iBLOPPER/s is an Arduino device (ESP8266) there monitor your fermentation by sound in regards of yeast activity though motioning CO2 blops pr. minute (BPM). Furthermore it use the sum BLOPS to calculate an indicative SG estimate by 1st degree polynomial approach. The information is passed till the cloud e.g. into Ubidots or Brewfather. Last, and unique, it can also control a heating-argent and cooler based on the temperature reading every 6 min.

In general iBLOPPER/s works just as iBLOPPER, but main differnece is ofcouse the detection system and hence the possibility of including a relay.

Fermenter on heating mat. iBLOPPER/s box with NodeMCU and relay inside standing just next to mat. This picture likewise shows my blow-out setup I merely use when dealing with high OG beers. S-airlock can ofcouse also be directly added till fermenter.

Diagram and needed components

Diagram for iBLOPPER/s. Temperature probe on D7, relay on D5 and D6, and the sound sensor on D3. OLED screen is on D1 = SCL and D2 for SDA.

It needs an NodeMCU LOLIN, Sound Sensor Detecting Module LM393, OLED screen of SSD1306 type (4-pin type of 128×64 pixels can be found in 0.96″ and 1.3″ sizes) and a 2-channel relay. Some 3 pins wires and some 2 pin wires is also needed. Please notice the OLED and Relay is optional and hence a lighter version can be build whiteout.

  • one NodeMCU Version3.x of LOLIN type.
  • one ds18b20 probe temperature probe (including a resistor 4,7K ohm) and attached it on pin D7 of NodeMCU.
  • one Sound Sensor Detecting Module LM393 at D3.
  • OLED screen on D1 = SCL and D2 = SDA.
  • 2-channel relay on D5 and D6.
  • USB Changer of min. 1.0A to give stability as power load is high.
  • slow-working actor/heating agent should be used (e.g. 6min runs).

Relay and warning = beta software

This software is in beta and even I have included all the safety I can think off please treat it carefully. The Relay do turn off before each data treatment to secure the heating is off if it goes down. The Bubble Logger do not support temperatures below 2´C or over 60´C and will turn relay of if set outside this range. If the wifi is unstable, and hence if the logger lose wifi it will restart to secure a new connection, hence, there is build in a behavior of restarting. If you experience any melt-down where the logger get stuck in either heating or cooling mode, please, let me know! If you do not wish to use the relay set “start temperature” at 0´C as this turns it off.

For stability reason only use USB charger with 1.0A or more as else you will see issues (the power drain is high).

Building Sound sensor with “condom” and placement in airlock.

The LM393 need a moisture protection, and this is done by a small water balloon, and it should be rather tight around the noose, but still loose as below pictures shows. It needs to sit tight in the airlock making an seal to restrict any water from vaporization. To allow the pressure to equalize a small hole needs to be drilled. Align it so the micorphone is place over the direct hole in the airlock, so the sensor get the direct sound “blop”.
As the sensor got some shapes edges there will flence the balloon and secondly as the microphone rather easily can break off, try steady the sensor by some tape as first picture shows!

Buidling the sensor – Notice the small  a tiny drilled hole at top (pressure equalization).

Besides the water amount of 4-4,5ml and the use of a calibrated censor the foremost important factor is the alignment of the probe, and it need to be pressed all the way down in the s-airlock and aligned directly over the tube-hole and hence get the direct release of C02 sound/pressure-burst. If not fitted precisely you loose BPM and hence the rG estimate goes wrong if you choose to make use of the polynomial approach as second opinion of SG estimation.


Make a brew and Put on the “condom” (small water balloon) on the LM393, se below picture! When the BPM is around 15-30 by hear and see count adjust the potentiometer of the sensor till it reflect this by the logger (simply turn the potentiometer down until it stops lighten green and then fine adjust until you get the same BPM as hear and see count).

This give a high resolution sensor there miss a few and also post some double bubbles, but this is fine as long the avenge BPM do reflect you hear and see count. This calibration should give you between 30 and up till 100-150 SBM at high krauzen depending on OG/temperature/brew size (I brew in 14-25L amounts), etc! This setting is prone to high sounds, but light talking, music, drier and washing machine is ok to have nearby!

Uploading the software NodeMCU LOLIN

Download below file containing esptool.exe + bin-file + 2 “Window batch files” and extract in “your” folder:

iBLOPPER/s ver1.0 (13 downloads)

  1. Install CP210x USB to UART Bridge VCP Drivers, if not already done. If you played with Arduino IDE and NodeMCU before you most likely have done this before.
  2. Ensure NodeMCU is pugged into USB.
  3. Go to “Devices” (e.g. use win10 search and write “devices”).
  4. Under “Ports” in Devices. Notice this USB port number for “CP210x USB to UART”!
  5. Edit the “Window batch file” named “SETUP_USB_COMX” to reflect the port you using (eg. change the port number ONLY: “esptool.exe --chip esp8266 --port COM4 --baud 115200 --before default_reset --after hard_reset write_flash -z --flash_mode dio --flash_freq 80m --flash_size detect 0x0 iBLOPPER/s_ver1.0.bin“)
  6. Hit and run the “Window batch file” named “SETUP_USB_COMX”
  7. Now the iBLOPPPER/s software get installed.

If something goes wrong you can erase everything after editing accordingly as above by running “Erase_USB_COMX” (esptool.exe -p COM4 -b 115200 erase_flash). 

If updating to new build and/or making use of an NodeMCU from earlier project, ensure to erase everything as else you will get instability issues.

Secondly, always pull the power from iBLOPPER/s after installing before setting it up.