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:

AIS Alarm PCB V0.1

It looks pretty sparse now that it is off the breadboard and onto a PCB.  I am soldering by hand using an inexpensive reflow station for the SMD components.  The parts that remain to be placed are the buzzer, dual MOSFET, and the bright 5 mm right angle LED.  I've been able to test the switches and LED indicators and they are OK.  All the traces look OK.  The board is programmed using the header on the far left.  The inside header will connect to the dAISy radio via ribbon cable.  Here are the observations so far that will need to be addressed before the next revision:

  • The boards were attached in the original panel by tabs with mouse bites that had to be taken off with a dremel tool for it to fit in the enclosure.  I will look at V-cuts  or possibly making the board slightly less wide in the final design to avoid this.
  • The board is going to slide in over the radio in the enclosure.  There is very little room between the indicator LEDs on the right and the board with the radio below it.   This prevents the use of a connector and will require hand soldering of the ribbon cable between the radio and the Alarm PCB.  I knew this was going to be a problem and am still looking for a way around it.
  • The MOSFET footprint is pretty small and will be difficult to hand solder.
  • Should add some test points.
  • The button switch on the left needs to be moved to better clear the enclosure.

 

A funny thing is that most of the issues are mechanical in nature and I am a mechanical engineer.  I find that the mechanical issues are the ones I usually iterate on the most when it comes to the PCB.

 

The remaining parts are expected by Friday but I am expecting guests for the weekend so probably won't get back to this until early next week.  But it looks like this will be good enough to iron out most of the hardware issues as well as make the next upgrade to the firmware.

 

Past Posts from this Project:

AIS Alarm

AIS Alarm - The Process

AIS Alarm - Prototype Hardware

AIS Alarm - Timers and GPIO

AIS Alarm - Prototype Code Outline

AIS Alarm - UART

AIS Alarm - First AIS Messages

AIS Alarm - First FRAM Storage

AIS Alarm - Debouncing Momentary Button Switches

AIS Alarm - FRAM Ring Buffer

AIS Alarm - Schematic

AIS Alarm - PCB Version 0.1

 

References and Links:

WEGMATT LLC - dAISy AIS Receiver - low cost AIS receiver

Texas Instruments MSP430FR2xx FRAM Microcontrollers - Post No. 4

TI MSP430FR2111

Maximize the Sound from a Buzzer