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kk99's Blog

5 posts
Test Instrumentation Enter Your Electronics & Design Project for a chance to win a Grand Prize for Originality, a Tool Set, and a $100 Shopping Cart! Back to The Project14 homepage Project14 Home Monthly Themes Monthly Theme Poll   Micro:bit has a BLE interface which we could configure to work as UART service. In this example value of voltage on PIN P2 is transmitted via Nordic UART service present on micro:bit on every one second. When Bluetooth device is connected to micro:bit ...
I would like to present a simple thermometer with support for humidity measurement based on DHT11 sensor. This sensor is connected to the atmega328p which is responsible to reading the data. Recived data is presenedted on two seven segment displays: HP5082-7356. Below there is schematic. Both displays have BCD input and they are directly driven by atmega328p. For receiving data from the DHT11 sensor I have used library from this page: http://davidegironi.blogspot.com/2013/02/reading-temperatu ...
kk99

The Belson FM/AM radio

Posted by kk99 Oct 18, 2018
    I would like to present the really old transistor radio called Belson AM/FM. This radio was made in Japan. It is supplied by three 1.5 V batteries. It probably has around 45-48 years. It is preserved in very good condition. I have cleaned it inside. Below there is video from clean up process:   Below there is test of AM and FM band reception: I am really impressed quality of reception and sound generated by small nine-transistor radio with single speaker (0.25 W / 8 ohm ...
kk99

Wireless ECG

Posted by kk99 Jun 23, 2018
I would like to present my project which I made four years ago. It was wireless electrocardiograph which work with mobile device. Main presumptions of project: - simple analog front-end working with ARM device and responsible for data collection and transferring, - mobile device with android system as receiver which was responsible of data presentation, - Bluetooth connection via BTM-222 module.   As device responsible for data collection and pre-processing I had choose STM32F0Discovery bo ...
Few days ago I got TV with following issue: there is no way to power on TV (only standby LED is on). I have checked that all voltages on IP board (power supply and inverter) were correct. Next I have checked key elements on main board. After analyze of schematic I have found guilty: it was electrical capacitor 100 uF / 16V (C5068) located near 1.2 V LDO (placed under metal shield near the MCU). After replace of this element TV works properly. ...