Looks like the circuit has a builtin HV power supply, so an external one is not needed, is this correct?
JaneYu 2022-05-18 04:04:45 55 Views9 Replies Looks like the circuit has a builtin HV power supply, so an external one is not needed, is this correct?
the original tubes are M4011 which are not easy to find in case one needs a replacement. Can you recommend any other model number, like the J305?
Thank you.,
JaneYu Sorry, we have not tested the compatibility of other geiger tubes with this Module.
Even if it can be installed, we think it is necessary to modify the conversion formula of the underlying function regarding the number of interruptions and radiation values.
We think you could found the M4011 on other online store, like Aliexpress or somewhere else.
This is what I found:
https://www.gqelectronicsll...
At the same time, if you are not measuring an environment with extremely high radiation, you don’t need to worry about the life of the Geiger tube.
Adding now that after about three month's use the tube is failing to quench properly, resulting in bursts of 2 to 10 pulses within 2 to 5 milliseconds. My guess is this is not unusual for these cheapo tubes. A reminder that this is a toy, not a real instrument.
To work around this I modified my code to ignore pulses less than 8 ms after the preceding one. This seems to provide reasonable counts again.
I also measured the voltage on the tube and it is only about 230V. I thought these tubes were supposed to operate at about 400V? (Multimeter impedence is 2M ohms per volt.)
JaneYu Some info:
Pulse goes from VIN to 0V.
Pulse Type: Falling / Low
Pulse Drop Speed: ~4.0µS
Pulse Rise Speed: ~86.0µS
Pulse Low Time: ~176.0µS
Total Time D- is Below VIN: ~270.0µS
JaneYu You won't be able to use background radiation very reliably to generate random numbers. As "obstruse" found, where you put the detector can change the background radiation count. In addition, average background level is pretty low and it would take a long time to generate numbers directly; production hardware random generators use a grain of radioactive material to get the level high enough to be useful. It might be practical to use the detector to seed a pseudorandom generator in code, though. Wikipedia: https://en.wikipedia.org/wi...
JaneYu It operates with 5V DC, HV is generated from this voltage and is builtin.
JaneYu Evidently the older M4011 Geiger tubes had a problem with photo-sensitivity. The tubes provided by DFRobot (2022) don't have that problem. Here's a link discussing the problem (from 2017): http://www.gqelectronicsllc...
I'm using an ESP32 to count the pulses and upload to ThingSpeak.com. Background count is 25 CPM, but it depends on where you place the sensor. Looks like my fireplace is slightly 'active':
https://uploads.disquscdn.c...
It's also possible to download CSV from ThingSpeak.com and load into GeigerLog for Stats, Poisson, FFT, etc: https://sourceforge.net/pro...
Some interesting links:
GeigerLog - Potty Training for Your Geiger Counter
https://sourceforge.net/pro...
This article is about the use of natural Potassium to give your Geiger counter a little bit of a training workout when you get tired of measuring just the background. Potassium is omnipresent on the earth, essential for all life, may already be available in or around your home or garden, and has a little bit of natural radioactivity – though well below any danger zones. I show how to best use it, taking advantage of GeigerLog on today’s Geiger counter technology and software.
GeigerLog - Going Banana
https://sourceforge.net/pro...
Ever heard the term ‘banana equivalent dose’? It refers to the Potassium content of bananas, which gives the bananas a tiny little bit of radioactivity. Nevertheless, I demonstrate that you can measure this with a Geiger counter, but it is tricky as the activity is very low and demands in-depth statistical considerations.
JaneYu Looks like it might be a piezo buzzer. Don't want to get moisture in it. So that sticker is to protect it during assembly and while washing the flux off after that.
JaneYu 
