Near Field Communication, NFC and the CR95HF


I started work on a Near Field Communication (NFC) module.  The design uses ST Micro’s CR95HF chip.   The module above is the first shot prototype unit.  This device uses a 13.56MHz RF carrier frequency and amplitude-shift keying .  The CR95HF carrier frequency powers the loop antenna shown on the module above and the resulting field couples with a similar loop antenna on an NFC enabled card.  The field coupling, like two loops of a transformer, powers the card.  Powering up the card allows the CR95HF to transmit data to and from NFC cards.  That’s the theory anyway.

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Arduino clone controlled robot chassis

We’ve been pretty busy around here doing contract work, so there’s not been much time for just doing fun things.  As part of the design effort going into an Arduino clone that control servos and motors independent of the Arduino Atmel part we put together an experimental robot chassis.  The chassis was designed in Sketchup and the parts were fabricated from Plexiglas by Ponoko.

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Arduino Compatible Robot Controller 2


We’re getting pretty close to finishing up the Arduino compatible robot controller design.  We’ve completed the design, re-design, prototype, re-prototype, assembly, and initial testing (those “re-’s” are not always required).

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Using the new Solutions Cubed USB to Serial Converter

I’ve been working on a project for a client over the last few months.  Like most embedded systems, it needs a simple communications interface for use during manufacturing.  The interface is used for such things as testing, calibration, and fine-tuning.  For a bunch of embedded systems, the easiest and most cost effective solution is a serial interface.  In an effort to reduce cost, all of the level conversion circuitry and the serial connecter were removed from the PCB.  Logic level signals needed to interface directly to the system.  So, in the factory, a separate dongle is necessary to provide the level conversion.  In addition, the vast majority of computers now days no longer have serial ports – they only have USB ports.

Luckily Solutions Cubed has recently come out with a small USB to Serial convertor in our Breakout Module line: the BM010. Taking something off the shelf to use made it very easy to quickly get a convertor up and running for our customer.  I simply laid out a PCB to carry the BM010 and the connector to the client’s board.  I used the $33 PCB special from Advanced Circuits to get a low cost dongle for our client.  The photo below shows the carrier board with the USB to Serial Converter attached;  the BM010 is in the lower left corner.


The neat thing about the convertor is that it is based on an FTDI FT232R IC, so the USB drivers downloaded automatically in Windows and I was able to get rolling quickly.  The device showed up as a COM port that I was able to access with a Visual Basic program and I could then run the client’s system through its paces.  The picture below shows the dongle attached to the target system.  I knew that the the break out modules were going to be slick, but even I was impressed by how easy everything came together for the USB to serial converter.

full system

Robot Wheel Design


Robot wheel controller and mechanical progression.

I’ve spent a lot of my spare lab time messing around with a robot wheel mechanical concept, and an electronic design that controls a pair of DC motors and 4 RC servos.  Here’s an update.

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More Open Source Designs in 2013


In December we released 5 more open source SIP modules, bringing our current total to 10.  In early 2013 we’ll introduce 3 more with larger footprints that are microcontroller based.

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Arduino Motor Control



We carry a few products that can be used to implement motor control with an Arduino (or any other controller).  A recent addition is the BM001 Single H-bridge Controller.  Pictured above is the BM001 attached to a test board “Arduino shield”  I put designed.  It allows me to easily wire our breakout modules to an Arduino.  Since the breakout modules don’t have pins I used spring-loaded test points to connect the modules to the shield.  Then jumpers are used to wire from the module connections to the Arduino pins.

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Arduino Data-Logger

bm003 flash mem

I built an Arduino data-logger around our 64Mbit Flash memory (BM003) module yesterday.  The BM003 is a carrier board for the Macronix MX25L6445E, an SPI Flash memory IC.  Flash memory retains its values for years after power is removed.  The module has some signal conditioning circuitry to allow you to use 3.3V or 5V i/o connections, and a linear regulator to provide 3.3V to the IC if that’s not available in your system.  The Arduino program accepts serial commands at 9600BPS to erase the EEPROM, take and store 3 analog measurements in memory, or read back all of the data stored.

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Arduino Clock

bm005 real time clock

An Arduino clock and calendar is easy to build using the BM005 clock module.  The heart of the module is Microchip’s MCP79400 I2C RTCC.  The MCP79400 has a number of cool features, including leap year compensation, battery back-up (with an external battery), time/date storage on power failure, 12 or 24 hour format, and even some extra RAM if you need it.  Our BM005 puts it all in an easy to use module for a retail price of $12 (BM005 datasheet).

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Microchip PIC16F1829 Serial Communication


I’m writing code for a Microchip PIC16F1829 and thought I’d share the serial communication routine.  I’ve completed the schematic capture and PCB layout for the servo motor controller design.  But it’s a good idea to get some code written before moving forward with the PCB prototype production.  I’ve written a good chunk of the code for this design.  When the design is complete we’ll open source the files and place them on our web site (including the firmware for the microcontroller).

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