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[POTM] dAISy - A Simple AIS Receiver

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You will have to post a picture or a link to what circuit you're referring to regarding the 220pF capacitor.

 

The are decoupling caps near the radio IC to remove noise from the power rail. That's good practice and implemented as recommended in the radio's datasheet or a related app note.

I'm sorry, I mean the C4 in this schematic. what is it for?

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Ah sorry, I was looking at the original schematic posted in this thread.

 

The 220pF is an AC coupling cap. It's there to avoid any DC from the antenna port to get to the radio. Anything on the order of 100pF should be fine. 220pF was what I had at hand.

 

Here's a good explanation of coupling caps:

http://www.learningaboutelectronics.com/Articles/What-is-a-coupling-capacitor

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@@chicken I have another question. how torun the test at main program? because i'm new at programing the MSP. Thx before

Ah sorry, I was looking at the original schematic posted in this thread.

 

The 220pF is an AC coupling cap. It's there to avoid any DC from the antenna port to get to the radio. Anything on the order of 100pF should be fine. 220pF was what I had at hand.

 

Here's a good explanation of coupling caps:

http://www.learningaboutelectronics.com/Articles/What-is-a-coupling-capacitor

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@@chicken I have another question. how torun the test at main program? because i'm new at programing the MSP. Thx before

Are you referring to the TEST sections in the code? If so, the CCS project for dAISy includes a Test build. It should be available where you select between Debug and Release.

 

I haven't built the project test in a very long time. I used it to debug packet handler and NMEA encoding without having a real AIS signal available. Notsure if there will be any meaningful output or whether it will work at all.

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@@chicken how to use openCPN for this AIS Receiver?

and i dont know how to display string from uart.

i'm stuck at using openCPN, i use configure at serial then baud rate 9.6k but the Signal not received. Thx before

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@@chicken how to use openCPN for this AIS Receiver?

and i dont know how to display string from uart.

i'm stuck at using openCPN, i use configure at serial then baud rate 9.6k but the Signal not received. Thx before

Did you build this project or are you using the finished receiver I sell on Tindie?

 

If you built your own, which Launchpad are you using?

 

For the bought receiver the baudrate is 38400.

 

In OpenCPN, the input filtering should be "Ignore sentences" and the field below empty.

 

Did you test if you receive anything over the COM port with a serial terminal?

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Did you build this project or are you using the finished receiver I sell on Tindie?

 

If you built your own, which Launchpad are you using?

 

For the bought receiver the baudrate is 38400.

 

In OpenCPN, the input filtering should be "Ignore sentences" and the field below empty.

 

Did you test if you receive anything over the COM port with a serial terminal?

 

i build the project.

 

i used msp430

 

i don't know how to receive from COM port at serial terminal. because when i try the output was empty.

 

sorry cz i'm newbie at programing msp series. Thx before.

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@@adilnooril do you use a Launchpad for the MSP430? Or did you build that part yourself as well?

 

With the Launchpad, there should be a COM port showing up on your PC when plugging it in. Connect to that port using Putty, Hyperterm or something similar, using 9600 baud, 8 bit, parity none and 1 stop bit (8N1) and no flow control.

 

dAISy will only output something when a signal is received. So you might want to test with a basic program that just prints out a string every few seconds.

 

If using a Launchpad, you could use Energia and it's Serial.Print example to test the basic communication. There are a few gotchas in connecting serial with the MSP430G2553 Launchpad. The Energia documentation explains how to get that part working. Once Energia works, you can be relatively confident that serial works and concentrate on the dAISy code.

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dAISy Ethernet Adapter

post-45284-0-12949200-1466451519_thumb.jpg

The dAISy Ethernet Adapter packages a dAISy AIS Receiver in an enclosure with a W5500 Ethernet module and a MSP430G2955 to control it.  With the addition of a marine VHF antenna, power via USB, and an Ethernet connection local marine traffic can be reported to the internet:

post-45284-0-03036500-1466451604_thumb.jpg

The simplified block diagram below shows the main components:

post-45284-0-17419400-1466451707_thumb.jpg

The MSP430G2995 was chosen over the more common MSP430G2553 for its additional RAM and was adapted to Energia and an Ethernet library ported.  Relatively large SMD components (e.g. 0805 resistors and capacitors, 38 pin TSSOP microcontroller) were chosen to allow hand soldering if desired.

 

The finished product is shown below with the enclosure open:

post-45284-0-64751500-1466451816_thumb.jpg

The project was a collaboration with @@chicken.

 

Links and References

dAISy 43oh thread: http://forum.43oh.com/topic/4833-potm-daisy-a-simple-ais-receiver/

dAISy Tindie:  https://www.tindie.com/products/astuder/daisy-ais-receiver/

MSP430G2955 Energia: https://github.com/fmilburn3/MSP430G2955_EnergiaPinmap

W5500 Energia: https://github.com/fmilburn3/W5500_Ethernet

 

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Tindie business slowed down considerably over the last two months. Not sure yet if it's the cheap competition that started showing up, or whether everyone's just out sailing.

 

Anyways, the upside is, that I finally have some time to tinker on new things again..

post-9974-0-00631700-1471837875_thumb.jpg

 

Love the new steel stencils from OSH Stencils. I managed to reflow 4 boards without a single bridge, including the big QFN which gave me a lot of grief in the past. Maybe it's the combination with OSH Park PCBs instead of the cheap Chinese ones. Also OSH Park turned around my last few orders in two weeks from ordering to receiving the boards in my mailbox. I seem to remember that this was closer to three weeks in the past. 

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Tindie business slowed down considerably over the last two months. Not sure yet if it's the cheap competition that started showing up, or whether everyone's just out sailing.

 

Anyways, the upside is, that I finally have some time to tinker on new things again..

attachicon.gifdaisy_hat_revB.jpg

 

Love the new steel stencils from OSH Stencils. I managed to reflow 4 boards without a single bridge, including the big QFN which gave me a lot of grief in the past. Maybe it's the combination with OSH Park PCBs instead of the cheap Chinese ones. Also OSH Park turned around my last few orders in two weeks from ordering to receiving the boards in my mailbox. I seem to remember that this was closer to three weeks in the past. 

I had one of my OSHpark boards "super swift" upgraded on its own recently.  Love the service OSHpark is delivering.

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