Announcement

Collapse
No announcement yet.

Sandbanks

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #76
    I see no second (EF) sample on this schematic, how is this suppose to work stable without one?

    Comment


    • #77
      Here's my take on Sandbanks & Proscan. Changed Gain 1000, instead of the insane 10,000; Simplified timing control; Added EF sample and integrator from Dooley TD3X; Diode for mosfet drain; PSU as in MiniPulse Plus;

      Sandbanks - Proscan - GT.pdf

      Comment


      • #78
        Here's my take on Sandbanks & Proscan.
        Interesting collection of ideas, you are switching Q1 and Q3 with only 5 volts from the micro is that enough ?

        Comment


        • #79
          Voltage should be right. The micro/jfets configuration is same as in Minipulse so this should work just fine.
          Will the micro provide enough current, hope so !
          From datasheet: "- High current source/sink for direct LED drive"..


          Maximum output current sunk by any I/O pin............................................... .................................................. ... 25 mA
          Maximum output current sourced by any I/O pin .................................................. ............................................ 25 mA
          Maximum current sunk by GPIO.............................................. .................................................. ...................... 90 mA
          Maximum current sourced GPIO.............................................. .................................................. ...................... 90 mA

          Comment


          • #80
            Here's update on the schematic. You can use PIC code from Hammerhead II thread to run this, though will probably require code tweaking.




            Proscan GT.pdf
            Attached Files

            Comment


            • #81
              Originally posted by eclipse View Post
              Voltage should be right. The micro/jfets configuration is same as in Minipulse so this should work just fine.
              Will the micro provide enough current, hope so !
              From datasheet: "- High current source/sink for direct LED drive"..


              Maximum output current sunk by any I/O pin............................................... .................................................. ... 25 mA
              Maximum output current sourced by any I/O pin .................................................. ............................................ 25 mA
              Maximum current sunk by GPIO.............................................. .................................................. ...................... 90 mA
              Maximum current sourced GPIO.............................................. .................................................. ...................... 90 mA

              Scoped my MPP and yes it only uses 5 volts on gate, this could be handy for another project.

              Comment


              • #82
                Hello Everyone,

                My name Wahyu from Indonesia,
                Video my PI Polones base, i modified with Mosfet IRF740

                https://www.youtube.com/watch?v=WoD_NUfBYmk

                Comment


                • #83
                  What happened to the sandbanks post ?

                  Comment


                  • #84
                    Originally posted by Wahyu View Post
                    Hello Everyone,

                    My name Wahyu from Indonesia,
                    Video my PI Polones base, i modified with Mosfet IRF740

                    https://www.youtube.com/watch?v=WoD_NUfBYmk
                    Can you show as the scheamatic or circuit of this modification?

                    Comment


                    • #85
                      I built sandbanks project using a modified power supply(555 pump charge). I also modified the delay on sampling. It works very well. Depth is very good. I used NE5534 preamp stage redesign instead of 709. This is non motion pi. I also did follow up mods as described in sandbanks article.very good. The schematic posted above is fundamentally different. It resembles minipulse plus. Apples and oranges.

                      Comment


                      • #86
                        Originally posted by dbanner View Post
                        I built sandbanks project using a modified power supply(555 pump charge). I also modified the delay on sampling. It works very well. Depth is very good. I used NE5534 preamp stage redesign instead of 709. This is non motion pi. I also did follow up mods as described in sandbanks article.very good. The schematic posted above is fundamentally different. It resembles minipulse plus. Apples and oranges.
                        What did you do to the Delay ? What Follow Up Mods . Thank You.

                        Comment


                        • #87
                          HI
                          Can anyone explain what exactly is the role of the C7?
                          Considering the fact that Pin 8 in the op-amp LF357 is N.C!
                          tnx
                          Click image for larger version

Name:	PIPO.jpg
Views:	1
Size:	162.6 KB
ID:	346723
                          Click image for larger version

Name:	LFDATA.jpg
Views:	1
Size:	44.2 KB
ID:	346724

                          Comment


                          • #88
                            Originally posted by koohyar View Post
                            HI
                            Can anyone explain what exactly is the role of the C7?
                            Considering the fact that Pin 8 in the op-amp LF357 is N.C!
                            tnx
                            [ATTACH]37389[/ATTACH]
                            [ATTACH]37390[/ATTACH]
                            It looks like a mistake to me. Here's the original Sandbanks article:
                            http://www.geotech1.com/cgi-bin/page...anks/index.dat
                            and it doesn't use an LF357. So I assume the PCB you posted is someone's modified version.

                            Comment


                            • #89
                              Looks like a Cap that may have been used with some other Op Amp.

                              Comment


                              • #90
                                The original used the LM709. It was used for Freq Compensation. Pin 1 / Pin 8.

                                Comment

                                Working...