Replies to Minipulse Plus

[ivconic]

I knew it! [/FONT]


On the REV-B board there was a connection missing between U2 pin 5 and U2 Pin 3. This caused the audio volume to decrease when a large target was close to the coil. I'm not sure whether I'm hearing the same thing in your video, but since you're using a 7660 this may not be useful information.

There should be a small increase in amplitude, as well as a large increase in frequency, as the target gets closer to the coil.

[/FONT]

There is large increase in frequency alright, but at strong detection signals there is obvious decrease in audio amplitude.
Listen carefully on video, there is a moment when you can hear audio amplitude decrease down to some level and that's the same moment when detection signal is very strong.
And funny; loudest audio you may hear on video is when moving target is distant and producing not so strong detection signal.
Next time i'll try to shoot better video with targets and coil.

[Davor]

Since you are so fast, you could try this time base as a GB for minipulse too. It will take you 20 minutes at most
Ask me for details if you are interested.

[Davor]

BTW, try LF353 instead of TL062 in integrator

[Qiaozhi]

I am fast because i don't read manuals!

More haste less speed.

[Qiaozhi]

There is large increase in frequency alright, but at strong detection signals there is obvious decrease in audio amplitude.
Listen carefully on video, there is a moment when you can hear audio amplitude decrease down to some level and that's the same moment when detection signal is very strong.
And funny; loudest audio you may hear on video is when moving target is distant and producing not so strong detection signal.
Next time i'll try to shoot better video with targets and coil.

This appears to be the same problem I mentioned with the missing connection on the LT1054. It's probably related to the 7660.
My version doesn't have the same issue, even with a Cola can sat directly on the coil.

[ivconic]

Since you are so fast, you could try this time base as a GB for minipulse too. It will take you 20 minutes at most
Ask me for details if you are interested.

I am so missing schematic done in ExpressSCH!
"Alive" schematic with "movable" components where we can add your ideas faster and clearer.
Don't mind me if i do that first, right?
First i will transfer schematic in ExpressSCH and later we will talk further. I'll try to do that tomorrow.

[ivconic]

BTW, try LF353 instead of TL062 in integrator

Now he tells me that!
I soldered ic's directly without sockets, except 7660 which is on socket.
Ok, no problem, i will destroy 062 and put socket there too.

[ivconic]

This appears to be the same problem I mentioned with the missing connection on the LT1054. It's probably related to the 7660.
My version doesn't have the same issue, even with a Cola can sat directly on the coil.

I can check that when 1054 comes to my hands, soon.
What are the chances we to include motion/nonmotion mode switch?

[6666]

Since you are so fast, you could try this time base as a GB for minipulse too. It will take you 20 minutes at most
Ask me for details if you are interested.

Davor have you built your time base ? how does the 4017 cycle through with the clock connected to the reset ?

[Silver Dollar]

There is a clock on the reset line to restart the sequence. You get a first pulse,
a double GB pulse then a second pulse then after a time the reset starts it all
over again...

See here, the blue pulses are the reset or restart pulses;
http://www.geotech1.com/forums/attac...6&d=1406921335

[6666]

Maybe I dont understand how a 4017 works,
the counters need to be reset at some point in the sequence,but if the 555 pulse is connected to the reset pin (15), (not the clock pin 14), the 4017 will reset the counters back to zero with each 555 pulse, how do the counters cycle if the 555 is continuously resetting the 4017 with each pulse.

[6666]

Hmmm is U4 somehow running as a independent clock
how does this thing operate Davor ?

[josewashere]

[QUOTE=Qiaozhi;194910]Did you carefully follow the instructions in the Build Document? ->

---------------------------------------------------------------------------------------------------------------------
If you go through the following steps carefully, and in order, you will have a greater chance of
ending up with a detector that actually works. Do not proceed to the next step until you have solved
any problems encountered in the current step. If you get stuck at any stage during the build, then
seek help in the Geotech forums before moving on. Do not simply populate the whole board;
discover it doesn't work (which will be the most likely result) and then post in the forums: “I've
built the Minipulse Plus, and it's not working. What's wrong?”, as you will receive little sympathy
from other Geotech members.
To reiterate:
Please follow the instructions step-by-step.
---------------------------------------------------------------------------------------------------------------------

I suspect you've been a bad boy and populated the whole board before testing.
haha I've been a bad boy too but its nice to know the steps are there and one can refer back to them if something does not work as expected. Rainig here today so its hard to make a video. In doors here is mostly all tiled floor with wire mesh under it except for my man cave but that's full of equipment and many sources of interference.

[Qiaozhi]

What are the chances we to include motion/nonmotion mode switch?

To remove the SAT permanently and use non-motion, you can swap C15 (470nF) for a 100k resistor, and R29 (1M) for a 470nF cap. (See original MiniPulse schematic.)

Or - you can probably simply add a switch in series with R29 to toggle between the two modes. I haven't checked this as a solution, so you'll have to try it.

[Davor]

Frankly, non-motion makes more sense, and with additional LP it will most probably take care of the residual charge injection spikes and become more calm.