Replies to Minipulse Plus

[Qiaozhi]

The Minipulse Plus details are posted in a sticky thread above.
Details of external controls, connectors, and description of operation coming soon .....

In the meantime, this is your chance to find any errors before I send the Gerber files to Silverdog for processing.

[Davor]

It looks good. I'll check it tomorrow.

[Tepco]

!Problem! On both schematic and PCB problem exists with +5V distribution, pin 7 U2 is connected to 0V (bat+) via R11, on original PCB goes to +5V so U 2,3,4,8 are powered from +\-5V.


Also, too small raster for C10, better change to 200mil. I also suggest replacing C7, from 22u electrolytic to 470n film cap. Original value is unnecessarily high, not needed even for original PPS, just can produce trouble (increased LF\powerline leakage into integrator), and better not to be electrolytic type.


I tried to post this earlier, but due some forum problem I was unable to login. Suspected someone hacked my profile, ( message says i'm on my 6^th login attempt, I was not log once, no reset after timeout ?), even sent mail to Carl, to prevent someone to post stupidities here in my name (i'm doing well on my own), now everything seems to work, hope this is OK. Probably forum reliability issue.

[Qiaozhi]

!Problem! On both schematic and PCB problem exists with +5V distribution, pin 7 U2 is connected to 0V (bat+) via R11, on original PCB goes to +5V so U 2,3,4,8 are powered from +\-5V.


Also, too small raster for C10, better change to 200mil. I also suggest replacing C7, from 22u electrolytic to 470n film cap. Original value is unnecessarily high, not needed even for original PPS, just can produce trouble (increased LF\powerline leakage into integrator), and better not to be electrolytic type.

Tepco - brilliant! ... thanks for checking.

Oops! That was a silly mistake on the preamp power supply. Obviously that should go to +5V.
I will increase the pin spacing on C10 to 200 thou as you suggest (100 thou might be a little too small) .
In the original circuit, C7 is a 22uF tantalum, but these tend to be expensive are getting difficult to find nowadays. Anyway, I agree, the value is too large and I don't like using electrolytics in filter circuits. It might even be worth reducing it to 220nF to set the cutoff frequency at 72Hz, which is above the 50Hz and 60Hz mains frequencies (depending where you live). I'll set it to 470nF for now, and let others experiment.

Updated schematic and PCB coming later.

[Qiaozhi]

I tried to post this earlier, but due some forum problem I was unable to login. Suspected someone hacked my profile, ( message says i'm on my 6^th login attempt, I was not log once, no reset after timeout ?), even sent mail to Carl, to prevent someone to post stupidities here in my name (i'm doing well on my own), now everything seems to work, hope this is OK. Probably forum reliability issue.

It sounds like someone was trying to log into your account, but failed to do so. Hence the message.

[Qiaozhi]

Finally, at last, and with no further delay, ... please find the complete details for the Minipulse Plus (updated / modified version of the original Pulse Technology Minipulse design) in the sticky post at the top of this section ->
Minipulse Plus

[WM6]

Exemplary made project, Thank you.

[sinclairuser]

thanks george, i'm going to enjoy this one.

[Qiaozhi]

Some good news ... the Gerber files are now with Silverdog, so hopefully we'll have some PCBs available in a few weeks.

Please note that I've made some minor changes to the PCB at Silverdog's request:
1) Changed the PCB footprint for the cermet trimmers to 4-pin, to allow the use of both staggered and in-line types.
2) Improved the appearance of the bottom layer by eliminating an isolated island in the ground plane.
3) Tweaked a few traces (while making these changes) to improve track spreading.

Of course, this means I've had to update the project files. Also added a parts list and BOM with the missing external potentiometers that are not shown on the schematic.

[6666]

I was curious about the 555 circuit in the Pulse Technology Minipulse PI Detector, because it was a bit different from the normal 555 circuits we see, anyhow i knocked it up and it works ok.

Video with audio at http://www.youtube.com/watch?v=P-B-5...ature=youtu.be

[satdaveuk]

Hi
Thanks Qiaozhi
Looks a nice project , when I first seen Mini pulse I thought it was going to be a revised version of the Minipulse 3 I built a couple of years ago which was based round the ATMega 8, but of course its not.
Has anyone here thought about making a single sided board layout of this project for those of us who prefer to make are own boards?
Regards

[Qiaozhi]

Hi
Thanks Qiaozhi
Looks a nice project , when I first seen Mini pulse I thought it was going to be a revised version of the Minipulse 3 I built a couple of years ago which was based round the ATMega 8, but of course its not.

The name Minipulse was originally associated with Eric Foster, as per the detector in this project. Later Minipulse designs have simply purloined the name, but (as far as I'm aware) they have nothing in common with Eric's designs.

Has anyone here thought about making a single sided board layout of this project for those of us who prefer to make are own boards?
Regards

I'll leave that to someone else, as I don't have the time available.

[satdaveuk]

Well enough said
If its anything to do with Eric Foster its a must build job , Eric has proberly forgotten more about PI format than most of us know on here, soon as time permits will join you here, In the meantime shall just observe and see how you all get on.
Just a quick question please, Was Erics version on single or double sided, also really interested to be able to see his original circuit etc first hand if your able and Eric doesnt mind.
Thanks again qiaozhi your a gent.

[satdaveuk]

Sorry George just noticed you already put them on the sticky, im tired

[Qiaozhi]

Sorry George just noticed you already put them on the sticky, im tired

Yes (as you've noticed) the original layout is in the sticky thread. The layout was single-sided, and there are a few links on the top layer. Actually the links are zero ohm resistors. However, there's some odd tracking in the original layout, and a few components fitted that are unused in the model I disassembled. The Minipulse Plus version is more sensitive, the main delay can be adjusted down to 10us, it's much more stable and less susceptible to external EMI, and has a slow SAT. It hardly seems worth messing around with nasty chemicals, when you will be able (in the next weeks) to purchase a high quality double-sided PCB from Siverdog for a reasonable price. I think there will also be a kit available with all necessary components.