Good point. I agree.

My pleasure!

Yes, a little while without producing videos was good for me (I still had my normal job)...

Agreed (I made a video about POE). I could have added the use case for projects with wired Ethernet, you are right. Concerning PODL: Is this already widely adapted? I never heard of it

You are welcome!

I only had a break from UKposts. Because this is my hobby, I still had my normal job :-( But I had the two weeks bike trip with my wife.

Happy to hear that!

Great to hear! Thanks.

That is what I also had in mind. But this Holtek datasheet www.angeladvance.com/HT73xx.pdf says 90mV (@40mA). That is where I had my value from

@@AndreasSpiess Oh my!! I was very sure about that 150 mV, but indeed the datasheet says 90... Is my memory soo bad? Noo! :) I must have remembered the value well from the time you showed it in episode 58 (small cell battery powering sleeping ESP8266) many years ago!! There you said and SHOWED on the datasheet the value 150. They must have changed the datasheet in those few years :). Plus my own tests always showed consistent 0.15 dropout.

We can agree on 150mV. As I said, I also had this value in mind. But then I looked it up to have a "proof"...

I added the links to the two boards to the video description.

Thank you kindly, Andreas! 👍

I agree. They work fine for many applications, particularly if you can charge them easily (not remote).

Super caps could be interesting for solar powered low power projects because for the capacity, they are quite big. For which use case QI coil charging would fit?

You are welcome!

Very interesting. Did you also compare how many circles were possible without the library? And is the library available?

Hi, I use FRAM: 10'13 read/write cycles, 150ns...! See Fujitsu for example.... 🧐

I think we did at as filesystem. enough writes to certain block it swapped to next. I think all our blocks had info what file chain it belongs and what is write amount. so when we boot we scan eeprom block headers and create toc in ram. Edit: Need to check these FRAM chips. I think they also wear out when reading

Love it. The simplest version I know of is to zero everything, then only ever write in full eeprom write blocks. Scan to the first available detected block and write there. When full zero everything. using a smarter algorithm like yours on battery is probably wise to minimize cpu time scanning.

@@LimbaZero Please get Fujitsu Product Overview datasheet. Also UKposts will Show you good Comparison. When write speed is a concern: also FRAM. At least in my projects. Greetings Henry...

I like the T-Beam for my projects, too. Just keep in mind: These boards are not optimized for deep-sleep.

I assume it will appear in one of the next videos. It is quite useful...

I want something like this - community mailbox has a key they put in your box for the larger parcels that don't fit. I would build a slot for that key, in addition to a 'please come get your crap' button that triggers a notifier. almost all mail is junk except the parcels. Knowing they want the large box back I think the delivery person would be inclined to take the time to use the key slot, and/or the button so the box doesn't get overstuffed.

Glad you liked it!

Maybe a lot of people think that rechargeable batteries are better. This is the case for many use cases, but not for all...

@@AndreasSpiess Split the difference, and replace rechargeable batteries?

I only used Li-Ion batteries during the last winter and one was dead a few weeks ago ( I do not know, why: Low or too high temperature or something other). The voltage also behaves as you describe. I will see how the LiFePo4 battery behaves during the next winter. This one is also better protected and probably will not get the full temperature swing like the one on the roof.

Good that we agree...

Great! You are welcome.

I do not know how they behave at low temperatures. All data I found so far was for charging with high currents. In our applications we only charge with low currents. Do you have info or tests for that use case?

If you start with a high enough voltage that is a good idea. Others call it PoE (Power over ethernet)...

The motorbike trip is still ahead. Tajikistan was cancelled and I drove 1000km along the Rhine river with my wife and our bicycles.

@@AndreasSpiess Canceled due to all the turmoil in Afghanistan? Hopefully you can do it later, you have more nice traveling to look out for. I looked up the road and it really must be an amazing and adventurous journey! I hope/assume the Rhine journey was also very nice and you had a great time. Stay safe!

Yes, it was cancelled because of Afghanistan. I do not think I can doo this trip soon. But there is hope ...

Good point. If I remember right, Kevin Darrah has one in his trigboard.

I like it very much. One of my better builds so far!

During the Super Power project they looked at different LDOs. But so far, I do not have a plan to create a video about it. Mainly because most of them are not available as a module and so useless for a lot of viewers.

That is interesting! You even can blink the LED!

Here life is not so easy. I agree with 433MHz OOK and maybe I should use it more (I have an RFlink-Wifi Bridge). The mailbox notifier is inside the mailbox which is a faraday cage. Only LoRa was capable to escape this prison ;-) And using Wifi for sensors for me is easier because I do not need an additional 433 transmitter chip. I have a few Zigbee sensors in my lab and I love them. But so far I did not program one myself. So I can only use what I can buy (PIR, switch, temperatue, etc. Did you already program a Zigbee device?

@@AndreasSpiess No, Ifor zigbee, Homematic & 433MHz I just use the sensors, which I can buy.. And that is a lot. The rest is done with ESP sensors.

You are welcome!

Thank you for your nice words! I once mentioned how I create my videos (in a channel update video). The most important ingredient is to have a clear use case and a typical viewer in mind...

@@AndreasSpiess Yes indeed, but you have a plethora of other production values that make a huge difference, to clarity and efficiency.

Thank you for your support!

Thank you!

Glad you think so!

Thank you!

1. We often use ESP32 modules that include everything needed for barebone usage. 2. You can design your PCBs and, if you do not choose too small SMD parts, can solder them by hand or by using a hotplate (google) 3. JLCPCB offers a service where they assemble your board with their machines. A service I often use lately

LiFePo4 is now even more accepted than when I made this video. So you made a good choice.

@@AndreasSpiess 😁

I hope a quick question: I'm pretty new to the esp32 dev world. I have an intent to do some home automation for a zoned HVAC upgrade. Main interest in that regard is to make esp32-based LCD displays for each room. (System manager will likely be on an STM32 device.) So, in addition to the LCD, there's a need for temp sensors with each device. I'm familiar with I2C, SPI and other protocols (primarily with msp430 devices using C with direct port management and access). The problem is the bewildering array of ESP32 devices. Suggestions for a dev board for initial development and testing??? I'm a NOOB in the wilderness when it comes to what I thought would be a "simple" search... TIA

@@Bob-Is-A-PotterNow Most ESP32 dev boards use the same chip (if you do not select an -C3 or -S2/3 version). The form factor and other components (like battery management) are different (none offers LiFePo4). You should find a video with an overview of some boards on this channel. Maybe you will even find a board with an LCD on it that suits your needs.

@@AndreasSpiess Thank you for the suggestions. In fact, I followed your advice before you left it! Found some very good information, as usual.😁

Glad you think so!

It heavily depends on the voltage levels and the Vgs voltage of the FET. Buit you can try. If it works, it is ok.

Thank you @@AndreasSpiess. I built it with just a p-channel mosfet, and tried (Arduino Uno, with NDP6020P or IRF4905PBF), it did not work. With the new circuit you showed in this video it did. Thank you!

:-)

Lead acid is very good if size/weight does not matter. They also withstand harsh environmental conditions.

@@AndreasSpiess Indeed, and even below freezing point they still are able to charge/uncharge quite well.

I do not know. Most coin cell batteries I know are very low current.

LIR2450~120mAh, Can last for a couple of hours.

For small currents some negative Temperatures is no big Problem for many Battery types.The Impedance rises, but the Voltage is still the same. LiFePo4 Batteries don't like to be charged at temperatures near or below 0° C - you have to reduce the Charging current significantly. In outdoor applications I placed the Battery in the mounting post below the ground, to keep it warm. For the Electronics You might use some kind of conformal coating to protect it from moisture.

Thank you!

You are welcome! The normal schedule started today...

I do not know the ESP32 cam in particular. But they are most probably 3.3-volt designs with an LDO to reduce the 5 volts as most development boards. So it should be possible to power them with 3.3 volts (as showed in this video). If you want to power them with 5 volts then a power bank is probably the easiest way. I also did a video about "poor man's" UPC which also could be used. Pay attention to power banks: Often you can only charge or discharge them. Then they are not useable for continuous operation.

@@AndreasSpiess The ESP32-Cam might amuse you because they can support facial recognition on your cats to prevent them from coming through their pet doors with birds or mice in their mouths. While the ESP32 board in the ESP32-CAM is certainly 3 volt logic, the data sheets specify 5 volts (and sometimes 2 amps) to ensure there's enough juice to power the camera module. There's a 5 volt on board regulator to drop the voltage to logic level. Many, MANY thanks for your SUPERB videos! I have learned so much from you.

Sorry. I forgot the link. Now it should be there: drive.google.com/file/d/1oJCdEHmf03SkHnGSDLGGOvvTDBBSBPix/view?usp=sharing

With your numbers you can calculate the size of the battery. It is probably quite big. I think you would have to build an optimized board with lower sleep current or switch the board completely off as I showed in the video

@@AndreasSpiess isn't the ULP of esp32 in deep sleep mode consuming

Is good option? Or to shift some other chips

Your board does not only contain the ESP32. Maybe you watch my board comparison videos. Or you measure the current consumption of your board in deep sleep

You are right. But keep in mind that a lot of power banks switch the output off if you start charging them. And you do not get this information before you buy and try them.

The pins on these boards are marked (usually 3.3 or 5 volts)

I think that my 2 transistor solution is very similar to Dave’s proposal. We need the mechanical switch to give the signal that the mailbox lid is open and the GPIO to signal that the work is done…

Mine stops delivering power as soon as it charges. I even thought it is defective. So pay attention if you buy one.

If you use a properly designed setup and deep sleep you can get a few month life. But pay attention to ultrasonic sensors, You also have to switch them completely off during deep sleep. So you need a custom-designed diagram probably using an ESP32-WROOM module plus a FET to switch the sensor (use case 4). Use case 3 does not work for a long time because they are always on.

@Andreas Spiess Not quite sure what this is about...

My light sensors also sleep during night (from sunset do sunrise). But you need a clock or a WiFi connection for that.

I do not own such a board :-(

I do not think that you find a valid definition for that.

:-)

@@AndreasSpiess I'd like to see pictures from your trip. Are those coming?

No, I do not think so. Anyway, Tajikistan was cancelled due to Afghanistan :-(

:-)

By searching in the mouser or Digikey database for a transistor with similar values. I found one variant (NVD3055L170T4G) that is still on stock. But I did not compare its datasheet.

I do not know of Zigbee modules for DIJ. But maybe you can use the PCB of one of the devices you described. They should have an output pin you can use for your purpose.

I had it from Aliexpress (Xiaomi)

I never used an SD card in my projects. I always connect my ESPs to the Wi-Fi. So I am no help here :-(

Maybe I will have a look at it. But only for solar powered devices. Otherwise the caps become very big.

No, You do not need to connect them in your scenario. The 4V pin can be used if you do not want to use USB to power the board. And 3.3V is an output.

I made a video on how to work with Neopixels

Super caps are good for low power application. My awning wind protector uses such caps. Maybe they are also better for harsh weather conditions. I do not think they will blow up if you solar panel is small. They just might loose their capacity if overcharged.

This concept has to be proven. You get small bistable relays

I never looked at idle power. I usually use Baseus or Ugreen. But I have no "proof" that they are better.

You are right. I used the picture from the other video. It also works with 3.6 volts.

Gern geschehen! 73 de HB9BLA

I probably would add 2 supercaps in series and a Shottky diode from the battery to the super caps.

I plan a video about these batteries. You get now protectors as well as chargers for them.

Most of our solar powered garden lights work like that. They simply have an LDR and a transistor to switch the light on when there is no light anymore.

I am not an audio (noise) specialist. There are better sources for such technology, I think.

@@AndreasSpiess OK, thank you for the answer.

What chemistry does it use?

@@AndreasSpiess Lithium but you need a supercapacitor for rush current

AFAIK they sell these small ones in 2 versions. Becaus I know the issue I pay attention (and have a few of each version in my drawer). But solder bridges are also a good idea.

@@AndreasSpiess Yes there are both versions, but my experience is that it does not help studying the Aliex ad. On the positive side, I get a partial refund when the delivered differs from photos. ;-)

Absolutely. Lead Acid batteries are very robust and can be used in low temperatures.

The one mosfet version depends a lot on the Vgs voltage vs the battery voltage and you need a FET with a very low Vgs.

@@AndreasSpiess thanks a lot

I prepare a video on Enocean switches. They use Energy harvesting. It would probably work for the door because it is big. For the lid it would probably block the opening while generating enough energy.

It depends if you sleep it. I think you have to do your own tests with your setup. A typical ESP32 consumes around 100mA.

A few other viewers commented also on those FRAMS. I never used them. So far I had no use case.

I suppose depends on the area - in some places disposable batteries are easier to recycle than others. Anywhere that you can recycle one you can probably recycle the other.

I propose primary batteries only for applications where they live for a year or longer. So I do not see big problems compared to all other waste we produce. For the other scenarios I propose rechargeable batteries.

Yes.

I never ordered Helium Hotspots

@@AndreasSpiess Then i misunderstood another video. Apologies.

@@chioz Andreas was sarcastic in that video. Helium seems to be a scam. Watch that video again.

@@eugy2008 oh, i didnt get that. got a few on the way anyway. I think If poeple get roi pretty fast, it should not matter if is a scam as long as it works. And looking how the neighbours are earning I think it ok. Looking forward to adding sensors to the helium network myself by the way. I love making things works, so when i some day have the time, i hope andreas videos is avalable for me to make more serious use of it. But I seriously dont understand why some say it is a scam...

This is a complex project with many aspects. So I can not give an answer. There are many problems to be solved. But you have a list and you can start one after the other ;-)

You are welcome!

Bandpass filters only help if you have a strong transmitter on a different frequency close to your hotspot.

FANUC has used this technology to replace battery backed SRAM in their CNC and robot controllers.

I did not know this technology. It is probably a good solution for special cases. Most of my use cases do not run so long.

@@AndreasSpiess They are pin interchangeable with EEPROM, so painless, and fast.

The HT7333 should be ok for an ESP32. Always include a 10uF capacitor across 3.3 and GND of the ESP.

@@AndreasSpiess Thank you

Maybe you consult the diagram of your board to understand what the LED is used for. There are many different boards around.

@@AndreasSpiess I found out its a problem with the current, low batteries. I don't know what is the DC-DC doing then...

I never worked with the ME6211 and the board with one of the lowest deep sleep current in my test used an HT7333… Maybe somebody else has more information?

For HT7333 the max. quiescent current (the one you have even without a load - the one you care about in the deep sleep) is 7 uA. For ME6211 it's 60 uA (looking at the datasheet). (other sources say it's 4 uA vs 40 uA). Still it's 10 times more current (energy) drawn by the LDO during the sleep time - something that makes HT7333 vs ME6211 choice rather obvious :). For example the ESP32 processor lowest deep sleep current is 10 uA. It doesn't take the other things (like the crystal) into account - but still for my board the HT7333 + ESP32 (WROOM32D module) when they sleep, together they consume around 50 uA - still lower than the ME6211 alone :). Doubling that with ME6211 would make the device last 2x shorter on the battery..

While looking at specs, HT7333 may not provide sufficient peak current (250 mA max vs 500 mA min required for ESP32-S2). Same check for ME6211 gives 500 mA max that sounds good. Not sure what a block consumes so much power inside ESP32-S2, maybe Wi-Fi (~310 mA peak) plus something else? In no RF mode chip takes mere 19 mA max, so HT7333 fits here well. Do you know other LDO's for 500 mA?

@@NikolaiVarankine Sorry for late reply. I won’t touch any LDO supplying less than 500mA when using WiFi etc. in a ‎project. May be bulk capacitor can used to cover spikes in current demands. Sometime ago ‎I saw a list of LDOs somewhere. I haven’t verified all the data. But it seems a good spot to begin ‎when choosing LDO. Here is that list. ‎ LDOs (Low power dropout regulators)‎ MAX1724:‎ Range voltage: 0.91 - 5.5 V‎ Max current out: 150mA Quiescent current: 1.5 uA Drop out voltage: MCP1700:‎ Range voltage: 6 V Max Max current out: 250 mA Quiescent current: 1.6 uA Drop out voltage: 178 mV Ht7333:‎ Range voltage: 12 v Max current out: 250 mA Quiescent current: 4 uA Drop out voltage: 170 mV HT7833:‎ Range voltage: 8 v Max Max current out: 500 mA Quiescent current: 4 uA Drop out voltage: 360 - 500 mV‎ MCP1825:‎ Range voltage: 6 v Max Max current out: 500 mA Quiescent current: 120 - 220 uA‎ Drop out voltage: 210 - 350 mV‎ XC6203(XC6203E33):‎ Range voltage: 8 v Max Max current out: 400 mA Quiescent current: 8 uA Drop out voltage: 300 mV ISL91107IR:‎ Range voltage: 1.8 V to 5.5 V Max current out: 2A Quiescent current: 45 uA Drop out voltage: Buck-Boost 96% efficiency TPS73633:‎ Range voltage: 5.5 V Max current out: 400 mA Quiescent current: 10 mA???‎ Drop out voltage: 75 - 200 mV‎ AP2112:‎ Range voltage: 6 v Max Max current out: 600 mA Quiescent current: 55 uA Drop out voltage: 250 mV RT9013:‎ Range voltage: 5.5 v Max Max current out: 500 mA Quiescent current: 25 uA Drop out voltage: 250 mV AAT1217:‎ Range voltage: 6 V Max current out: 600 mA Quiescent current: 300 - 500 uA‎ Drop out voltage: stepup 93% efficiency TLV73333:‎ Range voltage: 5.5 v Max Max current out: 300 mA Quiescent current: 34 uA Drop out voltage: 150 mV LM2936:‎ Range voltage: 5.5 V to 40 V‎ Max current out: 250 mA Quiescent current: 20 uA Drop out voltage: 400 mV TC1262:‎ Range voltage: 6 V Max current out: 500 mA Quiescent current: 130 uA Drop out voltage: 650 mV SPX3819:‎ Range voltage: 16 V Max Max current out: 500 mA Quiescent current: 8 uA Drop out voltage: 550 mV AMS1117:‎ Range voltage: 12 v Max Max current out: 1 A Quiescent current: 5 mA Drop out voltage: 1.3 V Hope its helpful.

@@zenzeni77 Thank you very much!

You do not need a regulator. But its current might not be sufficient for and ESP32.

@@AndreasSpiess Thank you for the answer! I saw that the esp board can consume little power in deep sleep, can you tell me why do I need more than 1,2 A? Or I could use a LS14500 with 2,6 Ah.

Maybe you mixed A an Ah. According the datasheet, the LS14250 only should be used at 35mA continuously.

Very good to know. Thanks!

I use small buck converter modules (to 5V) for that purpose.

@@AndreasSpiess I'm amazed you saw this! I'm having a good catch up on the videos now. Thanks for all the advice :)

You get small buck converters for that voltage range. And do not forget the fuse ;-)

Thank you❤️

Most of us use Chinese boards with either ESP32 or ESP8266 chips because they offer WiFi and the ESP32 Bluetooth. And a Raspberry as a server. Then the price is not too high. You find many videos on this channel where I compare the different boards. I would always start with the needs in mind. There is no "one size fits all" board

Usually we add a 1000uF capacitor right across VCC and GND of the ESP modules. You find more info in my deep-sleep videos.

I thought I had this solution in my video? One or two batteries in parallel do not matter for the concept.

These are probably special cases and ok, if they fit.