Yet another DYI Plato scale

[mper]

Yes, its the same pins. 4k7 as pullup as normal! I have not updated the schema yet.

 

[Lalo_uy]

Is the DS18B20 connected the same way:
GND ---> GND
VCC ---> 3V3
DQ ---> D7
And a 4k7 between DQ and VCC "as usual" ?

4k7 is “usual” on 5v vcc. On 3v you are better off with 3k3.
Lower pullup get better noise inmunity. I go as low as 820 ohms on long lines.

 

[mper]

4k7 is “usual” on 5v vcc. On 3v you are better off with 3k3.
Lower pullup get better noise inmunity. I go as low as 820 ohms on long lines.

Thanks, will try that instead

 

[beren]

Nice to find this thread. I has been experimentig with hx711 and load cells to weight the fermenter.
I want to find the delta as co2 exit to calculate the amount of alcohol and then the Plato.
As you mention time drift make it almost impossible.

Is evaporation not large enough to make a difference?

 

[Lalo_uy]

After some chemistry calculations, for every 40g of alcohol 44g of co2 are produced. Some of it remains in the liquid and in head space. But the co2 that goes out in the bubbles leave the system, the weight goes down.

 

[mper]

After some chemistry calculations, for every 40g of alcohol 44g of co2 are produced. Some of it remains in the liquid and in head space. But the co2 that goes out in the bubbles leave the system, the weight goes down.

So if you have a 23 liter batch (make that 23 kg for easy math) and the alcohol content is 5% that would mean that the alcohol would weigh 23*0,05=1,15kg and the co2 weight would be 1,265kg. Would the weight then be reduced by 1.265 kg or the difference between 1,15 and 1,265 (165 grams) ?

 

[Lalo_uy]

So if you have a 23 liter batch (make that 23 kg for easy math) and the alcohol content is 5% that would mean that the alcohol would weigh 23*0,05=1,15kg and the co2 weight would be 1,265kg. Would the weight then be reduced by 1.265 kg or the difference between 1,15 and 1,265 (165 grams) ?

1.265g - the co2 inside the fermenter. You know the exact weight cos you know the OD.

 

[mper]

1.265g - the co2 inside the fermenter. You know the exact weight cos you know the OD.

Well this might be worth testing in practice. I will build another scale base and put that under my fermenter to collect some data.

 

[mper]

I have been running Kegmon v0.6.0beta1 with ESP32-s2 for a few days now. Stable and no big issues.

When I first built the unit with D1 mini, I connected VDD on DHT22 to 3V3 according to the schematic at that time.
Yesterday, I changed DHT22's VDD connection to JP1.5/D6 as in the latest schematic.
ESP32-s2 did not recognize any temp sensor unless I flashed firmware via Web interface again. Then it worked for some time before temp sensor was gone again (Web interface/ MQTT).
Today, I connected VDD back to 3V3. All ok.

I wonder if the voltage level from ESP32-s2 I/O's is on the edge to be too low for the DHT22 (Rated 3.3 - 6V). Sorry, forgot to measure.
DHT22 current (1-1.5mA) should be ok.
Any voltage differences on the I/O ports for D1 mini vs ESP32-s2 maybe?

Is likely that there is not enough power from a GPIO pin towards the DHT22, I modified my build with an transistor to ensure that there is enough power and I steer the transistor with the GPIO pin.

I added an CAT6 2m cable and there was no drop in voltage over that distance so its probably a power issue (Amp) and the latest beta worked with both an esp8266 and esp32s2

I have asked a friend of mine to make a PCB and look over the schema. So we will see what he comes up with, he is much better at the electronics side than me.

 

[mper]

Just published a new version.

https://github.com/mp-se/kegmon/releases/tag/v0.6.0

 

[DaveS]

@mper Thanks for sharing this project,this stable keg scale is brilliant.
I suppose to substitute an I2C 20x4 LCD for the 2 x OLED displays would require a lot of code changes ?
Possibly 2 lines per keg showing numeric value and possibly a bar graph of the remaining volume.
All other information could still be viewed on the web interface or pushed via MQTT.
Would you consider this option ?
Cheers

 

[mper]

I suppose to substitute an I2C 20x4 LCD for the 2 x OLED displays would require a lot of code changes ?
Possibly 2 lines per keg showing numeric value and possibly a bar graph of the remaining volume.
All other information could still be viewed on the web interface or pushed via MQTT.
Would you consider this option ?
Cheers

Sure, give me a link to the display you consider and i can see whats possible.

 

[DaveS]

https://www.robotics.org.za/LCD-2004-5V-WB-I2C
These LCD's work well with the I2C backpack.

The LCD needs 5v to operate properly and the ESP boards IO's are not 5v tolerant.

I lift the 2 x 4k7 pullup resistors for SCL and SDA on the backpack,disconnecting them from the 5v supply and connect to the 3.3v supply instead,this drops the SCL and SDA voltage levels to 3.3v which is suitable for the ESP boards IO's and no level shifter is needed.

I can post a picture of the 2 resistors that need to be unsoldered,if needed.

This is very fiddly and a level shifter is much easier to wire up and no component modification is needed.

Would be great if you could look at this.

Cheers

 

[mper]

https://www.robotics.org.za/LCD-2004-5V-WB-I2C
These LCD's work well with the I2C backpack.

The LCD needs 5v to operate properly and the ESP boards IO's are not 5v tolerant.

I lift the 2 x 4k7 pullup resistors for SCL and SDA on the backpack,disconnecting them from the 5v supply and connect to the 3.3v supply instead,this drops the SCL and SDA voltage levels to 3.3v which is suitable for the ESP boards IO's and no level shifter is needed.

I can post a picture of the 2 resistors that need to be unsoldered,if needed.

This is very fiddly and a level shifter is much easier to wire up and no component modification is needed.

Would be great if you could look at this.

Cheers

Would not be to hard, I have used a similar lcd in another project. There are 3.3V versions of this display which would be much easier than having both 3.3V and 5V in the same build. You can also change the i2c address so using 2 displays will be possible.

 

[mper]

@mper Thanks for sharing this project,this stable keg scale is brilliant.
I suppose to substitute an I2C 20x4 LCD for the 2 x OLED displays would require a lot of code changes ?
Possibly 2 lines per keg showing numeric value and possibly a bar graph of the remaining volume.
All other information could still be viewed on the web interface or pushed via MQTT.
Would you consider this option ?
Cheers

Just for clarification did you want to replace the 2 oled with one LCD ? You can chance address for most of the LCD i2c controllers so I can add support for 2 LCD displays, one per keg. This would allow for more information to be shown and use the layout from the OLED as well. I can add both options as well.

 

[DaveS]

Just for clarification did you want to replace the 2 oled with one LCD ? You can chance address for most of the LCD i2c controllers so I can add support for 2 LCD displays, one per keg. This would allow for more information to be shown and use the layout from the OLED as well. I can add both options as well.

Your idea of having 2 LCD displays sounds good.
The option to use OLED or LCD displays would be brilliant.
Please see what you can do when you have a chance,
Thanks

 

[mper]

Your idea of having 2 LCD displays sounds good.
The option to use OLED or LCD displays would be brilliant.
Please see what you can do when you have a chance,
Thanks

Im still working on it but you can try the latest build in the dev branch. It supports the lcd driver. You need to change display type in the web config page and reboot for it to work.

 

[DaveS]

@mper Thanks for heads up,I have the ESP8266 binary flashed and running on a nodeMCU dev board,will play with it further.

Have flashed the ESP32s2 binary to my node32s board,I do not have an S2 version dev board, but the AP failed to come up on reboot.
Assuming this is because the binary is built for the S2 and not the S version of the ESP32 ?
Would like to confirm this is why the AP is not starting up and not me doing something stupid.
Cheers

 

[mper]

@mper Thanks for heads up,I have the ESP8266 binary flashed and running on a nodeMCU dev board,will play with it further.

Have flashed the ESP32s2 binary to my node32s board,I do not have an S2 version dev board, but the AP failed to come up on reboot.
Assuming this is because the binary is built for the S2 and not the S version of the ESP32 ?
Would like to confirm this is why the AP is not starting up and not me doing something stupid.
Cheers

S2 is a different board and processor so it will not work.

 

[DaveS]

@mper Sorry to be a pita but my LCD backpacks I2C addresses are in a different range to the OLED displays.
They are reporting addresses of 0x21 and 0x25 would you mind compiling a binary for the ESP8266 using these addresses ?
Just getting blocks displaying on the LCD

 

[mper]

@mper Sorry to be a pita but my LCD backpacks I2C addresses are in a different range to the OLED displays.
They are reporting addresses of 0x21 and 0x25 would you mind compiling a binary for the ESP8266 using these addresses ?
Just getting blocks displaying on the LCD

The adresses should be 0x27 (default) and 0x26 for the lcds. These are the default one on the ones i have. Can you show a picture of your driver board?

 

[DaveS]

I changed LCD addresses to 0x26 and 0x27 and is now working.
Thanks

 

[mper]

I changed LCD addresses to 0x26 and 0x27 and is now working.
Thanks

Great, feel free to give me some input one what data you want displayed on them. I just put up some values as a start.

 

[DaveS]

@mper The LCD displays look good as you have them,showing all the information needed.
Only change i can think of would be if the displays showed Tap 1 and Tap 2 respectively on the LCD top lines.
Cheers

 

[mper]

@mper The LCD displays look good as you have them,showing all the information needed.
Only change i can think of would be if the displays showed Tap 1 and Tap 2 respectively on the LCD top lines.
Cheers

I can add a 1: and 2: before the beer names, there is not that many characters per line...

 

[DaveS]

Good point regarding the number of characters.
Please add the 1: and 2: before the beer names

 

[mper]

@mper The LCD displays look good as you have them,showing all the information needed.
Only change i can think of would be if the displays showed Tap 1 and Tap 2 respectively on the LCD top lines.
Cheers

You can try the new build in the dev branch, has the requested update

 

[DaveS]

Thank you,this is brilliant.
The bargraphs look really good,btw !

 

[DaveS]

What percentage infill for the 3d printed bases would you think is adequate to carry the heavy weight of a full keg being put on top of the relatively small surface area of the load cells ?
Do not want the printed bases to crack over time.

 

[LBussy]

When I had a similar need, I printed the area immediately over the load cells and about an inch around at 90%. That worked fine, so there's one data point.

 

[mper]

What percentage infill for the 3d printed bases would you think is adequate to carry the heavy weight of a full keg being put on top of the relatively small surface area of the load cells ?
Do not want the printed bases to crack over time.

I used 40% infill and increased the wall thickness to 6. Has worked well for my kegs

 

[DaveS]

@mper Please give me the addresses to flash the firmware and partitions files to ?

I have got hold of an ESP32S2 mini board.

 

[mper]

The easy way is to use brewflasher.com

 

[DaveS]

The easy way is to use brewflasher.com

I need to flash the binary from the dev branch for the 20 x 4 LCD's .
Can this binary be flashed from brewflasher ?
Was looking to use ESP flash downloader tool where multiple binaries can be flashed to different addresses.

 

[larsh]

I need to flash the binary from the dev branch for the 20 x 4 LCD's .
Can this binary be flashed from brewflasher ?
Was looking to use ESP flash downloader tool where multiple binaries can be flashed to different addresses.

I found it easiest to use brewflasher for the initial setup with whichever latest firmware version is there. Then, after kegmon is set up, use kegmon's web interface to upload/install the devbranch binary.

 

[DaveS]

That does make good sense.
Thanks Larsh

 

[mper]

https://github.com/mp-se/kegmon/releases/tag/v0.7.0
I have added the version with LCD support as a release and its now available on brewflasher.

 

[mper]

I've been playing around with a new feature for kegmon, dashboards. The memory on the device is a little limiting so i've been experimenting to deploy this as a web app (pwa) which can be installed on most devices as an app. Below is an example if the test i've done (this dashboard is actually available on the device as well) but this gives me more options for doing a graphics view.

I did this since I wanted to display the dashboard on a larger screen (i have a small 8" tablet) that I will use.

So is this a feature that could be useful? Would love some ideas for dashboards. I'm not a graphic designer so any help is appreciated.

Due to security restrictions on the browsers the app needs to be installed via http so I cant publish this on my web page.... So the option was to use docker instead. I've published the test on docker hub here; Docker

The only setting needed is the ip-address for the kegmon installation, and you need to use v.7 or later.

 

[DaveS]

This is definitely an upgrade to the already brilliant kegmon.
I am no graphic designer either but are sure some other chaps will have good ideas.

I am battling to flash the ESP32-S2 mini board using brewflasher on Win10,have had no issues flashing ESP8266 boards using brewflasher.
The log reports that flash was erased and flashed with the selected firmware except after flashing completes there is a message that pytool raised an error and flash has failed.
I have tried this with slower baud rate with the same result.
Avira and all windows AV and firewalls are disabled.
The captive portal opens and scans my wifi network and tries to connect but no IP address shows in the DHCP lease table.
Does anyone have a solution ?

 

[mper]

This is definitely an upgrade to the already brilliant kegmon.
I am no graphic designer either but are sure some other chaps will have good ideas.

I am battling to flash the ESP32-S2 mini board using brewflasher on Win10,have had no issues flashing ESP8266 boards using brewflasher.
The log reports that flash was erased and flashed with the selected firmware except after flashing completes there is a message that pytool raised an error and flash has failed.
I have tried this with slower baud rate with the same result.
Avira and all windows AV and firewalls are disabled.
The captive portal opens and scans my wifi network and tries to connect but no IP address shows in the DHCP lease table.
Does anyone have a solution ?

What is the exact error message? What happends if you try to flash again without full erase? Can you try another version of kegmon or gravitymon? Then try the file upload flash.