Pressuremon, DIY pressure monitor for kegs

[ClaudiusB]

I've been browsing and wondered if these sensors would also be an option? Quite comprehensive info with the advert, has the added benefit of a display.

https://www.aliexpress.com/item/1005008761403544.html?spm=a2g0o.detail.pcDetailTopMoreOtherSeller.5.6905ZoWhZoWh1z&gps-id=pcDetailTopMoreOtherSeller&scm=1007.14452.396806.0&scm_id=1007.14452.396806.0&scm-url=1007.14452.396806.0&pvid=144f4353-c40a-4daf-b57e-d38bdbffa209&_t=gps-idcDetailTopMoreOtherSeller,scm-url:1007.14452.396806.0,pvid:144f4353-c40a-4daf-b57e-d38bdbffa209,tpp_buckets:668#2846#8109#1935&pdp_ext_f={"order":"32","eval":"1","sceneId":"30050"}&pdp_npi=4@dis!NZD!1.45!1.45!!!6.13!6.13!@2103244617508933126444476e663a!12000046560147677!rec!NZ!1963044316!X&utparam-url=scenecDetailTopMoreOtherSeller|query_from:&search_p4p_id=202506251615126904467071280536175276_4

I use a similar pressure sensor for one of my CO2 applications.
The one you linked only allows you to select the pressure range, omitting other important options such as output type and thread option.

 

[DuncB]

AHH when I read the view all section of the advert on a PC, it showed connection options and also output options, voltage, analogue etc.
I thought I could select those just needed to clarify which ones might work with pressuremon.
I'll see at home if I can screen grab the bit I was reading.

 

[nzm]

It looks like that device is designed primarily as a pressure switch for industrial use (e.g., controlling solenoid valves or start equipment). The 0 - 250 kPa unit is in the range a homebrewer would use and there is a 1 - 5V analogue output option. It is also very cheap, NZ$10 delivered so an interesting option if that price is correct and it does get delivered (see the one comment).

I guess it depends on what you want to use if for. If just a local readout, this would work and it should even work for a remote readout using Pressuremon with it's analogue input. However, there are a few things to consider:

• This sensor/gauge requires a 12 - 24 vdc power supply so you would probably need to run power to it. Pressuremon runs on a 3.7V rechargeable battery which also powers the sensors that have been recommended. A decent size Li-Ion or LiPo battery can run them for months.
• Only one pressure connector is available on the Asair unit, a PT1/8. Assuming that is a BSPT1/8, it shouldn't be too difficult to find a way to connect it to your fermenter or keg. Manufacturers like Xidibei do offer more options like NPT, BSPT and BSPP.
• The Pressuremon code now supports the 0.96" OLED display connected to the esp-32 to provide a local readout option.

 

[DavidWood2115]

Struggling to get a really nice solder of the pins onto the board, seems to be balling up on the top of the pins.

Sounds like you need some flux.

 

[DuncB]

Sounds like you need some flux.

The solder has flux in it, nice clean tip On the iron.
Soldering fine to the circuit board and wires, it's just the connection into the Pico where the solder isn't flowing down the hole and around the pin.
Could oxidation of the pins be the issue?

 

[nzm]

Could oxidation of the pins be the issue?

Not sure about the pins but another possibility is oxidation on the pico hole traces. I did notice there was some difficulty in soldering the LED and vbat bridges on all 4 units I built. We use to remove oxidation on plug in circuit board contacts fairly easily with an eraser. You might try that.

 

[DuncB]

So using PC I saw all of these options for the sensor. But can't seem to see how to select any of them at the purchase stage?

Plenty of choice for outputs and threads not sure which ones I could / need to ask for.

 

[ClaudiusB]

So using PC I saw all of these options for the sensor. But can't seem to see how to select any of them at the purchase stage?

View attachment 878623

Plenty of choice for outputs and threads not sure which ones I could / need to ask for.

Unfortunately, you can't select any options. Based on my experience, they send you the ARD20-A-X-G.
Look for a different vendor.

 

[DuncB]

Unfortunately, you can't select any options. Based on my experience, they send you the ARD20-A-X-G.
Look for a different vendor.

Thank you I won't waste anymore time on that.
I've managed to load the firmware and configure the wifi, now to plug it into my circuit board and probably blow it up!!
Will update.

 

[DuncB]

Well a long awaited update of progress.
Made the circuit board up using wires and solder, my dodgy looking pin connections onto the Pico seemed to work.

I had a frustrating hour installing the firmware, firstly a power only cable, the laptop didn't power the chip enough so I used another computer and then could only get firmware installed via the Brewflasher not the link from the pressuremon site to webflasher.
The ADC1115 and the pressure sensor seems to work and I've managed to get forwarding and updates on SensorSpy which is for different sensors instead of ispindel etc using Brewspy.
I will add a temp sensor to the system and find a little box to fit it all in.
Thanks again to @mper. Will update if I manage to get signals going to raspberrypints.

 

[DuncB]

This is very odd, @nzm couldn't find the option for custom analogue sensor that I found when setting up.
Now mine has not got a pressure sensor and no option for the custom analogue sensor. It's disappeared mid afternoon.

I've reflashed the firmware but no change. Very odd.

 

[mper]

v0.6 is now releases with support for analog sensors and second i2c sensor, available in my own webflasher (gravitymon.com) and brewflasher

https://github.com/mp-se/pressuremon/releases/tag/0.6.0

 

[DuncB]

v0.6 is now releases with support for analog sensors and second i2c sensor, available in my own webflasher (gravitymon.com) and brewflasher

https://github.com/mp-se/pressuremon/releases/tag/0.6.0

Pretty sure that's the one I have installed.

I think my issue was a rubbish 18650, changed this now and with the power lead plugged in the ADC and pressure sensor work as the custom analogue.
However I calibrate it with no pressure to 0 PSI and then subject it to 10 PSI but get no change of reading.
I must be doing something wrong but I'm unsure what?

 

[mper]

Pretty sure that's the one I have installed.
View attachment 878867

I think my issue was a rubbish 18650, changed this now and with the power lead plugged in the ADC and pressure sensor work as the custom analogue.
However I calibrate it with no pressure to 0 PSI and then subject it to 10 PSI but get no change of reading.
I must be doing something wrong but I'm unsure what?

How does you hardware schema and configuration look like ? What is the sensor params ?

Can you verify that the voltage from the sensor changes when you apply pressure ?

 

[DuncB]

Good evening,
Pico esp 32, no temp sensor, li ion 18650 battery.
Analogue pressure sensor 0 to 30 psi, range 0 to 4.5 V output, input to sensor 5 to 12v, I'm using 5V off the PSU, ADC 1115 and a 5V 1amp PSU.
Using firmware above, it did at one stage have reading of 0 psi which went up when I blew into the gauge pipe.
I suspect I have not calibrated correctly, but I'm not sure about the correct way to do this.

Testing the output with voltmeter I for some daft reason this am checked across the positive and negative of the sensor and got the blue smoke from I'm presuming the ADC as the Pico still sends but doesn't have the analogue sensor anymore as an option so Defaults to a digital option.

I will replace the ADc and test voltage across data line and ground from the sensor?

Up until the cooking event I think it's my wrong settings of calibration.
The blue led light is on all of the time, with force configuration turned off and voltage to force config set to above 5.

 

[mper]

Good evening,
Pico esp 32, no temp sensor, li ion 18650 battery.
Analogue pressure sensor 0 to 30 psi, range 0 to 4.5 V output, input to sensor 5 to 12v, I'm using 5V off the PSU, ADC 1115 and a 5V 1amp PSU.
Using firmware above, it did at one stage have reading of 0 psi which went up when I blew into the gauge pipe.
I suspect I have not calibrated correctly, but I'm not sure about the correct way to do this.

Testing the output with voltmeter I for some daft reason this am checked across the positive and negative of the sensor and got the blue smoke from I'm presuming the ADC as the Pico still sends but doesn't have the analogue sensor anymore as an option so Defaults to a digital option.

I will replace the ADc and test voltage across data line and ground from the sensor?

Up until the cooking event I think it's my wrong settings of calibration.
The blue led light is on all of the time, with force configuration turned off and voltage to force config set to above 5.

Well, you should not mix 5V and 3.3V design, this might damage the i2c bus pins without a voltage stepper for the i2c. The ESP32 is 3.3V and all the devices should be using the same voltage or you might damage the ESP. If you power the ADC from the 5V that will be always on (as well as the sensor) and will drain the battery much quicker. I would recommend to use 3.3V and also pressure sensors that are built for that part (which is what I have been testing on). This is the draft schema that I'm working on a PCB for. In my design i power the external devices from pin5 so I can turn them off during deep sleep.

 

[DuncB]

Thank you @mper

Although I've fitted the battery to my setup I planned on just powering it all the time as it's for keg fridge.
I thought that the Pico could be powered by a 5V supply to Pin 16 or via USB. If powered by USB it can supply 5V at pin 16 with a limit of mA and I'm not sure whether this would be enough to run the pressure sensor.
The ADS1115 can be powered with 2 to 5.5V.
Hence I originally had the pico powered from the pin 16 via 5V and off the same rail the ADS1115 and the Sensor.

All grounds were to the common ground rail.

But based on your above suggestion I have rebuilt with USB power to the Pico, ADS1115 powered from the MOSI Pin 4.

I've only got 4.7K ohm and 220K ohm resistors so not the spec for fitting a temp sensor at the moment, I'll order some though just in case I decide to fit. Apparently info about the ADS " The voltage to be measured should not exceed the gain set in the ADC, nor the Vcc +0.3V, or we can destroy the ADS1115."
Does this meatn that if I power the ADS off 3.3V from the pico my max input voltage from the pressure sensor would be 3.6V and the max voltage the sensor can produce is 4.5V. This might not be a problem if it was powered off 5 V which I thought was a possibility.
However I do remember in brewpiless that the pressure sensor had a setup that allowed you to change the gain.

The remaining question now is about the 5V supply I need to the pressure sensor, can I just supply off a separate 5 V supply to the Sensor? or take a spur off the cable to the USB C socket ?

I have not at this stage considered fitting the I2C SH1106 display I found in my box of bits.

Thanks for your ongoing patience.

 

[mper]

Thank you @mper

Although I've fitted the battery to my setup I planned on just powering it all the time as it's for keg fridge.
I thought that the Pico could be powered by a 5V supply to Pin 16 or via USB. If powered by USB it can supply 5V at pin 16 with a limit of mA and I'm not sure whether this would be enough to run the pressure sensor.
The ADS1115 can be powered with 2 to 5.5V.
Hence I originally had the pico powered from the pin 16 via 5V and off the same rail the ADS1115 and the Sensor.

All grounds were to the common ground rail.

But based on your above suggestion I have rebuilt with USB power to the Pico, ADS1115 powered from the MOSI Pin 4.

I've only got 4.7K ohm and 220K ohm resistors so not the spec for fitting a temp sensor at the moment, I'll order some though just in case I decide to fit. Apparently info about the ADS " The voltage to be measured should not exceed the gain set in the ADC, nor the Vcc +0.3V, or we can destroy the ADS1115."
Does this meatn that if I power the ADS off 3.3V from the pico my max input voltage from the pressure sensor would be 3.6V and the max voltage the sensor can produce is 4.5V. This might not be a problem if it was powered off 5 V which I thought was a possibility.
However I do remember in brewpiless that the pressure sensor had a setup that allowed you to change the gain.

The remaining question now is about the 5V supply I need to the pressure sensor, can I just supply off a separate 5 V supply to the Sensor? or take a spur off the cable to the USB C socket ?

I have not at this stage considered fitting the I2C SH1106 display I found in my box of bits.

Thanks for your ongoing patience.

Well if you are going to power it always then you should be able to power the ADS from 5V but add a level shifter to switch i2c from 5v to 3.3V for the esp so you dont damage the esp.

or get a analog pressure sensor that is made for 3.3V, this is the one i tested with (3.3V 0.4-2.4V output), the digital one probably has better accuracy than the analog.

https://www.aliexpress.com/item/100...MNc0SroN&utparam-url=scene:search|query_from:

 

[dtashmore547]

on the ads1115 there are 2k7 resistors on the board which pull the sda and scl lines high to Vcc, if you remove these you can run the device from 5V and pull the Comms lines high to 3V3 with 4k7 or 3k3 resistors separately instead. the 18B20 can be treated similarly by supplying with 5V and pulling the data wire high to 3V3 with a 3k3 resistor

 

[DuncB]

Thank you @mper and @dtashmore547

I've set it up now to run the ESP via USB and the ADS is powered off the ESP as per the circuit diagram.

I'm not currently using the temp sensor but will wire it as per circuit diagram once the 3.3K resistors arrive.

Can I power the pressure sensor via a separate 5 V supply with the data wire going to ADS ?

Thanks

 

[dtashmore547]

on I2C devices the power supply is not transferred to the data and clock lines as these are open drain so they only switch low and need to be pulled high via a pullup resistor, some modules have these on board so if you wish to use 5V they should be removed and replaced with resistors to the 3V3 supply, to be sure just check the resistance between supply and signal wire.

 

[DuncB]

A few words of caution for any new builders.

I never managed to get the ADC and analogue pressure sensor to work.

So when the I2C sensor arrived I thought I was all good to go.

I had also bought the 1mm spaced connector to wire onto the pressure sensor straight into the I2C socket top left of board.

BEWARE this circuit pin diagram below is WRONG

GND is wired into the Left
3.3 V is on the far right.

SDA is next to ground
SCL is next to 3.3V



If you wire your sensor up as per the circuit diagram you'll cook the PICO as I found out and also @nzm who kindly has helped me sort this out.

Is it very difficult to get a 1.3 OLED as opposed to a 0.96 OLED working on the pressuremon? I would be keeping my pressuremon powered all the time, or powered on periodically when I'm in the bar area.

 

[mper]

A few words of caution for any new builders.

I never managed to get the ADC and analogue pressure sensor to work.

So when the I2C sensor arrived I thought I was all good to go.

I had also bought the 1mm spaced connector to wire onto the pressure sensor straight into the I2C socket top left of board.

BEWARE this circuit pin diagram below is WRONG

View attachment 883760


GND is wired into the Left
3.3 V is on the far right.

SDA is next to ground
SCL is next to 3.3V



If you wire your sensor up as per the circuit diagram you'll cook the PICO as I found out and also @nzm who kindly has helped me sort this out.

Is it very difficult to get a 1.3 OLED as opposed to a 0.96 OLED working on the pressuremon? I would be keeping my pressuremon powered all the time, or powered on periodically when I'm in the bar area.

The pinout in the official schematic is correct.

Adc is still work in progress and with the current design you will need a 3.3v sensor. 5v is not tested and would require a new design with voltage divider that would decrease the accuracy further.

I would recommend the i2c sensor.

Using the i2c will work if you power it always, if you run it on battery it will drain that quickly