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Using WiFi with the GPS-Synchronised Analog Clock By Geoff Graham ur new GPS-Synchronised Analog O Clock Driver featured in the September issue has been a great success, it with the new GPS Synchronised Clock. If you want the full details, read the original article at siliconchip.au/ Article/15466 The recommended WeMos D1 Mini WiFi module is available from many sources, including Altronics (Cat Z6441) and Jaycar (Cat XC3802), as well as on eBay, AliExpress etc. The original module is made by a Chinese company called Lolin, but many clones exist. While they may look different, they have the same form-factor and pinout and work just as well. When buying the module, make sure it is the D1 Mini version. There are other variations called D1 but without the Mini suffix; they are much larger and will not fit in the space reserved for the GPS module. with hundreds built. It was so popular that there was a two-week backlog of kits until early October (kits are now back in stock). However, some constructors have reported difficulties with the GPS module being unable to get a signal. This is usually because the GPS signal is blocked or heavily attenuated when used in a multi-level house or building, a building with a steel roof or even heavy rain. The solution is Tim Blythman’s “Clayton’s GPS”, described in the April 2018 issue (siliconchip.au/Article/ 11039). This is a WiFi module that emulates a GPS module, but it gets the time from a public time server on the internet using the network time protocol (NTP). Besides the WiFi module, it does not require any extra components and is a drop-in replacement for the GPS module specified in the September article. You could swap back and forth between the two, and the clock would not notice the difference. This article briefly describes how to set up the WiFi module and use Loading the firmware To make the D1 Mini emulate a GPS module, you need to load the appropriate firmware, which can be downloaded from siliconchip.com. au/Shop/6/52 The following description is based on the Windows operating system. You can load the firmware using other operating systems, but that will require the Arduino IDE software. That process is described in the original Clayton’s GPS article from April 2018. First, plug the D1 Mini into a USB port on your Windows computer. It will connect as a serial-over-USB device. No device driver is required for Windows 10 or 11. Open Device Manager and you should see it listed as “USB-SERIAL CH340” – see Fig 1. Note the COM port number, which is COM23 in this example. Next, run the program file named “ESP8266Flasher.exe”, which is included in the firmware download. This is an easy-to-use programmer for ESP8266 devices developed by www. nodemcu.com When you start the programmer, it will guess the COM port number (see Fig.2), so the first thing that you should do is check that it has selected the correct number for the D1 Mini. Then you need to click on the Config tab and enter the path to the firmware file, “ NTP_client_for_ESP8266_GPS_ OUTV12.bin”. Leave the starting address at 0x00000 (hexadecimal value) and do not change any of the settings in the Advanced tab. Finally, return to the Fig.1: when you plug the D1 Mini into a computer running Windows, Device Manager will show the COM port allocated to it. ► Fig.2: ESP8266Flasher.exe is an easy-to-use programmer for the D1 Mini. It has correctly guessed the module COM port here, but you should still check it. 76 Silicon Chip Australia's electronics magazine siliconchip.com.au Operation tab and click the Flash(F) button. The programmer will load the firmware. While that is happening, the blue LED on the D1 Mini should flicker rapidly. When the programmer has finished, it should show a green tick on the bottom left corner of the program, indicating that it was successful. If you do not see that, click on the Log tab and scroll to the end of the log to view any error messages. NTP GPS Source Setup: Current Baudrate:9600 1.Set 4800 Baudrate 2.Set 9600 Baudrate 3.Set SSID. Current:SSID 4.Set Password. Current:PASSWORD 5.Set NTP Server. Current:pool.ntp.org 6.Set Dummy Coords. Current:3351.000,S,15112.000,E 9.Exit and save Enter a number: ❚ Fig.4: the WiFi module fits neatly in the space usually occupied by the GPS module, and only three connections are required. Configuring the firmware After successfully loading the firmware, disconnect and then reconnect the USB cable. That will reboot the module, and the blue LED on the top of the module should illuminate and stay on. Open a terminal emulator like Tera Term (https://tera-term.en.lo4d.com), set the baud rate to 9600 and connect to the COM port used by the D1 Mini. You will see the output of the module, which will be emulating a GPS module that cannot find a signal. Using the terminal emulator, enter the tilde (~) character on your keyboard and you should see the setup menu as shown in Fig.3. Change the SSID and Password to suit your network, then save and exit the configuration menu by pressing 9. None of the other settings need to be changed. Finally, disconnect and reconnect the USB cable, and the D1 Mini module should start up with the blue LED coming on solidly. That indicates the firmware is connecting to your WiFi network, accessing the internet and contacting a public time server. The blue LED will change to a brief flash every second when the firmware has received the current time. If you reconnect with your terminal emulator, you will see that the module is now producing GPS-­compatible messages indicating the correct (UTC) time. Installing the module The module fits neatly into the space reserved for the GPS module on the clock controller PCB, as shown in Fig.4. Only three wires are needed: the pin labelled 5V on the module connects to the solder pad labelled “RE” on the controller board; pin G on the module to pad “BK” on the main PCB; Inductor part code mix-up The 10 × 10mm inductor (L1) used to build the prototype, RS Components 496-0401, fit the PCB nicely and worked well. As such, we provided the part code from that item’s description in the parts list (EPCOS B82462-A4). We now know that the correct part code is B82464-A4 (that code appears on the RS page, just further down). By the time customers clued us in, we had supplied hundreds of EPCOS B82462-A4 inductors in kits from another supplier. They are electrically compatible, just smaller at 6 × 6mm. If ordering that part from RS, you will need to use the part code we gave in the parts list, as that is what they use, but from any other supplier, use the correct part code (B82464-A4-472M). If you already have the part (eg, you got it as part of a kit), we recommend you solder one side to a pad on the PCB, then use a component lead off-cut to bridge the gap between the other side and the opposite PCB pad. Many constructors have successfully built the kit that way. To make construction easier, we will be supplying a redesigned PCB that will accept either size of inductor. Those new PCBs should be available by the time you are reading this and will be included in future kits. siliconchip.com.au Fig.3: this is the configuration menu for the module. You need to change the SSID and Password entries, but the remainder of the settings can be left as they are. Australia's electronics magazine and pin TX on the module to pad “BU” on the PCB. Finally, attach the D1 Mini to the controller board using double-sided tape. When you insert cells into the clock, you should see the module’s blue LED illuminate for a few seconds while it accesses the internet, changing to a flash when it gets the correct time. Almost immediately, the clock controller’s microcontroller will power down the module (because it has the correct time) and the LED on the controller board will start a long flash every second. That indicates that it is waiting for the next hour or half-hour to start the clock running. That’s it! You can hang your clock on the wall, and it will keep accurate time for as long as it can reach the internet via your WiFi network. Incidentally, your clock will keep going even if you turn off your WiFi (for example, if you go on holiday). Then, when you re-enable your WiFi, the clock will get the correct time when it next tries to synchronise (within 24 hours) and immediately correct any error that accumulated while you were away. D1 Mini module kit (SC6472) We will be offering the D1 Mini as an option for the current kits instead of the GPS module – note that the D1 Mini will require programming. SC November 2022  77