Tag Archives: antenna

Low-profile antennas can be mounted on metal surfaces

Julien Happich @ eedesignnewseurope.com discuss about a new low-profile 2.4GHz antenna that can be mounted on metal surfaces:

Antenova is shipping its first 2.4GHz antenna from its new Reflector series. The Zenon has been engineered to operate without de-tuning on metal surfaces or where the product housing is mainly metal.

The Reflector antennas are formed of two layers, one electrically isolated from the other, so as to provide RF shielding to the second layer. This means that the antenna can be placed on any kind of material and it will radiate effectively in the direction pointing away from the base material.

Low-profile antennas can be mounted on metal surfaces – [Link]

10km ESP32 WiFi Using Directional Antenna

[Jeija] was playing with some ESP32s and in true hacker fashion, he wondered how far he could pull them apart and still get data flowing. His video answer to that question covers the Friis equation and has a lot of good examples of using the equation, decibels, and even a practical example that covers about 10km. You can see the video below.

Of course, to get that kind of range you need a directional antenna. To avoid violating regulations that control transmit power, he’s using the antenna on the receiving end. That also means he had to hack the ESP32 WiFi stack to make the device listen only on one side. The hack involves putting the device in promiscuous mode and only monitoring the signals being sent. You can find the code involved on GitHub (complete with a rickrolling application).

Of course, antennas are nothing new–look at all the Pringle can antennas we’ve seen in the past. However, the use of a long range receive-only module is interesting and we can see this technique having applications to remote drone video or telemetry and — of course — wardriving. If you don’t have a big boss antenna lying around, you might try some duct tape. If you want a more detailed refresher on decibels, we did that last month.

Source: Hackaday

PureModules, IoT Building Blocks

New range of building blocks for IoT development are just out there! Just like LEGO, PUREmodules by Pure Engineering are the building blocks for IoT connected smart sensors where there is no need to solder, using breadboard or wires. It’s all done just by snapping the modules together and writing some lines of code.

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The modules that are already designed are:

  • COREModule
  • SUPER SENSOR module
  • General Purpose IO modules via I2C Expanders
  • I2C ADC and DAC modules
  • Energy Harvesting Modules
  • Low power chemical Sensors
  • PIN diode Radiation Detector Module
  • I2C thermal camera modules
  • Dual I2C DC motor Module
  • GPS and IMU Module
  • Long Range LoRa RF modules (10+ miles)
  • Li-Ion and other Power modules
  • Ethernet Module
  • Low Power LCD module
  • User IO button and LED modules
  • Multiple Core modules; CC2650, EFM32, ESP32 and more.
  • Adapter modules to other sensor systems such as Grove and LittleBits
  • Adapters to popular platforms such as Arduino and Raspberry Pi.

Only COREmodule and SUPER SENSOR module are live now in the Kickstarter campaign that Pure Engineering has launched, check the campaign video:

COREmodule

The brain of other modules based on nRF52832 SOC. It is compatible with Arduino and a number of other open source frameworks, it has an onboard antenna and able to update its firmware over the air. Also it supports these IoT operating systems: Mynewt, Zephyr, Contiki OS, RIOT-OS, and mbed OS.

puremodules-internet-of-things-building-blocks

SUPER SENSOR module

This multi function sensor can be used in home automation and monitoring, health tracking, and industrial measurement. It contains the following embedded sensors: barometric pressure, humidity, temperature, accelerometer, magnetometer, UVA UVB, RGB, IR, and heart rate pulse oximetry.

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PUREmodules goal is to simplify IoT development for hackers, tinkerers and designers and to propose a new easy way of interaction and control everything through the Internet. More details can be found at the official website and the Kickstarter campaign. You can pre-order a COREmodule and SUPER SENSOR for $59 as an early bird pledge.

Badgerboard, LoRa Future IoT Development Board

The LoRa Alliance™ is an open, non-profit association of members who believe that the Internet of Things era is now, its LoRaWAN is a Low Power Wide Area Network with features that support low-cost, mobile, and secure bidirectional communication for Internet of Things (IoT), machine-to-machine (M2M), smart city, and industrial applications. LoRaWAN is optimized for low power consumption and is designed to support large networks with millions and millions of devices. Innovative features of LoRaWAN include support for redundant operation, geolocation, low-cost, and low-power – devices can even run on energy harvesting technologies enabling the mobility and ease of use of Internet of Things.

Check this video to learn more about LoRa and its protocol:

Badgerboard is an Arduino compatible LoRaWAN™ open source development kit, that can be easily extended to a prototype or even a small batch product. Development board has a battery charger and antenna connector on board.

Using as small as the battery you have in your watch, you can power your Badgerboard to send and receive radio waves, that can reach from 1km to 3km in the urban area up to 10+ km in the rural areas

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The communication is powered by widely used Microchip LoRaWAN module. There are two editions of the module one using  RN2483-I/RM101 for the 433/868 frequency bands and the other is using RN2903-I/RM095 for the 915 MHz band and its sub-bands. The LoRaWAN stack is already part of the module and all needed libraries for LoRa functionality are included.

Here are the features of the module:

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Check Badgerboard in action and the possibilities that can be done using it:

Badgerboard is now live on a Kickstarter campaign, you can pre-order the early bird board for $45 here. You can check their website to keep involved with the latest updates www.badgerboard.io

Build Your Own Cheap Antenna Analyser

Ham radio is the use of radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, etc. Developing a ham radio project may requires using an antenna analyser, a device that is used for measuring input frequency and impedance.

There are many types of antenna analysers such as Anritsu VNA Master, RigExpert, MiniVNA, and others. But these analysers are very expensive to buy. They starts from $500 up to thousands of dollars and they are also hard to hack. This guide shows how to construct and use a DIY HF antenna analyzer using Arduino for less than $50.

The project consists of three parts; a Microcontroller, AD9850 DDS module, and a VSWR Bridge.

Block Diagram
Block Diagram

The AD9850 is a CMOS highly integrated device that uses advanced Direct Digital Synthesis (DDS) technology coupled with an internal high speed, high performance, D/A converter and comparator, to form a complete digitally programmable frequency synthesizer and clock generator function.

dds_moduleAD9850 module is a $9 stable, low drift VFO (Variable Frequency Oscillator) fed by a 125 MHz crystal clock. The module covers from 0 to 40 MHz, which are all the HAM HF(High Frequency) frequencies. There are 4 output pins on the device, 2 for Sine Waves (only one Frequency at a time) and two Square wave outputs. The blue pot on the board adjusts the duty cycle of the Square Wave Outputs but has no effect on the Sine Wave Outputs.

AD9850 features:

  • Signal Frequency output range: 0-40MHz
  • 4 Signal outputs; 2 sine wave outputs and 2 square wave outputs
  • DAC SFDR > 50 dB @ 40 MHz AOUT
  • 32-Bit Frequency Tuning Word
  • Simplified Control Interface: Parallel Byte or Serial Loading Format
  • Phase Modulation Capability
  • +3.3 V or +5 V Single Supply Operation
  • Low Power: 380 mW @ 125 MHz (+5 V)
  • Low Power: 155 mW @ 110 MHz (+3.3 V)
  • Power-Down Function
AD9850 Pin Definition
AD9850 Pin Definition

The VSWR (voltage standing wave ratio) bridge is an impedance bridge circuit, which is used to measure the ratio of maximum voltage (Vf+Vr ) to the minimum voltage (Vf-Vr) on a transmission line. The bridge will balanced (0 volts across the detector) only when the test impedance exactly matches the reference impedance. This bridge is easy and cheap to implement and works with up to few GHz frequencies.

VSWR Bridge Diagram
VSWR Bridge Diagram

The microcontroller works as an interface between the DDS and the PC, it receives the sweep parameters from PC, and then it reads the collected voltage and frequency to the PC for each sweep. There are multiple choices about the microcontroller type, you can use either Arduino Micro or PIC. If you choose Arduino, the cost of the project will be around $50, while the cost will be reduced to $20 when using PIC.

Arduino Solution
Arduino Solution
PIC Solution

To display the results which are collected from the device, you need to develop a simple software and run it on the connected PC. The software GUI contains configuration buttons on the right side and 2-axis plane, which will hold the signal shape, on the left side.

If you want to make the project portable, you can replace the PC with a LCD display to show the collected data.

This project is open source, you can find and download schematics and code from here. You also can apply your ideas to enhance the project, such as amplifying power for accurate VSWR, adding bluetooth connection to use with tablet, increasing supported frequencies range, and more.

External antenna modifications for the Raspberry Pi 3

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In this post dorkbotpdx.org show us a couple of different ways that an external antenna can be added to the Raspberry Pi 3.

It’s not clear why an external antenna is not an option for the Pi 3, there are a number of possible reasons and I don’t presume to know the Raspberry Pi Foundation’s exact rationale. It could be to improve the out-of-box experience, an integrated antenna “just works” and there’s no potential for the antenna connector to be broken plugging in an antenna. It could be to reduce complexity, the unit with an integrated antenna is compact and self-contained.

External antenna modifications for the Raspberry Pi 3 – [Link]

Contactless payment ring – A tutorial on NFC antenna coil design

Jatinder has tipped us with this latest post. He writes:

 I have a done a video about a contactless payment (NFC) ring that I have made. The video talks about NFC antenna coil design and how I used the concepts to make the wearable ring.

Contactless payment ring – A tutorial on NFC antenna coil design – [Link]

4×1 WiFi Wireless Antenna Switch

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Horacio Bouzas published a 4 way WiFi antenna switch:

I started playing with electronics back when I was 10 years old in Argentina, where I grew up. Then I got my ham radio operator license when I was 16 years old and I was very active in the ham club and on the air. It was then when I built my first vacuum tube transmitter and refurbished and old receiver (also vacuum tubes) that somebody from the club was throwing away. My interest for science and electronics grew and I ended studying physics but always tinkered with electronics, whenever I could.

I’ve moved a lot around the world for work (oil and gas) so my dedication to ham radio pretty much faded away. But it came back! Just recently, I got my ham radio operator license back and started to get active on 2mtr and on digital.

Due to lack of space outdoors, I had to settle for installing my center fed dipole on the attic (I have a long attic), but I quickly realized I needed more than 1 antenna. 80 mtr, 40 mtr, 20mtr….

And I didn’t want to run multiple lines to the attic, so an antenna switch was necessary.

4×1 WiFi Wireless Antenna Switch – [Link]

Arduino DDS AD9850 Antenna Analyzer

This is a no frills DIY Analyzer intended for frequencies ranging from 1.6 to 30 Mhz. This simple Antenna Analyzer could be a nice project for anyone just getting started in setting up a station on the HF bands.

Arduino DDS AD9850 Antenna Analyzer – [Link]