Nice to see that at 10:15 all the meters gave near enough the same readings, unlike near the start when you had that other board attached, was good to see you did away with it. Nice build.
You can make Arduino MCU enter in Power Down and wake it up every 8 seconds using Watchdog Timer. Maybe a button to turn on the display for a couple of seconds or use a Nokia LCD if it needs to be on all the time. With this strategy, I bet you can run for more than a month. I have doing this way in my DIY smartwatch.
I should join, my entire garage is full of this and I can't even see my desk anymore. Speaking of projects, you should build a 3D printer. They are arduino based :)
Great little project a another great step would be a wireless connection, then internet to make this available via mobile phone to monitor while away. Keep up the projects, they will finally hugely increase your views, Thanks.
Nicely done. Now how would I place ESP8266 CH340G WIFI and sensors (with or without oled) around my home and send to a central single screen or multiple oled's. AcuRite/ like?
Can you list all the part numbers and the item used to hold the 9v battery etc... My only wish is this had Wifi so I can connect to my wifi to submit data to a database.
There are several videos explaining the power consumption and a lot can be done just with switching off analogue/digital conversion pins(if not needed). Another thing is brownout but that might be better kept on with a battery usage.
So for a complete newby... Where should I go for the basics of programming these little things. I'd love to do this little project but if I can't figure this part out - it'll never work. hahaha
Based on the last video I was expecting you to piggyback the three sensors on the same I2C pins and display an average. Because what is better than 1 sensor ? Three of them obviously.
Any idea how long of a cable run you can use with i2C? I want to put a sensor in my attic, but the arduino and display would be several feet away in a living space.
Got myselt the same module; it takes about 2 to 8 mA depending on the displayed content. The Arduino takes the most current if not programmed with any sleep modes. Also found out that the white cover is supposed to be a filter, so it should remain on there.
I'm having an issue with my 140w solar and I wonder if someone here already have that My panel shows 20v open circuit but when goes to the grid tie it drops to 9volts I check the panel and looks all good, the bypass diodes are ok too. I really have no idea why it can't hold the voltage high under load
+David Buchanan it seems that doesn't matter is its full sun or overcast! I ran a test using a motorcycle lamp and from 20v it doped to 9volts at 4.5amp ! Should I try to buy new bypass diodes? I've been seeing 9volts for 2 weeks when plugged into the grid tie Maybe the diodes are holding voltage when under load
+David Buchanan they tell normal voltage I think they go 9>15>20 left to right ! I believe that's it if I remember right, I'll try to check again tomorrow and make a video
hi I've looked at your sketch I'm new to this ,..how do you get the info on how to use the library that you include ? this is a general library question thanks
Surprised you didn't attach the arduino to the battery box, then stick the battery box to the back of the display, would be a bit more robust. If you still want to remove the display for testing, you could use velcro
Swap out to a 3.3v pro-mini and you could easily fit a lithium battery in between the display and the board. Personally however I would have done away with the headers and used ribbon cable wire between the display and the pro-mini to get it even thinner.
Nice project, love the pro mini's as well. Just a thought... ;o) Add a feature to your new hygrometer - calculate the dew point and display it. The calculation is not trivial, but doable. Now you know, how cold your walls can get before they potentially grow mold. Next step: add a second temperature sensor and a LED. Tape the temperature sensor to the coldest wall and let the LED illuminate in case the wall temperature is lower than the dew point. Now... the LED will show you when it's time to open the window to lower humidity. Next step: construct something with a motor to open and close the window... ;o))) You see, home automation could be a never ending hobby as well.
Dunkelheit667 next step have an alarm for when the window opens without having the motor open it. Next step give the device a SIM card and allow it to call the police when needed
Hehe, usefull as well! But don't mix up the routine which should call the police. It's 'window_opened_not_be_myself' and not 'open_window_dew_point_reached'. ;o)
Measure the current draw of the display when fully lit and completely dark. I think the MCU speed is the least of your worries with that display continuously on. Instead of slowing down the MCU implement some sleep mode. That's a way more efficient way to reduce power consumption. By slowing the clock you might run into difficulties with the sensor or display. Check what the minimum I2C clock speed is for them or if they have some other kind of time dependent behaviour. Check if the libraries you use need timer0 (that's the one that counts the "time"). If not disable it, because it wakes up the micro every millisecond if you try to send it to sleep.
The new OLED might look blue if the screen protection film is tinted perhaps? edit: Ahh nvm I see you took it off towards the end, although it looks like there's still a blue filter adhered to the screen, so it might still be a white OLED beneath.
An interesting idea i just saw in other videos: try to modify a 9v battery to fit in a small lipo battery, a tp4056 and an adjustable step-up, something like the MT3608... that way, you will have a rechargable 9v battery, so you can just leave it plugged-in in any 5v usb port, or maby to your solar wiring, stepping down the voltage a bit... and then take it out to wherever you want!
That's a nice project. But the values change so quickly. You can take ten measurements and then average them before displaying to stabilise it. You should also center the values on screen, it shouln't be hard as they are fixed width.
Hi Julian, have you considered designing and having your own PCB's fabricated with all the Arduino components on a single board in order to further miniaturise your (Arduino or other) based projects? A few tutorials would be great to see! Thanks for sharing and keep up the good work.
Perhaps add a light sensor so it doesn't run at night? an e-ink display would be good for low power operation and only update the display when the humidity changes by +- 1%?
haha.. there isn't much to that code at all. I expected it to do more. The hardware does more than I thought. It's just a matter of taking readings every 50 ms and using a built-in print command with some built-in fonts and telling it which pixel on the display to start at for the print. Cool... this makes me want to play with arduinos and graphical LCD displays.
Maico probably not the board but you can get a batch of the chips. The board is just a breakout with USB anyway. you can program the chip with i2c I believe.
Hrnek Bezucha oops I missed that you were talking about a attiny85-on-a-BOARD. I was meaning the bare attiny85's price.I'll probably need to order a couple of 1000s to get a lower price and I only need a few. I already ordered 5 for 99 cents each and thats not a bad price I guess. I just thought maybe you knew an even cheaper deal :)
I wouldn't mess with the fuses or CPU speed, too much bother in my experience. You can instead put the Arduino into one of its power down sleep states, and only have it wake up every second to make a reading and update the display. Since that update only takes a few milliseconds, I bet, it should make the display itself the largest energy consumer.
Use an LCD screen without backlight, desolder power indicator LED from Arduino Pro Mini and use low power modes of ATMEGA328. You can make it work for months on a lithium coin cell.
Yeah, no reason to swap the OLED since it don't have any backlight. The light comes from each pixel directly, which pretty much gives this a much lower power consumption with regards to its visual quality. Sure a small 7-segment LCD with no backlight would possibly draw less, but that's not even in the same ballpark.
Engin Yeğnidemir Well that depends highly on which models you're using, but in general no, a similar LCD won't be as efficient as an OLED, but as I said, if you sacrifice quality, like with an 7-segment LCD, then yes, you would lower the power consumption since you're getting rid of backlight and resolution.
Hi Julian. thats a nice project. I have two ideas. Add an on/of switch somewhere and use an angled header in between the hygrometer board and Oled screen so it is bend backwards (facing upwards). Also maybe use a tiny lipo battery and a tiny boost board (but where to hide that huh).
Julian, about the battery life problem. Kevin Darah did a great series on his channel about low-power Arduino projects, I highly suggest you to check it out. You could put the whole thing to sleep when it's not being used and wake up on a button press, this way the battery will last for a extremely long time.
Shame the arduino code for this has gone now. Water to try it out.
8 ปีที่แล้ว
You probably lost some accuracy with that design: Those xyz21 humi-temp sensors are actually measuring the temperature of the PCB below them, so you want to keep it as small as possible, and you pretty much merged it with that display.
If you would like to make a video about digispark 85 that sends HUM and Temp with RF433, than i can send you a script about them. One digispark reads dht11 signal and sends it with rf433 and the other digispark receives the signal and displays it to oled display. Im using a digispark that has a usb connection on board so i can plug them in my powerbank. If everything is connected and soldered, it looks very small in size and looks good. Note: One digisparks needs smaller bootloader. It can be done with original bootloader, but then there would be only displayed values and no text.
Isn't OLED a lot more power hungry than LCD. Slowing down MCU won't be enough. Of course you can also update once ever 2-3 seconds and sleep between updates, so the MCU clock will be less of a problem. Even though LCD would last longer, OLED is much cooler :). Also character LCD displays burn more power than 7 segment LCDs, but I haven't found 7 segment LCD display with a driver. driving it from a PIC is an option, but wiring would be nightmare.
Maybe less than TFT. You still need to power at least 10-20% of the pixels. Character LCD draws 1-1.5 mA with no backlight. Nokia display - 0.4mA with no backlight. With 7 segment LCDs you can get lower than that. You won't power backlit devices from batteries anyway. Here is some article: www.bigmessowires.com/2011/06/07/low-power-lcd-smackdown/
Running it off 9V means you're dissipating considerable power in the 3.3V regulator on the Nano board. This will result in artificially elevated temperatures. The battery power is mostly going to heat up the regulator. A 18650 would be far more efficient, have higher capacity, and run longer.
Here a project idea!?..a sorta combination of a few of your projects - obtain multiple sensors, couple them with RF transmitters and fit them in in/to USB mains mains adapters and plug them in about the house....have each of them transmitting back to a master Arduino which could then display temp and humidity of each room on an LCD.
Hi Julian! You could try to do that project with the ESP8266 Microcontroller (maybe the esp-12) so that you can check various sensors via WiFi network. keep teaching us!
Good job with the project, nice thinking with stacking the boards. How about using one of those usb rechargeable 9v PP9 batteries you can then just give it a boost from one of your many power packs.
I've checked the data sheet. It can take 18 seconds for the sensing element to respond to changes in air humidity. There's no limit on how often you can read the temperature and humidity registers.
I notice now that this unit is much closer in reading to the 2 cheapo units, as I said on the previous video is this because you do not have the double level shifting and dual voltage regulators to the sensor.
I'm sceptical. The double regulator may result in a low voltage, but the Si7021 works down to 1.9 volts. The level shifters aren't going to alter the data sent over I2C - corrupted data would result in errors, not readings that are either too low or too high.
So the moral of the story is that the 2 dollar ebay units are the best solution. The fact that we built it ourselves is not really important especially when the project isn't really a challenge for us anyway.
github.com/rocketscream/Low-Power - use this for longer battery life. however, the display will still consume too much to run months from one battery. may be you need to switch the display off after some time (power it from one of digital pins controlled from code) and have a button to wake it up and of course you need to downclock the atmega and don't use onboard linear voltage regulator (I suggest to solder it off to avoid current leak) and power the whole device directly from 3V battery pack (2xAA or 2xAAA)
Nice to see that at 10:15 all the meters gave near enough the same readings, unlike near the start when you had that other board attached, was good to see you did away with it. Nice build.
You can make Arduino MCU enter in Power Down and wake it up every 8 seconds using Watchdog Timer. Maybe a button to turn on the display for a couple of seconds or use a Nokia LCD if it needs to be on all the time. With this strategy, I bet you can run for more than a month. I have doing this way in my DIY smartwatch.
This maybe the first project I've ever seen you finish. I think I started some time during the bike battery videos
Yes, I'm a fully paid up member of the "start projects but never finish them" club :)
teckmoan i would have thought :-)
I should join, my entire garage is full of this and I can't even see my desk anymore.
Speaking of projects, you should build a 3D printer. They are arduino based :)
You say anymore but you mean you've never been able to see your desk.
+Julian Ilett what is the cost of that membership ? I'd like to join :D
Hi Julian,
Great little project, glad to see you doing an Arduino project.
Regards,
Stan
Great little project a another great step would be a wireless connection, then internet to make this available via mobile phone to monitor while away.
Keep up the projects, they will finally hugely increase your views, Thanks.
When you get back to this project, try using an ATTINY85, or perhaps one of the mini ESP8266's for a processor, thus reducing your size even more.
Julian where is the video that you reviewed humidity sensors for Arduino? Having problem finding it. Best regards !
Nicely done. Now how would I place ESP8266 CH340G WIFI and sensors (with or without oled) around my home and send to a central single screen or multiple oled's. AcuRite/ like?
can't wait to see what you are going to do with the barometer... might go well in my model aircraft...
Can you list all the part numbers and the item used to hold the 9v battery etc...
My only wish is this had Wifi so I can connect to my wifi to submit data to a database.
Can the humidity sensor be remote mounted with unshielded ribbon cable? If so how far can one go before data is corrupted?
That mystery breadboard project was from your XOR Gate tutorial video.
you should try wemos D1 mini or NodeMCU, they are pretty cheap with a bigger memory and wifi connectivity
There are several videos explaining the power consumption and a lot can be done just with switching off analogue/digital conversion pins(if not needed). Another thing is brownout but that might be better kept on with a battery usage.
What about sticking a lipo between the lcd and the arduino?
have you checked out the OLEDuino boards on Hayri 's channel?
How long will this system work with that battery? assuming continuous work. thanks.
+Julian Ilett well done! But have u though of minimizing or shrinking it to attiny85? ;)
So for a complete newby... Where should I go for the basics of programming these little things. I'd love to do this little project but if I can't figure this part out - it'll never work. hahaha
Hi can you make a humidity and temperature sensor with a relay to switch on fan or heater (60W) light bulb?
what about using atryny85 for cpu it will be cheaper
Hi, Julian! May be you can build this thing with PIC (for your PIC tutorial series)? I assume tiny PIC use less energy than ATmega microcontroller?
I'd be very interested to see how you minimise power from this great first optimisation in size. can you make use of hibernation functions?
Nice little project Julian. Good job!
Simple coding as well!!
Julian "It's morning somewhere" Ilett :D
Morning fella xD
could you go for low power mode and use a timer interrupt to save power?
I enjoy the little comedy bits. Please continue with those.
Exactly the video which I was searching for hours thanks really... Keep in the good work...👍👍👍👍👍👍👍
nice work - though the link to code does not work - "missing access token" ?
Based on the last video I was expecting you to piggyback the three sensors on the same I2C pins and display an average. Because what is better than 1 sensor ? Three of them obviously.
Any idea how long of a cable run you can use with i2C? I want to put a sensor in my attic, but the arduino and display would be several feet away in a living space.
About a meter. Almost certainly not long enough.
The display will take a good chunk of battery. Is the white cover part of the sensor arrangement, or is it really just a transport protective cover?
Got myselt the same module; it takes about 2 to 8 mA depending on the displayed content. The Arduino takes the most current if not programmed with any sleep modes. Also found out that the white cover is supposed to be a filter, so it should remain on there.
Very nice project. Where do you get the Robot kit
I'm having an issue with my 140w solar and I wonder if someone here already have that
My panel shows 20v open circuit but when goes to the grid tie it drops to 9volts
I check the panel and looks all good, the bypass diodes are ok too.
I really have no idea why it can't hold the voltage high under load
TBH that sounds normal. What's the load, and how sunny is it?
+David Buchanan it seems that doesn't matter is its full sun or overcast! I ran a test using a motorcycle lamp and from 20v it doped to 9volts at 4.5amp ! Should I try to buy new bypass diodes? I've been seeing 9volts for 2 weeks when plugged into the grid tie
Maybe the diodes are holding voltage when under load
What's the voltage across the diode?
+David Buchanan they tell normal voltage I think they go 9>15>20 left to right ! I believe that's it if I remember right, I'll try to check again tomorrow and make a video
Julian, what OS do you use to program the Arduino? I wish to use an older Windows XP machine.
hi I've looked at your sketch I'm new to this ,..how do you get the info on how to use the library that you include ? this is a general library question thanks
Surprised you didn't attach the arduino to the battery box, then stick the battery box to the back of the display, would be a bit more robust.
If you still want to remove the display for testing, you could use velcro
I wish I had half your knowledge. Watch u all the time!
What is the tolerance of that tinny humidity sensor? How accurate is it for measuring % RH?
When he looked at the datasheet in the previous video, it was supposed to be 3%
I'm going to make one for my grow tent. Go along with grow lights I built.
Swap out to a 3.3v pro-mini and you could easily fit a lithium battery in between the display and the board. Personally however I would have done away with the headers and used ribbon cable wire between the display and the pro-mini to get it even thinner.
A little solar panel on top to boost the battery perhaps? Might give you an extra ten minutes run time.
Nice project, love the pro mini's as well. Just a thought... ;o) Add a feature to your new hygrometer - calculate the dew point and display it. The calculation is not trivial, but doable. Now you know, how cold your walls can get before they potentially grow mold. Next step: add a second temperature sensor and a LED. Tape the temperature sensor to the coldest wall and let the LED illuminate in case the wall temperature is lower than the dew point. Now... the LED will show you when it's time to open the window to lower humidity. Next step: construct something with a motor to open and close the window... ;o))) You see, home automation could be a never ending hobby as well.
Dunkelheit667 next step have an alarm for when the window opens without having the motor open it.
Next step give the device a SIM card and allow it to call the police when needed
Hehe, usefull as well! But don't mix up the routine which should call the police. It's 'window_opened_not_be_myself' and not 'open_window_dew_point_reached'. ;o)
what kind of overall power use would this project pull?
My guess is about 40mA
great job julian, the possibilities are endless :-)
Is it really 52% humidity there? Doesn't everything immediately turn to rust and get covered with mold?
It's bloody England, where there are only two kinds of weather: rainy and foggy.
Measure the current draw of the display when fully lit and completely dark. I think the MCU speed is the least of your worries with that display continuously on. Instead of slowing down the MCU implement some sleep mode. That's a way more efficient way to reduce power consumption. By slowing the clock you might run into difficulties with the sensor or display. Check what the minimum I2C clock speed is for them or if they have some other kind of time dependent behaviour.
Check if the libraries you use need timer0 (that's the one that counts the "time"). If not disable it, because it wakes up the micro every millisecond if you try to send it to sleep.
Anyone realized the length is 13:37?
The new OLED might look blue if the screen protection film is tinted perhaps?
edit: Ahh nvm I see you took it off towards the end, although it looks like there's still a blue filter adhered to the screen, so it might still be a white OLED beneath.
The oled is definitely blue, and the eBay listing says white - naughty eBay seller (secret-garden2015)
This is a single colour OLED, but you can get full colour OLEDs - th-cam.com/video/guNG9BhBmxM/w-d-xo.html
An interesting idea i just saw in other videos: try to modify a 9v battery to fit in a small lipo battery, a tp4056 and an adjustable step-up, something like the MT3608... that way, you will have a rechargable 9v battery, so you can just leave it plugged-in in any 5v usb port, or maby to your solar wiring, stepping down the voltage a bit... and then take it out to wherever you want!
are those temp sensors even accurate down to 0.01 degrees?
No, but he can't be bothered to use anything other than the basic print() command, which prints 2 decimal places.
Nicely done. Congratulations.
That's a nice project. But the values change so quickly. You can take ten measurements and then average them before displaying to stabilise it. You should also center the values on screen, it shouln't be hard as they are fixed width.
hmmm i also bread boarded one dht11 hygrometer, but i wanted to miniaturize it with 2x 7segments.
I'd recommend the smaller OLED. If you search eBay for 0.91" oled you'll see what I mean ;)
right !
Hi Julian, have you considered designing and having your own PCB's fabricated with all the Arduino components on a single board in order to further miniaturise your (Arduino or other) based projects? A few tutorials would be great to see! Thanks for sharing and keep up the good work.
Hi Julian, can you please respond the code for this as its a dead link now
good job, Julian. i like these MCU based videos.
If you could integrate a heating element and possibly cooling It would be great for my garage cigar humidor.:)
Hi Julian, Your probable aware of this but just in case, have you used any of the Low Power and Sleep Libraries?
I'll have a look at those - they could be very handy :)
Perhaps add a light sensor so it doesn't run at night? an e-ink display would be good for low power operation and only update the display when the humidity changes by +- 1%?
Here is a great video about sleep and pre-scaler: watch?v=iMC6eG24S9g ;-)
I'm keeping a close eye on e-ink displays - but there are very few available at the moment.
The Sharp LCD are almost as low power. Not cheap. But you might also check on the popular Nokia LCD module.
Julian, have you posted the code for this anywhere? and if not, could you?
0yeme0 hastebin.com/emugomosev.cpp
Moes
thanks
haha.. there isn't much to that code at all. I expected it to do more. The hardware does more than I thought. It's just a matter of taking readings every 50 ms and using a built-in print command with some built-in fonts and telling it which pixel on the display to start at for the print. Cool... this makes me want to play with arduinos and graphical LCD displays.
Yeah! It's easy :)
great work Julian
hi Julian, i love video and keep going like that !!
Ahh man, the link to the Arduino code no longer valid.
It's official. You must now end all segments with a small puppet show.
Great video as always, really entertaining!
also it might run on a ATtiny85 board that are available on eBay for next to nothing.
+Hrnek Bezucha I got mine for 99 dollar cents a piece. Have you seen them even cheaper ?
Maico probably not the board but you can get a batch of the chips. The board is just a breakout with USB anyway. you can program the chip with i2c I believe.
Hrnek Bezucha oops I missed that you were talking about a attiny85-on-a-BOARD. I was meaning the bare attiny85's price.I'll probably need to order a couple of 1000s to get a lower price and I only need a few. I already ordered 5 for 99 cents each and thats not a bad price I guess. I just thought maybe you knew an even cheaper deal :)
I wouldn't mess with the fuses or CPU speed, too much bother in my experience. You can instead put the Arduino into one of its power down sleep states, and only have it wake up every second to make a reading and update the display. Since that update only takes a few milliseconds, I bet, it should make the display itself the largest energy consumer.
Use an LCD screen without backlight, desolder power indicator LED from Arduino Pro Mini and use low power modes of ATMEGA328. You can make it work for months on a lithium coin cell.
Engin Yeğnidemir
this is OLED screen
Yeah, no reason to swap the OLED since it don't have any backlight. The light comes from each pixel directly, which pretty much gives this a much lower power consumption with regards to its visual quality. Sure a small 7-segment LCD with no backlight would possibly draw less, but that's not even in the same ballpark.
But an OLED draws way much power than an LCD.
Engin Yeğnidemir Well that depends highly on which models you're using, but in general no, a similar LCD won't be as efficient as an OLED, but as I said, if you sacrifice quality, like with an 7-segment LCD, then yes, you would lower the power consumption since you're getting rid of backlight and resolution.
Find the OLED with lowest power consuption possible. You can find an LCD that uses at least 10 times lower than that.
Hi Julian. thats a nice project. I have two ideas. Add an on/of switch somewhere and use an angled header in between the hygrometer board and Oled screen so it is bend backwards (facing upwards). Also maybe use a tiny lipo battery and a tiny boost board (but where to hide that huh).
Time to design a PCB to combine the AVR and the display using an ATtiny85.
Julian, you are a true "wizard'! Maybe it's time you explore making your own pcb's if you haven't already?
great video keep it coming.. very helpfull
Use Micro USB female ports. those gives 5v and easy to find and salvage.
Maybe someone could 3D print you the missing part?
Julian, about the battery life problem. Kevin Darah did a great series on his channel about low-power Arduino projects, I highly suggest you to check it out. You could put the whole thing to sleep when it's not being used and wake up on a button press, this way the battery will last for a extremely long time.
Hi Julian, great video. Take a look at the Talkie library by Peter Knight, and let your Arduino speak all the values.
Shame the arduino code for this has gone now. Water to try it out.
You probably lost some accuracy with that design: Those xyz21 humi-temp sensors are actually measuring the temperature of the PCB below them, so you want to keep it as small as possible, and you pretty much merged it with that display.
If you would like to make a video about digispark 85 that sends HUM and Temp with RF433, than i can send you a script about them. One digispark reads dht11 signal and sends it with rf433 and the other digispark receives the signal and displays it to oled display. Im using a digispark that has a usb connection on board so i can plug them in my powerbank. If everything is connected and soldered, it looks very small in size and looks good.
Note: One digisparks needs smaller bootloader. It can be done with original bootloader, but then there would be only displayed values and no text.
Isn't OLED a lot more power hungry than LCD. Slowing down MCU won't be enough. Of course you can also update once ever 2-3 seconds and sleep between updates, so the MCU clock will be less of a problem. Even though LCD would last longer, OLED is much cooler :).
Also character LCD displays burn more power than 7 segment LCDs, but I haven't found 7 segment LCD display with a driver. driving it from a PIC is an option, but wiring would be nightmare.
OLED are less power hungry because they can shut off individual pixels unlike LCD :)
Maybe less than TFT. You still need to power at least 10-20% of the pixels. Character LCD draws 1-1.5 mA with no backlight. Nokia display - 0.4mA with no backlight. With 7 segment LCDs you can get lower than that. You won't power backlit devices from batteries anyway. Here is some article: www.bigmessowires.com/2011/06/07/low-power-lcd-smackdown/
Running it off 9V means you're dissipating considerable power in the 3.3V regulator on the Nano board. This will result in artificially elevated temperatures.
The battery power is mostly going to heat up the regulator. A 18650 would be far more efficient, have higher capacity, and run longer.
True 9V isn't ideal - but this is a 5V Pro Mini, not 3.3V
Maybe consider checking how hot the regulator gets and if that affects your temperature readings.
Here a project idea!?..a sorta combination of a few of your projects - obtain multiple sensors, couple them with RF transmitters and fit them in in/to USB mains mains adapters and plug them in about the house....have each of them transmitting back to a master Arduino which could then display temp and humidity of each room on an LCD.
1337?
Hi Julian! You could try to do that project with the ESP8266 Microcontroller (maybe the esp-12) so that you can check various sensors via WiFi network.
keep teaching us!
Good job with the project, nice thinking with stacking the boards. How about using one of those usb rechargeable 9v PP9 batteries you can then just give it a boost from one of your many power packs.
There's a 9V lithium PP3 with microUSB charging port heading my way from China - that should triple the run time.
Always a step ahead :-)
You forgot again the "Response Time" for the sensor and it's 17s and not 1s
I've checked the data sheet. It can take 18 seconds for the sensing element to respond to changes in air humidity. There's no limit on how often you can read the temperature and humidity registers.
Very nice , Big J .
Why are your puppets from up North?
I think they've been watching too much TechMoan
Enjoyed this one...
Also put switch on it easy on switch or something as display does not need to be on 100% or even the arduino!
Wayne Johnson ldr ldr ldr!!!!
I notice now that this unit is much closer in reading to the 2 cheapo units, as I said on the previous video is this because you do not have the double level shifting and dual voltage regulators to the sensor.
I'm sceptical. The double regulator may result in a low voltage, but the Si7021 works down to 1.9 volts. The level shifters aren't going to alter the data sent over I2C - corrupted data would result in errors, not readings that are either too low or too high.
So the moral of the story is that the 2 dollar ebay units are the best solution. The fact that we built it ourselves is not really important especially when the project isn't really a challenge for us anyway.
Hi Julian. Thanks. You really should round up your displayed values. All those decimals are just wishful thinking.
github.com/rocketscream/Low-Power - use this for longer battery life. however, the display will still consume too much to run months from one battery. may be you need to switch the display off after some time (power it from one of digital pins controlled from code) and have a button to wake it up
and of course you need to downclock the atmega and don't use onboard linear voltage regulator (I suggest to solder it off to avoid current leak) and power the whole device directly from 3V battery pack (2xAA or 2xAAA)
these little things are cool, too bad nobody knows the actual use of the humidity for room temperature sensing.
If you need a 3d printed case for that, foc. Just send me some dimensions and I'll have it posted out to you. quick.
Yes !!! That is neat !!!
Remove the Arduino all together and just use an ESP module; cheap, low power, and can post to a website!
I love hygroneters
simple solution to the battery problem, wire it to a solar cell and a 80 mah battery.