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/
http://radiohobbystore.com/radiation-logger/
RH Electronics https://rhelectronics.store
Thursday, October 17, 2013
Friday, September 27, 2013
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.
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.
Saturday, August 3, 2013
Geiger Kit with PIC16F648A
Geiger Kit with PIC16F628A was sold out yesterday. It was nice project for DIY soldering with big PCB and all through hole components. I didn't ordered new batch of the PCB's because I decided completely to redesign this product and make it more fun with modern SMT components. Firstly I'm going to make a SMD kit that will require hot air soldering. Sorry if you expected DIP project, but I'm going to try something new.
The new goals of this project:
The new goals of this project:
- Small size, 3.3V VDD, Lipo 3.7V battery support and tiny current
- CPM, CPS with new algorithm of collecting data
- Gamma quantum counting, each particle can be counted on the display
- uSv/h and uRn/h selection
- UART logging
- Audio Jack for Geiger Bot or headphones
- Smart USB charging of Lipo.
- PWM high voltage generating
- Option for user to edit EEPROM table for changing settings
Practical method to make prototype PCB's at home it's press-n-peel toner transfer. The photo show one of the first PCB of the prototype I have made. The design is not final.
Lipo charge circuit with 3.3V stabilizer under test.
Almost finished board, just several components left to solder. Now PIC16F648A processor is used because the project require more memory.
And the finished prototype current only 3.50mA - 5.50mA
The work is still in progress. I like it has small power consumption that even 300mAh Lipo can be used.
Thursday, July 18, 2013
Radiation Monitoring Feed back online
RH Electronics monitoring feed back online!
https://xively.com/feeds/122314/
It was down since COSM service became Xively.com, they changed API and published new Arduino libraries. My simple Arduino code for sending CPM values from Geiger Kit via Arduino is here:
https://github.com/RH-Electronics/Xively
https://xively.com/feeds/122314/
It was down since COSM service became Xively.com, they changed API and published new Arduino libraries. My simple Arduino code for sending CPM values from Geiger Kit via Arduino is here:
https://github.com/RH-Electronics/Xively
Thursday, July 11, 2013
RH Electronics GitHub
RH Electronics GitHub is here:
https://github.com/RH-Electronics
The projects with open source can be found there!
https://github.com/RH-Electronics
The projects with open source can be found there!
Wednesday, July 10, 2013
XR2206 DIY Kit in stock again
http://radiohobbystore.com/function-generator-xr2206-diy-kit-20hz-100khz.html
XR2206 DIY Kit back to stock again. Now only for 20.00$!
XR2206 DIY Kit back to stock again. Now only for 20.00$!
Thursday, June 13, 2013
Geiger Counter DIY Kit with Nokia 5110 LCD Release
New Geiger Kit module is available for sale now:
http://radiohobbystore.com/diy-geiger-counter-kit-with-nokia-5110-lcd-pic16f876a.html
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