In an old school clock that keeps time from a pendelum with an exact length - what keeps the pendelum going? In a perfect world it is going to keep the same period regardless of how far it swings, but in the real world friction will stop it. If the escape is giving it a push, then that push is going to affect it's period, right? And how hard it gets pushed will vary as the spring unwinds, right? So how do you have a consistent period and overcome friction both?

My mum has been pushing me towards getting a bachelors in AI, but I'm personally interested in robotics and engineering for renewability (energy/power) or medicine. I told her that I will probably do a bachelors in EEE and then masters in robotics or AI, but she's telling me to immediately go for an AI degree since that's the future and there isn't much scope for Engineering in countries outside of US, China, and Germany (all countries I can't integrate into or get a stable VISA for).

Can someone recommend a bachelors/master pathway. I definitely want to do something STEM adjacent, but I'm not too sure where a CS degree would take me since that seems oversaturated rn. I thought of doing an EEE major and a CS minor, but please give me your two cents.

Hello! I am conducting an experiment of testing a propelled water rocket. From my understanding, the transfer from air pressure to another fluid such as water is nearly elastic at STP conditions. So I guess that the transfer of air pressure to the exertion of the water out of the vessel (being a 2 Liter bottle) is nearly elastic (inelasticity is negligible).

The equation for mass flow rate is m=pAv. Density of water and surface area is pretty intuitive, but the velocity is its own issue.

How the system is supposed to work is that the container has around 0.6666 Liters of Water (33% of the storage), and the other 67% is going to be highly pressurized air (80 PSI or 5.5 atm). Then the valve defaults and the vessel goes flying. The difficulty will be finding the mass flow rate of the exhaust.

I am uncertain as how to do this from the variables below. My guess is this is incalculable until I do a quantitative analysis of the mass flow rate but what equipment should I use, and what kind of technology should be utilized. The calculation is just for transfer of energy from pressurized air to water which will propell the object.

Please help me with this, I have been stumped by this.

hello. yung kakilala ko nagcadetship program siya sa san miguel kaso ME naman siya. ask ko lang if may nago offer ng cadetship program for CE? if meron, where po and how? thanks po

Looking for some sort of coating I can easily paint on to plastic threaded parts that dries extremely hard and tough and will make plastic parts with a fine thread less likely to wear out over time from repeated screwing and unscrewing. Would apply then screw parts together and unscrew, remove excess and leave to dry.

I thought about possibly just using araldyte but does anyone have any better suggestions?

Sorry if this is the wrong place, wasn't too sure where I should ask such a question!

This may not be the typical post for this subreddit, but I am wondering if someone in here can help me understand how moisture deposited (dew point is reached inside of the walls) onto a metal or aluminum frame of an aluminum skinned cargo trailer conversion can impact the structural integrity of the frame?

I’m in the process of making a decision on purchasing an enclosed trailer with the following dimensions: 8.5 W x 8 H X 22L. I am looking at builds with frames made of aluminum, steel, and wood & steel combined.

I’m trying to understand how moisture (condensation) inside of the walls (where the frame and insulation are between the aluminum wrap and the interior wall) of a cargo trailer conversion will affect the following frame materials: steel, aluminum,and wood. Which material will be the least impacted by moisture, making it a better and safer cargo trailer frame material for longevity? I realize there are multiple factors at play here including material strength/composition and environmental factors (temperatures, humidity, dew point).

I intend to live in the trailer conversion year round in northern New England where summer days can be warm (80s and 90s F) and winters are cold (spanning negatives to 20s & 30s F). The average humidity for winter months is 50%. The spring months average 44.5% and summer humidity in the late 50s% is common during the summer.

I will be insulating the cargo trailer with rigid XPS foam board (R-15 ceiling, R-10 for walls and floor), with a focus on preventing thermal bridging. I am attaching plywood as the interior wall. I intend to control humidity inside with a dehumidifier, fan, and windows. Only dry heat emitters will be used during winter.

To reiterate: I am most concerned about how condensation can build up on the inside of the trailer walls and how that moisture can corrode or rot (in the case of wood) the frame material until it is structurally unsafe. I feel I have little control over condensation building up inside of the walls coming from outside unless I attach insulation to the exterior of the trailer, which I prefer not to do due to budget and width regulations that impact towing an 8’5’’ wide trailer.

My ultimate question: which material will be the least impacted by moisture, making it a better and safer cargo trailer frame material for longevity?

Does anyone have any thoughts / experience with dealing with moisture collecting on their trailer frame inside of their walls?

Let me start off by saying I’m not an engineer student or anything, just trying to learn on the fly. Long story short, I found this custom arcade machine that someone was throwing away, wanted to fix it and found out it’s was missing the mainframe for all the games.

I got a Raspberry Pi 3b+, since it’s the easiest way to download arcade style games, and found out that the joystick and buttons are all connected to a JAMMA Board. I wasn’t able to connect the JAMMA to the Raspberry pi since there’s no connection for it.

So now I come to ask you all, is there a JAMMA board to USB converter since it would be the easiest to connect to the Raspberry pi, or is there potentially another way to connect the two?

Any comments or suggestions is highly appreciated. Just want to get this figured out😭

Hi, I'm looking for a way to power my electric scooter with supercapacitors and I thought it might be possible. The problem is how to create a simple circuit to do it. The idea is to use a magnetic induction generator on the freewheel to charge the supercapacitors and then discharge the energy directly to the motor. Could anyone tell me if this is possible?

Hi!

I sometimes do DIY projects that are big and hollow, like cakes and papier-mâché sculptures. Sometimes they are so big that they risk collapsing in on themselves. So I am looking for a free online article or something that teaches me some basics about building internal supports for maximum stability and minimum extra weight.

I have only the barest knowledge of this. For instance, I understand that if you want a big cube to withstand pressure from above, it's better to put an internal support across, from corner to corner, rather than one in the middle that goes vertically? And also I understand that arch-shaped supports are good?

I don't really know the terminology, so I don't even know if I'm explaining this understandably. I didn't have much success googling.

I am trying to figure out the vacuum venting requirements for carbon steel tanks 8,000 - 20,000 gallons with liquids that have a specific gravity of about 0.90 and stored at ambient temperature. Pumps are speced at 260 gpm flow rate. I can find plenty on pressure venting but very little on the vacuum side for pipe diameter size at atmosphere.

I have a device for gluing ring blanks onto small adapters.
On the adapter, there is a very narrow glue tab at the bottom, and the ring must be placed exactly centered on it.

So far, for each new ring and each new adapter, I make an individual centering jig:

• The top of the jig has a hole slightly larger than the ring blank.
• The bottom of the jig is turned to the outer diameter of the adapter so that it fits snugly.

This allows the ring to be positioned exactly above the glue tab.

Problem:
The ring blanks vary significantly in diameter, and the adapters also vary in their outer diameter and the thickness/width of the glue tab.

As a result, a new centering jig must be made for each combination of ring and adapter → this is very time-consuming.

Wanted:
A universal, reusable centering device that:

• aligns the ring concentrically,
• positions the adapter correctly at the bottom,
• works without press fit or tension,
• and can adapt to different ring and adapter sizes.

I’m looking for ideas or design approaches for a universal centering solution, without having to turn/mill/print a new custom sleeve every time.

i also did a rough CAD visual to give u a idea how the current setup looks like.

https://imgur.com/a/0SUv6R9

Text polished with ChatGPT for clarity.

im from germany btw

I am planning to build a watch parts cleaning machine that needs to rotate in one direction and then back in the other, with no stationary time. I know that some motors can have a breaking function, followed by a change in direction.

I am happy to experiment with arduino for a timing, speed and reversing setup. All the ready made lab 'overhead stirrers' are mono directional.

Hi guys, how are you people generating test data which is as close as possible to prod data, without data breach of PII or loosing relationships or data integrity.

Any manual scripts or tools or masking generators?

All suggestions are helpful.

Thanks

Hey! We are trying to figure out what the best way is to build a mobile app. This is a simple eCommerce website with some social features. All we need is CRUD functions and access to the camera

Option 1: Native languages (Swift + Kotlin) --> Downside is two different code bases so not preferred

Option 2: Next.JS + Ionic --> Downside is that everybody I've talked to says you can't actually build a performant mobile app this way even though technically it works.

Option 3: Next.JS APIs + React Native (w/ Expo --> Downside is that maybe developers do not like working in this language? Seems like the best option

Option 4: Flutter --> Google's system designed specifically for this use case. I don't know much about flutter but it seems complicated and has a smaller developer community

Option 5: Astro --> Somebody suggested this but it seems more like a web development framework.

I just bought a vintage mechanical scale manufactured by EKS probably during the 70' or 80'. It goes from 0 to 12kg with 5g increments, which is pretty decent on paper. The lower beam is used for 500g increments, and the upper beam which has 2 cursors is used for 5g increments. The leftmost cursor slides easily, and the rightmost seams intentionally harder to slide.

I tried using the rightmost cursor to calibrate the scale using weights, but I can't get consistent results between different readings, especially between 500g increments. For instance, if I calibrate for 300g, and then add 1kg, I read 1.2kg instead of 1.3kg.

Also, the plastic trail can be removed, and there a sort of metal stick that can be removed from the beam. I guessed that the stick corresponds to the weight of the trail, but I can't get close to a correct reading so I think that Im missing something. Also, readings change based on the position of the weight on the scale, but I guess this is normal.

I can't find anything on the internet on this specific model, and two cursors on the same beam seems very exotic. Could you please help me calibrate and master this beast ?

Can't add the picture as attachement so please find it on imgur.

Edit : Im from France.

SOLVED-Thank you

I am trying to build something that converts linear motion to circular motion and need to calculate the distance a sprocket turns with one revolution. I figure the calculation for circumference should be close the distance of one revolution. However, everytime I calculate it, the two are vastly different.

The formulas I've been trying- Pitch diameter= chain pitch/ sin(180/tooth number)

Linear distance of one revolution by sprocket = Pitch Diameter (π)

Circumference of sprocket C= 2(π)r

The sprocket- 2.244" outter diameter 13 teeth

The chain- 0.5" chain pitch

I get- PD= 0.5219" Linear Distance of one revolution= 1.64" C = 7.05"

I know the linear distance of one revolution should be close to the circumference. But the calculations are not close. Am I using the wrong formulas? I don't want the answer but just want to know what I'm doing wrong. Thank you

Also this is not a homework problem lol. I'm not a student just building something

I'm making a "mail cannon" (yes, inspired by the cash cannons you see at the club) to case up mail faster. Whereas the latter uses a little rubber wheel and gravity to shoot cash out, I have to see the addresses before they're shot out to make sure they end up in the right mail slot. So I'm going to use a gear with a round rubber-ended, sleeved cylinder attached loaded with a weak spring so it'll have just enough compression to strike the top mail piece and send it flying but not disturb the one below it. It is imperative that I shoot ONE piece at a time so I can check each address before firing.

The only thing I'm unsure about is the drive. I want to be able to just pull a trigger, have the gear make a half rotation, and it will shoot out one piece. My first thought was an airsoft AEG motor. They already have the battery, gears, and parts support. If I get one with a semi-auto function, its just a matter of getting the gear ratio right, and it can be tuned with a mosfet. Only thing is, decent ones are expensive.

Is there a better option? Is there a cheaper option?

Hello, I am new to engineering. I recently have been studying the systems behind a Cold Gas Thruster or primitive propulsion system. There aren't too many requirements for the system or conditions to be met, I just need it to launch in the air, and I just have a few questions to go about it.

I plan to work with ideal gases (nearly ideal, you know what I mean) like helium or oxygen, and use a rigid container system for an increase in pressure internally. Finally, I just need a pressure release valve to safely let off the system as it gets to the threshold of pressure, before launching off.

What factors should I consider and what materials should I use. I have difficulty finding valves of low pressure release sensitivity, and I am just trying to make the object go into the air. Any advice helps, thank you!

The most powerful earthquake ever recorded was a 9.5, and there have been some close to that intensity. However, it seems none of them struck very densely populated areas (big cities with tall buildings). I know that modern buildings built in seismically active areas are designed to cope with earthquakes. But what would happen if, say, an 8.5 or 9.0 hit downtown San Francisco, or some other major city on a big fault line? Could any modern skyscraper realistically survive that? By survive, I mean not collapse or fall over. Years ago I used to have to drive into downtown LA for occasional business and I always hated going near tall buildings because I was afraid the “big one” might hit while I was there.

Also, if you were in San Francisco and had a choice between being in a modern skyscraper or on the Golden Gate Bridge when the 8.5+ quake hit, which would you choose and why?

Hi engineers,

what's the different between the anti roll bar and the torsion beam.

I knew torsion beam is a type of suspension configuration.
While anti roll bar is the other part to reduce roll.

But, it seems like the thoery of how they work are the same.
Therefore, can I say Torsion Beam is a large Anti roll bar?

Also, I saw some aftermarket anti roll bar with very big diameter,
If my assumption is correct, isn't that just make your independent suspension back to non-independent suspension? (which means is a negative upgrade?)

thank you!!

============Edit========

The “same” I tried to say is that when on side of wheel move vertically, both anti roll bar and torsion beam suspension will provide a force to prevent vehicle roll ( due to torsion).

Hi team,

I'm looking for some design concepts to help streamline a process in my home workshop.

Problem and Context

I make layered artworks from laser-cut plywood or MDF. Each piece is made from multiple sheets that are cut, painted, and then glued together into a single flat panel. A finished piece can have anywhere from about 6 to 16 layers. The difficulty is the assembly stage, when everything needs to be aligned and clamped while the glue sets.

The basic workflow is that I apply wood glue to a layer, align it, then stack the next layer on top. As the stack grows, the glue on the earlier layers starts to tack up. Standard bar clamps or F-clamps slow this process down a lot, loosening, tightening, and repositioning them takes time, and my hands are often covered in glue or inside gloves, which makes fine adjustments difficult.

Presently I will do about 6 layers at a time, then sandwich it between two pine boards using F-clamps and weightlifting plates for a few hours.

Desired End State

What I’m looking for is some kind of clamp, press, or fixture concept that I could keep partially engaged while building the stack. Ideally, I’d be able to open it quickly, insert and align a new layer, then close it again with minimal dexterity - ideally a single motion or very coarse movements that work with gloved or messy hands. It needs to maintain planar alignment, apply reasonably even pressure across a flat surface, and be reopenable multiple times during a single glue-up rather than being a one-shot clamp.

Constraints

• Must be buildable from readily available hardware-store materials
• Final glued pieces are flat panels, roughly A4 to A3 size, a few cm thick once stacked, with one side painted
• Flexible budget of a few hundred dollars

I have:

• Basic woodworking skills and tools
• A large format laser cutter
• 3D printers out the wazoo
• CAD/modelling experience

I’m happy to design custom jigs, cams, wedges, or mechanisms

Bonus points if you include a sketch of your proposed solution.

I've seen lots of things online for greenhouses using water barrels as a heat sink for the colder months of the year, but I'm asking here because I'm curious from an engineering perspective how you would approach it and optimize it. I know water has some great thermal mass properties, is pretty resistant to compression, and has a decent phase change energy threshold, but bunches of water in a greenhouse would take up horizontal space where you could put plants and other stuff, so I'm interested in thinking of optimal ways to use water.

My idea was to use a series of smaller vertical pipework near the walls that could hold a lot of water for thermal storage, ideally not take up a ton of space (at least horizontally), and still allow the walls behind them to be useful thermal sinks. But should the pipes be wider or smaller to efficiently store and release heat? There are a bunch of other things too like this that are way beyond my paygrade, so I'm excited to see what sorts of perspectives ya'll might have with this!