![]() ![]() The max current of the circuit was 940mA with all LEDs on max brightness (brightness=15). There is no communication back to the ESP32, thus the SPI MISO of the ESP32 is not used.įor later use of an external power supply, I did some power consumption testing. To send commands and data to the LED matrix the SPI interface of the ESP32 is used.on the breadboard just use a jumper wire instead of the switch for testing.ESP32 pin numbers are the GPIO Pin numbers, depending on the board you use, they could have different names, but the GPIO pin numbers are the same. ![]() The breadboard can be powered via the USB connector of the ESP32, which we need to connect anyway to download the software.Connect the free end of the LDR to the ground rail.Connect the free end of R1 to the 3.3V rail.Connect the Gnd pin of the LED Matrix to the ground rail.Connect the Vcc pin of the LED Matrix to the 5V rail.Pin23 GPIO-day light savings switch, the other pin of the switch is connected to ground.Pin34 ADC-voltage divider with R1 10KOhm and the LDR (see schematic).If you need to sync more often, this can be set up in the dclock software, see Step 3.ĭrawing the schematics on a piece of paper was quickly done (see picture), then put the components on a bread board and make following connections: With synchronization of the RTC with the internet time two times a day, accuracy is within 1 to 3 seconds late - good enough I think. The ESP32 has an internal real time clock (RTC), which is used for the Dclock, but the RTC is not very accurate. Matching these specifications with my electronic component stock on hand, I took an ESP32 node MCU board, a light dependent resistor (LDR) and the LED Matrix board with max7219 controller chips to build what I call the "Dclock". A real time clock to operate independent for some time and reduce internet traffic.A switch to cater for daylight savings time change.Idea: wouldn't it be nice to have an ambient light dependent automatic brightness control?. ![]()
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