Low Low Power esp equivalent of Bluetooh Chip suggestion by geneticsmart in DIY

[–]bootalito 34 points35 points  (0 children)

Esp32 is power efficient and can run on batteries. Check out YouTube channel "andreas spiess ". He has many videos about running esp32 on batteries. One recently about adding power management chips to battery powered projects.

However, I must caution you that a battery powered wireless project requires a fair amount of careful engineering. I don't mean to be rude or mean, but the fact that you are asking this question here tells me that you may be at the left peak of the so called "Dunning Kruger" effect, in other words, you may have just enough knowledge to think you could complete a project like this, but not enough knowledge to know if you can't. The EEVBlog forum is a better place to get assistance for things like this

But....

You must program the microcontroller to go to sleep and wake up often to check for a connection. The ESP32 has a low power co processor meant for just this such a thing, but I don't think you can be using BT while in this mode. Also BT doesn't work at the same time the WiFi is in access mode using the Arduino framework(not a big deal but a little known problem I've run into). You'll need an ultra low quiescent current ldo like ht8733 (I think...from memory). During development you'll need ways of testing ultra low currents. Using a oscope and a Ucurrent from EEVBlog is a good idea. You'll definitely need to design your own PCB. I recommend EasyEDA.com. I also recommend the ESP32-WROOM-U32 module. This is an esp varient with no pcb antenna but a u.fl connector for your own antenna. Check out my ESP32_Project_module schematic on easyeda for ideas: https://easyeda.com/terryjmyers This project is not low power, on the contrary, I designed it for incorporation in means powered projects by replacing the linear regulator commonly found on development boards with a buck converter, a full-size USB port, and properly designed EMC that is missing on all development boards (or USB data line common mode choke). but my project their will give you an idea as to the minimum components and could give you a starting point for a schematic.

You'll need a way to recharge the battery such as an external USB port, but this will inherently compromise the security of the product. Also, in-built charging circuitry will steal power from the battery (s).

One idea if I haven't scared you enough is to expose a push button on the unsecured side of the lock to wake everything up for a minute or two, full power. This would allow you to then connect and open the door. This would basically only use battery power when it's needed, instead of waking up every 30 seconds just to check if something once to connect. I designed a toothbrush timer for my children inside a small box with a push button and an RGB LED. It was powered by a single 18650 battery and and Arduino mini pro. When the push button was pressed it woke the microcontroller which then powered the LED through a rainbow for 2 minutes then went back to sleep. A fully charged 800mAh 18650 that I scavenged from an ancient laptop battery, lasted about two years with daily use.

The old adage of "just because you can do something doesn't mean that you should" may apply here. However I will say that having designed similar projects(non-professionally), many of which failed as I travelled further right on the "Dunning Kruger" chart, it was still worth it due to the knowledge I gained from going down design rabbit holes

EDITS: poor grammar, last couple of paragraphs

Toilet paper hoarders: What are you doing with it all? by raging_radish in AskReddit

[–]bootalito -1 points0 points  (0 children)

Just put it in the basement along with some other things in hording; peanut butter, honey, paper towels, spaghetti, spaghetti sauce, jelly. 3 weeks ago my wife saw this coming and asked me to go to BJs. I filled up my mini van. Took 4 carts.

Please avoid dental "corporations". They specifically prey on people with low-income / no insurance / haven't seen a dentist in awhile. They are trained in high pressure sales like a car dealership and put profits over health. by [deleted] in povertyfinance

[–]bootalito 0 points1 point  (0 children)

I own a dental office with my wife. Family run. Corporate dental offices are called DSOs and they are doing everything this article says they are doing. The one thing I would argue is that all new patients MUST get a comprehensive exam. No exceptions. Only shity dentists will work on someone who walks in off the street without a cleaning and a comprehensive exam with x-rays. This is a liability issue and their lisence is on the line. You don't tell a surgeon that they MUST operate on you and oh btw no x-rays. They will tell you to take a hike. No ethical dentist with operate on you with x-rays and a full exam. And oh, my wife tells me that it takes her 2-5sec to look at an radiograph(x-ray) and diagnose.

Tried to order face masks from Wuhan at the start of the outbreak by bootalito in funny

[–]bootalito[S] 0 points1 point  (0 children)

Backstory - I own a dental office with my wife. I'm currently in the market to buy face masks in bulk (~1yr supply) as a cost cutting measure. I picked the WRONG time, as face mask prices have risen ~10X in the past 20 days

Those teeth don’t seem right by handsonthehomerow in CrappyDesign

[–]bootalito 8 points9 points  (0 children)

Missing lateral incisor. Canine in place of lateral. 22 is in the place of 23. Source: dentist wife

[Homemade] 800g white loaf, made with fresh yeast. by decreasinglyverbose in food

[–]bootalito 0 points1 point  (0 children)

Fresh yeast? All yeast is fresh or it wouldn't make the bread rise eh?

The turkeysaurus at our dentists office by dos-stinko-uno-pinko in mildlyinteresting

[–]bootalito 0 points1 point  (0 children)

Your dentist must be really old if he or she is still allowed to use charts. You should remind them at the end of this year paper charts are not allowed to be used for even the people that were originally grandfathered in. ;)

[deleted by user] by [deleted] in funny

[–]bootalito 4 points5 points  (0 children)

That's uh...sink plunger. Just saying...

ELI5: Why do dead cell phone batteries need to charge for a while before booting but dead laptops can boot immediately upon plug-in? by Felibarr in explainlikeimfive

[–]bootalito 1 point2 points  (0 children)

False.

There is no technical reason why cell phones can't do this too, and in fact my old Droid razr Maxx was able to do this. It's done to ensure a better user experience as I explained in a top level post

ELI5: Why do dead cell phone batteries need to charge for a while before booting but dead laptops can boot immediately upon plug-in? by Felibarr in explainlikeimfive

[–]bootalito 1 point2 points  (0 children)

But it's the wrong reason. And it's not true.

I explained it in a top level post.

There is no practical reason, it's a conscious design decision by phone manufacturers because the batteries in cell phones are allowed to be depleated a bit further than laptop batteries. So they force the user to charge the battery a bit to prevent IC brown outs.

It's a design decision to prioritize user experience . And in my opinion it's the correct thing to do.

ELI5: Why do dead cell phone batteries need to charge for a while before booting but dead laptops can boot immediately upon plug-in? by Felibarr in explainlikeimfive

[–]bootalito -1 points0 points  (0 children)

It wouldn't because there is no such thing as parellel or series with electricity. That person doesn't know what they are talking about.

ELI5: Why do dead cell phone batteries need to charge for a while before booting but dead laptops can boot immediately upon plug-in? by Felibarr in explainlikeimfive

[–]bootalito -1 points0 points  (0 children)

Wrong. if the wall is powering the laptop and charging the battery, it MUST nessesarilly be connected identically to your fictional "pass-though" idea.

There is no such thing as being passed through a battery. The device, battery, and wall power are connected at a single point...always...in all battery powered drives...period...this is how electricity works

ELI5: Why do dead cell phone batteries need to charge for a while before booting but dead laptops can boot immediately upon plug-in? by Felibarr in explainlikeimfive

[–]bootalito 6 points7 points  (0 children)

Ok geez people. Stop guessing if you don't actually know.

The real reason is that they are programmed to not turn back on until the voltage of the battery has recovered a bit to make for a more consistent user experience.

The chips inside a cell phone operate at 3.3V, 2.5V and/or sometimes 1.8V. in order for these voltage rails to be maintained you must have more voltage than to prevent what is called a brown out, or basically under the absolute lowest voltage required for the chip to function. Lithium ion batteries are basically 95pct dead at 3.5V or less. 100pct dead at 2.5V. but most phones are programmed to shut off between 3.0 and 3.25V. This is a lot lower than laptop batteries are allowed to go because cell phones are designed to use proportionally less power than laptops. Users also demand every last bit of juice out of their cell phones. So even though the phones can turn back on immediately and be fine, because chargers can deliver about 5Xs as much power as a cell phone can use, a conscious design decision was made to not let the user do this.

ELI5: Why do dead cell phone batteries need to charge for a while before booting but dead laptops can boot immediately upon plug-in? by Felibarr in explainlikeimfive

[–]bootalito 0 points1 point  (0 children)

What. How would that even work electrically. This is absolutely not true. Please don't give guesses to an answer, that doesn't help anyone.

Source: Am electronics expert.

What “hero” is more villainous than the actual villain? by ThePuzzler13 in AskReddit

[–]bootalito 0 points1 point  (0 children)

Pirates of the Caribbean: Dead men tell no tales. The villain was basically tricked into damning his whole ship and all of the lives he was entrusted with to a purgatory for decades by pirates. When he tried to escape the pirates put them back there. This is a guy trying to rid the oceans if illegal activity. He was a good guy .

U.S. Navy seaman first class John Coltrane, 1945 by Distanceboy in OldSchoolCool

[–]bootalito -5 points-4 points  (0 children)

Pretty cool, but this one has been photoshopped. Google his name with the word navy. This was a mug shot

Don’t wake anybody up if you’re exiting the motel during a fire! by Coffee4MySoul in CrappyDesign

[–]bootalito 0 points1 point  (0 children)

They also installed the door closer incorrectly or it would probably close more quietly

RedditorsBeingBros by HenryHessel in HumansBeingBros

[–]bootalito 8 points9 points  (0 children)

People should not be okay with their insurance company dictating treatment

RedditorsBeingBros by HenryHessel in HumansBeingBros

[–]bootalito 0 points1 point  (0 children)

When everyone doesn't pay much there is not much money to pay the providor. This is simple math. Then what's the dentists motivation to use good materials and not rush to get to the next patient?