00:00.00 archpodnet Welcome back to the archeitech podcast episode 175 and I am talking to Brian Fritz about the paleo digger machine that he invented so we've talked about the auger portion of it now. The auger portion you dump that material into um, a screen that is round. Circular rotating at least in the videos that I saw rotating off the ah looks like ah a belt driven off the other machine and um and it's at it's at like probably a fifty degree angle or so can you describe that a little bit see how I did. 00:33.30 Brian So yeah, it's around kind of like a tub. It's got the standard quarter inch screen or one hole per or four holes per inch screen that we use in archeology and so it's one side is open and it's tilted so that you can dump the soil into that screen. 00:41.29 archpodnet Um. 00:51.74 Brian And it's powered by Adro hydraulic motor and it rotates and this is really the most efficient way to move soil rapidly through a screen as opposed to maybe a reciprocating screen it shakes back and forth and because yep. 00:53.36 archpodnet Okay. 01:02.17 archpodnet Did you well real quick. Did you iterate on that and and I mean because I've seen screens like that before like powered screens that do shake back and forth and things like that. What what led you to this. What led you to this model was it was it. You know. Research and development. You know, just trial and errors. 01:22.30 Brian Well Tromel screens a rotating screen where you dump the soil. It's like a cylinder and you dump the soil or rock or material into one side and it's tilted on an angle and everything falls out on the bottom that's too big to go through the screen. It's similar to that except the bottom side is closed so that you put the soil in. 01:34.00 archpodnet Sure. 01:41.76 Brian And it rotates and as it rotates the finds dissipate through the screen and then when I'm done. The screen is designed to Tilt over backwards. So the dump the contents out into another tub which then can be transferred to a stationary screen where we can sort for the artifacts. 01:45.35 archpodnet A. 01:57.39 archpodnet Okay, have you noticed any any significant I Imagine there might be minor sometimes but any sort of um impact to the artifacts themselves I'm thinking about stuff like Pottery I don't know how much you find of that up there but something like pottery might. Ah, might not handle the tumbling through the soil too. Well, you know what? I mean. 02:15.77 Brian This is an open question. We haven't been on sites with it enough to where there was ah many artifacts to really get a good gauge of that I don't think it's going to be any worse than hand tools and shovel testing back about five years ago we were on a phase one. 02:22.72 archpodnet M. 02:28.79 archpodnet Sure yeah. 02:35.40 Brian We were digging deep s t s deep one by ones down to a meter and a half and a crew. Actually they dug through ah a feature hearth feature didn't realize it until they cut the Kirk point in half with the shovel. So our shovels damage artifacts. 02:51.44 archpodnet Cloches. Yeah, for sure, we've all done. It. 02:54.83 Brian As well. Even hand trials but this ah yeah, this isn't an open question and and one of the critiques I often receive and I have a feeling. It's not going to be any worse but we really need to see results in in the actual artifacts to be certain. 03:07.41 archpodnet Yeah, you'd almost have to dump in some you know produce some experimental archeology right? and have some things created that aren't actual artifacts and dump them in the screen and and just let it run and and see what see what happens you know what? I mean different types of soil matrixes too. 03:24.57 Brian Yes. 03:26.16 archpodnet You know matrices to see how that goes so interesting. Interesting experiment. Um, okay so let's talk about then the machine that tracks all this and and how it works can you describe the the electronic interface you've got to to help monitor all this. 03:42.52 Brian Okay, the so as I'm raising a lower the bucket into the soil The the mechanism that does that has a chain that lifts the auger head up and that's powered that chain is then driven by a hydraulic cylinder but because it's a chain you can put a sprocket on it. 04:00.66 archpodnet Okay. 04:02.43 Brian And that sprocket will rotate as the as the bucket goes up and down in in the hole and because it rotates at a regular increment I can I can meter that so I have optical encoders on a shaft to connect it to that sprocket and so many revolutions. Represents so much distance up or down and I have 2 There's 2 optical encoders so that it can sense which direction whether it's raising or lowering and those optical Encloserss they all they are is ah an led and a sensor that senses the led light and there's a little disc. 04:22.33 archpodnet Yeah, yeah. 04:28.38 archpodnet 1 04:40.87 Brian In between those the led and the sensor and there's gaps in that disc. So as it rotates it pulses at led and a number of pulses corresponds to the linear distance that it moves so there's an there's a a micro pro an 8 bit microprocessor called an arduino that's connected to that optical sensor. 04:45.95 archpodnet Now. 04:56.34 archpodnet Yeah. 05:00.32 Brian And it counts as number the number of pulses and then does a little bit of math and calculates how far the auger has moved down into the hole or up out of the hole in which direction and that's how I measure the depth that the auger is digging. 05:13.12 archpodnet Okay, so does the equipment operator sitting in the equipment have to look at this. This is how they know when to pull it out or is it or does it just like stop it. A depth is it programmed to stop when it hits a certain depth or you just watch the machine. Okay. 05:24.98 Brian I Watch the depth gauge. So whenever I'm starting a new test Pit I lower the auger head to the ground and I hit reset and it ah it resets the instrument to a new test pit and it zeros it out. Basically. 05:38.52 archpodnet Um. 05:42.28 Brian There's ah, there's a digital display that shows the information on the screen. So then as I start to lower I rotate the auger and start to lower into the ground um say I go down ten centimeters it increments One centimeter at a time as I'm as I'm digging down into the ground so when I reach my ten centimeter level I stop. 05:43.81 archpodnet Um, yeah. 05:54.53 archpodnet A. 06:01.65 Brian And then I reverse the rotation counterclockwise of the augur bucket and that closes the bottom the bucket. So I don't lose any soil as I pull it out of the ground. So as I pull the augur bucket out of the ground then it it'll count backwards back to 0 or even to the negative as I bring it up above the ground and it'll record. 06:08.13 archpodnet Gotcha nice. 06:21.80 Brian Level one zero to 10 and that'll show on display level one zero to 10 then I empty the I swing out the auger bucket I open it up and empty it soil goes into the revolving screen and while the the rest of the crew is working on screening the soil and collecting artifacts. 06:22.38 archpodnet Yeah, okay. 06:40.95 Brian I'm sending the bucket back down in the hole and start I start excavating level 2 and the and the electronics automatically records level 2 is ten centimeters and increments up to twenty centimeters and then logs that level 0 to 20 or 2010 to twenty centimeters as the next level. 06:43.86 archpodnet Yeah. 06:56.48 archpodnet Sure, okay, and is this programmable to like what would the end user be able to program this and say I want five centimeter levels or I want I don't know twenty Centimeter levels or something like that. 07:00.60 Brian And it just repeats after that. 07:10.25 Brian You can set you could do whatever you want because you're actually I'm actually controlling the depth as it's going down and watching the meter as it increments down into the ground. So say if I was in a plow zone and we know that the plow zone is roughly say fifteen centimeters deep 07:17.25 archpodnet Ah, okay, okay. 07:26.90 archpodnet Sure. 07:27.82 Brian I could pull the first level from 0 to ten centimeters out and screen it and I could use maybe a split zoom so split so spoon sampler to check how much how many centimeters was left in that plow zone and I could actually excavate that specific depth as the next level and then continue with the third level. 07:38.68 archpodnet Um. 07:46.80 Brian Into the subsoil with whatever that depth actually is and then then increment an even ten centimeter increment from there. 07:48.71 archpodnet Um, ah so you don't Okay I get it I think what you're saying is you don't actually have to you know it doesn't actually stop it. It stops when you stop it and then that is recorded at the next level so you could do. 08:00.64 Brian Yes, yes. 08:06.40 archpodnet Each level at a different depth if you really wanted to. 08:06.70 Brian I Guess I can choose I can choose how my levels begin and end. 08:10.49 archpodnet Nice, nice. That's really really cool I like that so somebody's digging more if they don't have much stratigraphy like I've done shovel testing in the coastal plain of the Carolinas and it's sometimes literally all one one type of soil all the way down. You know, as far as you can dig with a shovel. And we didn't really care what depth things came from because it's so turbulent out there on the coast with you know, hurricanes coming in and rearranging the soil every every couple of years and we just pulled everything out into 1 shovel test and dumped it into the screen. So. You could dig as much as you could fit in the auger probably and then pull it up and then do another level and call it. Good. Yeah. 08:49.72 Brian Yeah, yes, it it just depends on your the geology or your setting. Ah, ah your sediments. What the geology is in some cases. Our stratigraphy is pretty compact along some of our rivers. So I can actually excavate in five centimeter levels if it's called for. 08:55.29 archpodnet Sure. 09:06.31 archpodnet Um, yeah. 09:08.36 Brian Or in cases where you do have pretty sterile soil that you don't have a you're not really not likely to find much I can pull as much as twenty centimeters at a time. 09:14.40 archpodnet Um, yeah, and you know some of the benefits I'm seeing to this of course everything has a tradeoff right? And if you've got humans digging thirty Centimeter shovel tests my god I have seen everything from you know the bathtub where it's rounded at the bottom and and con concave on the sides because people just don't know how to make straight walls and and then not flat on the bottom. Um, you see the pinhole where it you know, kind of comes down to a point you see all kinds of different things and then you know people. Not super great about monitoring levels and strategicy now the other question scientifically is well do you need to be exact with that. But the answer is yeah as close as you can because you're doing a volumetric sample of an entire area and you want to know exactly what the volume you're pulling out is in order to say well, there's this many artifacts here. You know per per density unit measure type of thing and even if this machine is I mean let's say let's be honest, even if this machine crunches up an artifact or something like that. Um, you know in the process of doing it like you said we've all done that with a shovel and a trowel. So. That's not like a huge deal. Um. But it's able to do a more precise excavation and pull out the same if not better information as far as you know stritographic information goes. 10:34.11 Brian Yes, and particularly well here in Pennsylvania our standard shovel test pit is fifty seven centimeters in diameter because that works out to one quarter of a meter in area and if you if you were to dig down eighty centimeters 10:41.56 archpodnet Um, okay, okay. 10:52.15 Brian And your walls tapered tapered to forty centimeters in diameter that's a 30% reduction in the diameter of the test pit but it's a 50% reduction in the volume of soil in that level from seventy to eighty centimeters so you're so there's you know it's it's a power. It's a factor of power because area is ah is. 10:53.71 archpodnet Um, yeah, ah right. 11:11.67 Brian Ah, squared so our volume is is cubic. Um, so if you're if you're under sampling 50% by 50% at that level. That's that's a serious bias. 11:24.78 archpodnet Yeah, for sure for sure. So I exactly exactly and I haven't dug in Pennsylvania but I have in Vermont and New Hampshire and I'll tell you what some of the clays and stuff up there. 11:28.11 Brian Whereas my machine's clean, a straight wall the whole way down. 11:42.95 archpodnet I would rather have a machine do that Anyway, it's just such a pain in the ass Sometimes some of those really compact Soils I mean there was a mile of ice over where you're digging So you know the the compaction is real in that area. You know for what that is so all right? Yeah, go ahead. 11:59.20 Brian And and the standards vary from state of state pennsylvania has largest shovel test pits at fifty seven centimeters in diameter most are around 50 or 40 some of 30 my machine cuts a fifty two centimeter diameter hole 12:04.76 archpodnet Yeah that's that's big. Okay, yeah, nice. Nice. Yeah, most. Mostly what I've done to be honest down in the Carolinas Georgia when I was doing a lot of shovel testing down. There was actually thirty centimeters and then but the 1 place so obviously where you of course would run into somewhat of an issue some states mandate square shovel tests like I think um Florida was fifty Centimeters square shovel tests 12:37.80 Brian That that would be a quarter of a meter. Yes. 12:38.84 archpodnet So yeah, yeah, exactly exactly. So I mean if you're pulling out the same volume like you said does it really need to be square so you know there you go. All right? Well, let's take 1 more break and then I want to come back and talk about some of the technical challenges with the electronic box that I saw in the videos and then where you're going with this in the future. So let's do that on the other side of the break back in a minute.