Blog Archives
Posted on 08 May 2008
Author writes:This watt meter project is very similar to my last wattmeter project. The main reason I made a new project is becasue I needed a unit which could handle higher power than 1W. I found a 50 ohm dummy load which could take 50W of power. Of course I could use attenuates for my 1W meter, but I prefered to build a new unit. The new thing with this project is that it will only display the power in Watt on the LCD display. This means that I will not need so many EEPROM to store display data (more about this later).First we need to update our knowledge how to measure RF power: Some figures and text comes from my last wattmeter project, but it can be good to read it to remember. [more]
Posted on 13 Feb 2008
This is a Quickie Servo Tester.The project is based on a ATMEL AT90S2343 MCU with 8 pins. This little MCU is very nice in that it has 2k of Flash Program ROM, 128 bytes of RAM, and 128 bytes of EEPROM. That is a lot of power in a little 8 pin package. It has five I/O pins of which we are using four in this project.[more]
Posted on 13 Feb 2008
This is a very cool project for all hobbyists.It is a PIC16C71 based 4-digit LED frequency-counter & Volt-meter. Some hard to find parts used in the previous version, which are out of production for some time, has been omitted. A rather early PIC16C71 has also been replaced by 28-pin device PIC16F876. The later is capable of driving 4 digit LED display in multiplexed mode while measuring frequency, power supply voltage as well as handle two analog inputs to display SWR/PWR signal strength in a bargraph manner. There is no need for external LED display driver chip as well as external data EEPROM since it is already implemented in PIC16F876.[more]
Posted on 12 Feb 2008
The DTMF decoder 2 is a useful tool used for decoding DTMF (Dual Tone Multi frequency) generated by telephones. The decoded digits are viewed on a 16×2 LCD screen. The DTMF decoder can be directly connected to a Serial port to view the digits in HyperTerminal on a computer. The decoder stores the last 234 received digits in EEPROM. The contents of EEPROM can be viewed on the LCD screen via two scroll buttons. Total power consumption is 12mA. The DTMF decoder has two inputs. A RJ11 jack for connecting to the phone line and a 1/8″ audio jack for connecting to a scanner, tape recorder or other audio output device.[more]
