Summer Projects for students

This post is for my students at college of engineering Attingal . We are going to get vacation during May and June. I think your semester examination will be over by April end. I have a small project which some of you can take up during this summer vacation. The project is related to amateur radio. If you are able to do it, this will be a fine minor project for your sixth semester. However, my aim is to introduce some of you to micro controllers and embedded systems early in your course. I don’t find many home brewers among students nowadays. This will be an ideal opportunity to learn a few tricks.

Now here is the idea. I have a few fixed frequency VHF transceivers. They are Philips Portaphone SXA rigs made around 1977. The figure below show one.

The transceiver can take 6 fixed frequency crystals on the receiver as well as transmitter side. That means it has only six fixed channels. Now ,I have a pair of crystals cut for the Trivandrum amateur repeater. (RX 145.600Mhz TX 145.00Mhz ). That means I am operating it only on a single channel.

I want to convert it to a variable frequency transceiver by adding a DDS ( direct digital synthesis ) controlled oscillator, replacing the crystal oscillator.

Your Task will be to build a micro controller board and a DDS board and drive the tranciever for covering the amateur band of 144-146 MHZ. You can choose either a PIC or an Atmel processor. For the DDS , an Analog devices AD9851 will be sufficient. There are some similar projects on the net. You can look here.

Do a search on google for DDS VFO .You will find more links. This project will be on similar lines. But the programming and driver circuit for the transceiver will be different . The output of DDS should be switched between receiver and transmitter frequencies. I will give you more details later.

You are expected to do the following

a) Study of the chosen micro controller.

b) Design the board and simulate it .

c) Study about DDS.

d) Design a DDS board.

e) Design PCBs for both the boards and build

f) Test the prototype in lab.

g) Make a suitable cabinet and build the final product.

A detailed requirement specification will be given later.

I have the following stuff with me .

a) Some PIC micro controllers

b) DDS chip AD9851

c) Some LCD displays

d) Assorted components.

I can provide you with a PIC programmer if you choose PIC. I can fund you for any costly ( say greater than $2). Rest of the stuff ,you will have to find out.

I can take 3 guys . Each one should do it independently.

You must be willing to work during vacation. I will be coming to college on a few days to college during vacation. Otherwise, you can interact with me on internet . A PC and an internet connection at home is a must. All designs and programs should be posted on internet and must be under a suitable free license.

I will give some preference to second year guys. (but first years can also be considered.). If you are interested , drop me a mail at vu2swx at gmail. com.