Replies to Minipulse Plus

[Chet]

Here is a photo of my latest experiments with MPP all in a case ready to take into the field for testing.

Has a rotary encoder to select different timing / sample experiments as well as small OLED to display various settings. I have set the case up so that I have options for the future.

[ATTACH]32483[/ATTACH]

Hi CAS

Nice job. Let us know how well it works. I have a MPP and a ChipKit and would like to do a similar experiment. Did you program it with the MPIDE or the MPLAB IDE software? So far I have got an OLED programmed and working but haven't started on the pulses and sampling.

Have a great day,
Chet

[6666]

Nice thanks for showing us Cas

[Davor]

Nice. Can you measure how much juice goes to chipkit?

[CAS]

Here is a photo of my latest experiments with MPP all in a case ready to take into the field for testing.

Has a rotary encoder to select different timing / sample experiments as well as small OLED to display various settings. I have set the case up so that I have options for the future.

[CAS]

I am not sure I want to use the USB. Maybe hook up a BT module or WiFi module if I want to log data but that would be it. What IDE are you using to program it?

[scrungy_doolittle]

I only had an hour or so spare so at the moment its only doing tx pulse and the sample gate pulses. If I get time tomorrow I will add a couple of pots to some analog input pins so I can vary the sample delay and width.

I actually want to do some test sampling of the signal out of the preamp. Using the 10 bit ADC I want to take maybe 5 - 10 samples (about 2us apart) within each main sample and just get some data with different target materials so i can get some real world comparisons. Not sure if I would ever use the data but its fun to experiment.

I have ordered a STM32F411E discovery board - has 12 bit ADC, up to 108Mhz clock plus built in audio DAC which I will probably use in my other project but the data I get with the ChipKit and MPP will let me know if I am going in the right direction.

I'm working on a STM32F411RE nucleo board 10.33 spec says 100 mhz. but if you want to use USB you have to either go to 96 or over 100

[josewashere]

OK Excellent I look forward to seeing the results

[CAS]

I only had an hour or so spare so at the moment its only doing tx pulse and the sample gate pulses. If I get time tomorrow I will add a couple of pots to some analog input pins so I can vary the sample delay and width.

I actually want to do some test sampling of the signal out of the preamp. Using the 10 bit ADC I want to take maybe 5 - 10 samples (about 2us apart) within each main sample and just get some data with different target materials so i can get some real world comparisons. Not sure if I would ever use the data but its fun to experiment.

I have ordered a STM32F411E discovery board - has 12 bit ADC, up to 108Mhz clock plus built in audio DAC which I will probably use in my other project but the data I get with the ChipKit and MPP will let me know if I am going in the right direction.

[josewashere]

Good job! Is the chipkit just controlling the detectors timing or this there more to it. I'm interested in the GB if it can be done without loss of sensitivity. sent same question on YT

[CAS]

Well while I am waiting for parts on another md project, I got round to connecting the chipkit Uno up to the MPP. I only had a small coil connected as I am not going for depth but more small fine gold. Still have to program the GB but will try that over the next few days.

[sinclairuser]

Welcome back!
The important things to read are:
1) The Build Document,
2) and the notes in the relevant sticky thread.

thanks george, my boards are rev b, so ill look to see the differences between b and c, and check the errata etc.
i'm interested in davor's GB mod, but that's for the second board, i just want the first one as build plans.

[Qiaozhi]

hi all finally back to full fitness, the other half helped me clean and sort out the workshop yesterday, its amazing how much dust can build up in a room that is closed up.
anyway finally going to complete my mp, i only got to stage 2 before so i have only just started really, i am going to read the thread from the start, when i'm up to speed i will chip in.
also wanted to say thanks for the kind words and encouragement given to me while i was ill, thanks lads you know who you are.

Welcome back!
The important things to read are:
1) The Build Document,
2) and the notes in the relevant sticky thread.

[sinclairuser]

hi all finally back to full fitness, the other half helped me clean and sort out the workshop yesterday, its amazing how much dust can build up in a room that is closed up.
anyway finally going to complete my mp, i only got to stage 2 before so i have only just started really, i am going to read the thread from the start, when i'm up to speed i will chip in.
also wanted to say thanks for the kind words and encouragement given to me while i was ill, thanks lads you know who you are.

[Chet]

2 diodes in series ... no. It would require equal reverse polarity on both of them (too complicated), or otherwise it will not work as advertised.

Hi Davor, you are correct. I tossed the second diode idea in in haste as a possible expansion.


It would take some balancing by either closely matched diodes or some high value (meg ohms) resistors across each diode to equalize the reverse voltage drop across each diode.


Without perfect balancing there should still be a measurable reduction in total capacitance. Measuring the oscillation frequency with the damping resistor lifted with one diode then again with two diodes in series (anode to cathode) would be one way of testing.


I will experiment with this when I get through with some other modifications to my Minipulse.

[Davor]

2 diodes in series ... no. It would require equal reverse polarity on both of them (too complicated), or otherwise it will not work as advertised.