Call for Engineers: Tell us about your job! (2020)

my intention is for 3d printing the gears but need to simulate the motion

I was thinking about a 48V architechture to replace engine driven pumps and acessories as a way to make ICEs more clean and efficient, and one question I have is that if a pump, A/C compressor or any other acessory is direct current (DC), does that removes the need for an inverter as batteries as also DC? Because one of my fears is that making the entire system AC would make all the pumps, compressors and acessories need inverters, making the wiring complex.

Back in the day, we had an apartment sized washer on wheels and connected to the kitchen sink. You had to "balance" the load or it couldn't spin.

I'm listening to the washer and I'm washing mostly pants. I hear the thump, thump, thump of an unbalanced load, then the speed changes, and before I know it, it's spinning full speed. How does the machine correct this?

I have a soundwave image resulting from a Doppler Ultrasound (the "heartbeat" of an 8-weeks-old baby at 121 BPM). Currently, I only have access to this low-resolution photograph: https://imgur.com/a/HsGkHsi

I need assistance in reconstructing the original audio waveform from this image. The desired output should sound like the audio at second 10 in this video: https://youtu.be/yOJOpHeEyyY

I've already processed the image with Photoshop (https://imgur.com/a/csFhTXK) and loaded it in Python using OpenCV (https://imgur.com/a/xGdh6kC), but I'm not understanding how to reconstruct the waveform, and the resulting sound its just distorted: https://jmp.sh/s/sAkVLTWqwQ1RnrVULnEf

How should I proceed? Thank you in advance for your help.

Proponents of EV's say they are more efficient. I don't see how that can be true. Through losses during generation, transmission, and storage, I don't see how it can be more efficient than gasoline, diesel, or natural gas. I saw a video talking about energy density that contradicts the statement. What is the energy efficiency comparison between a top of the line EV and gasoline powered cars?

Hello,

I am exploring the design of a hollow, UV-protected ball capable of containing a liquid and injecting it through a tip. The concept is similar to a small, single-use super glue applicator. My goal is to achieve a controlled liquid output at approximately 15 psi.

Would such a design be feasible, and are there any recommendations for materials or mechanisms to meet this requirement?

Thank you for your time and assistance.

Hello all,

I am trying to converter the RPM signal coming from one of that stator windings of my alternator on a diesel engine.

Right now the signal that I am receiving is about a 100-400hz sine wave with an amplitude of 0.3v.

To get the tachometer in my vehicle to recognize the signal, I need to step the voltage of the signal up to 12v amplitude without changing the frequency.

By my math, I would need a transformer with a 1:40 ratio of primary to secondary winding. It doesn't need to carry much current as this is only a signal wire, not much load on it.

Does anyone know a particular transformer that would work? Or some other way to amplify the voltage?

I apologize for the lack of proper English terms, English is not my first language and I am not familiar with the correct wording.

Logically a wider pipe should be stronger, but as both are 1mm in thickness I wonder if this is true. The pipes would be used to make book shelves.
Thank you in advance for your reply!

I have 1 photo of me looking direct at my camera second photo i've turned my head looking slightly to the right. How would I work out degrees turned on a 3D image like this. Thanks.

Hey guys, I wanted to ask if anyone here has experience with RapidDirect's injection molding services. I know their CNC machining has a good reputation (a couple of friends recommended them), but none of them have tried their injection molding.
I’m looking to make a phone stand, but honestly, I don’t have much experience with injection molding, so I’m a bit lost on how to communicate with suppliers and pick the right one for my needs. Any advice or tips would be appreciated!

I'm trying to self-teach myself composite stress analysis for work and while I've found, read, and watched a lot of content on composites, all seem to focus mostly on the theory as well as CLT. Books like Tsai,Jones cover the theory very well, plenty of examples deriving ABD matricies all day, but did not find much as far as examples of just say a simple cantilever beam made of a composite material. I also bought Todd Coburn's book and worked through his series and a similar situation. Plenty of examples on deflection though, but for the actual stress part of taking a beam, doing a shear moment diagram and sizing the cross-section, material or ply orientation, I haven't found much there. Anthony Pickett's book gets close and has a couple simply supported beam examples, but I want to know if anyone has any recommendations for a book that focuses mostly on examples rather than the theory since there's plenty of theory and I want to see how it is applied to make sure I'm understanding it right.

Want to buy a vacuum chamber and make a cylindrical structure with plates of metal a micron apart. That’s just not doable at home is it?

I've connected an eductor to the coolant pump in my machine. This eductor sucks the leaked cutting fluid from a tray underneath the machine I.e coolant passes through the venturi(let's call it motive) and returns to the tank and in this process a vacuum is developed which is used to suck up the oil from the tray which travels with the motive and enters my tank.

Now the problem I'm facing here is once all the leakage oil has been sucked up the device keeps sucking air which is then transferred into the coolant sump thereby causing a lot of foam. How can I prevent air from entering the tank? I cannot use any timers or solenoids to turn off the system. Need a simple mechanical suggestion please.

We have tried to keep the return pipe submerged under the coolant level and kept it over the coolant level to see if either helped, but both situations created foam.

Please see a schematic of how the system is working right now : https://i.imgur.com/nZbOKG1l.jpg

Any help will be appreciated. Thanks.

So I get that the aircraft would have a gas turbine, which would be running off petrol, whilst outputting electric power to the motor, but how would the ratings work?

If the aircraft had a 260 kW electric motor, does it need a 260 kW gas turbine? And if so, I'm slightly confused from a physics perspective about how a gas turbine can output that power, and yet be lighter and consume less fuel than a regular engine. In other words - how does having an electric motor, gas turbine and fuel, end up being more fuel efficient than a regular engine?

So, the application is Trans Am era road race track day muscle car from the70's, not in sanctioned competition.

I am custom building front end suspension torsion bars for increased spring rate and lighter weight.

The bars are approx 1.38" Dia, OA length 41", out of polished and HT 4130. The inner dia is .875".

My slight concern here is the exhaust headers are within 1" of the TB for maybe 40% of their rear length.

I am wanting to incorporate a belly pan as much as possible under the car that will significantly restrict air flow at speed in the TB/header area. The pan will one of the last projects.

So, stealing an idea from severe duty sodium filled exhaust valves, I'm wondering if I should tap for plugging the ends of the TB's and partially fill (40%?) with a suitable coolant (not water as corrosion is an issue), and let slosh while driving/braking help even out/reduce the working overall temp of the bar?

We are not talking 1000F, but we could see 400F as a guess. Not sure how much heat increase over time will negatively effect spring rate, among other properties.

Not thinking any venting is needed.

Any thoughts/comments/suggestions on the project/liquids/quantities?

edit:
If anyone thinks what I am proposing here is "complicated", I suggest they first tackle fabricating two custom TB;s as noted above.

I have a potential concern about uneven heat on a 41' bar

I have a potential concern about heat variation over on say a 30 minute track session changing spring rate of the TB

With above modification, I can always later add heat shielding band aids based on applied heat strip indicators, but in the reverse order is much more difficult.

Wrapping/ruining carbon steel headers is not an option, it might be if I eventually go to custom stainless

Coil overs are not an improvement option on this chassis.

Without significant air flow in the area of my concern, any shield will mostly just slow down the rise, not stop it

We are talking maybe 6 oz of fluid per side plus two #12 AN o ring plugs?

There is not a lot of room to move the exhaust nor the TB;s, and moving the TB's would be highly problematic

Thanks for the comments.

With cars, if you want to add a turbocharger, you usually have to also add a new ECU, a new exhaust, a new intake, and new engine internals. So, the cost of the entire project is often much more than just the cost of the turbo itself.

Given how stingy Nvidia is with VRAM, is the same true of GPU memory? If you design a GPU with more VRAM, what else needs to be added or beefed up to support the additional VRAM? Do such secondary additions have a significant affect on costs?

Nova on PBS: https://m.youtube.com/watch?si=OlmsgHpfLQXKNQZ-&v=AmDhMT8fHEc&feature=youtu.be

I'm an electrical engineer that has experience in high voltage grid operation and low voltage switchgear design, but at work I will need to help with some medium voltage switchgear design too,

I don't want to make the mistake of thinking it's the same as what I've seen before, so I wan to ask people with medium voltage experience, what isn't so obvious about these systems that a newbie might overlook?

So I made one of my first PCB designs and ordered it recently it's for a weather station and I have one for led lights outdoor but under a roof I live in the Netherlands so fairly humid weather.

Now I want to know how to prevent water/condensation from killing it slowly?

Is it okay to place in an air tight box or is airflow recommended? How much airflow just a hole or more? Or is it necessary to coat it in nailpolish or something else?

Thanks for explaining how this condensation works with electronics.

In a pneumatic line in P&ID, there is a symbol showing PZ. What does it mean?

I've seen this being used on the side cover panels of the flatfix solar mounting system. reference image: flatfix-fusion-11-4.png (690×402)

I'm considering using a similar press- on mounting system in a project but am looking for dimensioning documentation. A term would be great because google searches is getting me nowhere. Link to a design guide would be even better. Thanks in advance.

Hey there - I'm conducting some research into the optimal layout and configuration for a light, firefighting aircraft in accordance with the requirements of the RHAF. Looking for engineers interested in the field of electric flight/aviation, to discuss ideas with, bounce ideas off, and ultimately come to a conclusion about the optimal layout/configuration. This ultimately has the potential to turn into a real project.

View image

(I'm not an engineer and I've looked around at ChatGPT, Google, and Youtube. I'm curious but don't understand the lingo enough to keep researching. Seems like I've hit a dead end.)

The device is "Sidewinder Pro Xtreme". It's an exercise tool for the forearms. There are two handles. Each can rotate independent of the other in both directions. The two handles are joined by a coupler in the middle. On one end of the device, there's a knob to adjust the force or how hard it is to rotate the handles. It's equivalent to lifting weights at the gym. First you lift 5 pounds, get stronger, then 6 pounds and so on. Instead of changing weights, you twist the knob. Twisting the knob makes the connected rod sink deeper into the device like twisting a screw.

There are a few things I'm curious about:

1. How does the internal mechanism work? I'm guessing that turning the knob compresses something inside. And if it's compressing in one direction, how can the force distribute evenly on both handles?
2. How can turning the knob be that easy? Instead of the knob increasing difficulty to keep twisting it for more pressure, it simply stays the same. This device supposedly can put up to 380 pounds of pressure on the handles. If it doesn't take the same 380 pounds of force to twist the knob then how does it work?

If you can't imagine the full solution, please point me in the right direction. Thank you!

I've began seeing a lot of YouTube videos on building a custom keyboard, but I'm wanting something specifically to replicate my MX Mechanical Mini - but in a custom ergodox form factor AND with the multi-device swap and connect via bluetooth capability.

I'm a Software Engineer looking to begin dabbling in Electrical / Embedded / Hardware so I think this would be a worthwhile project, but not sure where to go to find this information as Google Searches haven't been anymore helpful than Logitech products or really obscure protocol articles.

tl;dr: How can I build a mechanical keyboard with multi-device bluetooth swap functionality (more devices the merrier!) or where should I search to learn about this capability

We have a giant steel mandrel that’s a conical shape and is 3 individual pieces that have been welded together and the seams were ground flush. There’s some obvious pitting along the seams and has given us concern.

This is a tool for composites, so will be wrapped and bagged/sealed and cured in an autoclave. But there is concern that the manufacturing of this mandrel wasn’t done so well and that there may be pin hole leaks along the seams.

I’m curious if any of the great minds on here have any good ideas on how to check and indentify where leaks are short of X-ray testing methods?

Hi,

I have posted here before about using a 0603 resistor as a heating element, I was getting some success with some of the things suggested, but its not a scalable solution and its not viable in the long run.

I was wondering if anyone knows if theres such a thing as a "custom shaped resistor". or maybe we could call them "customized heating elements"

I am looking for basically an 0603 resistor but with a height between 0.7 - 1.0 mm.

I understand MOQs might be large but I want to at least know what ballparks we're talking about and whether its worth pursuing .

A friend of mine had an idea of using the same kind of process that a refrigerator uses to create a cooling blanket, the opposite of a heated blanket. They understand how all the parts in a refrigerator come in to play and they'd love to create it if they can but I just wanted to know the feasibility of it or if it's even safe to do so? Their idea was to place the condenser component inside the blanket and hook the rest up on the outside. TIA

Hello

I'm planning a solar collector ( thermal) project. This stems from an earlier post I made about a sand battery. After many of your suggestions and some thought, I've decided to go the fluid route.

Here is my initial plan.

A triple pane, acrylic " window" on the front of a box. The box will have a 1/2 thick aluminum plate at the back, painted black, with a copper pipe " rad" fixed to it, also painted black. This box will have 4 inches of xps foam insulation on all sides, except the front obviously.

My first question is, would a gap between the back of the aluminum plate and the insulation be beneficial, in the sense of " storing" a tad more heat in the air present there.
The point of the plate is to absorb and store any extra heat that the rad doesn't pick up. My thought is that way the box doesn't cool down the moment the sun isn't on it in the evening.

Second question is, would a rad of ¾ copper or ½ copper be better?

My instinct is to go with the ¾ to allow higher flow at lower pressure, but ½ would give more passes in that given area, giving it longer to grab as much heat as possible.

I plan to have the pump controlled with a temp switch. When t1(collector)>than t2 ( reservoir tank) pump kicks on.

Any thoughts, experience or insights?

Thanks

Trying to gather heat in cold Canada to supplement a greenhouse .

I've got a pneumatic golf ball launcher that I've designed and manufactured. It'll push a ball over 350 meters with compressed air at ~850 kPa. I have a standing challenge with some friends to play an entire round of golf at a local course with this launcher.

So, I'd like to be able to aim the launcher precisely, and for that I'm designing a sighting mechanism. However, I'm running into some issues with non-integer gearing.

As a brief background, I spent 11 years in the Army, with six of those as an Artillery Officer. I had the distinct pleasure of having a large amount of hands-on time operating mortars and various artillery pieces.

My objective is to replicate the function of the M64 Sight Unit, used on the M252 and M224 mortar systems. The sight allows the operator to input deflection and elevation adjustments in increments of 1 milliradian.

Diagram of M64 sight unit: https://www.inetres.com/gp/military/infantry/mortar/M252/M64_sight.gif

The milliradian increments for the M64 sight are not "true" milliradian, but rounded. For one complete revolution of a circle (360 degrees), there are approximately 6280 "true" milliradians, but in the land of NATO artillery and military land navigation, we round up to 6400 milliradians, or "mils".

So, one complete revolution of the sight unit corresponds to 6400 mils. The sight unit has a coarse scale in increments of 100 mils, and a fine scale in increments of 1 mil. The operator inputs deflection and elevation to the sight by rotating the knobs attached to the fine scales. Thus, if the operator were to rotate the fine scale knob 64 times, he would effect one complete revolution of the coarse scale.

So, to the crux of the question: How can I replicate a 64:1 gear ratio with off-the-shelf hardware and 3d printing? I have 90% of the sight designed, but the gear ratio problem is throwing me for a loop.

My initial idea is to use a 10:1 worm gear attached to the fine adjustment scale, and then a 6.4:1 pully system with a toothed timing belt to the coarse scale. However, I'm finding that the available options for belts (and dimensions of the teeth) don't quite allow me the exact 6.4:1 ratio needed. I'm hesitant to use a non-toothed belt, as I don't want any slipping to occur. That being said, if I slightly oversize and undersize some 3D printed toothed pullies, will a standard belt still work?

My access to machining is a bit limited, otherwise I would elect to make my own 64:1 worm gear with a 64 tpi tap (I have a strong suspicion that the M64 sight uses an ACME thread with this method).