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Remote controlled miniature 3 frequncies generator

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Feb 5, 2013
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Remote controlled miniature 3 frequencies generator

I am taking an electronics design class and we have a product-development project that is described below. I am trying to figure out how to go about it. The tricky part is the size of it. The frequency generation part has to be able to fit in about a matchbox and I have to spec out the parts required to built it.

Basically I need to be able to generate 3 different frequencies that are 5Vpp with 0.01-0.03mA. All 3 frequencies need to be independent of each other, meaning each one can be turned on/off irrelevant of the state of the others.

Example, all can run at the same time, or just 2 can run at the same time or any combination, etc. The circuit needs to be able to fit in a matchbox, be able to run for 60 mins and can be controlled in a very simple way from a remote control. I think the remote can be made to have simply 3 buttons , one for each frequency, where each button turns each frequency on or off.
Attached is also a small conceptual diagram that I came up with... Of course there might be other and more efficient or simple ways to do this ...Please advice! What is the simplest and smallest way built this? I will need to built a functional prototype of this by the end of the month.

Any input and help will be appreciated!
Thanks! design idea.jpg

TI CDCE906 PLL chip could be suitable - although you have not specified the frequency range and accuracy required so it could be an overkill.
Add to this a TCXO and microcontroller (+ firmware) and you could have a suitable design.
If frequencies and tolerance (jitter) requirement is low, a microcontroller could do, with the signal generated via software of internal timers.

The 3 frequencies that it needs to generate are 10Hz, 400Hz and 5Khz, independent of each other. Sorry but I am new to this but what do you mean by accuracy?

Personally I'd use a micro-controller for this job, and write some firmware to output these clocks. However presumably they would not give you a project that did not relate to your course contents (which I don't know). You could also do this with logic chips and even discrete transistors, resistors and capacitors. Using SMD parts you can pack a lot into a matchbox.
Good luck.

There are 2 parts to this; the remote and the frequency generation.

Use a microcontroller to generate 5 Khz; use this base to generate the other 2 frequencies on different pins.

Now, have 3 bit variables, the state of which is controlled by your remote.

Use each to 'AND' with the frequency being output from the micro Or use each to configure the pin as an input or output. You'll get the signal only when the pin is configured as an output, will be disabled if its made an input.


How are you getting the data from your remote to the micro? Assuming you have 3 separate pins for that, and the 3 pins you'd need for the output frequencies you need a micro with 6 or more I/O lines. I'm partial to pics, so I'd use a 16F628A. Also has hardware pwm, which would help.

Ard, do u know where I can find the code to program 16F628A, so that 3 of the pins will simple be trigger inputs(one toggle On, one toggle Off) and they will control 3 different outputs basically.... or may be just simple code that causes 16F628A to produce a sine wave, the frequency of which can easily be changed by changing a few numbers in the code...

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