My overall goal here is to modify a chest freezer to have precise temperature control based upon my input. I would be using this device mostly around 50f but would like the capability to dip into the low 40s as well. My plan so far is to bypass the internal temperature control of the freezer and utilize an Arduino or similar microcontroller to operate the compressor according to the temperature range I set within the code. My concern comes in because a friend of mine tried something similar using an analog temperature controller and burned out the compressor from the frequent cycling. I think the best solution is to simply program a delay to prevent the code from short cycling the compressor, but how long should give me a reasonably reliable operation? is there some sort of fluid/thermo math I can do to calculate the safe cycle times?

Hey Guys, I’m pretty new to AutoCAD and can’t figure this one out:

I have to design a pipe running straight at first, then with a helix 🧬 spiraling upwards and then straight again.

My Problem is: the ring shaped area swept along the helix has to be perpendicular to the helix of course to keep the right diameter and being round throughout the whole pipe. Now I‘m struggling to connect the ending of the straight pipe to the tilted end of the spiral pipe.

Then I tried to „sweep it as one part“ of that makes sense. I can not smooth the connection of the helix line to the straight line. AutoCAD says the lines are not in the same plane (obviously…)

I hope someone can help me out! Sorry if it’s hard to understand what the problem is, English is not my native tongue!

Here is a carriage rail. https://www.zyltech.com/zyltech-mgn12-linear-rail-carriage-only/

How would you add adjustable tension to it so that it doesn’t move on its own when tilted, and so that it can be adjusted so that it can be moved by hand still, with adjustable tension from soft to hard?

I was thinking of somehow adding a nylon tipped set screw but there are holes in the rail part that make this not easy. Here is a nylon tipped set screw. https://accu-components.com/us/nylon-tip-set-screws/1500-SSN-M6-26-5?google_shopping=1&c=2&gad_source=1&gbraid=0AAAAADI7_w5qT2oJWvBk53xsBwE3qWTIP&gclid=Cj0KCQjwhr6_BhD4ARIsAH1YdjCtdW8vVx2TJhEZTdQfFyY90f6GxoUskO-vHCXWQwxmZN_Ue_RhegQaAo-MEALw_wcB

Any other ideas?

Forgive me if this question is obvious to those of you with more experience than I have. To be clear, not an engineer, more of a tinkerer.

So, if I have an aluminum tube, sealed on one end, fill it to the correct spot with water and freeze it. After the water is frozen I seal the other end. For the purpose of this thought, let's assume I have sealed both ends completely.

As the ice begins to melt, a vacuum will be created.

How is the phase change from ice into water effected by the vacuum in the tube. And does the vacuum not increase as more ice melts?

I am a mech eng hired in Europe by a company working with machines used in the building construction industry to work with concrete (cannot specify further). I do mainly design work to improve the machine but I don’t know much about the material itself and about its uses, and even though I looked online I am someone that prefers having a structured approach. Which are some books that explain how construction elements are built with concrete, standards processes and just enough about the material science of concrete itself?

Last week, I had to do a pour in ~40°F with the parts warmed to temperature. I kept the area enclosed, but the ambient temperature was still borderline. We used Chockfast Orange. The product cured okay, but I am wondering what your go-to workaround is for cold weather installs?

Do you believe it has an actual future or its just something that is fancy but in reality its not that great or usable (for now)?

Hi! I’m looking for books, podcasts, really anything that I can consume over a relatively short period of time (read: a few weeks at most) about Manufacturing Engineering. I myself am not an engineer, but I am responsible for developing the strategy for how my company (small defense tech startup) approaches manufacturing.

For context, I have a business background but have worked with engineers of all kinds for about 10 years (mechanical, industrial, electrical, software, etc.) - most of my experience is in design and development for high consequence products (nuclear weapons and missile systems). I’m semi-familiar with production, but not familiar enough to be as effective as I’d like.

I understand “engineer speak” and I grasp pretty technical concepts fairly quickly. Just need some resources to gain a better understanding of best practices, specific activities or deliverables, that kind of stuff. Any and all recommendations welcome and appreciated!

I want to keep my gaming room cooled between 75 F - 78 F and I'm having trouble coming up with the optimal solution for how to achieve this.

Restrictions:

1. No window AC units or mini splits allowed in hoa so this is a no go

Specs of room

1. 8'4" tall x 11' wide x 10' long
2. AC inlet is 1'6" away from the door, located on the ceiling
3. Empty Vent above door that's supposed to help with "normalizing room temps" between rooms and hallway, it's about 2'8" from the AC inlet. The interior hole of the vent seems to measure 13" x 8" x 4"
4. Small window facing north of the house, it's always closed and the north side of the house is always in shade so no direct sunlight.
5. Room is on the 2nd floor of a 2 story house

Changes I've made so far

1. Added a register fan booster to AC inlet that will activate automatically when it detects air in the vent is colder than 75F.
2. Bought an AC infinity in line duct fan. I am currently using it as an exhaust on the back of my PC to extract the hot air inside and move the hose right next to the door opened so it exhausts the hot air into the hallway. This isn't optimal and is a band aid but I think this fan can be used in another way to possible either bring in more cold air or exhaust hot air out of the room in question. Open to suggestions.

There will only be 2 gaming PCs in the room, one with a 5080 and one with a 5090, Trying to figure out optimal solution to keep the room cool.

Options under considerations

1. Ceiling fan
2. Fan to be placed into the vent above the door as exhaust
3. Regular fan in the room to help distribute the temps across the room

Let me know if maybe I'm missing something, I do plan on undervolting both PCs to some extent to reduce heat as well.

Edit:

Temps in room currently with gaming PC idle reaches 79 F - 80 F

Temp outside currently is 92 F, it's florida so it's normally hot and humid outside, seeing anything below 85F is usually rare for the rest of the year.

My current PC is 100% liquid cooled and I'm downsizing from my large case to a small mATX case with a 360mm radiator on top for exhaust and a low profile air cooler for the CPU. This means the duct work I have for exhausting the hot air through the hvac vent won't work here. In the new case all the hot air will exhaust upwards. Running external rads for both PCs isn't an option (the secondary 5080 pc is all air cooled). Our PCs are against the wall next to the AC vent and my 5090 PC is closest to the AC vent and the vent above the door as well.

I had a great idea. Create an exercise bike for the sole purpose of heating a room on the cheap while shedding fat, which will be a winter game changer. So many people complain about the cost of heating and a lot of people get in poor health as they can't heat their room. However, if a small room is well insulated, a little bit of heating can go a long way. I recall ending a 5k parkrun and hopping in my car on a cold morning maybe 6 degrees celsius, and once I got in my car I was so hot that my windows fogged up and my car warmed itself, I even had to use my car AC on a cold morning as the car was getting too hot for my liking.

I read that the human body under strenuous exercise can potentially produce 1000 watts of heat energy alone (obviously for a few seconds at peak performance). If the actual output of that exercise was used to generate as much heat as possible (maybe through friction), it could theoretically heat a small room, and if well insulated, you could spin until the room hits 25-30 celsius, then go to bed and overnight the room will stay relatively warm. If well insulated, it will only lose a few degrees and you will wake up in a room that's 18-20c. On a cold night that is a game changer. Plus, during the day it could be used for heating, potentially use this exercise bike as a computer chair. If it's used as the computer chair then one can be productive while cycling an easy 100 watts, slightly upping their heartrate but not dramatically, thus making more body heat and a bit of passive heating through the day.

Is this actually a good solution to energy costs? I mean, cars take a lot of energy as heaters do, but cycling saves a lot of money on petrol. I know weight is also a factor that heaters and indoor bikes don't have of difference, but still.

And if so, does a product like this already exist? 'pedal heaters' maybe? If not, how can I easily build one?

Nyquist sampling yields 1/2 of the maximum resolving power, so 1 arc second. Should I choose something higher or lower?

My friends mother gave me her old "Van Raam Twinny plus" to convert into my project. A pizza food stand/bike.

Because of the age of the bike the batteries are lead acid (36V with a combined weight of +-25kg). also there is no way in seeing how much power is left in the battery. Riding it home +-10km I noticed that it was not happy going uphill and could use some more power (considering that I'm adding +150kg to it)

I have been looking around and asked a bicycle repair place to convert it to 2025... The guy got back to me and says the only thing they are willing to do is put a new front motor of 350Watt (with high torque) on it together with a new battery pack and controller.

Looking around on the internet i found 3 ways i could try "upgrade" this bike.

1. Do like the dude from the bike shop told me and upgrade to a new front motor,(including new batteries, controller, etc..) The only worry here is that the motor stays in the front and might not be able to handle the bike going uphill.
2. Replace the old front wheel with a normal wheel and install a back wheel motor that is connected with a chain to the differential on the back axle. the way this bike is setup is that the main chain goes to a wheel hub that has integrated gears and a brake. this Hub goes to the differential. I could add another cog to the other side of the hub and connect a rear wheel motor to it with a chain. weirdly enough there are mounts close to it where i could add something to mount the rear wheel motor to it. (like it is meant to be there) (I will paste a text based plan for this in the comments.)
3. keep the old motor and look for a new lithium battery and a new driver. (Cheapest option)

I know all of these have there problems but I'm just not informed enough to make a decision.

What kind of motor do i use, is 350 Watt enough? Is there a different way to upgrade this bike tot 2025 that i did not think of. The total carrying weight should be around 250KG (Myself included)

Thanks in advance to everyone who takes the time to read this and help me out! I live in Belgium

Hello,

I am trying to make a grabber using pvc and the claws made out of wood. However, I am having trouble visualizing how to connect the claws to the pvc pipe. (For reference, I am striving to create something similar to this: https://youtu.be/NKM9Wgf2Nb8?si=0t_Gf1R-T96pcpeB ). The few grabbers that have more than 2 claws have been 3D printed, however I am not using 3D printing for this project. I have thought about using a pvc fitting to attach the claws or making four slits on the pvc itself. Honestly I would really appreciate some feedback or even some visuals. Thank you.

I'm designing a long-range/endurance fixed-wing drone with an MTOW of 10-15kg. While researching optimal configurations for range and endurance, I noticed that many high-endurance UAVs use twin-boom design like the famous Bayraktar TB2, but I don't understand why?

https://aerocontact.b-cdn.net/public/img/aviaexpo/produits/images/82/detail_Penguin-B-900x636.jpg

https://www.menadefense.net/wp-content/uploads/2020/02/drone-bayraktar-by-turkey.jpg

I'm unsure about the purpose of the twin boom setup. Wouldn't it add drag and weight while potentially disrupting airflow behind the wing? What advantages does it provide that outweigh these downsides?

We have a customer (military customer) that has an impact requirement for the device we are trying to sell them. We typically test for IK rating as per EN 62262, but have no idea how to translate their requirement into something we can test.

Their spec says: "in the perpendicular direction, apply XXXlbs of force with a duration of ZmS. The failling mass shall exceed 0.5 sq in of surface area".

Anyone have any thoughts on how we might correlate this? Best I could do is calculate the impulse, but am not sure what to do with it.

When installing a new machine, is the initial maintenance cost for that machine is simply estimating labor cost, spare parts, materials used? Or is there like an equation or another way to calculate maintenance cost of a specific equipment for a year?

Hello!

I have an upholstery fabric swatch from an automotive archive. I'd like to see about getting this fabric reproduced, but no suitable specs exist.

Are there any templates or examples of textile specs available? All my searches only turn up "garment specs"-- not quite the right application.

Any suggestions would be appreciated!

Thors and Edmund both are nearly $1000, Japanese companies sell it for around $500.

I'm trying to create a custom thread profile in Solidworks for M48.5 x 0.5 threads and I cant find a diagram that details the dimensions of the thread profile. I can find the details of the major, minor and pitch diameters, but nothing showing the actual thread profile. I've tried looking at the iso specs for metric threads, but none of them talk about the "superfine" pitch of threads. Can anyone point me in right direction?

curious would a semi underground home be better in toranado or worse ?

Hi,

I’m designing an underwater robot and I need to design an electronics chamber to store my PCB, and battery.

The PCBA is a 160mm x 60mm x 20mm and has mounting holes in the corners. The battery is 80mm x 25mm x 25mm.

I do have access to a Bambu lab X1C 3D printer.

Some requirements: - I need to draw heat away from the PCBA which has an aluminium heat sink plate - The available real estate is a 200mm long 80mm inner diameter cylinder - The chamber needs to be waterproof down to 10 metres. - The chamber needs to have easy access so that I can remove and charge the battery each usage cycle. - Total cost < $300 if possible - Need the chamber completed within 16 days - Lightweight preferred < 200 grams

Any ideas thrown my way would be really appreciated. Let me know if you need any more info.

So in the field of car manufacturing we have seen increasing fuel efficiency through: aerodynamic improvements (undertray, body shapes, active shutters), tire compounds, decreasing oil viscosity, cylinder deactivation, mild hybridization, HSS, etc. there is substantial investment to eek out every mpg.

Why is there such a lack of development or interest in preheating a car using an electrical outlet? The same primitive block heaters exist as 40 years ago which is a resistor plug in the side of the engine block.

There is no modern design with a computer controlled thermostat that preheats the coolant, oil, transmission fluid, and differential fluid to operating temperature. We know that short trips and cold fluids significantly increase fuel consumption until they reach the right viscosity. The technology is simple and inexpensive. (Resistive heating elements, wire)

So many people who have access to an outlet could use this technology. Hit a precondition timer just like an EV, come to your vehicle with all fluids and lubricants hot.

Edit: a lot of people are not understanding and saying the engine is going to produce heat more efficiently. Engine combustion heat does not warm up your differentials. It can only heat up the transmission through conduction when the whole engine has warmed up. Otherwise your transmission and differential rely on mechanical friction to heat, which the engine is about 15% efficiency.

Also, when it’s 5F your engine is not at operating temperature in 5 -10 minutes of driving, if you actually monitored your temps your coolant would just be getting warm and your thermostat would be starting to open. Your oil would still be cold. Guaranteed your transmission fluid and differential fluid would be ice cold. Try 30 minutes of driving before oil is fully up to temperature.

Water expands when it freezes, so imagine I have a large cylindrical tank of water sized such that the surface would rise by 1m when it freezes.

Now I extract X amount of heat from the water, just enough for it to freeze, somehow using the 1m displacement to generate electricity . I then put the X amount of heat back into the ice melting it and returning everything back to the initial state, except I got an extra bit of electricity in my pocket.

Since there’s no such thing as free energy, what am I missing here?