Sunday, April 28, 2013

Review of Playduino One PTH DIY Kit

I purchased this simple DIY kit from eBay ( Item number:180977979792) for 10 usd. The kit do not include MCU, but I already have several Atmega328 chips and decided to try it. I found some online description for this product here. It Arduino Duemilanove compatible PCB with all DIP components, really easy to solder. Not from the newest versions of Arduino, but still useful. After the solder work was done the kit look like:

The PCB comes without FTDI chip. External CP2102 TTL module required for communication with software on the computer. But first, Atmega328 should be pre-flashed with bootloader. Because my MCU was blank I used USBasp programmer to upload the bootloader to Atmega. The board has ISP connector with MOSI, MISO, SCK, RST, VCC, GND pins. Follow this link for "How to upload bootloader". Arduino software reported some SCK synchronization warning after programming, but seems everything was successful and  bootloader was installed correctly. I connected FTDI module and tested the default LED blinking sketch.

I would recommend this DIY kit because of low price, but it require soldering and some firmware workaround. The drawback is that you need external TTL module, MCU and AVR programmer, but if you already have all of them, then it maybe good solution for cheap Arduino board.

Monday, April 15, 2013

New Design Simple Radiation Detector DIY Kit

High voltage converter based on self-induction circuit, where square waves drives NPN transistor to produce high voltage spikes over 10mH inductor. After multiplication we can get 350V-450V anode voltage. As before the PCB include high impedance voltage divider for easy calibration.

The kit compatible with Arduino, i.e. it can be used for sending interrupts to MCU. Please download user manual for more technical details about the kit.

PCB allow installation of SBM-20, STS-5 or J305 Geiger tubes. Soldering process require moderate solder skills. 

The kit can be used as nuclear radiation detector or, if you connect it to Arduino, as a part of COSM monitoring station / dosimeter. We supply 2 simple arduino sketches for the beginners, you can modify it to your needs.

Saturday, April 13, 2013

New Geiger Counter with PIC16F876A Prototype worklog updates

I'm working on new Geiger Counter based on PIC16F876A. It has absolutely new design. All functions including high voltage generating are assigned on the processor now, its mean no additional IC's. No more 555 timers and no logic IC's. So lets say more about software:

1. Measurement time is auto adjusted, depend on radiation level. It guarantee better accuracy on low background levels and also fast response to high levels. Time countdown is also displayed on the LCD.
2. PWM controlled high voltage stage. User can calibrate high voltage from 300V to 500V in menu. The tube voltage is also displayed on the LCD in real time. The ADC use different Vref, not from supply rail.
3. UART, Arduino, Geiger Bot communication.
4. Calibration menu with Alert threshold, Conversion factor. Parameters may be saved to EEPROM.

This work is still in progress, please follow updates. When it will be finished I think I'll run it like a new kit.

Wednesday, April 3, 2013

Online Radiation Monitoring Feed with Cosm

For online monitoring of current radiation level I created COSM feed here:

I will try to keep it online most of the day time. The hardware that used its my DIY Geiger Counter, Arduino UNO with Ethernet Shield and SBM-20 tube. I modified the example arduino sketch to feet my conditions. Please follow.