Project14 | You Decide the Next Monthly Project Competition!

In the Forums or as an Idea: Send Your Suggestions for Future Themes and vote on them!

Forum / Theme Suggestions

How are Themes selected?

Project14 | Quick Update on Upcoming Competitions + What Would You Like To See Happen In Project14?

Top Comments

dougw over 8 years ago +24

I guess the suggestion box moved here so I will reiterate one idea I mentioned earlier and add one: - a classroom demonstration of some physics phenomenon ( jc2048 had some good ideas ) - a solar powered…
jack.chaney56 over 8 years ago +11

Keeping with July and (northern hemisphere) Summer time, I like Douglas' ideas. Demonstration of physical phenomenon for classroom is a great avenue, I was thinking lots of solar stuff. Charging systems…
balearicdynamics over 8 years ago in reply to Workshopshed +11

I will ad also a time machine. Sound good ? Enrico

Parents

zombie80 over 8 years ago

Similarly as bitscope mod, there should be a proper DIY function generator, not that arduino DDS crap i've seen.
- Cancel
- Vote Up +2 Vote Down
- Sign in to reply
- More
- Cancel
zombie80 over 8 years ago in reply to zombie80

Arduino based solutions won't do for me because of too low output voltages and voltage changes when DUT input impedance isn't stable.
- Cancel
- Vote Up +1 Vote Down
- Sign in to reply
- More
- Cancel
Jan Cumps over 8 years ago in reply to zombie80

Still doesn't make them crap, right?
- Cancel
- Vote Up +4 Vote Down
- Sign in to reply
- More
- Cancel
Workshopshed over 8 years ago in reply to zombie80

Some kind of buffer or amplifier on the output should rectify that?
- Cancel
- Vote Up +5 Vote Down
- Sign in to reply
- More
- Cancel
Jan Cumps over 8 years ago in reply to Workshopshed

Yes. And commercial ones are also specified for a single impedance. Often 50 Ohm. If the impedance changes, so does the voltage. That's the nature of these instruments...
- Cancel
- Vote Up +3 Vote Down
- Sign in to reply
- More
- Cancel
shabaz over 8 years ago in reply to Jan Cumps

Agree.. I suspect some people assume such devices are not functioning correctly. I've played with the so-called c*** DDS $15 sig-gen modules from ebay and their performance on several important parameters (within a realistic frequency range) is not far removed (actually way better for some parameters) from some HP sig-gen's from the 1980-1990's which are still sold on ebay for $500+..
They are missing features of course (like decent adjustable output) but to call them junk is not accurate.
- Cancel
- Vote Up +6 Vote Down
- Sign in to reply
- More
- Cancel
shabaz over 8 years ago in reply to Jan Cumps

And since the proof is in the pudding.. (this is from such a cheap DDS)
- Cancel
- Vote Up +5 Vote Down
- Sign in to reply
- More
- Cancel