Labor savin' devices

On 03/10/2020 14:28, Jim Wilkins wrote:






I think a lot of the maintainability with C is down to style and organisation. My background was in mechanical engineering but got into computing during my degree and went on to get a job at a software house and trained in C where the company's in house style made the code easier to follow IMO than K&R style and my engineering background helped with organisation. I provided a university technician with the source code for a port of his PCB program to Windows in C and he found it easy to follow whereas he often found students C code difficult because of how they were taught to write C.
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"David Billington" wrote in message
On 03/10/2020 14:28, Jim Wilkins wrote:

.................... I think a lot of the maintainability with C is down to style and organisation. My background was in mechanical engineering but got into computing during my degree and went on to get a job at a software house and trained in C where the company's in house style made the code easier to follow IMO than K&R style and my engineering background helped with organisation. I provided a university technician with the source code for a port of his PCB program to Windows in C and he found it easy to follow whereas he often found students C code difficult because of how they were taught to write C. ===========================Yes, I've seen some that looked like the programmer's main goal was job security. Perhaps engineers are more relaxed when programming because they have other valuable skills.
I began with an LSI-11 flavor of Pascal customized for hardware control, an uneasy fit due to Pascal's strict typing versus variables that were bit-mapped binary register contents, but most of my early programming experience was hand-written assembly code for the 8080 computer I scratch-built. It forced me to be careful to comment everything well enough that I could understand and improve it later. Eventually I wrote a text editor that could assemble new or disassemble older code line by line, but by then I had coded perhaps 10,000 lines by hand and needed to expand the 16K memory.
As soon as I had acquired enough RAM I dropped the habit of writing tricky, tightly condensed code. The company made production memory wafer testers for National Semi et al and the engineers received pre-production samples of new devices like the 6116, which were typically too slow (500nS) to use for much beyond evaluation, so after they were done they gave them to me. http://ee-classes.usc.edu/ee459/library/datasheets/6116SA.pdf
It can use the same socket as a 2716 UVPROM. There's also a 2816 EEPROM variant. I backed them with NiCads so I wouldn't have to boot from the Teletype each time.
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DESCRIPTION The bpp driver provides a general-purpose bi-directional interface to parallel devices. It supports a variety of out- put (printer) and input (scanner) devices, using programm- able timing relationships between the various handshake sig- nals. ====================================================================    Beyond that -- you would need to write your own C library routines to take place of the built (or loaded) into the kernel drivers.
    For the first unix box I had -- a "Cosmos CMS-16/UNX" (MC-68000 on Intel Multibus) I wound up writing a program to access an I/O device from a hamfest -- Nicad cells along the top edge, and a crystal oscillator and a bunch of counters which served as a clock/calendar, and I could use it to automatically set the clock when I booted the system. Before that I had to key the time in every time I booted.
    To access it -- I needed to use a root only system call to map the memory of the board's registers into the program space, so I could access the registers. I also wrote a similar program which would copy the current date/time into the card, to set it *once* -- or after a DST change. (Oh yes, speaking of DST -- this was just after a change of the offsets of DST -- and a open-source library and database for those, so they can be changed at need. (It is still in unix/linux flavors.) I compiled that on the system, and used it in my own programs which needed to deal with the date and time. But many other programs used the original library -- and I did not have source to change them. Also, the OS had compiled in a PST/PDT constant. Since I did not have the source for the kernel, I had to learn how to find and change the constant to move it to the east coast. I named the machine "Owlsley", figuring that someone who made and used his own LSD would have a weaker linkage to his current location than most people. :-)

    O.K. So -- the clock update would override the access to the parallel port registers?

    Makes me think of GWBASIC (or the BASIC which came with early MS-DOS system) which was derived from the BASIC for the Altair disk 8800. (8" disk, hard sectored, IIRC). On the Altair, the system booted BASIC off the floppy, and then BASIC controlled read/write to the disk, for saving programs and data files.
    It happened to bypass the drivers in MS-DOS, so a program written in it could create files with spaces in the file names. No way to rename or delete the files from the OS command line. The only way was to do it from within BASIC (not documented anywhere that I could find -- but I had to figure it out to get rid of a file left behind by someone running the typing tutor program.
    Sort of like a unix system providing networked file systems to a lot of (mostly unix) systems, and one or two Macintoshes. The Mac user could name a file something like "data-04/23/80", where unix systems will not allow a '/' or a null in a filename. The only way to clean up the filesystem (so backups would not fail) was to unmount the file system, and then use emacs (super-editor) to edit the directory in the raw. Change the '/'s into '-'s and then I could delete them from the mounted filesystem. (Of course, now not a problem, because Mac's OS-X has a unix under the GUI, so the '/' in a filename is no longer allowed. :-)

    :-)

    Sigh!

    Enjoy,         DoN.
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"DoN. Nichols" wrote in message wrote:

O.K. Depending on the model, it may have been one I worked on. For a while I was in the test equipment repair division. IIRC, that was about the time that Tek was moving from listing input capacitance in uuF to pF on the front of vertical plugins.
555555555555555555555555555 My 531A and 541 suffer high voltage arcing. What's an acceptable cleaning method and solvent? I realize they are good mainly for backup heat on chilly mornings, except that I have type W and 1L5 plugins. 555555555555555555555555555

555555555555555555555555555 The only job I did that needed the full speed of machine language was experimenting with an open-loop driver to step a drum printer head with critical damping, ie as fast as possible without overshoot. So I wrote it in 80286 Assembly. The non-contact position sensor was a small Radio Shack solar cell partly shaded by the head.
The printer port is hardware-limited to about 1 uS minimum pulse width, plenty fast for 100 KHz I2C data. 555555555555555555555555555

555555555555555555555555555 It's an interrupt that paused whatever my program was doing, such as counting a timing loop. I had to complete a time-critical task in less than 55mS and then poll the timer until it changed. I2C has a synchronous clock and isn't too fussy about timing, but the computers the program might run on could have CPU clocks anywhere between 50 MHz and ~1.5 GHz so I needed to measure the speed of timing loops and adjust them into a more reasonable range. 555555555555555555555555555
Sort of like a unix system providing networked file systems to a lot of (mostly unix) systems, and one or two Macintoshes. The Mac user could name a file something like "data-04/23/80", where unix systems will not allow a '/' or a null in a filename. The only way to clean up the filesystem (so backups would not fail) was to unmount the file system, and then use emacs (super-editor) to edit the directory in the raw. Change the '/'s into '-'s and then I could delete them from the mounted filesystem. (Of course, now not a problem, because Mac's OS-X has a unix under the GUI, so the '/' in a filename is no longer allowed. :-)
555555555555555555555555555 I've modified file structures without OS interference by passing the raw data through an HP1000 minicomputer running my assembly program. That's not the easy way but the boss liked to challenge me.
Mitre avoided PCs after the Cuckoo's Nest incident. We had Macs and SPARCs which were less well supported than PCs as CAD and lab machines. I had to design and build a 16-bit A/D data acquisition board for a Mac and write its LabVIEW driver. The Mac was a fine computer as long as you did what Apple knew you should, but our research needs went much further. I don't avoid them now out of ignorance. The $5 - $20 laptops I find at flea markets are retired business-class PCs like this D630, and I know how to upgrade and use them for what I want; HDTV recorders, data acquisition, SDR radio, etc.
https://en.wikipedia.org/wiki/Software-defined_radio "SpeakEasy, the military software radio was formulated by Wayne Bonser, then of Rome Air Development Center (RADC), now Rome Labs; by Alan Margulies of MITRE Rome, NY;"
Rome Labs didn't have technicians who could build it (I was told) so SDR landed in my lab at MITRE Bedford, MA, as unlike the radio/radar techs I had considerable experience in A/D converters and computer hardware and circuit board design, and can solder tiny surface mount parts.
The concept of SDR receivers is old, the enabler was an A/D converter fast enough to digitize the IF frequency, not just the baseband. The fastest available went into digital oscilloscopes so they were what we used. A few years earlier it had been a struggle to obtain an A/D fast enough for an optical document scanner. The scanner processor was that same TMS320, for which I designed the DRAM controller, another see-if-he-can-do-it challenge.
The enabler for SDR transmitters is the Direct Digital Synthesizer. I was using Molybdenum-cased hybrid modules with hand-written single digit serial numbers. I milled an aluminum model of the DDS at home to avoid handling the static sensitive parts while figuring out how to fit them and an adequate heatsink into the narrow space of a VME slot. https://en.wikipedia.org/wiki/Direct_digital_synthesis 555555555555555555555555555
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"DoN. Nichols" wrote in message wrote: ...

I have no idea. I haven't used the parallel printer port for I/O like that. I would have been more likely to wire-wrap up a custom MC-6800 or MC-6809 board with enough PIA chips to do the readings, and transfer them via serial port.
=============Here's how to control the printer port in C: http://electrosofts.com/parallel/
A useful first exercise is to write a program that displays a graphic of the port and the state of each bit.
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"DoN. Nichols" wrote in message ... The first digital voltmeter was a NLS (Non-Liner Systems) which used a Kelvin-Varley divider implemented in stepper switches, and a digital readout consisting of sheets of Lexan with the digits engraved in them, and lit from little aircraft lamps (327 if 28V, 328 if 6V, other numbers for other voltages.)
The big nuisance was when the voltage you were measuring was drifting up and down a little. As it goes up, you would hear click, click, click, but if it went down you would get rrrrrr, rrrrrr, rrrrrr, rrrrr, click, click, click. At least it had sound deadening in it, but when I had to work on them in the shop, the noise was a real pain. ... Enjoy, DoN.
====================Stepping switches and relays arose after an undertaker became upset that the local telephone operator, the wife of his competitor, was diverting phone calls away from him, so he invented what became the dial system to eliminate her. https://en.wikipedia.org/wiki/Strowger_switch "Early advertising called the new invention the "girl-less, cuss-less, out-of-order-less, wait-less telephone".
In 1940 US cryptographic researchers figured out that the Japanese cipher machine used telephone stepping relays to implement a complex automatic version of the Crackerjack secret decoder ring. The researchers happened to choose the same model of relay to build their decryption device. https://ciphermachines.com/purple
It didn't help predict Pearl Harbor because the Japanese hid their real plan among a flood of plausible fake ones such as destroying the lock gates of the Panama canal. We did the same to disguise the target of D-Day.
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    I'm very familiar with those. I built a small dial exchange with original versions of the Strowger switches -- one line finder, one selector (one dial digit), and one connector (two dial digits). (Later AT&T cloned them, and called them 10x10s.)
    And I think that, based on the complexity of the Strowger switches, he was mis-employed as an undertaker. :-) He really had to be a good machinist to make the prototypes, and good with relay logic to design the circuitry.
    Those steppers were two-axis -- first up to one of ten levels, and then rotate to one of ten positions. And they could reset directly with a single pulse to a solenoid.
    The ones in the NLS were unidirectional, 11 positions, with three sets of wipers at 120 degrees, so it took 33 steps to do a full rotation of the wipers. And there was no reset, so you had to go at least 10 steps to reach a zero point again.
    There were other steppers, ten position after stepping off the at rest positions, and a single pulse to a solenoid to let the stepper spring back to the rest position. I used one of these as a line finder before I got the proper Strowger two-directional one. With the right relays, the line finders, or the connectors could really jump through hoops.

    And the associated telephone set, was mis-called "The world's most beautiful telephone". :-)

    Interesting. Probably made the task easier.

    Of course.
    Enjoy,         DoN.
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"DoN. Nichols" wrote in message
And I think that, based on the complexity of the Strowger switches, he was mis-employed as an undertaker. :-) He really had to be a good machinist to make the prototypes, and good with relay logic to design the circuitry.
-----------------
All he lacked was an assistant named Igor.
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"DoN. Nichols" wrote in message
O.K. The inexpensive style. :-) I prefer crimpers which are ratchet controlled -- or the hydraulic ones which have a release at a specific pressure -- 8500 PSI for the ones by AMP -- including electrically pumped as well as foot pumped.
===================================I'll gladly order and use the proper crimper if the company will pay for it; the hand tools can cost hundreds of dollars. For home use I collect what I find at flea markets, otherwise I rely on pull and resistance testing to determine the suitability of a crimp with alternate tooling. At Mitre we had a pull force tester to check wiring for aircraft.
https://www.andilog.com/How-to-check-crimp-terminals-on-wires.html
My HF carbon pile load tester allows a voltage drop check of crimps at 100A. Even 1A is enough to measure the voltage drop and resistance in an inch of 12 AWG wire. For my solar wiring I short the far end and measure the total loop resistance to see if it matches what that length and gauge of wire should show. As a result I've upgraded most of my solar house wiring backbone to 10 AWG and reassigned the older, thinner wire.
Ox-Gard appears to protect exposed outdoor connections such as SAE (flat trailer) connectors for several years.
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    It helps that I used to work with the crimpers at Melpar, where we built (among other things) flight simulators to mil-specs. So I could recognize the crimpers at hamfests.

    O.K. For that, you really do want to measure the resistance.

    Good thing to know. This is the compound used to protect aluminum wiring connections, or something similar?
    Enjoy,         DoN.
P.S.    I may have just answered another of your articles by 'r' (Reply)     instead of 'f' (Followup). At least on gmail it will get to     you.
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"Snag" wrote in message
Time marches on ... and with it my desire to work any harder than I absolutely have to . There is wood involved in this project , along with the metalworking . A year or so back I built myself a small pivoting jib crane to move firewood from the trailer to the log splitter . With a boat winch for the lifting , it worked remarkably well . I was using a cable with a choker loop in the business end up until a few days ago , and it too worked . But the other day my neighbor (not the blacksmith neighbor , this guy is fairly new to the neighborhood) brought me a set of unfinished log tongs . I had to drill for and install a pivot bolt and I did a little rework of the ring and shackle assembly . That made things a lot faster and less work too ... so today , just to ice the cake , I bought a HF 2500 lb 12V winch to replace the hand cranked unit . I'm kinda laid up right now with a couple of probably-cracked ribs from a slip while dismounting the Rusty Tractor , so I'm using the time for things that aren't as strenuous as handling 100-150 pound chunks of log . Just took the dog for a walk and got to thinking , I need to make the winch mount removable so I can also mount it on the Rusty Tractor and use it out in the woods to drag logs into position ... I think something resembling a trailer receiver hitch . I'll still have to deal with the power cables , maybe something like a dryer outlet so it's just all plug and play . This winch came with only a wireless control , the first thing I did when I got it home and open was take the cover off the control unit . Looks to be very easy to convert to a cabled control when this wireless remote dies . And it surely will , just a matter of when and where . ...-- Snag Illegitimi non carborundum
======================I've been through all that too. At first I put the 12V ATV winch on the pickup truck trailer hitch but the cable all wound on one side and logs dug into the dirt and jammed when they hit rocks or fallen trees, Winching worked better from the swiveling truck bed crane that helped lift jammed logs, like the short crane on a skidder.
After struggling with cheap cable pullers and boat winches for a long time I upgraded to chain falls and lever chain hoists for lifting and short horizontal pulls. A 3/4 ton lever hoist has been the most useful for logging and works well horizontally, which is awkward with chain falls. I use those mainly on the sawmill because I can stand further away from the load. My HF electric hoist is too fast and jerky for precise positioning on the saw bed, though fine for stacking beams from a safe distance.
I quickly learned not to trust log tongs until the tips had been hammered in a ways. A chain with a grab hook is nearly as simple to connect and doesn't fall off as easily if unloaded. I only use the tongs to lift one end of logs for clearance, then toss the chain underneath. 5/16" x 5' is a handy size, with a longer and stronger 3/8" chain for backup on logs bigger than 5' around. I looked at but didn't buy log skidding chain hardware because I'm less concerned with speed and more with safety, since I lift while standing near the log instead of from the cab.
Anderson (or clone) connectors are a better choice than a 30A dryer plug for high current DC connectors. Since the pins are shielded and bidirectional the same connectors are safe to draw load current from the battery or put it in from a charger. AC plugs aren't safe if the male side is hot. All the DC connections in my solar system are Andersons because battery and inverter/charger power can flow either way. https://www.truckelectrics.com/blogs/news/anderson-connectors-what-size-cable (Amazon.com product link shortened)
Mine were surplus with cables attached. The connector pins had been crimped onto the wire in several placed with a round punch.
The U1R battery in my small tractor didn't take well to the current a 2500# winch draws. When I load-tested a new, freshly charged U1R it couldn't quite reach its CCR rating.
A regular chainsaw chain can rip log sections too heavy to lift or too tangled to split in half or quarters quite efficiently as long as you don't cut exactly parallel to the grain, which clogs the saw with strips.
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On 8/18/2020 8:16 AM, Jim Wilkins wrote:




Since the upper section of the crane is removable , I bolted the winch to it . I'll build a "pin" that will mount on the trailer and one that will fit into the trailer hitch socket for the crane section to drop into . The swiveling upper section is female .

I'm not trying for precision positioning , I just want to get the rounds off a trailer and onto the splitter .

Ive ordered a battery for this , will be kept on a trickle charger most of the time . I won't be getting anywhere near the capacity of the winch as a general rule . If i decide the battery isn't working out , I have a backup plan to draw power from the camper's deep cycle battery . I need to find some more 8 ga or heavier wire for the hookup , I'm a few feet short . I'm undecided about how to handle the power hookups when it's not on the crane base .
--
Snag
Illegitimi non
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"Snag" wrote in message
Since the upper section of the crane is removable , I bolted the winch to it . I'll build a "pin" that will mount on the trailer and one that will fit into the trailer hitch socket for the crane section to drop into . The swiveling upper section is female .
I'm not trying for precision positioning , I just want to get the rounds off a trailer and onto the splitter .
--
Snag

==============================
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"Jim Wilkins" wrote in message ... If [the table] was larger I could position it between the splitter and the trailer and roll or hoist large rounds onto it. =====I had to stop editing for a dental appointment.
To summarize, I think your answer is a dedicated or temporary table that you can hoist rounds from the trailer onto at one end and roll them onto the splitter beam at the other. It could be as simple as planks or loading ramps resting on sawhorses or the side of the trailer. My experience is that the table top should be at least large enough to hold half plus a quarter of the round back out of the way while you split the other quarter, and high enough to roll heavy pieces onto the beam but not so high that they snag on it while being split. About 6" below the top of the beam works for me.
https://www.motherearthnews.com/diy/build-a-log-splitting-table-zmaz02onzgoe -jsw
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On 8/19/2020 8:18 AM, Jim Wilkins wrote:



I made a small, sturdy table to store the splitter on so it can occupy the same covered space as my non-folding shop crane. When splitting I put the table under the wedge end so splits fall onto it instead of the ground. If it was larger I could position it between the splitter and the trailer and roll or hoist large rounds onto it. I don't because I can put the splitter under the sawmill's overhead gantry hoist.
--

I built a rack on my splitter . About 16" wide total , I can balance
a piece on the edge while splitting another . Pieces too big to balance
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"Snag" wrote in message
I built a rack on my splitter . About 16" wide total , I can balance a piece on the edge while splitting another . Pieces too big to balance on the edge get suspended on the jib crane and swiveled out of my way . I do have to make sure the column is plumb or pieces can come back ...
=============Gravity must be female, she always gets her way.
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"Snag" wrote in message
I built a rack on my splitter . About 16" wide total , I can balance a piece on the edge while splitting another . ===================That seems to be the common solution. I think a larger table works better but it requires storage space and a separate trip to the firewood.
--

...The original plan was to haul the
jib crane out into the woods , but as it turned out that's just not
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On Fri, 21 Aug 2020 08:50:08 -0400, "Jim Wilkins"

Ooh, sweet crane setup. Probably a couple grand when available.
--
There is nothing more frightening than ignorance in action.

--Johann Wolfgang von Goethe
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"Larry Jaques" wrote in message wrote: >

Ooh, sweet crane setup. Probably a couple grand when available.
==================================If I was to make a portable take-down gantry from scratch instead of material already on hand I'd buy 4" channel iron which the Harbor Freight 1 ton trolley fits without modification, and make connections between the channels and legs that are less flexible than a chained tripod. Mine is meant to move logs and boulders to the trail on a forested hillside and requires considerable care to keep it from swaying and tipping. At the trail the shop crane converted to a low-bed trailer can take over. The gantry isn't high enough to load a pickup truck because I wanted to assemble it without climbing a stepladder on soft sloping ground. You could make it higher for firm level ground or pavement.
The last time I used the gantry more or less free-standing was with an electric hoist so I could stand back the length of the control cable. The beam was bolted to vertical wood posts braced with diagonal legs borrowed from tripods, and guyed to everything within reach.
To set it up I place a W-folding step ladder at the center with boards across the rungs at beam height, then balance the two channels on the boards and attach the supports to the ends. Once the beam is suspended I remove the boards and lift the ladder over the beam. Disassembly is the reverse. Two channels aren't ideal structurally, they just reduce lifted weight to allow assembly without a helper. They came from a heap of disassembled pallet racks and I had to use what was available, mostly C3x4.1 and a few C4x5.4, all 8' long.
https://jonochshorn.com/scholarship/calculators-st/index.html
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On Sun, 6 Sep 2020 10:01:48 -0400, "Jim Wilkins"

Be careful when using those calculators. The closest I saw that applies to the problem at hand assumes continuous lateral bracing, which is a reasonable assumption for a typical building floor system, but not for a simply supported lifting beam. https://jonochshorn.com/scholarship/calculators-st/example8.6/index.html
A potential failure mode of a slender beam is somewhat analogous to column buckling. https://en.wikipedia.org/wiki/Buckling#Lateral-torsional_buckling
The AISC steel construction manual's beam tables & graphs take the beam's unbraced length into account.
Also keep in mind that both the AISC and (I presume) that calculator use a factor of safety of 1.67. The FS for a lifting device is typically much greater.
--
Ned Simmons

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