Capturing WiFi Beacon Frames, Probe Requests and Probe Responses in Python with Scapy

WiFi is almost everywhere. Wherever you go there are WiFi packets emitted by smartphones, tablets, computers, access-points, etc. All WiFi packets “flying” around are divided into four main groups (802.11 Frame Types) – management, data, control and extension. In this article we will take care of capturing some interesting subtype packets of management group (Beacon … Read more

Packet sniffer in Python with Scapy

The common method of making a packet sniffer in User-Space is to use low-level operations on RAW sockets. But, instead of that, you can just use a powerful Python library – Scapy (see documentation), which exposes a user-friendly high level API. So, it hides all unfortunately low-level abstraction which we don’t really like in Python. … Read more

Generating true random numbers using floating ADC input – myth or facts?

This article shows the feasibility of using ADC input of AVR chip as a source of True Random Number Generator (TRNG). I have prepared the testbed and recorded via UART (115200; 8N1) about 50’000’000 of 32bit random numbers. The tests took about 11 hours (including a time I spent to pray to UART for a … Read more

AVR development board for ATtiny13, ATtiny85, etc.

This is an upgraded version of MBAVR-1 – a minimalist development board for tiny AVR microcontrollers like ATtiny13, ATtiny15, ATtiny25, ATtiny45 or ATtiny85. The board has been designed for a rapid prototyping of devices based on tinyAVR chips. The small-size MBAVR-1t board can be installed directly on protoboard or used as shield by other PCB. Also, by adding DIP8 holder you can … Read more

How to make ATtiny13 running at 128 kHz clock source

The ATtiny13’s default clock source setting is the Internal RC Oscillator running at 9.6MHz with clock divider /8 (fuses L=0x6A and H=0xFF; see fuse calculator). This short article explains how to downclock the ATtiny13 by swtiching to Internal RC Oscillator running at 128kHz without clock divider (fuses L=0x7B and H=0xFF) and still have a control to program AVR … Read more

ATtiny13 – PI metal detector

This experimental project shows how to build a simple PI (Pulse Induction) metal detector based on ATtiny13 / AVR microcontroller. My goals were to make a circuit as simple as possible and to use only popular / cheap electronic parts. The device has been tested with very small coil (55mm diameter, about 30 turns of 0.5 … Read more

ATtiny13 – 8bit mono class D amplifier

I always wonder whether it is possible to make an amplifier of class D on ATtiny13 or not. Some time ago I found George Gardner’s project based on ATtiny85 – TinyD. It was a sign to start challenging it with ATtiny13. It took me a few hours but finally I made it! The code is very short and useses a … Read more

ATtiny13 – randomly flashing LED with PRNG based on BBS

This project is very similar to ATtiny13 – randomly flashing LED with PRNG based on LFSR. However, this time I used BBS (Blum-Blum-Shumb) algorithm as PRNG (Pseudo Random Number Generator) to generate 16-bit (pseudo) random numbers. The less significant bit of randomly generated number is a major factor in decision to on/off the LED. The code is on Github, click here Parts Required … Read more

A few funny projects using my simplified implementation of DFT

Bilexa Bass – Singing Fish, Sound-Actived 3D-printed Vibrator and Scared Spider Toy. I wanted to highlight these funny (sometimes crazy!) projects as they are using my version of simplified implementation of DFT I created for project ATtiny13 – dance lights with DFT and because the authors are very idea-driven, original and just awsome. Bilexa Bass – Singing Fish (Bob, ATtiny84) … Read more