MyGeiger second edition DIY Geiger Counter Kit released

MyGeiger Dosimeter DIY Kit is officially released on RH Electronics website.
MyGeiger ver. 2.00 has carefully crafted electrical circuit with new and reliable software. As a result, now we have more professional and stable device with all important for portable dosimeter functions.  The project still kept easy for soldering. You need to solder only DIP through hole components when all SMD already pre-soldered.

 

The kit has built-in USB logging support and lithium charger on-board, ready for your 3.7V Li-Ion battery.

MyGeiger ver.2.00 now support 400V and 500V popular Geiger tubes, such as SBM-20, SI-29BG, LND-712, LND-7317 and more.

 

Arduino IDE Geiger Counter DIY Kit with SD Shield Board

New Arduino based DIY Geiger kit released. It comes with 2 models. The simplest and cheaper version support eeprom logging and the second version comes with SD card shield. The main pcb board of both kits are same, SD shield allows to use micro SD card for saving lots of radiation logs with GPS data.
For more technical details please follow product links:

1. Arduino IDE Geiger Kit with eeprom logging
2. Arduino IDE Geiger Kit with SD Shield

New website launched

New website launched:
http://www.rhelectronics.net/store/ 
You should be redirected by auto from old http://radiohobbystore.com  to the new store.

Arduino IDE prototype of Geiger Logger with SD cart and GPS function

Arduino IDE prototype of Geiger Logger with SD cart and GPS function. Will be open source project.
I have used bargraph from BroHogan geiger kit. The project is not pin to pin compatible with BroHogan, has different schematic and different code. Schematic has less components that make the project simple to solder.
It took for me about 2 weeks to study Arduino IDE, have never used it before, so it my first Arduino project.  

DIY Thorium Isotope Generator made by Weirdmeister

http://weirdmeister.de/thorium-cow.htm

Weirdmeister provide excellent guide for DIY Thorium Isotope Generator. You can find more photos and information about this project on his website.

New version of Radiation Logger software 1.4.0.0

New version of Radiation Logger software 1.4.0.0 is available for download. Now it support direct logging to http://xively.com

http://radiohobbystore.com/radiation-logger/

AD9850 DDS Module from eBay

Some time ago I purchased several modules from eBay AD9850. It's cheap and can be controlled almost with any micro by parallel or serial load mode. But when you see something cheap beware, there is some trick possible, especially when it come from China.

It took me several hours to read and understand how to calculate 40-bit word for loading desired frequency. I made small program that can be used for controlling HF receiver DDS VFO.

During experimenting with the module I have noticed that the board produce to much heat. The current was about 120mA that seems to be not OK. I rechecked all connections and resistors, but not found any reason. The module was stated for 5V power supply in the datasheet and also all circuits I found online use this module with 5V. My ham friend, who rapidly found the reason for exceed heating, said that probably 125MHz oscillator installed on this module originally are 3.3V and not 5.0V oscillator. We reduced the power to 3.3V and added LC-filter. The heat disappear and the current measured about 60mA that's seems to be a normal for AD9850 chip (20mA) with Oscillator (40mA).

  Unfortunately the module PCB designed in way that's it's impossible to separate AD9850 and Oscillator VDD lines. We need to run it on low 3.3V and lose some stability of chip start-up. Probably the blue potentiometer calibrating voltage on pin#15 may help with the issue.

I think this modules was originally designed for 5V Oscillators, but 3.3V was installed in the manufacturing. That's why it's was sold with cheap prices on eBay. Anyway we can use it. The stability of sine waves and module usability cost it's several bucks. The quality of total harmonic distortion are excellent for home-brew.