Ham Radio Operators

Homebrew 90 watt CW / AM transmitter built by N5RMS. The transmitter uses a 6AG7 oscillator and a 6146B in the final. The tubes on the right side are a screen modulator and the two tubes in the power supply are voltage regulators for the screen voltage and bias. He done a great job on this project. This is the type of homebrew project I like to build.

 

Mauldroppers CB Radio Forum

20*4 LCD

Dear all,

We have done 20*4 LCD being driven by Arduino for one of the Bsc College project for science fair.

. 

SOLAR USB CHARGER

Dear all,

We have made a Solar USB charger for science exhibition in one of the Bsc college,

Tuesday, February 25, 2014

ALCOHOL SENSOR USING PIC16F887

Dear all,

As a College project we  made an Alcohol sensing micro controller using PIC16f887and MQ3 sensor. When it sense the alcohol the buzzer will turn ON.

BATTERY BOOSTER TESTING

Dear all,

Test setup of Battery booster is in the below figure:

This battery Booster is designed for 20A and claims for 10A. We tested it upto 5A.

Bootloading/Burning hex file to Atmega328 using Parallel port

Dear all,

While working using arduino, Bootloader has crashed, we came with the solution for bootloading/burning hex file into Atmega328 without arduino using icsp pins in microcontroller and parallel port. we have taken the circuit and explanation from avrprogrammers.com.

Here is a solution for Bootloading/programming Atmel atmega328 uisng ICSP pins.

Connect the atmega328 pins(MOSI, MISO, SCK, RESET and GND) as shown in schematic, power up the circuit with five volts. To do this I have used the ISP Programmer 1.2.0.56.
For software click here.

Here is the procedure for using this software:-

Monday, March 10, 2014

VXO

Dear all,

We wanted to make a simple solution for Lake City Net operating at 7085KHz daily between 8:15Am and 8:30Am. We have chosen IF as 4915KHz for which standard low cost crystals are available. This requires a LO of RF+IF=12MHz, We have happily configured a 12MHz VXO. This VXO fortunately covers 11995KHz also giving rise to coverage of CHARMINAR NET operated at 7080KHz daily until 8Am. Below is picture of experimental VXO and the table contains test result.

Different values of the crystal with different capacitor in X position

LAKE CITY SPECIAL

Greetings to all,

Lake city special RX (7085KHz) comes with few modifications in the GR40 RX. VXO works @12MHz, BFO 

and IF filters works @ 4.915MHz. i.e (12MHZ-4.915MHz=7.085MHz).
The block diagram and schematic are given:

EXPERIENCE WITH BUCK REGULATOR

We want to see the characteristics of buck regulator given in datasheet of SG3524. This is our first experience of BUCK Regulator (5V) without using the transformer and is working very nice.

Instead of TIP115 PNP transistors easily available BC557 and BEL369 are used to form the Darlington pair. The Input current drawn is 100mA@20V with the output of 300mA@5V. The circuit is working at 10 KHz frequency and the inductance is 1.2mH. The Core and bobbin are purchased from the JINANICA.TO increase the efficiency of the circuit schottky diode is used.

The circuit Diagram is taken from the SG3524 datasheet: click here fig 3:

The pictures of buck regulator is given below:

BUJJI TX

Season's Greeting to all,

Here we come with a cute (BUJJI) Tx of 500 mW of power. This transmitter work at 7084 KHz or 7079 KHz frequency which is South India's famous LAKE CITY/GARDENCITY NET and CHARMINAR NET. The frequency of the Tx is stable because of the Crystal IF and is designed to operate with 9 V battery, 

The entire Tx will come in the NUTCASE box. Further details of the Tx will be updated soon.

0.1dB CHEBYSHEV L.P.F for Bujji Tx.

Dear all,

0.1dB CHEBYSHEV L.P.F for Bujji Tx  is given below, with a cutoff frequency of 10 MHz, The actual circuit is taken from the ARRL Hand book.

We connected 47E load in the output to the check the performance. The performance is satisfactory. 

AVR Electronics Kit Project

Page last updated on: Sunday, March 30, 2014 Share on facebookShare on twitterShare on emailShare on printMore Sharing Services10 Assembled My Morse Guide Badge 'My Morse Guide' -  an AVR Electronics Kit Project My Morse Guide is an electronics kit aimed at young people.  The kit delivers both some fun in soldering the kit together as well as having a kit for playing with Morse code   My Morse code is a project by Ivo PA1IVO, Leo PA0LEZ andMarianne, and is a successor to the successful Share Your Morse project for the Jamboree On The Air 2013 at Scouting Elfregi Zaanstreek.  The My Morse Guide electronics kit delivers the following functionality after it is successfully soldered together. • the (pre-programmed) name of the owner is sent in Morse code, or the radio call sign in case of a radio amateur • all the characters, numbers and NATO alphabet words are sent in Morse code one at a time • the (pre-programmed) secret words are sent in Morse code, one at a time • With the '(Speaker/LED)' key the speaker and LED can be switched on and off for sending Morse code • the pitch of the Morse tone can be set • the speed ('WPM') of the Morse code can be set It is possible to send Morse code yourself with the kit, or an external Morse key can be connected.  Circuit diagram and further information is at http://ivok.home.xs4all.nl/electronics/MyMorseGuideElectronics.html Share your Morse  http://ivok.home.xs4all.nl/electronics/MorseSounder.html 'My Morse Guide', an AVR Electronics Kit Project My Morse Guide is an electronics kit for children and other people interested. The kit delivers both some fun in soldering the kit together as well as having a kit for playing with morse code. My morse Guide is a project by Ivo PA1IVO, Leo PA0LEZ and Marianne, and is a succession of the successful Share Your Morse project for the Jamboree On the Air 2013 at Scouting Elfregi Zaanstreek. This page contains a technical description of the project. At the moment only a Dutch version is available, and will be sold and build during the VERON Pinksterkamp 2014 (Dutch site). On this page also information about ordering a kit can be found. Sorry, currently we do not do deliveries outsite of the Netherlands, unless the demand is sufficient to produce an 'English' batch. Er is ook een pagina met algemene informatie in Nederlands aanwezig. Main functionality The My Morse Guide electronics kit delivers the following functionality after it is successfully soldered together. With the 'Mijn Morse' key the (pre-programmed) name of the owner is sent in morse code, or the radio call sign in case of a radio amateur. With the 'ABC...789...Zulu' key the all characters, numbers and NATO alfabet words are send in morse code one at a time. With the 'Woorden' key the (pre-programmed) secret words are sent in morse code, one at a time. With the '(Speaker/LED)' key the speaker and LED can be switched on and off for sending morse code. With the '(Toonhoogte)' key the pitch of the morse tone can be set. With the '(Snelheid)' key the speed ('WPM') of the morse code can be set. With the 'Key' key it is possible to send morse code yourself with the kit, or an external morse key can be connected via the PCB terminal block (short-circuit for key down). Schematic The schematic of the electronics is displayed below. Electronic schematic. Component list Description Name/value Part(s) AVR Microcontroller ATtiny85V - PDIP IC1 IC socket 8w IC socket machined contacts N.A. Speaker 41.T70P015HLF Ls1 Battery clips Keystone 2468 N.A. Batteries Panasonic Batteries LR03XWA/B2 Bat1/Bat2 LED Multicomp OVL-3324 LED1 Capacitor 100 nF C1 Switches Alps SKHHARA010 Mijn Morse Woorden Key ABC PCB Terminal Blok 2WAY, 26-12AWG N.A. Resistor 560 Ohm R1 Resistor 100 Ohm R2 Resistor 10k Ohm R3 Table 1: Component list. AVR Selection The heart of the logic of this kit is based on a small AVR microprocessor. The selection for a chip in the AVR range is only based on previous experiences with AVRs, and therefore the availablity of software, programmers, and knowledge. A PIC microprocessor should probably also be able to do the job. The AVR selection was based on the following criteria: Low price Dual in-line package, so easy to solder for small childeren Low voltage, minimum 1.8 Volt was preferred over 2.7 Volt, as we are using two AAA batteries Maximum memory taken the criteria above into account By using the AVR Compare Devices page (well done!) we selected the ATtiny85V, which has only 8-pins in a DIL housing, a supply voltage down to 1.8 Volt, and the maximum memory in this range. Speaker Selection We looked for a small speaker, being a speaker and not a piezo buzzer. With a real speaker you are able to change the tone frequency, which is not possible with a piezo. The speaker selection was based on the following criteria: Low price Easy to mount on a PCB by just soldering Availability on the semi long run (in case more kits have to be produced) Reasonable sound production, both in volume and in tone clearness. It is hard to find small PCB mounted speakers that are not piezos. We found one at Farnell (it's really a speaker, we opened one ....). It clearly peaks in volume at the resonance frequency of 2048 Hz, but it is still usable a few hundred Hz above and below the resonance frequency. Software The AVR software was developed with Atmel Studio, and therefore written in the C programming language. Pictures All (electronic) components to build one kit. Front and back side of the printed circuit board (PCB). Connection for an external morse key and the empty battery holder. Research and development for the My Morse Guide project. An AVR Dragon programmer is used to perform high voltage serial programming (HVSP) to the AVR. HVSP is required to be able to use the reset pin of the AVR as an extra input. © 2014 by Ivo Klinkert, PA1IVO - Contact Share Your Morse, a JOTA 2013 AVR Electronics Kit project A project by PA1IVO and PA0LEZ. A link to the non-technical page for the JOTA scouts (in Dutch) can be found here. Last update: 3 September 2013 - This page will be completed later..... Idea To be added here. Schematic Electronic schematic. Component list Description Name/value Part AVR Microcontroller ATtiny85V - PDIP IC1 IC socket ASSMANN WSW AR 08 HZL-TT N.A. Speaker 41.T70P015HLF Ls1 Battery clips 2468 N.A. Batteries Panasonic Batteries LR03XWA/B24 Bat1/Bat2 LED Multicomp OVL-3324 LED1 Capacitor Murata RPER71H104K2K1A03B 100 nF C1 Switches Alps SKHHARA010 S1/S2/S3 Power switch safety pin Veiligheidsspeld Resistors 100/560/10k Ohm R1/R2/R3 Table 1: Component list. AVR Selection The heart of the logic of this kit is based on a small AVR microprocessor. The selection for a chip in the AVR range is only based on previous experiences with AVRs, and therefore the availablity of software, programmers, and knowledge. A PIC microprocessor should probably also be able to do the job. The AVR selection was based on the following criteria: Low price Dual in-line package, so easy to solder for small childeren Low voltage, minimum 1.8 Volt was preferred over 2.7 Volt, as we thought of using two AAA batteries Maximum memory taken the criteria above into account By using the AVR Compare Devices page (Well done!) we selected the ATtiny85V, which has only 8-pins in a DIL housing, a suuply voltage down to 1.8 Volt, and the maximum memory in this range. The ATtiny85V has two 8-bit timers, where one is used for the morse audio tone and the other as a random number generator to randomly select new 'secrets words'. Speaker Selection We looked for a small speaker, being a speaker and not a piezo buzzer. With a real speaker you are able to change the tone frequency, which is not possible with a piezo. The speaker selection was based on the following criteria: Low price Easy to mount on a PCB by just soldering Availability on the semi long run (in case more kits have to be produced) Reasonable sound production, both in volume and in tone clearness. It is hard to find small PCB mounted speakers that are not piezos. We found one at Baco in IJmuiden, and one at Farnell. Because of the slightly better tone and the availablility of 16000, we select a small PCB mounted speaker from Farnell. PCB To be added here. Software The AVR software was developed with Atmel Studio, and therefore written in the C programming language. Morse tone using PWM To be added here :-). Encoding the morse words and program into 512 kB To be added here :-). Pictures and movies All electronic components. The batch of 30 PCBs arrived from China. Movie of a ready badge with a small explanation in Dutch (original video on YouTube). Improvised movie (in Dutch) of the prototype, taken during a JOTA preparation meeting. "Share Your Morse" badge prototype: Software testing. © 2013 by Ivo Klinkert, PA1IVO - Contact