Simplest PI detector possible?

[6666]

Cool, thanks for that

Love the simplicity of these

My goal is to make a really bare bones simple micro PI with complex software :P

That way, anyone can attach an ADC to a micro and download my software and have a PI.

Brucester did you make any progress on this idea ?

[bernte_one]

one simple quaestion before i waste some more boards for this mysterious thing
just open the picture




and how to calibrate the trimpot from ic2 20K?
for what is it

[scrungy_doolittle]

Are you going to show us your work ?

I intend for the project to be fully open source, open hardware.

[DOOLEY]

ah, well spotted burnte one,
problem there ,
trim pot for frequency adjust, which will also adjust on time,
unfortunately.
that's the draw back with that configuration.

anyways,
that's not the problem,
theres no resistor across the diode between
pins 6 and 7,
that's poss not going to even run........


I had a brief look at the design and thought....
hum, that's interesting.....
but never looked too closely.....
till now.
lol.


suppose when the 555's sorted out then poss it'll be ok.

[6666]

I intend for the project to be fully open source, open hardware.

Excellent, thank you, is there any software yet ?

[Beenthereuk]

Hi Burnte, from simulation, both designs will run:

The first has F= 125 Hz, 400 uS PW
Your has F = 140 Hz, 100 uS PW
The Russian 555 based circuit has F= 4 kHz (250 uS cycle time), 150 uS PW

I'd stick with yours..

[bernte_one]

hello beenthereuk

thanks for trying it in the sim
i caculated longer time before with a ne555 caculator
problem is that longer pulse on time will overheat the irf in reality and maybe some other parts
i have one 1/4w resistor melt down by a fusion i have never seen before on a resistor
that is some thing that is forgotten

so i thing the hode thing also with new parts is very misunderstood, and nobody (maybe one or two here) can reallly tell how this unit work

[6666]

The link from post #9 now seems to be this link.
http://forum.cxem.net/index.php?show...%20111009&st=0

[kt315]

The link from post #9 now seems to be this link.
http://forum.cxem.net/index.php?show...%20111009&st=0

desalex there wrote a note (by red) that those schematics have mistakes. you have to go on 5th page and there you have to see the schematics without mistakes.
ie 5 page - http://forum.cxem.net/index.php?showtopic=123088&hl= 111009&st=80

[kt315]

http://forum.cxem.net/index.php?app=...tach_id=174835

[6666]

Thanks KT315.

[Beenthereuk]

Hi Bernte, dropping 12V across a 330 Ohm resistor will dissipate 12^2/330 = 436 mW which is almost twice what a 1/4 W resistor can handle.

To be safe, use 3 x 1k resistors in parallel on the PCB so that the final resistance is 333 Ohms and the dissipation per resistor is less than 1/4 W. Or use a 1 W 330 Ohm resistor.

I think that the IRF will most likely have to run hot as it is in these circuits. The best you can do is add a heatsink to it (bolt it to a large piece of aluminium or copper).

If you use the circuit shown below, it is possible to set the frequency as per this table:

Variable set to lowest resistance, F = 125 Hz, 100 uS PW
Variable set to max resistance, F = 1000 Hz, 150 uS PW

[bernte_one]

i think i will try it a last time with this mystery machine
1000hz with 150µs PW ohhh thats much

[kitsof]

I've built the pirate based on this this schematic here with a slight modification-a 100k pot and a 10k pot instead of R12 and VR13.Here is my pirate.I've discussed the schematic at the original site that invented the pirate here. It works but they recommended to change R3 to 100К, R1 to 1К, R10 to 47К, С3 на 1,0*16v.Why are these differences?

Furhermore this schematic does not work with a small coil with a 11,5 diameter and 45 turns.The pirates makes noise on end.

[bernte_one]

i have made my 3rd pirate with original k157... chip and smal pcb layout
now i finally have success

some improvements are needed

i have only a coarse tune
so i will add e second fine tune

and if this works i will try a trimmer and the ic555, to change the pulse Timing

coil is under 300µH and the depth is not got
but i feel it can get a bit more with better Settings

circuit is powerd by 3*18650 (a bit more than 12v)