-old whom we first met at the Big Birthday event we held to celebrate four years of Pi back in February. He showed Liz and Eben a work-in-progress version of PiBakery, and they’ve been raving about it ever since.

This crafty program enables users to mix together a customised version of Raspbian with additional ingredients, and you need absolutely no experience with computers to set up your custom image.

In PiBakery, you drag and drop blocks (just like Scratch) to add extra components. PiBakery then mixes the latest version of Raspbian with its additional sprinkles, and flashes the result directly to an SD card.

PiBakery_script

“The idea for PiBakery came about when I went to a Raspberry Pi event,” says David. “I needed to connect my Pi to the network there, but didn’t have a monitor, keyboard, and mouse. I needed a way of adding a network to my Raspberry Pi that didn’t require booting it up and manually connecting.”

“PiBakery solves this issue,” he explains. “You can simply drag across the blocks that you want to use with your Raspberry Pi, and the SD card will be created for you.”

“If you’ve already made an SD card using PiBakery, you can insert that card back into your computer, and keep editing the blocks to add additional software, configure new wireless networks, and alter different settings,” says David. “All without having to find a monitor, keyboard, and mouse.”

PiBakery is available for Mac and Windows, with a Linux version on the way. It can be downloaded directly from its website. As well as the scripts and block interface, it contains the whole Raspbian installation, so the initial download takes quite a while. However, it makes the process of building and flashing SD cards remarkably simple.

PiBakery_success

David has written a guide to creating customised SD cards with PiBakery. It’s a very easy program to use, and we followed his guide to quickly build a custom version of Raspbian that connected straight to our local wireless network. Guess what: it worked first time.

Behind the scenes, PiBakery creates a set of scripts that run when the Raspberry Pi is powered on (either just the first time, or every time it is powered). These scripts can be used to set up and connect to a WiFi network, and activate SSH.

Other options include installing Apache, changing the user password, and running Python or command line scripts.

The user controls which scripts are used with the block-based interface. You drag and drop the tasks you want the Raspberry Pi to perform when it’s powered up. Piece of cake.

We love PiBakery, and cake. Did we mention cake?

 

The post PiBakery – foolproof custom Raspbian setup appeared first on Raspberry Pi.

ESP8266 Killer?

via hardware – Hackaday

We’ve seen rumors floating around the Twittersphere about a new integrated microprocessor and WiFi SOC: the NL6621 from Nufront. Details are still scarce, but that doesn’t seem to be because the chip is vaporware: you could buy modules on Taobao.com and eBay right now for between two-and-a-half and three bucks, and Nufront’s website says they’ve produced a million modules since 2013.

The NL6621 WiFi SOC is powered by a 160 MHz ARM Cortex-M3 with 448 KB of RAM, and everything else is integrated in the SOC. The module has 32 GPIOs, SPI, I2C, I2S digital audio, and most of the peripherals that you’d expect. They say they have a completely open source SDK, but we can’t find a link to it anywhere. An English-language forum has sprung up in anticipation of the next new thing, and they say that they’ve contacted Nufront about the SDK, so that’s probably as good a place as any to lurk around if you’re interested. With an ARM core, it shouldn’t be long before someone gets GCC working on these things anyway.

It’s also worth noting that we’ve announced ESP8266 killers before, and it hasn’t come to pass. The mixture of community and official support that (eventually) came out of Espressif seems to be the main factor determining the ESP8266’s success, and we don’t see that yet with the NL6621. So take the question mark in the title seriously, but if this turns out to be the next big thing, remember where you heard it first, ok?

Thanks [David Hunt] for the tip!


Filed under: hardware, news

Cheap WiFi Devices are Hardware Hacker Gold

via hardware – Hackaday

Cheap consumer WiFi devices are great for at least three reasons. First, they almost all run an embedded Linux distribution. Second, they’re cheap. If you’re going to break a couple devices in the process of breaking into the things, it’s nice to be able to do so without financial fears. And third, they’re often produced on such low margins that security is an expense that the manufacturers just can’t stomach — meaning they’re often trivially easy to get into.

Case in point: [q3k] sent in this hack of a tiny WiFi-enabled SD card reader device that he and his compatriots [emeryth] and [informatic] worked out with the help of some early work by [Benjamin Henrion]. The device in question is USB bus-powered, and sports an SD card reader and an AR9331 WiFi SOC inside. It’s intended to supply wireless SD card support to a cell phone that doesn’t have enough on-board storage.

The hack begins with [Benajmin] finding a telnet prompt on port 11880 and simply logging in as root, with the same password that’s used across all Zsun devices: zsun1188. It’s like they want to you get in. (If you speak Chinese, you’ll recognize the numbers as being a sound-alike for “want to get rich”. So we’ve got the company name and a cliché pun. This is basically the Chinese equivalent of “password1234”.) Along the way, [Benjamin] also notes that the device executes arbitrary code typed into its web interface. Configure it to use the ESSID “reboot”, for instance, and the device reboots. Oh my!

zsun_gpio_bootstrap_annotFrom here [q3k] and co. took over and ported OpenWRT to the device and documented where its serial port and GPIOs are broken out on the physical board. But that’s not all. They’ve also documented how and where to attach a wired Ethernet adapter, should you want to put this thing on a non-wireless network, or use it as a bridge, or whatever. In short, it’s a tiny WiFi router and Linux box in a package that’s about the size of a (Euro coin | US quarter) and costs less than a good dinner out. Just add USB power and you’re good to go.

Nice hack!


Filed under: hardware, wireless hacks

ESP8266 WiFI LED controller hack

via Dangerous Prototypes

P1020335

Andreas Hölldorfer of ChaozLabs wrote an article detailing how he hacked the cheap WiFi LED controller:

This pictures show the PCB. As you can see there are pins labeled as RX,TX,GND,3.3V. I simply connected an USB-Serial converter to the pins. The two other pins are GND and GPIO0. If you set a jumper between this two pins, the controller starts in bootloader mode.
The chip above is a NXP HC245, a 3-state Octal bus transceiver. It is used to drive the N-channel MOSFETS (20N06L – 20 A, 60 V, N−Channel DPAK).
The power supply is a 2 stage design. A AOZ1212 3A Simple Buck Regulator to convert the input voltage to about 5V and an AMS1117 low dropout voltage regulator to get 3.3V.

More info at ChaozLabs site.

Check out the video after the break.

Enter the Photon

via Dangerous Prototypes

tmp5722

Peter Scargill writes:

So, what differentiates this from say, something like an ESP-12 or similar boards? So this is a small WIFI-enabled controller, programmed in something that looks suspiciously like the Arduino language – this is course is deliberate to give it that familiar look and feel. But looks can be deceiving – this is a powerful ARM Cortex M3 processor with a Broadcom WIFI chip complete with on-board v3v3 power supply – oh and the design is open-source.
Pins include D0-D7, A0-A5, ADC, DAC and serial I/O an the unit supports battery operation. You get 1 MB Flash and 128KB RAM. There’s an RGB status LED (nice touch) and FreeRTOS is pre-installed. There is a softAP setup mode and the unit is FCC,CE and IC certified. There is an internal ceramic aerial and a connector for an external aerial. You also have SPI,I2C,I2S (whatever that is), CAN, USB and PWM.

More details at Pete’s blog.