Tag Archives: Wireless

Raspberry Pi Zero Goes Wireless

The Raspberry Pi product line has added a new member, the Raspberry Pi Zero W (RBPiZW), an updated version of the RBPi Zero, with the added advantages on on-board Wi-Fi and Bluetooth capability.

Although the new RBPiZW lacks the Ethernet and full-sized USB-A ports, it is only a fraction of the size of its flagship brethren the RBPi, and less expensive as well. Almost identical to the RBPi Zero, the RBPiZW is twice as expensive, and boasts of a wireless chip supporting the 802.11 b/g/n Wi-Fi for 2.4 GHz only, and Bluetooth 4.0.

Both the RBPiZW and RBPi Zero use the same BCM2835 that powered the original RBPi. However, the single-core chip is now clocked at a higher speed of 1 GHz, as against 700 MHz earlier. On the RBPiZW is a Cypress wireless chip, the same the RBPI3 also uses. Although the Raspberry Pi Foundation has claimed the maximum wireless speed of the chip as 150 Mbps, in reality it generally hits about 20 to 40 Mbps.

Apart from the addition of the Bluetooth and Wi-Fi, there has been no change from the RBPi Zero to the RBPiZW. The designers added the Bluetooth and wireless LAN chipsets to the board, and included a PCB antenna layout licensed from ProAnt, Sweden.

The RBPiZW contains 512 MB RAM, a HAT-compatible 40-pin header, a CSI camera connector, a Micro-USB for power, Mini-HDMI port, a USB port for OTG, and headers for composite video and reset.

Although the new RBPiZW is a trifle heavier than its predecessor the RBPi Zero is, their dimensions are identical at 2.6×1.2×0.2 inches. You can also get a new case with the RBPiZW, with three interchangeable lids. The first lid is solid, the second has an opening in it for the GPIO pins, and the third has an opening for the camera module.

As the RBPiZW (and the RBPi Zero) come without the GPIO pins installed, they are able to maintain their slim profile, despite their full-sized GPIO headers. The user can solder the GPIO pins if the project demands, but the small size of the Zero boards are an advantage when using them to build a small robot or any other small system.

Even though the price is slightly higher, the RBPiZW remains incredibly cheap and is far more useful out of the box. Measurements of the performance of the tiny SBC confirm this. However, considering general performance when comparing with the RBPi3, such as during web browsing, it may be a frustrating experience. The RBPiWZ will have long pauses as the data loads and graphics renders in the Epiphany browser.

That means the RBPiZW is geared more towards hardware and software hackers, rather than those trying for a desktop experience. Those who want a replacement for their desktop computers would do well to use the RBPi3 instead.

Another factor weighing in for the RBPiZW is its low power consumption. Considering this board is meant for small systems and tiny robots, its low power consumption is a very big advantage when powering projects with batteries. Of course, the Wi-Fi support and network performance will affect its power consumption pattern.

Comparing Wireless Standards 802.11ad & 802.11ah

Wireless LAN standards were first set up for serving the needs of laptops and PCs in homes and offices. These were IEEE 802.11a and b, and these later served to allow connectivity in different places such as in shopping malls, Internet cafes, hotels and airports. The main functionality of the standards was providing a wireless link to a wired broadband connection for email and Web browsing.

Initially, speed of the broadband being a limited factor, a relatively slow wireless connection was enough. Therefore, 802.11a offered up to 54Mb/s at 5GHz and 802.11b up to 11Mb/s at 2.4GHz, with both frequencies being in the unlicensed spectrum bands. To reduce interference from other equipment, both standards were heavily encoded using forms of spread-spectrum transmission. In 2003, a new standard 802.11g used the 2.4GHz band maintaining the maximum data rate of 54MB/s.

However, by this time, people started realizing the need for higher throughput, especially with increased data sharing amongst connected devices in the home or small office. By 2009, a new standard, 802.11n came up, which improved the single channel data rate to over 100Mb/s. The new standard also introduced spatial streaming or MIMO, multiple inputs, multiple outputs. The new modems had up to four separate transmit and receive antennas, carrying independent data that was aggregated in the modulation/demodulation process.

However, new WLAN usage models were continually raising the demand on throughput, such as projection to TV or projectors, streaming from camcorders to displays, video streaming around the house, airplane docking, public safety mesh and more. Catering to these VHT or very high throughput demands made it necessary to generate two new standards 802.11ac (an extension of 802.11n) and 802.11ad.

Standard 802.11ac runs in the 5GHz band, providing a minimum of 500Mb/s on a single link and 1Gb/s overall throughput. On the other hand, 802.11ad provides up to 6.7Gb/s using a spectrum of about 2GHz at 60GHz, but at short range. Operation at high frequencies limits the transmission range and obstacle penetrating capacity of the signals.

With the proliferation of local sensor networks working on low power, billions of IoT or Internet of Things and M2M or machine-to-machine device connections, a new standard is now deemed necessary. This new standard is the 802.11ah, working in the license-exempt 1GHz band and its final version is expected in 2016.

Standard 802.11ah is a down-clocked version of the 802.11ac standard. While adding some enhancements in the MAC and PHY layers, the new standard offers advantages such as power savings, multiple station support, better coverage and mobile reception.

For the standard 802.11ah, three main use-case categories are under consideration. These are Wi-Fi extended range networks, backhaul networks for sensors and meter data and sensor networks. The standard 802.11ah extends the transmission range with 1 and 2MHz mandatory modes, allows ultra-low power consumption, thereby offering multi-year battery life for large scale sensor networks and is optimized for long sleep times while handling small packet sizes.

Therefore, with 802.11ah, you can have several devices such as light sensors, temperature sensors and smart meters set up throughout the home, enabling your home devices and appliances to be considered smart.

The future of medical monitoring: Temporary tattoos in place of electrodes and wires

If you’ve ever had an EEG, you’ll remember all the preparation that was required to get you hooked up properly to the monitoring device. There was sticky gel and tape and those pesky electrodes. According to the journal “Science”, researchers have developed a patch which bends, wrinkles and stretches like skin. The patch would be applied to the body like a temporary tattoo and would contain the electronic components necessary for sensing, communications and relaying information from the body to a monitoring device.

In addition to the ease of applying these patches, another major benefit is that any testing could be conducted in a more natural and less stressful environment since results could be transmitted wirelessly to the monitoring equipment.

Not only could the patches contain the electronic components for medical monitoring, they could also be used with patients that have muscular or neurological disorders, such as ALS. The patch could facilitate communication with computers. In addition, the researchers have shown that when placed on the throat, the patch can detect muscle movement.

The patch is constructed in the shape of tiny wires called filamentary serpentine. This configuration allows them to be bent, twisted, scrunched and stretched while maintaining functionality and contact with the skin.

Wired or wireless or both: What is best for small businesses?

Whether you are updating your office’s networking component needs or starting from scratch, there are many things to think about when you are considering wired vs wireless. For starters, ask yourself:

  • How many people are on your network? How about in 2 years?
  • How long will this system be in place? (any moves planned within 2 years?)
  • How fast does the network/internet access need to be right now? How about in 2 years?
  • What kind of files have to be moved across your network right now? How about in 2 years?
  • How fast does this need to be done?
  • Is this a temporary or permanent solution?
  • What is your budget?

Wiring a space can be cost prohibitive – especially if this space is temporary, but if the budget is unlimited, then hard wiring could be the way to go for speed and security. Very often a combination of both wired and wireless are the best solution.