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Frank Milburn's Blog

22 posts
Project Objective: Develop an open source AIS Alarm that alerts sailors that a new marine vessel with AIS is within range   The faceplates came back today and here is a photograph: If I make another order there are a few tweaks I will make but overall I am happy with it.  I might make the holes slightly smaller.  I hit the edge of the PCB with sandpaper where the tabs were and then a sharpie to make it blacker but otherwise it is as received.   Time to finish off the fir ...
*** UPDATED 2nd April 2018 - At bottom - first attempt at soldering QFN   For sometime I have been using the Texas Instruments MSP430G2553 in most of my projects.  It is relatively inexpensive at $1.98 in small quantities, comes in DIP and TSSOP packages that can be hand soldered, and there is a community of users as well as good TI documentation and training.  My two complaints are the amount of RAM (512 bytes) and the limited serial with hardware SPI and I2C being on the same p ...
Project Objective: Develop an open source AIS Alarm that alerts sailors that a new marine vessel with AIS is within range   Two boards have been populated and tested now and everything seems to be working.  This update will cover thoughts on the PCB, faceplate design for the enclosure, and an update on the firmware.   I am satisfied with the PCB for the most part now but will decrease the drill hole size for the LED as the fit is a little loose.  Three different buzzers were ...
Project Objective: Develop an open source AIS Alarm that alerts sailors that a new marine vessel with AIS is within range   I worked most of last week to complete my RoadTest of the TPSM84A21EVM DC-DC Converter but on Friday the revised PCBs for the AIS Alarm arrived and today I populated two of the boards.  This is an update on how things are coming along.   The revised board is shown fully populated on the right.  If you have a look back at the first version it is clear ...
Project Objective: Develop an open source AIS Alarm that alerts sailors that a new marine vessel with AIS is within range   Over the weekend I modified the PCB design, submitted it for production, and started thinking about refactoring the firmware.  This post will show the new PCB design and outline some of the thinking that went into it.  A first pass at the state machine will also be introduced.   Here is a rendering of the new PCB that is now being manufactured: The main ...
Project Objective: Develop an open source AIS Alarm that alerts sailors that a new marine vessel with AIS is within range   Over the weekend the remaining parts arrived and I finished populating the board.  I found a few more problems and will document them here.  Normally I don't document problems unless they are somehow unique and instead give the final state but for this project I am going to publish warts and all.   Here is the populated board next to a dAISy receiver.& ...
Project Objective: Develop an open source AIS Alarm that alerts sailors that a new marine vessel with AIS is within range   The PCBs arrived today but unfortunately I was slow in ordering the more obscure parts for the design and they have not yet arrived.  This blog post will describe populating the board with the parts I have on hand and first impressions of what will be needed for the next revision.   Here is a photo of the board as it currently stands: It looks pretty spa ...
Last summer my 5 year old grandson spent the week with me and I promised his mother it would be educational and him that it would be fun.  Early in the week we wired up LEDs, beepers and switches, learned about polarity, etc.  We played with a simple robot that could be programmed to run a route.  I kept it to only a couple of hours a day and allotted  time to do other stuff.  The highlight was a project we did at the end of the week.   My objective with the projec ...
Project Objective: Develop an open source AIS Alarm that alerts sailors that a new marine vessel with AIS is within range   With the schematic complete it was time to design a PCB.  This blog entry will outline the PCB design and layout along with the primary considerations. The "L" shape of the PCB is a direct result of the enclosure that will be used and is necessary to avoid interference with other components already inside the case.  The dAISy radio receiver will reside un ...
fmilburn

AIS Alarm - Schematic

Posted by fmilburn Jan 12, 2018
Project Objective: Develop an open source AIS Alarm that alerts sailors that a new marine vessel with AIS is within range   The breadboard prototyping and first pass at firmware are sufficient to proceed to hardware design.  After exchanges with the developer of dAISy and some early layout I have modified the pins used by the microcontroller and foresee the need to refactor the firmware.  At this point though no show stoppers are foreseen.  This post will describe the prelim ...
Project Objective: Develop an open source AIS Alarm that alerts sailors that a new marine vessel with AIS is within range   The prototype now receives AIS messages from the dAISy module and stores them in a persistent FRAM ring buffer.  The ring buffer will be described in this post and code to test the concept by emptying the ring buffer and displaying it implemented.   The ring buffer uses an algorithm presented by Jack Ganssle in Embedded Muse 110 and published in 2005.  I ...
Project Objective: Develop an open source AIS Alarm that alerts sailors that a new marine vessel with AIS is within range   The prototype now receives AIS messages from the dAISy module and stores them in a persistent FRAM ring buffer.  My intention today was to test the ring buffer but I discovered lots of bounce with the button used to push the buffer contents to UART.  This post will outline a software debounce scheme that makes use of the millisecond counting ISR already in t ...
Project Objective: Develop an open source AIS Alarm that alerts sailors that a new marine vessel with AIS is within range   The prototype is now receiving AIS messages from the dAISy module.  In this post a method for storing the messages in a persistent FRAM ring buffer will be described.  This is important to the project because persistent storage means the messages will not be lost when the device is unplugged from power.   The screen shot below taken from the CCS debug vi ...
Project Objective: Develop an open source AIS Alarm that alerts sailors that a new marine vessel with AIS is within range   In this post the dAISy receiver will be connected and the first AIS messages received. The green LED on dAISy indicates an AIS message!   The dAISy receiver is easily accessible.  A header is provided with RX, TX, GND, 5V, 3V3, and even RST and TST for the very brave.  Here TX on dAISy has been connected to RX on the FR2111 prototype breadboard. ...
fmilburn

AIS Alarm - UART

Posted by fmilburn Dec 30, 2017
Project Objective: Develop an open source AIS Alarm that alerts sailors that a new marine vessel with AIS is within range   This post will add 38400 baud UART to the existing code and test it. /* * dAISy_Alarm_V002 - adds UART at 38400 baud * dAISy_Alarm_V001 - implements millisecond timer and blinks LED * * MCLK, SCLK set to 8 MHz * ACLK set to 32768 Hz * Milliseconds counted on timer B0 * UART at 38400 baud * * Frank Milburn    30 December 2017 * Developed on MSP ...