Homebrew Function Generator

Thread Starter

kyle7119

Joined Feb 11, 2011
84



Frequency Counter

The square wave is fed into a digital input on an ATMega328 microcontroller. The digital input is triggered every time the square wave rises above the logic high threshold. The microcontroller samples the pin at a high rate and counts the number of cycles per second. This number is sent to the display via the MAX7221 display driver.

https://forum.allaboutcircuits.com/attachments/frequency-counter-png.74142/

Power Supply

The step down isolation transformer is fed through a bridge rectifier. The center tap is tied to ground to provide both a positive and negative supply. The rectified voltage is regulated to a ±12 V line and a +5V line (for the digital logic ICs).

https://forum.allaboutcircuits.com/attachments/power-supply-png.74141/

XR2206 and Amplifier

The XR2206 is configured according to the recommended circuit on the datasheet. The output is selected via a 3x3 rotary switch. This toggles the output feed, the symmetry adjustment, and the amplitude fine adjust, allowing these variables to be configured independently for each waveform. The XR2206 output is fed through a buffer amplifier and then a potentiometer to control amplitude. After this, the wave is summed with a DC voltage to adjust the DC offset. The AD811 amplifier drives the final output stage.

https://forum.allaboutcircuits.com/attachments/xr2206-png.74140/

 

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Wendy

Joined Mar 24, 2008
23,415
If you want I could send you a bunch of decals from my label maker. Modern label makers leave the old ugly Dyno labellers in the dust, and look quite good. PM me if interested.

Nice work, very professional looking.
 

studiot

Joined Nov 9, 2007
4,998
Looks good outside, will certainly look better with labels.

Any inside pics?

You have a sync output socket (good idea), but I can't find it on the schematic?
 

Thread Starter

kyle7119

Joined Feb 11, 2011
84
Looks good outside, will certainly look better with labels.

Any inside pics?

You have a sync output socket (good idea), but I can't find it on the schematic?
This was actually a school project and I ended up cannibalizing parts after the project was turned in. I just used protobard with socketed chips and some static free foam to insulate it from the case. Kinda a hack-job.

I tried adding the sync but never got it working in time. The output was there as a place-holder just in case.
 

Thread Starter

kyle7119

Joined Feb 11, 2011
84
Where is the microcontroller code? It is going to be required to make this a Completed Project entry.

The format was kinda strange, so many posts. I have merged them into one post for better clarity.

This post will be removed when the code is posted.
Alright, I attached the code to the original post.
 

Wendy

Joined Mar 24, 2008
23,415
Price is always an object though. Like I said, my labeler is 20 years old. Every couple of years I change the batteries out, and that's it.
 
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