Function generators are useful in a ton of applications from RF to embedded logic. They’re not usually super cheap though. Good news: we found a kit. The FG085 MiniDDS Function Generator is a ‘some assembly required’ kit that becomes a flexible, functional and easy to use frequency generator. Just solder the through-hole parts in place, attach the face/base plates and before you know it you’ll be generating sinewaves at frequencies up to 200KHz! But that’s only one of the tricks this thing can do. Three different operating modes allow the FG085 to generate 7 different types of continuous waveform as well as servo test and control signals in micro-second resolution.
The LCD screen and menu system make this an easy instrument to operate. Frequency, amplitude and offsets can all be set with the number pad and incrementally adjusted with the rotary encoder. The incremental step size can even be adjusted to make sweeps over a wide range easier to handle. The FG805 can generate a peak to peak amplitude up to 10V with an offset range from -5 to +5VDC. It can even be used as an adjustable DC voltage source by setting the amplitude to 0.
If you have a blinking/flashing LCD display, it’s most likely a bad power supply or a short circuit somewhere in your soldering. Double check your solder joints and verify that you have a stable 15 volt output on the power supply.
This skill defines how difficult the soldering is on a particular product. It might be a couple simple solder joints, or require special reflow tools.
Skill Level: Rookie - The number of pins increases, and you will have to determine polarity of components and some of the components might be a bit trickier or close together. You might need solder wick or flux.
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Whether it's for assembling a kit, hacking an enclosure, or creating your own parts; the DIY skill is all about knowing how to use tools and the techniques associated with them.
Skill Level: Noob - Basic assembly is required. You may need to provide your own basic tools like a screwdriver, hammer or scissors. Power tools or custom parts are not required. Instructions will be included and easy to follow. Sewing may be required, but only with included patterns.
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If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.
Skill Level: Rookie - You may be required to know a bit more about the component, such as orientation, or how to hook it up, in addition to power requirements. You will need to understand polarized components.
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Based on 32 ratings:
4 of 4 found this helpful:
Nice kit, easy to assemble if instructions are carefully followed. It is well designed and easy to use.
Two problems though: (a) the BNC connector on the output cable is too tight and doesn’t fit the output plug (!) this was not an issue for me because other cables I had work well, but this may be a problem for others and (b) the output signal is extremely noisy and not really suitable for many analog applications.
3 of 3 found this helpful:
I bought this to help my oldest son with a science fair project. We needed to generate specific frequencies to be pumped into a rubens tube for sound wave measurement. As a bonus I was able to teach him a bit about oscilloscopes when I checked the accuracy of the generator (which by the way was dead on). All in all a very nice little product, well packaged, and fairly easy to assemble. Good project for a beginner that is wanting to try out a build and challenge themselves. One note, the ground leg for the output connector is a hair too short to reach the board, and the instructions say to cut it off and solder in a piece of wire as a replacement. I opted to keep the leg, and make a pair of J shaped hooks to drop in and act as a bridge to the board. I felt that it gave a much sturdier connection that wouldn’t break if there happened to be any pressure applied.
1 of 1 found this helpful:
The kit went together easily in about 30-40 minutes.
The DDS firmware on the kit I received is a revision old. The latest is 113-08502-053 which fixes a bug with frequencies less than 40Hz (see the product page link below).
As Member #207448 already mentioned, the output is extremely noisy at line-level voltage and essentially useless for audio applications.
Frequency is pretty much bang on.
And lastly, be wary of the indicated amplitude. I took some sample measurements on my Rigol DS1074Z with a 10kHz square wave:
Indicated: 0.1V - Measured: 260mVpp
Indicated: 1.0V - Measured: 1.20Vpp
Indicated: 3.3V - Measured: 3.60Vpp
Indicated: 5.0V - Measured: 5.4Vpp
Overall, a good and fun kit but I was hoping to get better performance for audio amplitude and frequency ranges.
2 of 2 found this helpful:
I found more to this kit than what was directly represented on the order page. Designed/Manufacturerd by JYE, their web site opens the door for additional information and provide a path for firmware upgrades, newer user manual, and their JyeLab software; which allows for constructing your own waveform for uploading to the device.
Great for learning to use an oscilloscope, testing and establishing duty cycle for servo motors, or playing around as in the SparkFun Video.
Assembly was easy with the visual guide, but it is is not for the beginner. Soldering points are fine, thus good soldering skills recommended.
Takes some getting use to how it works; checking JYE for a more recent user manual was what I needed. Per heaps after this post SparkFun will download to their page.
For me as a beginner to the use of generated frequencies, I have found this a excellent versital platform for learning and long term project use. Other options exist on the market, but for the price and added joy of self assembly, this is perfect for me.
Your excitement may vary!
1 of 1 found this helpful:
Simple to assemble, it works very well !!! Perhaps white noise can be added …
The function generator works (sort of), but there are a lot of things that should have been fixed before they started selling these.
I have a detailed review (with plots) at https://gasstationwithoutpumps.wordpress.com/2015/07/16/fg085-function-generator-bugs/
Very pleased with it. I would like a cabinet or case for it. Would be nice if one was available. Even one made out of heavy cardboard would be very helpful. — I plan on making one with cardboard and some tape. Put in a chunk of metal for weight, and it will be much handier and usable, for me anyway.
Easy to build from their good directions, this unit has quality parts. Everything fit, everything worked first time. Very versatile, and has many functions. Fairly quick to learn how to access the different functions and parameters. The price is NICE.
Took about an hour or so to build the kit…i worked slow so that everything would line up with the faceplates on final assembly, which it did. At first, upon power on, it was giving a “f/t step ________” config screen and not the correct jyetech splash screen…after a few reboots / power resets, it just started to work correctly and continues to do so, so all’s well that ends well i gues…
If nothing else, soldering this brought me to realize how lame my soldering iron was and how much I needed a new one. But in fact, that wasn’t all.
The interface is a little strange, but easy to use if you read the manual. The rotary encoder is a little slow to respond, so be patient with that.
There are 4 modes: - Single frequency - Sweep range of frequencies - Servo single position - Servo run (sweep range of duty cycles)
Another interesting feature is the wave forms. It comes with sine, square, triangle, ramp (both directions), staircase (both directions), and user defined. Yep. You can define your own wave form and upload it via the USB port. I haven’t done so at the time of this review, but JYE Tech has good documentation on their website and forum.
While this device is not completely open source, there is a schematic available on their website.
After assembling it I hooked it up to a speaker to demonstrate it to my family. I highly recommend driving a powered subwoofer with this. (start with 200 mV and work your way up)
Good little Function Generator. Works well. Micro tends to hang up every once in a while. Good clean waveform. Instructions on placing the pushbutton switches should be explained better.
0 of 2 found this helpful:
I have got this unit in un assembled condition….this was not mentioned anywhere while ordering. please advice to return it back.
Hi, This is labeled a kit, and has instructions for assembly in the description. I apologize that this was not clearer that this is an assembly required kit. Directions for return can be found here https://www.sparkfun.com/returns
Easy to put together, but directions for use could be a little clearer. I’m using it to drive a Ruben’s Tube and Chladni plates in a physics class. Works great!
Building the 2nd one was easier because by then I knew how important the sidebar instructions were and how critical it was to keep those little switches straight. Also knew how to handle the coax ground kluge. The AC adapter was bad, but I used the one from my first kit to troubleshoot, and Sparkfun sent me a replacement. Once I got it all running, it worked well, although the frequency adjustment knob will sometimes increment in the wrong direction for one step (same issue with both units). In spite of all this, I still like this function generator.
Brings back memories of building Heathkit projects. Kids – ask your grandpa
Using it to verify bandpass filter values, and trying triangle waveform filters for music synthesis circuits. Easily assembled and tested. Instuctions on staircase parameter setup could be clearer.
Easy to assemble, although not a project for those who are a novice with a soldering iron. The instructions require close attention as some of the information is not in-line with the numbered steps. Be sure to read the instruction sheet from top to bottom and from left to right before beginning.
From the operational standpoint this is a great little signal generator. I wouldn’t mind having a couple more of them.
Unfortunately first unit would not function, returned for analysis by Chris in Technical Department who determined that it was a rare faulty board. Subsequent replacement unit works perfectly and is proving to be an experiments delight. Thanks.
Very inexpensive for what it does. I had only one glitch during construction–I mounted a push button switch backwards–I think I spent half of my assembly time getting that out of there and setting it right. Once assembled it performs exactly as advertised. It’s very nice that all the surface-mount devices are already mounted. But you should put aside several hours to assemble all the through-hole components because there are gobs of those buttons, each with six solder joints. And don’t put in any of the push buttons backwards!
The LCD display is very dim making it hard to read the numbers/info in a well-lit room.
The instructions included with the kit are sketchy and some important info is minimized or missing. Fortunately, this wasn’t my first kit ever built and could work through the missing steps.
Very capable soldering technique is required. Definitely not a kit for beginner soldering skills.
The kit was easy to assemble and the functionality is great.
Previous posters mentioned the final soldering step involving clipping a ring and adding a lead to the BNC connector. I didn’t clip the ring and bent the ring. It just reached the PCB. It is flush with the PCB which isn’t ideal, but i thought this would be sturdier since the part is so close to the edge. The thin lead recommended in the instructions could be torn off because of the open enclosure. I put an additional drop of solder from the top.
I had a few of the switches slightly off because my soldering wasn’t completely level. When I put the faceplate on, I discovered that the keycaps wouldn’t snap on. So, I centered the switches by poking them from underneath with a small screwdriver and was able to slide the caps on.
Only had one problem with the Square Wave function, sent email to vendor and they promptly got back to me that i had the percent function set to 100%, so the display was a straight line. Set it to 50 % and got a great square wave.
It was a joy to build and it performs great. I would recommend it to all my ham friends.
I was able to quickly assemble the kit and everything worked the first time. The unit works as advertised and is a great addition to my test/experimenter bench.
Very good assembly! Ideal for those application where you dont need over 1Mhz. Very easy to use! It would be nice to sell an enclosure or if you have a 3D printer, it’s your next project!
Very easy to operate in a NICE little package.
Easy to assemble but erratic operation. Keys don’t always work and instructions should be more complete, not sure what some of the keys actually do. Waveforms look good (when I can get them). Would really be an asset if I could get it to work consistently. Len Spina
My kit’s PCB was missing an SMD diode, making the rotary dial inoperative. No biggie, I ended up soldering a 1N4148 I had lying around. Other than that it’s a good kit at this price point.
The kit was easy to assemble and worked perfectly right from startup. Frequencies and wave forms are clean and accurate. Like to see it work at several MHz. This is a good buy.
0 of 1 found this helpful:
This kit was fun to assemble but there were certain items that drove me to this rating. Step 10b says to cut wing off spring washer and solder metal lead and bend to shape. OK, no problem. But, although the parts list calls out the metal lead, it wasn’t included in my kit! No big deal, I made one. Next, after assembly was complete, I powered the unit up and, as mentioned in the first time power up instructions, the screen remained blank. Per instructions, I turned the unit over and attempted to adjust the trimmer pot. Nothing, in fact it broke! I now have a perpetual blank screen. Perhaps I’ll play around and try to change out the pot.
I needed a signal generator for a hobby robotics project but couldn’t justify shelling out hundreds for something I wouldn’t use very often. Found this little kit and decided to give it a try. It has exceeded all my expectations! The kit itself is very well designed and fun to build. Took about two hours on a Saturday morning to put together. Powered it up and it worked great! Hung a scope on it and played around with a lot of the settings, then put it to use tuning an op-amp circuit on my robot. Worked flawlessly. I haven’t begun to scratch the surface of its capabilities either. The only thing I added, that it didn’t come with, were some stick-on silicone feet to give it a nice grip on my work table (a few bucks at Home Depot). I’ve already recommended this unit to a friend who builds circuits for a living. He was equally impressed and ordered one for himself.
0 of 3 found this helpful:
I was on vacation , and had a bout with a stiff neck wasn’t feeling very good ,all seems ok ,should start after the 4th of July as things will settle down , thanks for asking I’ll let you know n when I finished these two project for my invention . Al Cortes