Tag Archives: SPI

Wearable WiFi Detector


A WiFi (Wireless Fidelity) is a technology that uses the 2.4GHz UHF and 5GHz SHF ISM radio bands to allow devices such as computers, smartphones, digital cameras, tablet computers, etc. to network. Nowadays the WiFi technology is being used by cities to provide free or low-cost Internet access to residents. The WiFi is inexpensive and is easy to setup but it is also unobtrusive. The people may not know that they are in a hotspot unless they open their smartphones or tablets and stream movies on it.

This reference design is a simple circuit that helps WiFi users determine if there is a hotspot nearby. The circuit uses a WiFi chip, a crystal, an SPI flash and some other external components to detect if there is a WiFi network available within the area. The WiFi chip is programmed to spot wireless networks and display the result on a small light emitting diode (LED) connected to one of the GPIO pins of the WiFi chip. The LED will just keep on blinking if there is no wireless network available within the area. As soon as the WiFi chip detects a network, the LED will stop blinking and become steady.

The prototype of this circuit must be in small size so that it is wearable. The WiFi chip and the LED with the battery can be soldered into two different PCBs to make the prototype smaller. The TE Connectivity 87220-8 male and 5-534237-6 female header then connects the WiFi and the LED PCBs. The WiFi chip only consumes small power especially when it is in standby mode. But to conserve power when it is not used, the user can turn OFF the WiFi detector using the TE Connectivity MLL1200S slide switch.

Wearable WiFi Detector – [Link]

Wrist Mount Digital Altimeter

This project is a simple wrist mount digital altimeter which is a device used to determine altitude. This design uses atmospheric pressure to calculate the altitude of its location. The lower the atmospheric pressure, the higher the altitude. The project is comprised of a microcontroller (MCU), an 84×84 pixel graphic LCD and a barometric pressure sensor.

The barometric pressure sensor used in the design is the MS560702BA03-50 from TE Connectivity Measurement Specialties. It consists of a piezo-resistive sensor and a sensor interface IC. Its main function is to convert the uncompensated analogue output voltage from the piezo-resistive pressure sensor to a 24-bit digital value, as well as providing a 24-bit digital value for the temperature of the sensor. It is optimized for altimeters and variometers with an altitude resolution of 20cm. The MS560702BA03-50 measures the atmospheric pressure on its location then converts it to a 24-bit value through its internal ADC. The sensor reading is then transmitted to the MCU through SPI. Then the MCU calculates the altitude by using the pressure reading. The calibration of an altimeter follows the equation z = cT log (Po /P), where c is a constant, T is the absolute temperature, P is the pressure at altitude z, and Po is the pressure at sea level. The calculated altitude is then displayed through an 84×84 pixel graphic LCD which is mostly found on old phones. The circuit is powered through a 3.3V battery.

The altimeter is used to aid navigation and is mostly used in skydiving, mountaineering and hiking applications. It is usually hand-held or in wrist-mount form for the ease of use. Altimeters can also be found in aircrafts such as planes and helicopters and others that needs altitude indication.

Wrist Mount Digital Altimeter – [Link]

3D Print the Ultimate Helping Hands for a PCB Workstation

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by Giuseppe Finizia @ makezine.com:

I am the Senior Analyst of the Electronic Forensics Unit of the Carabinieri (Italian Military Police) and I deal with technical investigations on seized electronic devices. I spend most of my day in a well-equipped electronic laboratory, but I was lacking a tool for performing technical assessments on printed circuit boards (PCBs). I needed a way to secure small boards on my workbench and place multiple probes across the board for acquiring data from a circuit memory, analyzing an I2C or SPI communication bus using a logic state analyzer, and much more.

3D Print the Ultimate Helping Hands for a PCB Workstation – [Link]

8V97051 Low Power Wideband Fractional RF Synthesizer

This design features a low power wideband RF synthesizer that is used in GSM receiver cards. It has dual differential and open drain outputs with frequency range of 34.375MHz to 4400MHz(in continuous range). The logic compatibility is 1.8V while the system is running on a single 3.3V supply. It has -143dBc/Hz Phase Noise (PN) performance at 1MHz Offset for every 1.1GHz output. It is also capable of mute function at RF_OUT that is accessible via mute pin or SPI command. It is low power with only 380mW average power consumption while RF_OUTB is not in used.

The design is comprised of 3 major parts. The first part consists of IDT8V97051NLGi wideband RF synthesizer/PLL supports the output frequencies with Voltage Controlled Oscillator (VCO). The temperature compensated crystal oscillator close to the RF input helps in the precision of signal while the other parts are filters that are used in various purposes like minimizing undesired noise. The second part consists of the USB 2.0 high speed to UART/FIFO IC that is used for system interface while the I2C-bus to SPI bridge IC controls the sequences, protocol, and timing of the signal. The last part is power supply management of the system in which it is provided with RC filters in every line to ensure minimal noise are included in the supply.

The design is applicable in multi-carrier, multi-mode Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD) base station radio card. It optimizes multi-service base stations during its service as a local oscillator that generates a large variety of frequencies to mixers while maintaining excellent PN.

8V97051 Low Power Wideband Fractional RF Synthesizer – [Link]

 

 

Using Efficient SPI Peripherals for Low-Cost MCU-Based IoT Designs

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by Warren Miller @ digikey.com:

Efficient Internet of Things (IoT) designs must balance a host of requirements that often work against each other. Low cost is important, but often supporting all the key features required by the application increases MCU pin count and memory size—two things that work against low cost. Low power is also important for IoT applications where battery operation is a must. Adding features and improving performance can up the power requirement, however. Clearly finding the right balance between all these requirements can be a problem, but that’s just the type of challenge engineers expect from cutting-edge designs.

Using Efficient SPI Peripherals for Low-Cost MCU-Based IoT Designs – [Link]

IO expander board

C042

I/O Expander Board offers a convenient way to interface upto 16 I/O pins in your project using SPI/I2C bus.  This kit uses the famous MCP23S17 IO chip from Microhip.

Specifications

  • Supply sourced through the interfacing Box Header connector
  • The kit has 2 separate Box Header type connector for the 16 pins of I/O port and 1 Box Header for interfacing of the PCB with the host controlling circuit
  • Jumper selectable address option is also available for this kit
  • Four mounting holes 3.2 mm each
  • PCB dimensions 58 mm x 54 mm

IO expander board – [Link]

1Mbit SPI FRAM comes in chip-scale packaging

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by Graham Prophet @ edn-europe.com:

Fujitsu has used an ultra small package for this memory part, which it presents as a solution for power-critical miniature applications in sensor and wearable markets.

The 1Mbit SPI FRAM is in an 8-pin wafer level chip scale package (WL-CSP) which is an additional package variant to the existing product MB85RS1MT. In comparison to the industry standard SOP-8 package, the new WL-CSP package, which measures 3.09 x 2.28 x 0.33 mm, reduces the surface mounting area by 77%, and the device height by 80%.

1Mbit SPI FRAM comes in chip-scale packaging – [Link]

DIY soldering station

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MatthiasW over at DebuggingLab posted his DIY Weller station clone project, that is available at Github:

At the fpv-community.de Forum I read about a DIY Weller station. Basically an Arduino shield to drive a Weller soldering tip. As there is not much to it, the board simply contains an precision OpAmp, a power MOSFET, 2 buttons for adjusting the temperature and a display to show the current values. This design looks like a good starting point for my own advanced project. As I have lately discovered a 1,8 inch SPI TFT at banggood.com for an amazing price ( ~ 4.60 $ / 3,70 €), I started using them regularly in my projects. So I surely wanted to use it with this soldering station as well.

DIY soldering station – [Link]

LabNation SmartScope: unique multi-platform USB oscilloscope

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The SmartScope designed by the young Belgian company LabNation is — to our knowledge — the only oscilloscope that works with all popular operating systems: Windows 7/8, Linux, OS X, iOS (jailbroken) and Android 4.0+. So the software can run on a standard PC or laptop, but also on a tablet or smartphone. The control interface is specifically designed to operate with touch-screen or mouse and is equipped with various software decoders (such as I2C and SPI) for decoding digital signals.

The Smart Scope hardware consists of a small metal housing (for good protection) with the front two full BNC connectors for analog inputs, and at the rear a 16-pin header which has 8 digital inputs for the logic analyzer. Four digital outputs and an output for the built-in arbitrary waveform generator (AWG) are available. The sampling frequency of the analog and digital inputs is 100 Msamples/s, the maximum data rate of the AWG is 50 Msamples/s.

LabNation SmartScope: unique multi-platform USB oscilloscope – [Link]

Airbag System Basis Chip (SBC) with PSI5

The automotive industries are now into electronics applications in which embedded systems are already part of its major components. In this design, it features the Peripheral Sensor Interface 5 (PSI5), which is the most efficient standard interface of sensors and electronic control units in automotive. It supports complete airbag system that includes system power mode control, supplies for squib firing, satellite sensors, and local Electronic Control Unit (ECU) sensors and ECU logic circuits. It has dedicated safing state machine that complements the airbag’s MCU hardware/software safing approach. The system itself is capable of diagnostics and self-protection.

The design is comprised of MCZ33789 Freescale airbag system basis chip that manages the entire airbag partitions and some major components like squib driver IC, SPI communications with MCU, accelerometer sensor, satellite sensors, and dc sensors for monitoring. The squib driver IC supports air bag modules and seat belt retention that functions with accelerometer sensor. The MCU provide the connection of airbag system with the entire electronic applications of the vehicle. The LC filters are provided to ensure frequency range.

The design is used in different airbag system in which it optimizes the capability of providing safety to users. It can be used for further development of safety system in automotive and other vehicle that is prone to crash or collisions. It can help save lives during accidents.

Airbag System Basis Chip (SBC) with PSI5 – [Link]