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Archaeology Resistivity Meter

kltm

Hi I'm looking for ideas on an update to a resistivity meter for archaeology. The only published designs for diy were in 2 magazines. One was published in 1997 and the other in 2003. I have copies of both articles available. The reason behind this is the current high cost of available equipment, usually well beyond the reach of most archaeological groups. I've attached a basic block diagram. In the first magazine article the meter is very basic. It relied on the operators to write down the reading given as the survey was taken. Given that a normal survey grid is 20m x 20m and 1 reading is taken on every sq mtr there would be 400 readings to write down and then input into a program used to interpret the results. The later article is really an update to the first where a PIC has been added to record the readings. This again is prone to error, because eadings are taken manually by pressing a button.

I'm sure given the advances in electronics there must be better ways. 

 

 

 

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  • in reply to phoenixcomm

    I started putting in shelving today :-)

  • in reply to fmilburn

    Good luck, frank I'm still putting up shelving! Lots of Elfa top mounting rails, and standards. Rubbermaid etc (Home Depot) for the brackets (cheaper price). And sometimes I buy them from my Goodwill outlet store where it's only $1.50 a pound. image I also have some Metro wire shelves, and some HomeDeopt plastic shelves. In my garage, I put together a bunch blue of 2x4x6 used shelves with nuts and bolts ( image pain in the ass!) so have about 20 feet of that stuff. And I still need to put together a workbench down there as well. for a drill press and other things. Currently building a 12' long clothes rack, from 2x4s and two uprights from the blue shelves. Not quite a 3-foot base but all the way to the ceiling made like two right triangles. And its bolted together, with a cross brace near the top to rest the steel on. image

  • in reply to phoenixcomm

    Yep, I'm started with some metal wire shelving that is quick to put up in the garage and then building some 2x4 made to fit next.  I almost spent more time opening boxes to find the necessary tools than putting up shelves.

  • in reply to fmilburn

    " I almost spent more time opening boxes to find the necessary tools than putting up shelves." sounds very familiar!

  • I fear this project has died. It will be a shame if it has after all the hard work that has been put in. I know I haven’t contributed very much personally, mainly because I find it all a bit beyond my analog capabilities.

  • in reply to kltm

    Hi Ken,

     

    I certainly hope it hasn't died - both because of the need and potential, and because of the work Michael Kellett and others have already put in.

    I am afraid that my daytime work has been interfering with projects like this; but I have been working on a data set to provide some information to help with background for the design. To illustrate the injection aspect C1C2 and range of readings P1P2  I have, along a fixed 50 metre traverse, taken readings at 1,2,3,4,5, 10, 15, 20 ..50m using conventional square-wave excitation, capturing injection voltage V1 and current I C1C2, and the independent differential signal voltage V2 between P1P2 using 4-channel scope and then deriving injection resistance R1 and P1P2 resistance R2 with waveforms at each point both single-sweep to capture peaks and using modest filtering. I've then also got some control plots (e.g. no injection with, and without, mains on nearby) to capture background noise P1P2, and plots with the leads but using an appropriate dummy load. I've then run a series of tests using various excitation waveforms - conventional square wave, sine wave, triangle / symmetrical sawtooth, and an arbitrary trapezoid. Much of that is done and partly written up; problem has been the day-job and also getting time when it hasn't been driving rain outside! I hope to get time and opportunity to complete that within the next few days. Its looking so long that I may need to publish it in a couple of parts, or as blog posts (as Michael did for the input amp.), or as PDFs.

    Dave

  • in reply to kltm

    Ken,

     

    There is still work going on for this project.  The discussions have been moved to another area and split into separate topics.  If you use the search bar at the top of the screen and enter ARMP (for Archaeology Resistivity Meter Project) you will see multiple discussions that are focused on various parts/functions of the project.

     

    Gene

  • in reply to kltm

    Hello Ken,

     

    I'm sorry you are saying that:

    I've posted blogs and comments and schematics for the input amp and the ADC/DAC/FPGA, and inital design notes about the processor and display section.

    The schematic of that last part is nearly done.

     

    Maybe it's time for show of hands as to who is interested enough to think they would actually like to try and build one or be jointly involved in the building of several.

     

    MK

  • in reply to michaelkellett

    I'm up for it but my interest is in a LCR meter.  Even if it isn't suited for that I would be willing to build one and donate it to someone with a need if there is an archaeological interest from someone without the electronic skills to build one.

  • in reply to michaelkellett

    Me too, I'd like to build one although mine will be more likely spread out over perspex or something, to work on development, rather than a complete outdoor-capable unit.

    I'm tied up for a couple of weeks but much free-er after that.

    I can also help with building several.