by Avago Technologies:
Analog isolation is still widely used in motor drives, power monitoring, etc whereby applications typically use inexpensive analog voltage control for speed, intensity or other adjustments.
The HCNR201/200 analog optocoupler is commonly added to isolate the analog signal in the front end module of an application circuitry. The optocoupler will be placed between the analog input and the A/D converter to provide isolation of the analog input from the mixed signal ADC and other digital circuitries. The HCNR201/200 is an excellent solution for many of the analog isolation problems.
Fast analog isolation with linear optocouplers - [Link]
Some time ago, I stumbled upon an article about 25¢ I²C adapter. I usually use my Raspberry Pi to interface with I²C devices, but having it right on my notebook seemed like quite useful thing, so I decided to build a project around it. Altough the mentioned article says that I²C is not supported on Intel cards on Linux (all of this was tested on Dell Latitude E5530 which does have Intel HD4000), I decided to try anyway. A lot has probably changed since 2008 when it was written.
TWILight – VGA I²C breakout board - [Link]
Smartphone peripheral developers are limited to RF links via Bluetooth, NFC or WiFi when they need to pass data back and forth to the device. This can add significantly to costs and stand-alone peripherals also need batteries or an adapter for power. The Quick-Jack from NXP solves both problems; it turns the standard 3.5 mm stereo audio headphone socket found on most iOS or Android smart devices into a self powered data port and provides an interface for external switches, sensors or any other external equipment.
The Smartphone Quick-Jack Solution comprises a small board, a free example app for popular smartphone OSs, and design documentation.
Smartphone port? Try the Ear Hole - [Link]
This project started out from a need to build a simple device for monitoring the CAN bus. I choose the NUC140LC1CN 32K Cortex-M0 microprocessor from Nuvoton for major reason – it has both USB and CAN peripherals.
CAN to USB Interface - [Link]
This is a 8 channel relay interface board using ULN2803. All the relays are opto-isolated using optocouplers and can be controlled directly using a microcontroller of any kind (Arduino , 8051, AVR, PIC, DSP, ARM, MSP430, TTL logic) or a PC.
It’s easy to manufacture and have three pin screw terminals for easy connectivity.
8 Opto-isolated Relay board - [Link]
The CP2104 is a highly-integrated USB-to-UART Bridge in a compact 4 mm x 4 mm package. The CP2104 is a USB 2.0 full-speed device with integrated USB clock, voltage regulator and programmable memory reducing BOM costs and simplifying the design.
CP2104-MINIEK – USB-to-UART Mini Evaluation Kit - [Link]
by Kalle Hyvönen:
I’ve been thinking about making a temperature logger for my room and my computer, I set on using DS18S20 sensors from Maxim because they’re common, cheap and overally pretty ideal. My computer is so new that it does not have a serial port (not 100% sure, I think there might be a pinheader on the motherboard with serial port connections) so I have to use USB for interfacing. Next thing I had to do was to make an USB to 1-wire adapter so I could attach the sensors to my computer.
I browsed around for a while and set on using the DS2490 USB-to-1-wire adapter chip because the circuit for it looked pretty simple. I modded the component values a bit from the ones on the original schematic from Maxim to ones I had in hand. I used 0805 sized SMD components because I have those in store.
USB-to-1-wire Adapter - [Link]
Nabil Tewolde build a bluetooth OBD-II adapter. He writes:
The board is basically the reference schematic for the STN1110, which converts many OBD-II physical layers into RS232. The bottom of the board has a bluetooth module from Deal Extreme. The plan is to connect a smartphone or tablet to the device and log data.
Bluetooth OBD-II Adapter - [Link]
Andrianakis Haris describes in detail his B.Sc Thesis:
PLC (Power Line Communication) is the technology that allows data transmission over the existing Power Line network. Power Line can be the home power network or the national electricity transmission grid. The data that can be transferred is as diverse as its speed. With speeds of nearly 200Mbps, video transmission, voice, data and any other services can be transmitted successfully.
On this article i’m going to describe in detail my B.Sc Thesis in department of Electronic Computer Systems Engineer at Technological Education Institute of Piraeus, October of 2012 in Greece.
The project includes the design of two modules (transmitter – receiver) implementing a serial communication over the Mains connecting a remote large display to a weighing machine.
Power Line Communication - [Link]
The PCA9508 is a CMOS integrated circuit that supports hot-swap with zero offset and provides level shifting between low voltage (down to 0.9 V) and higher voltage (2.7 V to 5.5 V) for I2C-bus or SMBus applications. While retaining all the operating modes and features of the I2C-bus system during the level shifts, it also permits extension of the I2C-bus by providing bidirectional buffering for both the data (SDA) and the clock (SCL) lines, thus enabling two buses of 400 pF. Using the PCA9508 enables the system designer to isolate two halves of a bus for both voltage and capacitance, and perform hot-swap and voltage level translation. Furthermore, the dual supply pins can be powered up in any sequence; when any of the supply pins are unpowered, the 5 V tolerant I/O are high-impedance.
PCA9508 has B-side and A-side bus drivers. The 2.7 V to 5.5 V bus B-side drivers behave much like the drivers on the PCA9515A device, while the adjustable voltage bus A side drivers drive more current and incur no static offset voltage. This results in a LOW on the B-side translating into a nearly 0 V LOW on the A side.
The hot swap feature allows an I/O card to be inserted into a live backplane without corrupting the data and clock buses. Control circuitry prevents the backplane from being connected to the card until a stop command or bus idle occurs on the backplane without bus contention on the card. Zero offset output voltage allows multiple PCA9508s to be put in series and still maintains an excellent noise margin.
- PCA9508D CMOS integrated circuit (3 units)
- BUS Master
- Slave 400kHz (3 units)
- 10kΩ Resistor (6 units)
- Ground Source
Hot swap level translating I2C repeater - [Link]