Nmea2Wifi (2021) - SMD, TH and KIT Upgrades

Discussion and support for the Nmea2Wifi multiplexer - a 2-input Nmea 0183 wifi multiplexer.
Luis Sa
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Nmea2Wifi (2021) - SMD, TH and KIT Upgrades

Post by Luis Sa » Wed Feb 17, 2021 12:01 pm


From 2020 to 2021 the Nmea2Wifi multiplexer has gone through significant improvements. The main modification is the use of faster optocouplers and making the software to be almost identical to the Nmea4Wifi multiplexer. With firmware 6.4 it is possible to communicate with a computer or laptop through a USB cable as it was (and is) the case of the Nmea4Wifi multiplexer. If you have an older version and want to take advantage of this new feature you need to make a small modification as shown here. In this post I describe the technical details of the present multiplexer. Normal users do not need to read this as everything concerning the operation of the multiplexer is described in the acknowledgement webpage that you see when you type on the navigation bar of your browser.

The multiplexer is available in versions built with SMD (Surface Mounting Devices) and TH (Through-Hole) technologies. So I am using 3 designations:
  • Nmea2Wifi SMD
  • Nmea2Wifi TH
  • Nmea2Wifi KIT
All versions are identical in terms of functionality and software. The TH and KIT versions are also identical in terms of hardware. The obvious difference is that the KIT version is assembled by the user. As I referred to above you can use a USB cable to receive and transmit data from and to a computer. This USB cable can also power the multiplexer so that you do not need to supply 12V to the multiplexer. Both the USB cable and the 12V supply from a battery can coexist. If you use an USB cable the top cover box can not be used, except if you cut an hole on top cover in the case of the SMD version. Also note that the SMD version uses a mini USB type B socket strongly soldered to the PCB. All versions use the same type of connectors. They are good quality 1.5mm2 screw connectors. In the case of the SMD version all the 9 connectors are in a single line facing the front of the multiplexer. In the case of the TH and KIT versions the connectors are deployed in a kind of circle. Both versions have a PCB recession to facilitate the entrance of the wires with the top cover on.


The circuit diagram of the multiplexers can be downloaded from the links at the bottom of this post.


The remaining part of this post is addressed to the builders of the Nmea2Wifi KIT. Kits are supplied with the original Instruction Manual which does not reflect the present version. In the following we emphasize the main differences to the original Instruction Manual. The parts list is as follows:


The PCB (Printed Circuit Board) and the new parts in this KIT (voltage regulator and resistor arrays) are shown in the following pictures



Note that the diodes, LEDs and ICs are the only components that need proper orientation. The resistor arrays have no orientation. The diodes have a bar that indicates the cathode. You need to insert them so that the bar that exists in the body of the component coincides with that shown on the PCB. The LEDs have 2 terminals (anode and cathode). The cathode terminal wire is shorter than that of the anode and should go on the hole that is next to the connectors. As for the ICs please follow the indications on the Instruction Manual. Please see the following pictures that show some stages of the assembling. Also note that you need to flash the Wemos module as described here.


When ready your multiplexer will look this:


Regards, Luis
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