Turn-key PCB assembly services in prototype quantities or low-volume to mid-volume production runs

Simple NetworkAble RFID Controller

Simple NetworkAble RFID Controller

Popular known as SNARC, which is designed by Lawrence “Lemming” Dixon at the Hackerspace Brisbane (HSBNE). SNARC provides a simple platform for network controlled RFID access. It has a microcontroller, Ethernet module, connector pins for an RFID reader (5V, TX, RX, and GND) and an N Channel MOSFET output on board. This makes it a convenient solution for applications where a device needs to be powered or triggered via an RFID card while its access rights are stored somewhere in the cloud, e.g. doors in office buildings etc. SNARC comes with an ATMega328p chip and Wiznet Ethernet module (both of which are used by Arduino as well), which makes it fully compatible to the Arduino platform. The ATMega chip comes with an Arduino bootloader, i.e. you can use your Arduino IDE and run Arduino sketches on the board, by simply uploading them through an FTDI cable. SNARC is not released for official sale yet, but apparently will be soon. So stay tuned. Or shoot HSBNE an email if you’re interested to get a prototype. However, A minor disadvantage is that you… Continue reading

Simplest RFID tag on AVR

This is real electronics porn. Simply speaking RFID tag is built by using AVR Attiny85 and small inductor. The power pins of AVR aren’t connected at all. It works, but how? Secret lies behind nature of IO/O pins of AVR. Coil connected to input pins power chip itself via clamping diodes. Once power problem is solved there is one more – chip clocking. Because voltage is too low to start chip internal oscillator. So coil also is an external clock source. This is why it has to be connected to AVR clock input. As RFID frequency is 125kHz so the AVR is also clocked at this rate. Firmware also has to perform on edge of resources. Probably to have reliable operation you would add couple capacitors and bigger coil. In other hand this is great hack showing how low can AVR go. Continue reading