Accidental Science
how to make your own special potentiometers
updated
This is a two-parts video, previous one is about photovoltaic systems, link below.
Two years ago I installed a solar system on my house, and because of shortage of available technicians (and even materials!) I had to do everything myself, including some hardware components. It was an istructive experience from which I learnt some things that I did not expect to find. So in this two-parts presentation I share with you what I learnt, hopefully providing useful for you.
In this video you will get into the typical inverter, skipping the details and focusing on the conceptual blocks and how they may affect the whole photovoltaic system.
Why RCDs trips, why you may find unexpected voltages on the frames of your panels, and more.
The presentation does not address some topics such as overloads, reactive loads, and surge load such as those caused by induction motor start up. Maybe I will add another video for those topics if enogh request comes from you all.
First part, "Photovoltaic Systems and MPP (Maximum Power Point) ": youtu.be/TwyHmL_N5rs
Watch the full series of electronics: youtube.com/watch?v=ye9dguKy_Cs&list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
For more related/complementary content please visit my website: accidentalscience.com .
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This is a two-parts video, next is about how solar inverters work, link below.
Two years ago I installed a solar system on my house, and because of shortage of available technicians (and even materials!) I had to do everything myself, including some hardware components. It was an istructive experience from which I've learnt some things that I did not expect to find. So in this two-parts presentation I share with you what I learnt, with the hope it will be helpful to you.
In this video you have the opportunity to understand the various topologies and configurations, and their differences so you might make an idea of what would be best for you, if ever interested in installing one, or making further considerations if you already own one.
Furthermore it is discussed the Maximum Power Point: why it exists and how to deal with it.
Photovoltaic cells have limits due to their physical characteristics, so solar inverter or specialized equipment called MPPT is used to get the maximum amount of power from panels under every circumstance.
Second part, "How Solar Inverters Work and Avoid Mistakes": [link not yet available]
Watch the full series of electronics: youtube.com/watch?v=ye9dguKy_Cs&list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
For more related/complementary content please visit my website: accidentalscience.com .
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Stop blinding guessing what a fault could be, follow the path and a method to spot faults with awareness.
This video is inspired by the several comments on my previous video on this topic that you can find here: youtube.com/watch?v=ye9dguKy_Cs
With this presentation my hope is to provide an answer to all those questions.
Table of content
1:15 Gather information, from technicians on field and from other sources
3:19 Visual inspection, spot macroscopic causes of failure
4:04 Set up proper testing environment to reproduce fault and taking measurements
5:21 Check power rails on circuit board
6:07 Follow the path backward from faulty outputs
7:22 Check for consistency between voltages and currents and components involved
13:33 Intermittent faults, artificially stress to reveal hidden faults
For more related/complementary content over my videos please visit my website accidentalscience.com.
Watch the full series of electronics: youtube.com/watch?v=ye9dguKy_Cs&list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
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Website: accidentalscience.com
So I used a microcontroller in place of a single relay to manage all the cool features this remotely controlled safety socket sports. A blinking pilot light indicates when the socket is on, and more lights indicates other statuses of what we can now call the "smart" safety socket.
The most important feature is that when power is out, the socket turns off automatically, preventing risks when the power comes in again.
This project has been amended with some changes that I've shown in this video: youtu.be/gZ-LT26VJbg Please watch it for the required corrections.
This project is a must have in your electronics lab if you happen to tweak with devices that have to be plugged to the mains.
CAUTION
Working on mains voltage could cause serious
damages and kill living beings, including you.
** You MUST know what you do. **
Any showcased solution may fail, if you
replicate it you will do it at your own sole risk.
I shall take no liabilities.
Full series of #Electronics: youtube.com/playlist?list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
Visit the website: accidentalscience.com
In the first part of this two parts video, we've seen how music is mechanically machined into a lacquer disc using a very sophisticated lathe. If you missed that part, I recommend you to pause and go to watch that first following this link: youtu.be/kViGfE9-f44
As mentioned in the first part, the footage used to make these videos was filmed in 2014. When I met Filippo De Fassi, that still today is the general director of Phonopress International, he not only allowed me to film the factory, but he was also so kind to thoroughly explain the whole process in details. Unfortunately when we went back home we discovered the footage got damaged. The audio and video were split, and broken into thousand of small file segments. Almost impossible to recover. Nevertheless the footage remained in archive for nine years, and only recently using a piece of software that I wrote myself I've been able to reconstruct almost all the footage.
The lacquer disc by itself cannot be used for replication, and must be converted into a metallic stamper. This is achieved through a chemical and an electrochemical process, after which a negative stamper and a positive "mother" is obtained.
The stamper is then used into a complex extruding-labeller-moulding-pressing machine, resulting in a finished disc.
The last steps are testing, packaging and resting the discs so they stabilize.
Disclosure: this video was NOT sponsored by Phonopress International. I made it just because it is interesnting.
Link to the previous video: youtu.be/kViGfE9-f44
Link to the series: youtube.com/playlist?list=PLwbCeSU2Kq_zn9tgM_gjSEdBCX20dCN5J
A fascinating story that will make you fall in love with these old media.
This is the first part of two parts video. The second part is available at this link: youtu.be/Z-m0ozI_Qas
This video is made from footage filmed in 2014, at Phonopress International near Milan, Italy.
After filming we discovered that the footage got damaged, so the documentary that should have been done with this footage never aired, and the footage remained in archive for nine years.
It was only recently, toward the end of 2023, that I was able to reconstruct most of it.
Also, I wish many thansk to Filippo DeFassi who was the general director at Phonopress at the time, which accompanied us into this interesting journey.
Disclosure: this video was NOT sponsored by Phonopress International. I made it just because it is interesnting.
Links and references:
Link to the series: youtube.com/playlist?list=PLwbCeSU2Kq_zn9tgM_gjSEdBCX20dCN5J
Groove simulation by Tokyo Down Labs: docs.tokyodawn.net/groove-topology-sine
I used four nice plastic bowls cone trunk shaped, a copper pipe, some copper fixtures, four metal lamp sockets, and some more recycled material that I had at home.
The result is unusual, a mix of styles between industrial and art nuveau, with a hint that recall a sailing boat. A my personal touch having been a skipper when I was younger.
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But what's inside an encoder? Are you curious to see it?
Encoders are important devices used in machines, robots, vehicles, laboratory instrumentations and more, to gauge linear or angular positions. In this video a couple of encoders are opened to see what's inside, and learn how they work.
Encoders are devices that encode the position into a numerical signal. While magnetic, contact and more types of encoder do exist, in this video only optical encoders are discussed.
They can be linear or rotational giving the information of their position along a straight line, for linear encoders, or along a full revolution for rotational encoders. And they can be absolute or incremental.
The most common used encoder is the rotational incremental encoder, that usually comes with two or three channels. So their typical application is to provide an angular position, such as on an arm of a robot, or a converted linear to angular position in machines such as CNC machines when coupled with a lead screw that moves a carriage through the rotation of a motor and an attached encoder.
The internal electronic circuit is usually made of a photo detector that read from a disc (or a stripe in the case of linear encoders) where a number of marks or slots are printed or cut out, making the light to pass through. Follows a comparator that discriminates the light level and prevents uncertainties, making the reading stable, and a line driver circuit to output the signals.
Full series of #Electronics: youtube.com/playlist?list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
In this video you will learn why we do use PID controls, what they are and how they works.
Also as a bonus you will see a conceptual electronic schematic of a possible implementation of a #PID control.
Also watch this video: Driver for a washing machine motor with PID control youtu.be/5zRCCL2JZTI
Full series of #Electronics:
youtube.com/playlist?list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
Dismantling a machine or another device opens up information about the engineering choices behind the design of the apparatus.
In this case the protection against voltage surges from EMC or induced by EMP (discussed in a previous video, link to the video below).
In this video I show some valuable parts that have been #reclaimed from a PCB stencil printer machine and valuable information about the design of a tv sat receiver, besides some useful electronic components and more importantly the metal case.
Among the recovered parts a couple of micrometers, some pneumatic actuators, valves, a motor, and a whole cabinet that hosted the electric parts of the machine.
EMP, understanding what they are, where they came from and how to protect from them: youtu.be/eS8ik9JJHxE
#Electromagnetic pulses, or #EMP for short, can be a source of serious problems in eletronic equipments. While the most "spectacular" EMP comes from the detonation of a nuclear bomb in upper atmosphere that hopefully we'll never witness, the most common source of EMPs are #lightnings. They can cause severe havoc if not destruction to many electronic devices. In this video I'll discuss the three main types of EMPs, where they come from, and what to do to prevent them causing faults in your electronic #circuit board.
Full series of #Electronics:
youtube.com/playlist?list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
In a previous video (here: youtu.be/XGW_aqE4PVc) I've showcased a passive probe, unlike that one this active probe uses only one input channel of the oscilloscope.
The probe run on a 9V battery that lasts about 20 hours (based on Duracell's data sheet calculated for the current drawn by the circuit.)
It features an input impedance greater than 4MΩ, an output impedance of ~50Ω and an attenuation ratio of x200 (200:1). The theoretical maximum input voltage is 800Vp (given by the voltage limit of the resistors used in the attenuator). This allows to take measurements not only on common 230/240Vrms but even at 380/400Vrms (used in Europe), including phase-to-phase on a three phases system.
BEWARE that if you try to make this project yourself you'll do it under your own sole responsibility, I'll take no liabilities! Keep in mind that the circuit's performance and limits heavily depends by the components used and how the circuit has been made. I mounted two of the four resistors of the attenuator on the PCB and has been covered with an insulating resin that is NOT visible in the pictures.
The probe is built around an LM4562 in IA configuration, and a resistive attenuator. Tests confirmed that there is no need for capacitive compensation since the input capacitance is remarkably low (less than 2pF) and the frequency range of interest is about mains frequency (50/60Hz) and its harmonics, so rarely there is the need to read frequencies above 20Khz.
I hadn't the possibility to test the probe for its actual bandwidth, though.
For the sake of simplicity I used common 1% resistors (with 20ppm/C) rated 250V. The "high" voltage must be well separated by the low voltage part. The key point of this probe is the link to ground, or PE (Protective Earth) that provides its safety. It works on both TT and TN systems. The PE is also carried by the oscilloscope, but the provision of a separate connection for grounding (the green banana socket) is important in the case of fault of the cable, the use of a battery powered oscilloscope and the case when the plug is disconnected from the scope.
This probe MUST NOT be used where the line is not protected by a GFCI, RCD or RCCB.
Full series of #Electronics: youtube.com/playlist?list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
CAUTION: Working on mains voltage is dangerous, you MUST know what you do.
Directly using the probes of the oscilloscope to measure the mains is hazardous, it could lead to from destroying your probes to melting the traces of the PCB inside your oscilloscope, not to mention the risk of being injured. Depending by the grid system you may have 50% to 100% chance of causing a short capable to destroy your instrumentation.
In an old video I presented a depth analysis of why you can blow up your oscilloscope while making measurements at mains, follow this link: youtu.be/LJ9CO5ViKPI
Also the trick that uses two probes directly may end up in catastrophic results if you work on voltages above 110V RMS.
In this video is presented a simple attenuator made of just 1/4W resistors, that guarantees safe operations with the oscilloscope provided the PE (Protective Earth, the yellow-green/green wire) is actually tied to ground. It still requires two input channels of your oscilloscope but it is safer than directly hooking the probes to the mains.
Full series of #Electronics:
youtube.com/playlist?list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
But don't be afraid, in this video I provide some tips and tricks to avoid common pitfalls, besides a conceptual, hopefully easy to understand, explanation on how they works.
In the video we will go through the following:
- What is a buck converter and why you'd like one
- How it works (simplified)
- Pros and cons and how to avoid common pitfalls.
I've made a buck converter that operates also as a voltage regulator that, unlike linear regulators, sports a 93% efficiency in power conversion.
The circuit is purposely a mess of wires, with inductors and capacitors, and even the MOSFET and diode connected through long wires, to better show some of the typical problems that could be found in these kind of converters.
Watch the full series of electronics: youtube.com/watch?v=ye9dguKy_Cs&list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
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Website: accidentalscience.com
It is a little bit sketchy to use when you need to make two bends in a 90 degrees corner, because it needs some spacers that are difficult to be kept in place. However this is meant as a simple and cheap project so I haven't bothered to develop a more complex design.
Experimental circuits should be made quickly and inexpensively. For good quality the way to go is to design the circuit with a software such as Eagle or KiCad and hand over to a manufacturer the process. However this requires time: you have to prepare the files, check them, send them to the manufacturing facility and place the order, and wait for the boards to be shipped. Not exactly a fast route when it comes in experimenting an idea that could even be wrong.
Making circuit boards themselves is a useful skill for this stage of experimentation.
So I show you some techniques that I use for this purpose.
Watch the full series of electronics: youtube.com/watch?v=ye9dguKy_Cs&list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
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From power supplies to voltage references, voltage regulators provide the set point at which a circuit works. Because with no voltage you cannot have current. Whether you need to design or troubleshoot a circuit you really need to know about these basic blocs.
In this video we explore series, also known as pass regulators, and parallel, also known as shunt regulators. Linear and switching. Where they are best suited, why to choose one or another.
Watch the full series of electronics: youtube.com/watch?v=ye9dguKy_Cs&list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
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Website: accidentalscience.com
This is “hands on electronics” series from Accidental Science.
Many times it is necessary to detect voltage levels against a reference voltage. While OPAMPs can be used for this purpose, exploiting their high gain, performances are poor and the applications are limited where a slow response is acceptable.
Comparators are specifically designed for this application, enhancing their speed versus their linearity, as their output swings between just to levels: high and low.
Comparators are the ideal interface from the analog world to digital.
But some care in the layout design must be taken, particularly with fast comparators.
Watch the full series of electronics: youtube.com/watch?v=ye9dguKy_Cs&list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
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Website: accidentalscience.com
To learn more:
analog.com/media/en/technical-documentation/application-notes/an148fa.pdf
Watch the full series of electronics: youtube.com/watch?v=ye9dguKy_Cs&list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
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A sawtooth waveform generator such is useful in several testing applications, particularly for components characterization to drive the volt-amper measurement on an oscilloscope or with a X-Y plotter. Other applications include voltamperometric tests and other experiments in electro-chemistry.
This #VFO for #sawtooth waveform operates at frequencies between 10 Hz and 1 MHz in two bands, with an output voltage of about 4 Vpp.
In this video a the oscillator is part of a larger function generator project, covered in other videos that you can follow watching the full series: youtube.com/watch?v=ye9dguKy_Cs&list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
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This circuit has a dynamic gain of 18dB and a ratio of 80% over the target output level. With some further adjustments it can be expanded to a higher ratio but at that point other circuits would better suit. The advantages of this circuit are its simplicity, very low distortion and low noise. The stray capacitance of the photo-resistor could limit the bandwidth but with the VT900 the circuit has proven to work pretty well with very little attenuation up to 500KHz.
Watch the full series of electronics: youtube.com/watch?v=ye9dguKy_Cs&list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
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While more complex solutions do exist, this circuit has the advantage of simplicity and low component count.
Watch the full series of electronics: youtube.com/watch?v=ye9dguKy_Cs&list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
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Unlike the well known 555 IC that can be used also as Voltage Controlled Oscillator, the circuit presented in this video features much better characteristics, both for the range of frequencies (a full one order of magnitude for every single range) and for the quality of the generated waveform, low noise and perfect straight slopes of the triangular wave.
This circuit is the starting point for future developments that will be presented in next episodes, with the aim to achieve a complete instrument for the laboratory of electronics.
For further reading I recommend to read the description of the HP generator Model 3311A presented by Hewlett-Packard in its own publication “Hewlett-Packard Journal” on July 1973. Although the circuit is substantially different from the one showcased in the video, both start from the same concept of charging/discharging a capacitor through a variable voltage source driving a constant current source.
Without thinking too much, on video I've said: it's gotta be iron powder.
Is it really?
A viewer posted a clever comment to the video, pointing out that the powder was not iron but carbon, since hammers are made out of high carbon steel.
He had a good point, so I decided to carry a little experiment showcased in this video.
This video showcase an experiment using stronger concentration of weak acid and a revisitation of an old recipe to provide protection to the metal once it has been cleared from rust.
Also is presented a review of the various kind of oxides that attack iron or steel, providing a hint to distinguish them and thereby choose the best process to remove the oxide or rust.
By the way, did you know tetanus is not carried by rust?
Experiment series: youtube.com/watch?v=MWibZ754YlI&list=PLwbCeSU2Kq_wbNEUGGWLkCgvLpUz3eP-k
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0:00 Introduction
0:27 Distinguishing the various kind of rust/oxides
2:39 The misconception about tetanus and rust
4:09 Getting started with rust removal
5:09 Chemical experiment
6:46 Why this should work
10:04 Assessing the result
12:26 Protection of the metal
14:41 How to recycle and reuse wasted chemicals
Making the pulley that drives the spindle's lathe using the same lathe to make the very same pulley is a challenge. Because of the design of the spindle of my lathe I was not able to find a ready to use pulley off the shelf, and ordering one at the machine shop gave me a staggering long time to deliver. So I got creative and I made the pulley from scratch. With a piece of thick steel tubing and an old aluminum flange and some epoxy resin I made a pulley that is suitable to be driven through a poly-V belt, as required by the motors, salvaged from washing machines.
0:00 The problem
1:41 First step solution
2:19 Making a sleeve and FIRST CHIPS ever with this lathe!
3:08 Let's check the very first part turned with this lathe
4:18 Checking how the ways wipers worked
4:52 A makeshift indexer
5:58 Lathe drill holder jig from a scapped drill press
8:14 Making indexed angle holes on the side of the sleeve
8:49 Preparing the seats for the sleeve on the shaft
9:40 Step two: Installing the sleeve to gain more torque
9:59 Turning an aluminium ring from an old flange
11:00 Attaching the aluminium ring on to the sleeve
11:33 Making the composite secondary ring
14:18 Turning the pulley's secondary ring
14:31 The final pulley
15:05 Installation of the pulley and belt tensioners
16:20 Speed test
17:29 What's up next
In the video you'll see a linear scriber that I've made myself, video: youtu.be/f9tA4i2xqjM
The motors are driven with an electronic speed control (ESC) that I designed myself, video here: youtu.be/5zRCCL2JZTI
A contactless RPM meter (tachometer) is featured, I've shown how it is made here: youtu.be/RlAIcnxVLZE; here: youtu.be/iQ5vwq0JoKE; and here: youtu.be/fzcXJIGZSHA
Watch the full series of the minilathe: youtube.com/watch?v=KSE7DORiYfs&list=PLwbCeSU2Kq_wrUUInSUWJksA-LHhhMhFx
Watch the series of electronics: youtube.com/watch?v=ye9dguKy_Cs&list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
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Website: accidentalscience.com
Music (in order as played in the video):
Empire Seasons by Dan Henig
Hedge Your Bets by TrackTribe
Komputo by Francis Preve
Depth Fuse by French Fuse
Working with electronic circuits and equipment requires instruments that enable you to know what is going on there. But many are confused when they have to purchase their first instrument (and often many are confused even after they already have purchased one).
In this video I try to address these issues and showcase the fundamentals that you should know both for purchasing and using a multimeter.
How to avoid to fry your oscilloscope measuring mains: youtu.be/LJ9CO5ViKPI
Watch the full series: youtube.com/watch?v=ye9dguKy_Cs&list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
Bingewatch the full series: youtube.com/watch?v=KSE7DORiYfs&list=PLwbCeSU2Kq_wrUUInSUWJksA-LHhhMhFx
Previous episode: youtu.be/KCBGhkabXpQ
Website (one day it will work properly again): accidentalscience.com
A linear scriber comes handy in many occasions, in both metalworking and woodworking. It allows to trace lines following the profile of the workpiece. Useful to trace where holes should be drilled or where to attach other parts, as a reference, and many many other uses. In this video I recovered: a rod of stainless steel (you can use mild steel or brass), a parallelepiped of mild steel remained after a longer bar was cut, a small cylinder of brass (do not remember where it comes from), a piece of brass screw, and a broken bit.
The only part that is new is a small M4 screw.
Website: accidentalscience.com
Music:
"Invitation to the Castle Ball" by Doug Maxwell
"Island Coconuts" by Aaron Kenny
"Watch Me" by Geographer
Wonder how to #faultfinding without schematic? Watch this video too: youtu.be/yjxuMwLN7zI
For more related/complementary content over my videos please visit my website accidentalscience.com.
Watch the full series of electronics: youtube.com/watch?v=ye9dguKy_Cs&list=PLwbCeSU2Kq_zORt4un2iQ3JUYxzWF3cTJ
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Website: accidentalscience.com
Unlike in typical manual lathes, here the apron is much simpler as it is directly linked to the lead screw and to the axis driving motor. A double nut, with a particular linkage, is used to adjust the backlash.
Finally the spindle is put in rotation with a couple of DC motors salvaged from washing machines and controlled with a simple driver (AKA ESC, details in this video: youtu.be/5zRCCL2JZTI).
This work was put on pause for four months because a surge of work in my main job. I found two problems with the spindle's motor. One is a faulty contact somewhere in the control board that makes the motor running irregularly. And the other one is the belt that slips on the shaft of the spindle, because the pulley that was meant to pick the thrust from the belt to transmit it to the shaft is not yet in place. Hopefully that will solve the problem.
Previous episode: youtu.be/5rLqkpy2UQA
This is a simple DIY project that everybody can do for almost no money reclaiming metal from the scap bin.
This video was meant to be a "short" initially, but ended up to be long enough to make a regular video.
In this video a hands-on approach about how to drive these motors through the Phase Angle Control and Closed loop speed control.
Washing machine motors can be easily recovered from old machines, often are in good conditions, are powerful, they can spin in both directions,
and can be driven to control their speed with good torque from standstill. You can also squeeze out much power if a good ventilation is provided.
Since they are fitted with a tachometer they can be driven to rotate at a constant speed even when the load changes.
However to get the best from them a specific driver is required.
The theory of operation of these motors is presented and how the Phase Angle Control used to drive them works.
Finally a full driver that I've made is presented.
With a power of about 500W I will use one of these motors to temporarily drive the spindle of my mini lathe.
In the video is featured an RPM-counter that I've made, follow this link to watch the video of the project:
youtube.com/watch?v=fzcXJIGZSHA
youtube.com/watch?v=RlAIcnxVLZE
Content summary
Description of the Universal Motor and how it works.
Hands-on approach of the Phase Angle Control, and of the Closed Loop Control System theory of operation.
Discussion of the blocks diagram of the driver.
Test of the purposely built driver.
This video is meant to show some experiments and to understand how the underlying chemistry works, rather for fun than for any productive result. Nevertheless this method can be actually used to achieve some decent result.
Electroplating a piece of steel with copper can be useful not only for aesthetic but even to help protecting the metal from rust. Also on top of the copper layer it is possible to electroplate other metals such as nickel.
This method do not involve the use of a chemical bath for electrolysis, instead the electrode is moved directly onto the part to electroplate as if it were a paintbrush, and indeed even making it possible to “paint” the part. It is therefore less bulkier and easier to do at home, and does not involve nasty chemicals but items that can be found in any kitchen, such as lemon, vinegar, and table salt.
I am not a chemist, so I could have mistaken some points in the explanation, if you spotted any please feel free to provide your corrections in the comments section.
With many band saws if you have to cut a small piece or need to make a narrow cut, a cut that should be carried close to the vise, you may find it's an impossibile mission. In this video I share my solution and how I've made it.
This additional vise comes useful to cut small parts with precision, it is made starting from a cheap drill press vise.
The pins perfectly fit the holes that has been drilled and reamed to a tight diameter, so the pins need to be forced with the aid of a press (here the link to the video where I've made a DIY press: youtu.be/CyulPt2looU).
Next step will be to install the cross slide to the carriage.
In the previous episode I've made the cross slide ways, here the link: youtu.be/0BuqkRqqxyk
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A final episode will contain the whole assembly and alignment on the carriage and the lead screw.
You will notice that this cross slide is particularly long, this is because this lathe is designed to be ready to host a milling attachment.
Links to the previous episodes:
Part 6 - Oil ports and slideways for the cross slide : youtu.be/Uuvmki_gyOI
Part 7 – Headstock installation and alignment : youtu.be/w5DIehtaRM4
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When the mill scale is consistent and the steel is meant to stay indoor, the removal of the scale can be safely disregarded. This was the case when I made the frame of my hydraulic press that you can see here: youtu.be/CyulPt2looU. But in other cases it is really necessary to remove it.
The mill scale is a mix of various iron oxides that adhere to the surface of the metal forming a tough layer. Mechanical methods or heating can be used to remove the scale, but they may sport some undesirable drawbacks. No method is perfect but pickling is quite effective particularly on smaller parts and where no deformation and thermal stress is required.
So this video focuses on simple chemistry, applied to process mild steel in metalworking.
I just followed a class in chemistry, but I'm not a chemist therefore, even though I felt the need to explain the reactions showing the related formulas, I hope no major errors slipped in the show.
CAUTION-DISCLAIMER
This video is not meant to be a tutorial, it just shows my experience and experiments.
Working with chemicals requires precautions: always wear safety goggles, gloves and wear proper clothing to protect yourself. Wear closed shoes. Remove rings and jewels. DO NOT eat or drink while working with chemicals. Keep children and animals out from the area. Some chemicals may generate very harmful fumes so good ventilation is of paramount importance, and sometimes still not enough requiring a specially designed fume hood.
Also some chemicals may unexpectedly react with the materials the furnitures are made.
Credits for photos of oxides:
By http://en.wikipedia.org/w/index.php?title=User:Fuzic&action=edit - http://en.wikipedia.org/wiki/Image:Iron%28II%29_oxide.jpg, Public Domain, commons.wikimedia.org/w/index.php?curid=2777872
By Benjah-bmm27 - Own work, Public Domain, commons.wikimedia.org/w/index.php?curid=2116171
By Leiem - Own work, CC BY-SA 4.0, commons.wikimedia.org/w/index.php?curid=36973696
Other images shown in the video, when not proprietary, come from public domain.
Before going through the actual installation I've performed some simulations of the whole process. The headstock is installed using leveling paste that allows only small corrections once it is set. The headstock is equipped with compressing and expanding screws to let adjustments over the vertical plane and lateral screws to let adjustments over the horizontal plane.
DISCLAIMER: In the video some items show their brand because due to limitations of my editing skills I was unable to remove them. So I clarify here that there are NO SPONSORSHIPS, I DO NOT ENDORSE NOR DISAPPROVE THOSE BRANDS THAT ARE INCIDENTALLY VISIBLE IN THE VIDEO. Products are visible in the video because they are necessary for the purpose of the work shown and because I found them fitting my personal purposes, not because sponsorship or paid placement. In future videos I will try to overlay a message that clarify this point when brands appear too prominently.
Video is composed by the following sections:
0:00 Intro; 1:00 simulations; 1:42 the problem of test bar deflection; 3:40 ball-tip dial indicator may lead to erroneous readings; 4:54 counterweighting; 6:20 preparing leveling paste; 7:28 headstock installation; 8:02 alignment operations; 12:30 double check with a square and final considerations.
For more information about the stick-slip effect follow this link:
en.wikipedia.org/wiki/Stick-slip_phenomenon
Also you can follow me on Facebook: facebook.com/AccidentalScience
on HomeMadeTools.net
and soon on Instagram.
Website: accidentalscience.com
Mid-roll Music: “Connection” by Wayne Jones.
End music: “Ex Boxer” by Riot.
So how to make a true flat surface without a flat surface? Before any true flat surface was ever made there were only pseudo-flat surfaces, far to be really flat, a fact that had many implications in hampering the technological development. Who, for the first time, formalized a method to obtain a (quite) true flat surface (from scratch) was Joseph Whitworth who revealed his 3 plates method in a paper addressed to the British Association in Glasgow on 1840. There are no much information online about this method, and the few lines mentioning it, that one could find in a book of mechanical technology, are not enough to let understand how actually this method can be carried out. Eventually I found some information online, enough to try myself the method on the occasion to make the ways of my home made lathe.
This video is a revision of a previous one with the same title where some issues have been addressed. I provided both historical e technological context, and a detailed illustration on how I carried out this method, with some variations introduced to speed up the work.
Some caveats related to the described method are also discussed.
I made this video with the hope others will find it interesting and useful.
00:00:00 Introduction
00:01:00 About flat surfaces
00:03:05 History of the method
00:05:54 Why we need flat surfaces
00:06:13 Definitions
00:07:01 Description of the method
00:07:18 Caveat on the description
00:11:27 Discussion on the limits of the method
00:14:49 My experience and trick to overcome the limits
Acknowledgments
There is no much information online about this method, but digging the net eventually I came up to the original paper (a scan still available through Archive.org), its transcript on Wikipedia, and an useful article written by Eric Weinhoffer that directed me to an other document, a PDF titled “Reference Planes” written by Doctor Alessandro Anzalone, for the Hillsborough Community College - Brandon Campus, both helped me a lot and confirmed what I intuitively figured out when I read the paper for the first time.
Many thanks to both the cited authors, without their work I would not have been able to get the results I got.
Lately I had some more insights and many thanks goes to Johan (DIYSwede) that directed me to the good video of Robin Renzetti on the 3 plate method. Many thanks even to them.
Also I have to thanks “12L14” from Homemadetools forum who directed me to the comment of Forrest Addy at the Practical Machinist forum.
Links & References
[1] The Whitworth method presented in 1840 in “Miscellaneous Papers on Mechanical Subjects”, with the paper titled “A Paper on Plane Metallic Surfaces or True Planes”:
en.wikisource.org/wiki/Miscellaneous_Papers_on_Mechanical_Subjects/A_Paper_on_Plane_Metallic_Surfaces_or_True_Planes
Blog article of Eric Weinhoffer
http://ericweinhoffer.com/blog/2017/7/30/the-whitworth-three-plates-method
Reference Planes by Alessandro Anzalone, Hillsborough Community College, Brandon Campus
etshare.pbworks.com/f/Chapter%2014%20Reference%20Planes.pdf
Wikipedia page on Sir Joseph Whitworth:
en.wikipedia.org/wiki/Joseph_Whitworth
[2] “Foundations of Mechanical Accuracy” Wayne R. Moore – 1970
http://mooretool.com/publications.html
[3] Robin Renzetti ROBRENZ ATD #1 Intro, 3 Plate Method
@ROBRENZ
youtube.com/watch?v=Va4TGDnQqDs&t=202
[4] Forrest Addy, his comment on Practical Machinist forum (post #11):
[quoted post:]
«Square or round or rectangular plate makes no difference in the final flatness provided the work is rotated a RANDOM amount. The object of rotation of the plates in successive cuts is to prevent "radial lobing" of the surface. If the plates are rotated exactly 90 degrees, 72 degrees, 60 degrees, or any other angle corresponding to a regular polygon, there is the hazard of radial "lobing" to appear in the surface. » [...]
«I disagree with the Moore assertion of only square or round plates being capable of generating truly flat surfaces. Square or round plate shapes may be helpful but not essential. »
practicalmachinist.com/vb/machine-reconditioning-scraping-and-inspection/whitworth-three-plate-method-330634/#post2912880
Other sources: http://www.circuitousroot.com/artifice/machine-shop/surface-finishing/hand-scraping
The sensor detects this variation in dielectric and provides a signal proportional to the amount of the total volume of water the particles would form if joined together. This quantitative information is different from the one that comes from humidity sensors, that sense gaseous water, while this sensor detects actual liquid particles that are formed when condensation occurs and such particles can build up on cold surfaces.
Possible applications are mould control in buildings, warehouses, farms, in crop storage, and other food control quality. Also it can be used to detect condensation to prevent rust or damages in electronic components.
For more information here the link to a paper where the sensor is presented:
accidentalscience.com/docs/water_aerosol_sensor.pdf
This is the project's page on Hackaday:
hackaday.io/project/176496-water-aerosol-sensor-w-projected-electric-fields
This tool is used to make a gross removal of material, while the fine work will be performed with the aid of a stripe of emery paper glued on the retainer of the slide.
In this update I also mention the boards that I've designed to build the motor drivers. Since these boards are not yet fully assembled I just make an anticipation, while more details will be shown in a future update.
Follow the whole series (playlist): youtube.com/watch?v=KSE7DORiYfs&list=PLwbCeSU2Kq_wrUUInSUWJksA-LHhhMhFx
Last Q&A + Update video: youtu.be/wRTY7FXOd5I
With luminaires made in this way you can get better color rendering than using a single LED light bulb or stripe.
While I used metallic boxes to make the body of the luminaires, you can also use plywood or plastic. The important point is to make correct wirings following safety rules that imply you should be at least basically familiar with electric circuits and the use of electric parts.
The part list is really simple: four LED bulbs, four plastic bulb sockets, cable, a switch, a plug, a piece of steel flat bar (3x20mm) and a rod, 4 mm in diameter, mild steel, black paint (optional), black cotton fabric, clear non-woven fabric (cover for garden plants). Total cost is around € 30 (in Europe, probably less elsewhere).
Enjoy.
This is an In-Situ Resource Utilization (ISRU) project to make a portable source of power and electric scythe made by reusing things that was laying around. This project, made primarily for fun and far to be perfect, allowed me to mow a piece of land covered with wild vegetation.
It was also be used in place of an electric generator on a construction site where the electrical grid was not available, providing up to 1 kw of power at mains voltage.
It involves metalworking, welding, and power electric design and wiring.
- Could the ways be twisted?
- Why did I use steel on steel instead of bronze on steel, for the slide.
- Are the spindle's holder clamps are too flimsy?
- How to deal with the thermal expansion of the spindle's axle?
- What about chips that could build up on the screws that hold the ways in place?
ERRATUM. I don't know why but I've messed up the numbers when I talked about the issue #3. At 6:17 I've mistakenly said (and shown) the equivalence between 2400Kgf in 240 newton. That's obviously wrong: the equivalent force is 23KN (or more precisely 23535N).
Precision machinist's levels are very sensitive and can detect very small slopes. The one I've made has a sensitivity of 0.01 millimeter over 200 millimeter or 0.4 thou over 7.9 inches.
Spirit levels are made using curved vials, and to make a level one should make a bended vial in the first place, not an easy thing to do. I also experimented capacitive sensors, but reverted back to the traditional technology of the bubble trapped into a vial.
I've seen other people making rigs for an angle grinder to cut or grind parts to be used to make dovetail ways, but as far as in my experience these rigs are not capable to produce precise enough parts.
While I have an alternative idea to make a rig able to cut titled parts, for the cross slide of the lathe I'm eager to stay on a box design, rather than dovetails.


