It’s been quite a while that I wanted to treat myself to a new soldering station, and recently I found out about the Weller RT active tips which are great for building a soldering station. The whole station from Weller is really expensive, but the tips cost only around 25€. They are active, which means that they contain the heating element as well as a thermocouple temperature sensor. I got inspired by several similar projects on the web, like this one, this one or this one.
BLEthingy is a battery-powered, wireless sensor node device. The device is powered by a CR2032 coin cell battery and is designed to consume as little power as possible. Wireless connectivity is provided via Bluetooth Low Energy (BLE), which allows for low-power transmissions e.g. as a so called Beacon. The BLE functionality is provided by a RN4871/I module. It communicates via UART with the main microcontroller. The microcontroller used is an ATtiny3216 which is part of Microchip’s new tiny-1 series. Despite the name, it’s very different than the previous ATtiny’s (like the ATtiny85, ATtiny13 etc.) and has a lot more features and peripherals. Another feature I wanted to include is motion detection, for this purpose an accelerometer ADXL345 is used. In this post I’ll talk about the hardware design of the device.
In the last blog post, I showed how we can create audio sginals using PWM on a STM32F1 microcontroller. But since the memory space available on the microcontroller is really small, we can’t store a significant length of audio recordings. Thus I decided to use an external meory and went for a SPI flash memory chip, the Winbond W25Q64JV. In this post, I’ll explain how to use it and read/write it with a microcontroller, in my case I use the STM32F103.
In this post I’m going to show how we can use PWM to playback audio on the STM32F103 microcontroller. In the previous post I explained some theory about how to generate analog signals with PWM, now we’ll see an example of how to realize it.
Puls-Width-Modulation (PWM) can be used to implement a simple digital-to-analog converter to create analog signals with a microcontroller. There exist two modes of PWM, a left aligned asymmetric mode and a centered symmetric mode.
The serial port is a very commonly used interface for communicating between a microcontroller and a PC for debugging or sending or receiving some values. Most microcontrollers include a hardware peripheral called UART (Universal Asynchroneous Receiver Transmitter) which handles the serial communication, but some especially small microcontrollers (like the ATtiny24a that I am using) don’t have one.