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  1. Overview dAISy (do AIS yourself) is a very simple AIS receiver that I developed from scratch. It is built around the Silicon Labs EZRadioPRO Si4362 receiver, using a Texas Instruments MSP430G2553 MCU for processing and the MSP-EXP430G2 v1.5 LaunchPad as development platform. The complete project source code and schematics are available on GitHub: https://github.com/astuder/dAISy Update 5/18/2015: A finished, self-contained AIS receiver based on this project is now available for purchase on Tindie. AIS, short for Automatic Identification System, is a standard for tracking ships. Ships advertise their position, course and other information with short transmissions on specific frequencies (161.975 MHz and 162.025 MHz). More on Wikipedia. An AIS receiver, like dAISy, receives and decodes AIS transmissions. It then re-packages the raw data into NMEA sentences (specifically formatted ASCII strings). Finally, using a serial connection, these strings are forwarded to more capable equipment for further processing. If you're the lucky owner of a tricked out boat, you could connect dAISy to your navigation computer. For land lobbers like me, a more common use case is to run naval mapping software that supports AIS data input on a PC. In the screenshot below I've connected dAISy to OpenCPN (link), an open source chart plotter and navigation software. On the top right you can see my setup war-driving at the Seattle waterfront as my lab is too far from the coast to receive anything. The LaunchPad sits on the dashboard with a white USB cable connecting to the notebook computer in the foreground. dAISy's data is fed into OpenCPN, bottom right shows a log of the serial data received. OpenCPN maintains a database of all the collected data (lower left) and visualizes nearby ships on a map (top center), including past and projected course. Hovering the mouse over a ship will display its name (text on yellow ground) and clicking it will reveal more detail (top left). Hardware I wanted to build my own, non-SDR, AIS receiver for a long time. There are a few projects floating around the internet (e.g. here) which refer back to an article by Peter Baston, published 2008 in Circuit Cellar magazine (copy available here gone.. google for Peter Baston Circuit Cellar to find other copies). Unfortunately, the CMX family of modem ICs by CMS Microcircuits (link) used in these projects are relatively expensive ($15+) and hard to find for hobbyists. In addition you'd need a radio to do tune into and down-convert from the ~162 MHz carrier frequency. So I was quite excited when earlier this year a parametric search on Mouser brought up a new IC that covered the required range (162 MHz) and modulation (GMSK). And best of all, available in single quantities for $3.56 $2.27 $2.22! (link) The Silicon Labs EzRadioPRO Si4362 (link) is a single chip receiver that covers frequencies from 142 to 1050 MHz and supports various modulations, including GMSK. It comes in a tiny 20-pin QFN package and the only external parts required are a 30 MHz crystal, an antenna with a few capacitors and inductors for impedance matching, and finally some decoupling caps and pull-down resistors. Time to whip up a breakout board. I used the opportunity to give KiCad a try and quite like it. Here's the schematic: And the layout: I used OSHPark to make the PCBs. At a smidgen over one square inch it cost $5.15 for 3 copies: http://oshpark.com/shared_projects/QUWi71r4 Note that the layout still has three issues that I already fixed in the schematic: GPIO0 and GPIO1 were flipped SDO required a pull-down resistor as the radio leaves it floating when not actively sending, which confused the hell out of me while trying to figure out the communication protocol. Lastly, the holes for the headers turned out to be slightly too small to comfortably fit the cheap breakout headers I had at hand. Edit: Here's Rev B where I fixed these issues: http://oshpark.com/shared_projects/WI6u3Qmk Which brings us to the BOM: Silicon Labs Si4362 (U1) 30 MHz crystal (X1)Si4362 datasheet specifies <11 pF load capacitance, but a crystal specified for 12pF load capacitance seems to work fine too Antenna/LNA matching network, calculated based on SiLabs AN643 (link, approx. values, +/- 5% shouldn't matter too much):75 ohm (dipole): 10 pF (CR1), 5 pF (CR2), 280 nH (LR1), 200 nH (LR2) 50 ohm: 12 pF (CR1), 6 pF (CR2), 240 nH (LR1), 160 nH (LR2) Decoupling caps:100 pF, 100 nF, 1uF (C1, C2, C3) Pull-down resistors100 k (R1, R2) First thing I noticed when I received the parts: The 20-pin QFN at 4x4 millimeters is tiny! I mounted it by first tinning the pads with a small quantity of solder. I then added flux and placed the chip on the pad. I then used a hot air station to carefully reflow the solder. Worked the first time around. After using jumper wires to figure out how to talk to the chip, I mounted the breakout board on a makeshift BoosterPack using perfboard, double-sided tape and wire (see picture at the top of the post). Here's how I ended up connecting the breakout board to the LaunchPad / MSP430G2553: SEL -> P1.4 (SPI chip select) SCLK -> P1.5 (SPI CLK) SDO -> P1.6 (SPI MISO) SDI -> P1.7 (SPI MOSI) GPIO0 -> P2.0 (I/O unused) GPIO1 -> P2.1 (I/O clear-to-send) GPIO2 -> P2.2 (I/O RX clock) GPIO3 -> P2.3 (I/O RX data) SDN -> P2.4 (shutdown / reset) IRQ -> P2.5 (I/O channel-clear) Software The software of dAISy consists of three major blocks: Radio configuration and control over SPI Packet handler, including a basic FIFO for received messages NMEA encoding and transmission to the PC over UART For UART (TX only) and SPI (TX/RX) I use the MSP430G2553's USCI A0 and B0 respectively. In both cases I don't use interrupts which simplifies things considerably. Upon reset the following steps happen: Initialize MSP430 peripherals Initialize packet handler, which will also reset FIFO Initialize and configure of radio, which will also setup SPI Start packet handler, which will also put the radio into receive mode And in the main loop: If debug messages are enabled, poll packet handler for status and errors and report them over UART Check FIFO for new packets If there is a new packet, invoke NMEA processing (which sends the message over serial to the PC) and remove packet from FIFO Below follows a more detailed discussion of the radio integration and the implementation of the packet handler. Radio The communication with the radio is vanilla SPI using 4 wires: MOSI (SDI), MISO (SDO), CLK (SCLK) and CS (SEL). I used the MSP430's USCI B0 to implement SPI and a separate pin to control CS. The only tricky thing to figure out was, that the Si4362 keeps the MISO line floating unless it actively transmits data. This is unfortunate as the master is supposed to poll for a specific response (FF) to detect when the radio is ready to receive more commands. This is easily fixed by adding a weak pull down resistor to SDO. I did this on the board, but it probably also works with using MSP430's internal pull-down. Additional lines I used to control the radio are: SDN to reset the radio CTS, which by default is mapped to the radio's GPIO1, indicating that the radio is ready for the next command While taking up an extra pin, CTS turned out to be much more convenient than the SPI response code to properly time communication flow with the radio. In dAISy, I wait for CTS to go high after each command to ensure the radio completed its task. The communication protocol is quite extensive but well documented: EZRadioPRO API Documentation describes the complete API and all registers AN633 Programming Guide for EZRadioPro Si4x6x Devices describes how to use the API in common scenarios Both are available on the Si4362 product page (link), under Documentation > Application Notes and are still updated quite frequently. The radio is set up by dumping a large configuration sequence into it. This includes configuration of radio frequency, modulation, GPIO pins and more. This information is stored in radio_config.h, which has to be generated with a tool called WDS (Wireless Development Suite). WDS is available in the Tools section on the Si4362 product site. Above are the settings I used for dAISy. WDS will use this information to configure various amplifiers, filters, clocks and decoding algorithms inside the chip. As Si4362 supports GMSK encoding only indirectly (see this thread), I'm certain there's more optimization potential by tweaking registers, but that's currently way beyond my knowledge of RF theory. While the Si4362 comes with its own packet handler, it unfortunately does not support NRZI encoding (Wikipedia). So I set up the radio to expose the 9600 baud clock and received data on separate pins and implemented my own packet handler. Packet Handler The packet handler (inspired by Peter Baston's implementation) is implemented as a state machine that is invoked on each rising edge of pin P2.2 which receives the data clock. There are 5 main states: Off, no processing of incoming data Reset, start from anew, either on start up or after successful/failed processing of a packet Wait for Sync, waiting for a training sequence to arrive (010101..) and start flag (01111110), implemented with its own state machine Reset, start new preamble 0, last bit was a zero 1, last bit was a one flag, training sequence complete, now process start flag Prefetch, ingest the next 8 message bits to ease further processing Receive Packet, process bits until the end flag (01111110) is found or an error situation occurs Independent of state, the interrupt routine continually decodes NRZI into actual bit sequence. In the "Receive Packet" state there's continuous calculation of the packet CRC and some bit-de-stuffing. When the end flag is found and the CRC is correct, the received message is committed into the FIFO. If an error is encountered, the bytes already written to the FIFO are discarded. In both cases, the state machine starts anew by transitioning into RESET. This reads like a lot of code for an interrupt handler. However with the MCU running at 16MHz even the most complex state only uses a fraction (<10%) of the available time. Future Improvements Lastly a list of things I'd like to improve with the next version of dAISy. Software: Receiving on both AIS channels through channel-hopping done 1/5/2014 Tweak radio settings for better sensitivity and lower error rate LED(s) for indicating reception of valid/corrupt packets Hardware: Proper antenna connector Layout PCB as BoosterPack and/or USB dongle Receiving on both AIS channels at once with two radio ICs -- edit 12/25: replaced original post with high-level project description, more detailed documentation of implementation to come -- edit 12/28: added documentation for hardware (here and on Github), fixed some typos -- edit 12/31: added documentation for software and list of future improvements -- edit 01/05: implemented channel hopping (change to state machine) -- edit 01/15: changed state machine to reflect recent changes (see post further down for details), added link to shared project on OSHPark -- edit 01/25: major rework of sync detection state machine
  2. Hello, I am looking for a working Eagle library for the CC1310F64RHBT. I am not experienced with creating .lbr files for Eagle, but after some googling I have produced a rough one which is based on a conversion from the Ultra Librarian .bxl format. If anyone has a working library that they already use, it would be super helpful if they could share it with me. Taking a look at the library attached below which I have produced and confirming that the SMD footprint will work would be super helpful. Thanks, Cameron CC1310F64RHB.lbr
  3. Hello Folks, Here is Malkiat Singh from Punjab India.This forum has been doing a suberb job and lot of great topics enlighting various aspects on Low-power microcontrollers. I was reading " What's left for MSP430?" and decided to join a forum. Wonderful job by you guys. Currently, I am making various agro-based sensors and scratching web and 43oh.
  4. Hello, I want to make a wireless thermometer using two microcontrollers. How do I write the code in Energia to transmit and receive a variable using a 433 Mhz RF module? Transmitter Setup: I have a TM4C123G connected to a RF transmitter using TX(3) pin 34 on the MCU. The TM4C123G is also connected to a LM34DZ Temp sensor. I need help to modify this working code to send the temperature variable using tx(3) pin 34 /*TM4C123G*/ //initializes/defines the output pin of the LM34 temperature sensor int outputpin= A11; // (pin # 2), use A11 analog input //--------------------------------------------------------------------- //this sets the ground pin to LOW and the input voltage pin to high void setup() { Serial.begin(9600); Serial3.begin(9600); //---------------------------------------------------------------------- } void loop() { int rawvoltage= analogRead(outputpin); float millivolts= (rawvoltage/4095.0) * 3300; float fahrenheit= millivolts/10; Serial3.write(fahrenheit); //transmits temperature to receiver Serial.println(fahrenheit);//displays temperatur on Serial monitor delay(200); } Receiver Setup: I also have a MSP432 connected to a RF receiver using rx pin 3 on the MCU. The MSP432 is connected to a 16x2 LCD. I need help to modify this working code to receive the temperature variable using rx pin 3 and display to the lcd. /*Receiver MSP432*/ #include <LiquidCrystal_I2C.h> #include <Wire.h> #define rfReceivePin 3 //RF Receiver pin = pin 3 unsigned int data = 0; // variable used to store received data byte address = 0x3F; // LCD I2C address int columns = 16; // number of columns on LCD int rows = 2; // number of rows on LCD LiquidCrystal_I2C lcd(address, columns, rows); //----------------------------------------------------------------- void setup() { lcd.init(); // initialize the lcd lcd.backlight(); } //----------------------------------------------------------------- void loop() { lcd.clear(); lcd.setCursor(0,0); data=analogRead(rfReceivePin); //listen for data on pin 3 lcd.print("Temperature"); lcd.setCursor(0,1); lcd.print(data); delay(500); }
  5. Hi, I am designing a remote controlled system using an arduino uno board and a msp430 launchpad with the ASK RF module (HT12E and HT12D ICs). I am using the msp430 as the transmitter and the arduino uno for the reciever because of requirements of my application. Being familiar with Arduino, i am trying to use energia to program the msp430 with the VirtualWire library. #include <VirtualWire.h> int button = P2_2; int transmit_pin = P2_1; int a,counter=0; char msg[4]; void setup() { vw_set_tx_pin(transmit_pin); vw_setup(2000); // Bits per sec pinMode(button,INPUT); } void loop() { Serial.begin(9600); a=digitalRead(button); itoa(a,msg,10); Serial.println(a); if(a==1) counter=counter+1; vw_send((uint8_t *)msg, strlen(msg)); vw_wait_tx(); Serial.println("success"); delay(1000); } This code, when used on the arduino, compiles, uploads and executes succesfully. The transmitter board LED blinks to indicate successful transmission of data. But when i use it on energia, there is an error- any suggestions to get through with this error. Or if the same code can be implemented using another library. Cheers!
  6. Hi friends. I began to a project at school which is about connecting ARMs. I have two stellaris launchpads and I'm trying to connect them over an nRF24l01. I use keil platform. Project is about sensors when first module sees an obstacle it will transmit it to the other Launchpad through RF. However I couldnt find any rf libraries. I dont know what to do and I really need your advice. Hope you can help me. Have a good day:)
  7. Greetings, I am new to radio frequency field, I want to learn & work on RF modules. So please suggest this rookie some books and make him expert. Also suggest some books(or ebook links) about antenna, antenna design .. Thanks in advance
  8. Is anyone aware of any RF modules, booster packs or what ever that are made for the Tiva C Launchpad? Preferably ones that provide some example code. I need something that works at 433.92Mhz. It will be for remote control usage, range requirements are about the size of a large room in a home. I have seen the RF booster pack on the TI site (https://estore.ti.com/430BOOST-CC110L-CC110L-RF-Module-BoosterPack-P2734.aspx) but this does not include the frequency I need to work with and seems more geared to longer distances and/or higher throughput than I required. Glenn.
  9. I am currently playing with a nifty little module from Anaren called AIR (2pg pdf:http://www.anaren.com/sites/default/files/Part-Datasheets/A1101R09C.pdf), for a low-power embedded project and it works OK; but I was wondering if anyone else had experience with any other like type modules? My loose requirements are that I would like to reasonably (not pie-in-the-sky) hit 1/4 - 1/2 mile distances at slow speeds (9600 baud is fine). I would like to use an omni antenna (so no high directional antennas), would prefer the module to have pre-FCC approval, and would like the modules to be less than $15. Lower the power draw the better, but we know how that trade-off works! Those requirements really limit me, but the Anaren part seems like it could cover them; I am just curious what other things are out there that I might have missed. I am not married to the 900MHz spectrum, it just seemed like the most likely place for me to meet my goals. This is for an outdoor transmission.
  10. Hi, i try to implement an sensor network with msp430 and simpliciti. Is possible implement an security protocol with simpliciti, for defense from sniffer? Regards Gerardo Di Iorio