Dilshan R Jayakody’s Web Log

This project introduces an open-source, ATmega328 based, configurable NTP clock with a 2.3-inch, 7-segment display driver. This clock automatically obtains time from the configured NTP server and updates the date and time of the built-in RTC (real-time clock). If the connection to the NTP server is lost, the clock continues to run using its built-in RTC. Finished NTP clock driver PCB. All the parameters of this clock can configure using its USB base serial terminal. The firmware of this clock supports both static and DHCP addressing modes. Apart from that, parameters such as NTP server address, time-offset, and clock display formats can change through the menu-driven configuration terminal. This clock is designed to drive large common-anode, 7-segment displays. The prototype version is assembled using four individual segments of 7.2V, 2.3-inch, red color displays ( FJS23101BH ). To archive, the necessary high output voltage and the current, the 7-segment display output stage of this ...

This is an RDA5807M based FM stereo radio module. This module is designed to replace old, low-voltage, analog FM stereo radio receiver modules. Like many digital receivers, this module also got auto scanning, station memory, and digital volume control. This module can driver using 5V to 9V DC power source. FM stereo receiver module with seven-segment display unit. The frequency range of the receiver is 88MHz to 108MHz. The auto scanner of this module can tune the receiver with 25kHz increments in up and down directions. The memory manager available with the current firmware can hold up to 10 stations in MCU EEPROM. Bottom side of the receiver module The dimensions of this module are 72.85mm × 32.0mm. With the seven-segment display, the depth of the assembled module is 37.5mm. AF output power of this module is not sufficient to handle the pair of speakers. To drive speakers, this module needs to pair with a stereo AF power amplifier kit/module .  This is an open-source hardware pro...

I 2 C is a popular data bus to communicate with inter-board peripherals. Today I 2 C based chips and modules are widely available in many categories, including data storage, ADC/DAC, I/O Expanders, sensors, etc. The I 2 C master mode emulator allows communication with I 2 C devices by sending or receiving data to/from the I 2 C bus. To issue the I 2 C commands, the emulator should connect to a PC over the USB port. After initializing the emulator, the PC and directly control the I 2 C slave chip/module. Finished prototype of the I 2 C Terminal This emulator is base on ATmega16A MCU. The USB communication channel is develop using the V-USB firmware. Initially, we develop this emulator to work with 5V I 2 C devices, but later it has extended to work with 3.3V I 2 C devices. The 3.3V design is still under testing, and at the prototyping stage, we found a couple of issues in 3.3V mode.  In 3.3V mode, the required output level is available only if the emulator is in a "ready" sta...

This project is about a simple LED clock module based on STM8S103F3 MCU and DS3231 RTC. This clock module is designed to handle a generally available 14.2mm (0.56 inch) 4-digit seven-segment displays. This module use 12-pin (6-pin × 2) socket to connect the seven-segment display to the PCB, and it allows to mount the display unit off from the PCB. Prototype version of the clock module The " alarm terminal " of this module is available as an open-collector output. This terminal allows the user to connect an external circuitry to this module. The module can power up using 5V or 3V DC power source. The necessary power source can select using a jumper in the module. This module also provides a slot to install a small CR1220 type battery to backup the time and alarm configuration. Front side of the module (without seven segment display unit) Bottom side of the module   The dimensions of this module are 65.4mm × 29.6mm. With the seven-segment display, the depth of the assembled ...

UV exposure unit is a vital component in printing and mass-manufacturing industries. I decided to build a UV exposure unit to assist my screen-printing and PCB prototyping needs. After examining the market, I decided to construct this unit using black fluorescent tubes. Those black fluorescent tubes are usually available to purchase in many electrical shops here in Sri Lanka . Finished UV exposure unit with four fluorescent tubes. To drive the exposure unit, I build an electronic controller using ATtiny2313A MCU. This controller is capable to handle the exposure unit for up to 999 seconds ( approximately 16 minutes ). This electronic controller got two high-power relay driver stages, an audible notification unit, a safety lock, and a programmable timer. The fluorescent tubes are drive using four separate chokes and starter units. For this unit, I use four NEC 20W - 60cm (T10) black fluorescent tubes.  12V, 5A SMPS is used to drive the relays and electronic controller unit. PSU, c...

μSim is a lightweight PIC™ CPU and ALU simulator. This simulator supports the PICmicro mid-range instruction set and designed to work on both PC and Arduino platforms. Compare with most of the other emulators, μSim does not provide all MCU features and peripherals. This simulator design as a minimalistic system, and based on the requirements, it can extend with additional peripherals and features. To accomplish this μSim is written with minimum system dependencies and with less complexity. To avoid resource overflows/overruns the source code is carefully organized with a few functions and data types. μSim setup for Arduino and PIC16F84 MCU. Apart from the instruction decoder, this system simulates 1024 words of flash memory, 68 bytes of SRAM, two 8 bit GPIO ports, and register map similar to PIC16F84 MCU. Some of the common MCU peripherals and features such as interrupts, timers, and UART systems are not integrated into this simulator. The main objective of this project is to prov...

Today Carbon Monoxide ( CO ) meters are available in different forms. Overall, Carbon Monoxide meters sense CO fast and display the amount to the user and trigger alarm if it reaches a critical level. Compare with most of the DIY Carbon Monoxide meters, the project which we described in this article does not need any development platform or MCU / firmware. The Carbon Monoxide meter in this project design around using general-purpose ICs, such as NE556 and LM3914 . Prototype version of Carbon Monoxide meter The main component of this meter is the FC-22 CO Gas sensor module . This module consists of the MQ-7 sensor and can use to detect CO gas concentrations, anywhere from 10 to 10,000ppm. Apart from the sensor, this module consists of the LM393 comparator to detect the trigger level. In this design, we use both analog and digital output of the sensor module. The analog output use by the LM3914 LED driver and alarm system is drive using the digital output. Home made PCB with align...