Actions
Forum Thread Details
  • Replies 332 replies
  • Subscribers 321 subscribers
  • Views 44783 views
  • Users 0 members are here
Related

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. 

 

 

 

image

Parents

  • Maybe I jumped the gun a bit, as the instigator, and having a practical use for it I am very interested in this project. I don’t think building one would be beyond my capabilities as I have made loads of analog items over the years. I am pleased to see that all of you are all up for it too.

    Ken

  • in reply to kltm

    Hello Ken and Dave

     

    Search ARMP on the front page of E14 or in the Open Source Hardware Group.

     

    This started after the discussion about having our own group.

     

    MK

  • in reply to michaelkellett

      wrote:

     

    Hello Ken and Dave

     

    Search ARMP on the front page of E14 or in the Open Source Hardware Group.

     

    This started after the discussion about having our own group.

     

    MK

    Thanks very much Michael, have found and will study then now. Absolutely agree about the handicap of not having a suitable forum (sub) section. I would not have been searching every day and trying to spot topics (and then see if they had changed!).

     

    Meantime, could I suggest that whenever any any new threads are started, we post a link here so as to alert everyone who is following the main thread?

     

    cheers/Dave

  • in reply to davemartin

    Everyone,

     

    Further to the discussions on the injection aspect, and the linearity (or otherwise) of the ‘device under test’, I’ve run some tests, and started a separate thread to keep them in one place.

    ARMP Archaeology Resistivity Meter Project - base data

    I've chopped them up to make them slightly more digestible (and easier to post, since this BBS doesn't allow pasting fully-formatted from Word). Part 1 just posted is basic injection data, next section with control plots and alternative stimuli etc. will follow in part 2.

     

    Dave

  • in reply to davemartin

    Great stuff - it's always nice to see some real data !

     

    The other (and related good news) is that I've already been working on an enhanced power amplifier that uses 60V rated amplifiers.

    My plan was to use +/- 25V supplies which would give us about 46V pk, and 92V pk-pk so very little short of your test.

     

    The noise on your test results is better than I had expected - but obviously we shouldn't read too much into a single test with regard to background noise.

     

    The same amplifier will be able to manage +/- 100mA with reduced supplies (+/- 10V) - this won't be switchable but will require different components at build time.

     

    I need to to a bit more simulation work but should get the rest of the schematics posted this weekend.

     

    MK

Reply
  • in reply to davemartin

    Great stuff - it's always nice to see some real data !

     

    The other (and related good news) is that I've already been working on an enhanced power amplifier that uses 60V rated amplifiers.

    My plan was to use +/- 25V supplies which would give us about 46V pk, and 92V pk-pk so very little short of your test.

     

    The noise on your test results is better than I had expected - but obviously we shouldn't read too much into a single test with regard to background noise.

     

    The same amplifier will be able to manage +/- 100mA with reduced supplies (+/- 10V) - this won't be switchable but will require different components at build time.

     

    I need to to a bit more simulation work but should get the rest of the schematics posted this weekend.

     

    MK

Children