Quick look at: A cheap DIY function generator kit

Introduction

I recently bought some cheap electronic DIY kits from amazon, just because I wanted to improve my soldering skills. One of them was a cheap function generator, based on the XR2206-IC. The complete kit with an enclosure costs about 14€, and you can buy it here. If you find a cheaper one, let me know in the comments below, and I’ll update the article!

Building and soldering

Some of the pads on the PCB were hard to solder. When I design PCBs, I tend to make the pads fairly large because I find it more convenient to solder components on larger pads. However, it was possible, although I can’t recommend this kit to absolute beginners.

Building the case was a bit hard because these tiny laser-cut plastic parts tend to fall apart easily. But the hardest thing here was to get the protective film off the parts. Afterward, you have to put the shorter screws through the four mounting holes on the PCB and secure them with nuts from the other side. These just act as spacers, so that the board sits nicely in the case. Afterward, you just put the case together and close it up with the longer screws in the corners.

The finished product should look like this:

I really like the looks of it. It’s compact and makes a solid impression.

How to use it

You can select the range of the frequency and the waveform with jumpers. The little pins are labeled on the case:

As you can see, I gave up when I tried to remove the protective film on the insides of some of the numbers, like the zeros. If you have a lot of patience, you could remove them with a tiny pin or something.

However, you select the frequency range with a jumper, and you can then alter it with the two potentiometers on the right. The one on the left changes the amplitude of the wave.

The waveform is then output by the screw terminals on the right.

Measuring the accuracy

Now to the most important part: Is it accurate? Does it even work? Let’s find out. Unfortunately, the device doesn’t come with a display or something that tells the user what the frequency should be, so you’ll need an external device to tune it to the correct frequency.

I wanted to measure whether the range is as labeled and if the waveform stays the same over time. Let me give you the short version: Unfortunately, mine didn’t work at all. It just refused to generate any waveforms at all.

Conclusion

Should you buy it? Well, mine didn’t work, but it was fun to build, and it kept me busy for an hour (even though it took me 30 minutes to peel off the protective film).

However, I’d still say that you should buy it and give it a try if you’re looking for such a device. I’ve bought several kits online recently and they all worked, except for this one. But you can always send it back for free, which I’ll do.

Unfortunately, I can’t tell you right now whether the device accurate or not, but I might re-order this kit, create a short video of the build process, and then I’ll hopefully be able to test its accuracy.

Further readings

Sparkfun – XR2206 Datasheet
Amazon – Buy the kit here

Disclaimer

As usual, I bought all the products that I mentioned in this article myself. It, therefore, represents my opinion. Furthermore, I didn’t use any affiliate links.