Let's Make Robots!

Logic Probe (Logic "Box"?)

Tests the sorta stuff you would test on robots

Inspired by a post by Geir Andersen, I decided to make a little tester box. Nothing too fancy, and (I'm sure) not properly put together, but enough to be able to so some regular, every-day testing of robot stuff.

  • High and Low states
  • Continuity --Yes, I know that High and Low sorta covers this one but the rotary switch has 6 clicks! I has to use more than 2 or 3 or them!
  • Pulse Width (in uS) with a high trigger
  • Pulse Width with a low trigger
  • Audio (and the ability to turn the gosh-darn beeping off!)

The brain for the whole system is a Atmega 328 who's real home is as the backpack for the LCD. Everything else was selected because it happened to be in the parts box. As a matter of fact, I even found the rotary switch in there --which still had the resistor bridge soldered on from the last project.







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I like that! :D Simple and pretty useful!

Watch out CtC I'm making a PIC based Logic Probe!

Were you ever able to use your logic probe to detect tri state inputs?

Wouldn’t a tri state just report nothing like not connected?

Yeah I watched the video after I posted that question.

in my search for a piece of information I ran across mention of a resistor box, a variable reisistor box that assists in choosing the right value. Since you have all that space in the case maybe a variable resistor box and/or a variable capacitor box?

Coolio - it will serve you well.......... " Use the Probe Luke"

When i am too lazy to fire up and wait for my oscilloscope to beam its electrons......... i always reach to my magic draw and extract the trusty Logic Probe - faithful to the last......

If i could offer an add-on :-

Adjustable voltage trip level (with the beep please) , meaning you could set with a "pot" your custom logic trip level, not only to take into account 5V and 3.3V levels but also tricky "Fuzzy" levels. As soon as level has flipped .....BEEEEP. Would be useful when interfacing analogue to digital circuits.

My compliments on your upgraded video setup!


I find it awesome how little time elapses since an idea triggers in your head and you dish out a walkthrough!

Excellent results! Congrats!


Nice creation- I like the audio feedback feature, I'm sure you will find it very convenient as your eyes will typically be on the circuit under test.  Just a thought, it might also be snazzy to have an ADC tone feature that will interpolate audio tones for anaolog voltages between 0-5V, although perhaps impractical (what I'm trying to say is a higher pitch tone for a higher analog voltage, and vice-versa).

I recently ordered some continous rotation rotary encoders with pushbuttons (and nice knobs) from Mouser and they are awesome for user input without much real estate.  I also love the probe clips Radio Shack sells, I've got a set for both my meters!