AngusMcDoon
Well-Known Member
This is the latest YAPP, and may be the last, as will be explained later. This device has 3 NMEA-0183 inputs and multiplexes the data into one output. Two of the inputs are fixed at 4800 baud, and one of the inputs and the output can be selected between 4800 baud and 38400 baud as used by AIS. It's not possible to have 3 inputs at 4800 and the output at 38400 - it's (4.8, 4.8, 4.8) to 4.8 or (4.8, 4.8, 38.4) to 38.4. Because NMEA-0183 changed its hardware standard during its life from RS-232 like (data/ground) to RS-422 like (NMEA+/NMEA-) this device has both types of output and can accept either type as input. The inputs are all opto-isolated. Here it is in its box, although I don't have the grommets yet for the wire holes...
The software algorithm inside is pretty simple. There's no prioritizing of message types or ensuring that all message types get through equally. It doesn't look into the message contents at all. What it does do is take a complete message from each input in turn and send it to the output. If the rate selectable input is set at the higher rate then that input is given 4 times the chance to get its data through to the output than the other slower speed ones. If there is an overload condition then messages are just dropped equally between all the inputs. This algorithm is simplistic but works well when the data throughput is well within the maximum capability.
As all YAPPs, this project is completely open source and design and will appear on the YAPP website within a day or two, so anyone who wants to give it a go from the design files can help themselves (schematic, PCB layout, bill of materials, source code, build files). Alternatively I have a small batch (10) of printed circuit boards, so you can buy the components, get the software and make one yourself with a PCB from me at cost price. I can also stuff the components in a box and supply those at cost price as well, or I'll solder it up for you for no charge, and mount it in a plastic box if you want.
So how much will it cost? I'm not specifying a price. I have listed the cost of the components below and if you would like one let me know and I'll stick one in the post to you to try when I have collected together the bits and assembled it. No up front payment necessary. You can test it, and if you like it, keep it and send me a contribution for what you think it's worth. If not, send it back.
Now for the reason why I have reverted to this form of YAPPery of my sending one to you first to try and then your sending me whatever it's worth to you if you like it. A complaint has been made to the mods that I am promoting a business here and the mods have told me to stop. My explanation that YAPP Electronics is a forum based collection of collaborative projects which are all completely open and free and for which kits are sold on a non-profit basis got no response from them, I just have to cease. I also asked why the complainant was offended as other posters here who do have businesses promote them through their signature and continue to do so. Dylan promotes his videos through his signature for example and Simon his weather service. I asked if it was a company that was offended by a particular YAPP which I would willingly remove from the website and not discuss on the forum, but all questions remain unanswered. When the 10 boards for this YAPP have gone (9, I'll have one), they are gone. I won't be getting any more made.
The circuit boards for this YAPP had already been ordered when I was told this, so I'm going to continue with this one anyway and be banned, excommunicated, horsewhipped or whatever punishment they mete out for disobedience. However, it will be the last unless they have a change of heart. Planned ones in development (using colour touch screen displays) have been dismembered and thrown back into my bits box. For all the existing YAPP projects all indications on the website that links from my signature that anything can be bought have been removed although the source and design files will remain until the webserver subscription runs out.
Components with Farnell part number and price, including VAT (Farnell website prices do not include VAT). The formatting is pants I know...
Resistor 1K 250mW x 4 Farnell 9339051 11
Resistor 4K7 250mW x 2 Farnell 9339540 6
Resistor 10K 250mW x 3 Farnell 9339060 8
Capacitor 100nF ceramic 0.1" x 2 Farnell 2309020 7
Capacitor 10uF electrolytic Farnell 9452389 7
SFH615A Opto-isolator x 3 Farnell 1683348 78
PIC18F26K22 Farnell 1814975 299
BC237 x 3 Farnell 1574377 52
1N4148 x 3 Farnell 9565124 6
100mm x 1000mm PCB Itead 240
Header 0.1" per pin, 40 way x 2 Farnell 2356153 13
2 way screw terminal x 6 Farnell 2008019 202
Shorting link 0.1" Farnell 2078258 39
Regulator 100mA 5V load dump LM2931 Farnell 9489487 57
Carboard box Ebay 28
Bubble wrap 30cm x 30cm Ebay 2
Postage 2nd class not signed for PO 260
MAX 232 line driver Farnell 9725172 137
UA9637 RS422 line receiver Farnell 1210971 106
UA9638 RS422 line driver Farnell 1210966 70
Capacitor 1uF electrolytic x 5 Farnell 1236655 23
Box 125x80x35 Farnell 1635159 304
Grommet 8mm cable 1.6mm panel 11mm panel hole x 6 Farnell 1189041 30
Board standoff 3mm hole M3 thread 8mm height x 4 Farnell 1733395 65
Machine screw M3x6 brass countersunk x 4 Farnell 1419405 12
Components total 2062
The software algorithm inside is pretty simple. There's no prioritizing of message types or ensuring that all message types get through equally. It doesn't look into the message contents at all. What it does do is take a complete message from each input in turn and send it to the output. If the rate selectable input is set at the higher rate then that input is given 4 times the chance to get its data through to the output than the other slower speed ones. If there is an overload condition then messages are just dropped equally between all the inputs. This algorithm is simplistic but works well when the data throughput is well within the maximum capability.
As all YAPPs, this project is completely open source and design and will appear on the YAPP website within a day or two, so anyone who wants to give it a go from the design files can help themselves (schematic, PCB layout, bill of materials, source code, build files). Alternatively I have a small batch (10) of printed circuit boards, so you can buy the components, get the software and make one yourself with a PCB from me at cost price. I can also stuff the components in a box and supply those at cost price as well, or I'll solder it up for you for no charge, and mount it in a plastic box if you want.
So how much will it cost? I'm not specifying a price. I have listed the cost of the components below and if you would like one let me know and I'll stick one in the post to you to try when I have collected together the bits and assembled it. No up front payment necessary. You can test it, and if you like it, keep it and send me a contribution for what you think it's worth. If not, send it back.
Now for the reason why I have reverted to this form of YAPPery of my sending one to you first to try and then your sending me whatever it's worth to you if you like it. A complaint has been made to the mods that I am promoting a business here and the mods have told me to stop. My explanation that YAPP Electronics is a forum based collection of collaborative projects which are all completely open and free and for which kits are sold on a non-profit basis got no response from them, I just have to cease. I also asked why the complainant was offended as other posters here who do have businesses promote them through their signature and continue to do so. Dylan promotes his videos through his signature for example and Simon his weather service. I asked if it was a company that was offended by a particular YAPP which I would willingly remove from the website and not discuss on the forum, but all questions remain unanswered. When the 10 boards for this YAPP have gone (9, I'll have one), they are gone. I won't be getting any more made.
The circuit boards for this YAPP had already been ordered when I was told this, so I'm going to continue with this one anyway and be banned, excommunicated, horsewhipped or whatever punishment they mete out for disobedience. However, it will be the last unless they have a change of heart. Planned ones in development (using colour touch screen displays) have been dismembered and thrown back into my bits box. For all the existing YAPP projects all indications on the website that links from my signature that anything can be bought have been removed although the source and design files will remain until the webserver subscription runs out.
Components with Farnell part number and price, including VAT (Farnell website prices do not include VAT). The formatting is pants I know...
Resistor 1K 250mW x 4 Farnell 9339051 11
Resistor 4K7 250mW x 2 Farnell 9339540 6
Resistor 10K 250mW x 3 Farnell 9339060 8
Capacitor 100nF ceramic 0.1" x 2 Farnell 2309020 7
Capacitor 10uF electrolytic Farnell 9452389 7
SFH615A Opto-isolator x 3 Farnell 1683348 78
PIC18F26K22 Farnell 1814975 299
BC237 x 3 Farnell 1574377 52
1N4148 x 3 Farnell 9565124 6
100mm x 1000mm PCB Itead 240
Header 0.1" per pin, 40 way x 2 Farnell 2356153 13
2 way screw terminal x 6 Farnell 2008019 202
Shorting link 0.1" Farnell 2078258 39
Regulator 100mA 5V load dump LM2931 Farnell 9489487 57
Carboard box Ebay 28
Bubble wrap 30cm x 30cm Ebay 2
Postage 2nd class not signed for PO 260
MAX 232 line driver Farnell 9725172 137
UA9637 RS422 line receiver Farnell 1210971 106
UA9638 RS422 line driver Farnell 1210966 70
Capacitor 1uF electrolytic x 5 Farnell 1236655 23
Box 125x80x35 Farnell 1635159 304
Grommet 8mm cable 1.6mm panel 11mm panel hole x 6 Farnell 1189041 30
Board standoff 3mm hole M3 thread 8mm height x 4 Farnell 1733395 65
Machine screw M3x6 brass countersunk x 4 Farnell 1419405 12
Components total 2062
Last edited:
)
