Using DS18B20/DHT22 temperature sensor with internal pull-up resistors rather than external ones

From harizanov.com 7 years ago in Blogs

I’ve been meaning to try Josh’s 4-line change to the OneWire Arduino library that enables using the popular DS18B20 temperature sensor without the otherwise required external 4.7K pull-up resistor on the DQ line for quite some time now. It is sometimes hard to solder those pesky resistors on SMD PCBs, and...

Articles from Martin Harizanov

Meet the PS Thermo

From harizanov.com 2 years ago in Blogs Featured

PS Thermo is a control hub I developed for proSmart, it is designed to control/act as a gateway for various sub-GHz RF wireless sensors/actuators. In essence, it is a much more advanced version of the BBoilRF thermostat project. The PS…

Embeddica

From harizanov.com 3 years ago in Blogs Featured

It was roughly a year ago when I decided to spinoff the embedded software/hardware R&D activities I was heading at proSmart to a separate entity. This is how Embeddica was created, a team of highly skilled embedded software/hardware development professionals…

Thoughts on structuring a productive software development team

From harizanov.com 3 years ago in Blogs Featured

I recently spoke with a friend of mine, who is now a software development team manager in a Fortune 500 listed company. He shared with me that his managed teams work using agile methodologies and consist only of software developers.…

Using mTLS to secure IoT solutions

From harizanov.com 3 years ago in Blogs Featured

While delivering on the promise of streamlined efficiencies and operational insights, smart IoT devices also present a new and more widespread threat to users and personal data. No one really needs reminding of the security implications of IoT. Think of…

IoT sliding door opener

From harizanov.com 3 years ago in Blogs Featured

My front gate has joined the Internet of Things and is now controllable from my phone. The sliding door opener is a Beninca BULL 5M. The project is DIY, based on ESP8266 + MQTT and I can now open/close/read the…

Human-Machine Interface (HMI) modeling and implementation using event-driven finite-state machines

From harizanov.com 3 years ago in Blogs Featured

Modern HMIs are built as graphical user interfaces (GUI) with touch-based user interaction. Complex HMI development is always challenging because of the dynamic nature of the required behavior, underlying functions, and graphical design. Building a PoC prototype through code is time-consuming,…

Experimenting with a 3.5″ TFT

From harizanov.com 3 years ago in Blogs Featured

I decided to test a 3.5″ TFT version of the TFT32 project as the original version’s 2.4″ 320×240 TFT is a bit small-ish. The TFT I chose is an ILI9488 480×320 3.5″ with resistive touch. The upgrade was pretty straightforward,...

People-Tools-Processes

From harizanov.com 3 years ago in Blogs Featured

As an IT team manager, I am responsible for forming highly engaged and efficient teams. Building an agile team requires a fine balance of skilled and motivated people, fine-tuned processes and proper tool selection.Put too much focus on people and...

DEV.BG tech talk #3

From harizanov.com 3 years ago in Blogs Featured

I did a tech talk about the TFT32 project on Feb 5th 2019, here is my presentation, if interested. Some photos from the event: Page views: 8

ESP32 OTA firmware update using compressed firmware image over HTTP (s) / MQTT (s)

From harizanov.com 3 years ago in Blogs Featured

Performing OTA firmware update over a slow/unreliable connection may be challenging. I have had many cases, where the nodes to be updated are in a remote rural area with a 2G modem internet connection, and pushing a 1.1MB firmware file...