An extremely simple and low cost Sine/Square wave generator based on the Analog Devices AD9835 Direct Digital Synthesis (DDS) Generator chip. The frequency can be set for any frequency from 1Hz to 10MHz in 1Hz resolution steps! All this with three push buttons and a novel "sliding window" LED display. The controller chip is a Microchip PIC16F628. There is no wiring, and the PCB fits into a standard UB3 Jiffy Box.

Read the complete Project Article in HTML format.

The Schematic Diagram in GIF format.

The Front Component Overlay in GIF format.

The Back Component Overlay in GIF format.

The Front Panel in ZIPed PDF format

The Front Panel in ZIPed EPS format

The PCB file in Protel format.

The SOURCE CODE and HEX file for a 16F628 and HiTech PIC C Compiler.

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Here I am reviewing an Instek function generator:

STOCK UPDATE:

I have ran out of kits and PCB's for this project and I no longer support it in any way. All the information I have is on this website

Unfortunately I will not be selling the AD9835 chip, it is available in stock from Farnell Components for $33.79+GST, Cat# 334-3042

Other suitable components are:

50MHz XTAL Osc - Farnell# 788-533
R/A RCA Socket - Jaycar PS-0279
RCA to BNC daptor - Jaycar PA-3655

The Rev1 PCB as shown in the Silicon Chip article, this means that R1, R3, C13 have to be retrofitted on the underside of the board as shown in the article. The Rev 2 board downloaded from here does not have this issue.

The modifications are as follows:

- Cut the track from pin 1 U5 to C12
- Add C13 from pin 1 U5 to pin 6 U1 (positive to U5 if your cap is polarised)
- Add R1 and R3 from pin 1 U5 to GND and Vcc respectively

- Please note that C15 and C14 are marked with incorrect polarity on the supplied Rev 1.0 board.

Questions?/Comments? EMAIL:  david AT alternatezone DOT com

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