So, remembering my dad's old seed planter monitor (with the numitron tubes) reminded me of another agricultural dohickey™ I found. I promised next time I got out to my storage unit, I'd get photos. Before I get into that, here is an instrument with actual nixie tubes. Sadly, it was low in the stack, and I couldn't be bothered to unstack a 5 foot tall stack of rack mount instruments to snag it from the third to bottom position. I'd have plugged it into my car otherwise. Rest assured though, that it works. The unit is used for testing synchro transformers, and you use the buttons to advance it by 5° at a time, or to reset it to 0°. Pretty straight forward. The Nixies display the degrees of rotation that you are testing the synchro at.
It's a Gertsch Synchro Bridge, used in the manufacturing and testing of synchros. I actually have a thread on emulating synchros, to drive aviation equipment. That project is slow going, we shall say...
I'll get to it again. I did snag a resolver standard and a resolver bridge from he stack (thankfully near the top). No, they don't have nixie tubes, or even panaplex or numitron tubes, but they do have tape displays. I am considering salvaging those to make into tape meters fro my Kerbal Space Program controller. Tape meters are SO HARD TO FIND! (those are meters that have a fixed pointer, and a scrolling reel of "tape" marked with numbers that moves by to indicate). These resolver bridge/standards have a rather complex switch arrangement that provides absolute position feedback for where the tape is at, for 72 absolute positions... Not bad!
Now, I promised some numitrons! This is the Harvestall "Topdrop" Integrated monitor and control of differential temperature. I suspect it was built as some sort of demonstration unit for some manner of crop drying monitor. The chips have mostly 1978/79 date codes, and I suppose most digitally controlled anything was fairly new back then, at least in the ag industry. This unit once had a cover, as evidenced by latching hardware on either end. Likely, it had a cover that closed the whole demo unit, and had a handle at the top. The cover was not with it when I found it.
This contraption looks hand made to me, with a few manufactured components. The PC board was professionally manufactured. Much of the rest looks custom. Again, no idea how this would have been used to demonstrate the product they were selling. I don't know the nature of the demonstration, or how it worked, but there is a fan in the unit, and lights inside the assembly at the left. There are two temperature probes (not sure if thermistor or thermocouple). As per the function, it seems to monitor an internal temp and an ambient temp, and then show the difference, as far as I am able to tell.
No idea what the switch is selecting.
I do suspect the unit was related to grain drying. The object to the left is shaped like a grainary. For city folk, that's a concrete or steel building, typically cylindrical, that is used to store seeds and grain. They are filled by dumping the seed in through a hole at the top, and unloaded through a chute at the bottom. A lot of farmers use grain driers to dry the seed, which nets a higher payout for selling, as dry seed is lighter to transport, and has a lower chance of spoilage (mold, etc). There is of course, a cost benefit ratio in drying the grain yourself. The logo made from two arrows resembles a granary. The contraption tot he left resembles a granary. The function seems relevant to drying... It seems like that's probably what they were selling this for. I also LOVE that company's logo. It's got a very "Egyptian" theme! Don't know why I dig that.
Doesn't exactly scream "Minnesota", eh.
**EDIT**
Doing a little digging, it seems that Harvestall had been marketing a method of "chillcuring" grain. Rather than drying grain with heat, they were drying grains cool. They claimed it was more energy efficient, and was easier on the seed than hot air drying. They operated through the 1960s or 70s, and under the name Harvestall from 1977 until 1982, and continued some form of operation up to the 90s. The industry was heavily pushing hot air drying of grains, and agriculture got hit pretty hard in the 1980s by high interest rates and low profitability (at least in the US).
The controls make a little more sense now. They regulated airflow to maintain a lower temperature by drawing heat off with the moisture pulled away. Or something like that, I guess. The unit's switch has differential temperature detection points (in auto mode) for 0°, -4°, -8° (presumably F°, since this was marketed in the US). I suppose this likely regulates the fan. The only heat (besides efficiency losses of the electronics and mechanical systems) were a series of infrared lamps that were used for pre-drying intake air if the external ambient air conditions were unfavorable for drying. Their process didn't use kilns or propane for extreme drying, like how most grain drying is done. They mimicked the natural convection flows of old style corn cribs (a style of building for storing corn that has gapped slats instead of solid walls to allows air to flow through it). The more you know!
Further reading tells me the guy (Sylvester Steffen) who ran this business was into some weird pseudo-religious q/whack job new age thingamawhatsit that had him making
amazing statements like how people are making such a big fuss about the right to life with the abortion debate... but what about all the wasted life from improper seed drying? What about the seed's right to life?
SERIOUSLY!
He was touting energy savings and drying techniques for seeds that were "easier" on the seeds, not for the sakes of energy savings and increased yields, but cause it was morally necessary in the fight to convert as much energy in the universe into living molecular organisms and to fight against entropy, staving off the chilling of our mantle! This guy...
I can't stop laughing at this guy! That's the freakin' 70s for ya! Whack job new age nutters!
On a side note, totally explains the pyramids and the whole Egyptian theme... New age nutters freakin' LOVE pyramids! The actual reason they used the image of a pharaoh and the pyramids, is a reference to the "dream of 7 years of plenty, followed by 7 years of famine" told in the bible. In the story of the pharaoh, he built granaries to store food when it was growing well, so Egypt would not go hungry in the years that would follow, after Joseph interprets his dream. So I guess the whole granary thing kinda sorta makes sense? ish?
Now I'm REALLY glad I found this old demo tool... Satisfies my love of vintage electronics, AND gave me an epic laugh!
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