New and Improved Geiger Counter - Now With WiFi!

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Introduction: New and Improved Geiger Counter - Now With WiFi!

This is an updated version of my Geiger counter from this Instructable. It was quite popular and I received a good amount of feedback from people interested in building it, so here is the sequel:

The GC-20. A Geiger counter, dosimeter and radiation monitoring station all-in-one! Now 50% less thicc, and with loads of new software features! I even wrote this User Manual to make it look more like a real product. Here's a list of the main features this new device has:

  • Touchscreen controlled, intuitive GUI

  • Displays counts per minute, current dose, and accumulated dose on homescreen

  • Sensitive and reliable SBM-20 Geiger-Muller tube

  • Variable integration time for averaging dose rate

  • Timed count mode for measuring low doses

  • Choose between Sieverts and Rems as the units for the displayed dose rate

  • User adjustable alert threshold

  • Adjustable calibration to relate CPM to dose rate for various isotopes

  • Audible clicker and LED indicator toggled on and off from homescreen

  • Offline data logging

  • Post bulk logged data to cloud service (ThingSpeak) to graph, analyze and/or save to computer

  • Monitoring Station mode: device stays connected to WiFi and regularly posts ambient radiation level to ThingSpeak channel

  • 2000 mAh rechargeable LiPo battery with a 16 hour run time, micro USB charging port

  • No programming required from the end user, WiFi setup handled through GUI.

Please refer to the user manual using the link above to explore the software features and UI navigation.

Step 1: Design Files and Other Links

All design files, including the code, Gerbers, STLs, SolidWorks Assembly, Circuit Schematic, Bill of Materials, User Manual and Build Guide can be found at my GitHub page for the project.

Please note that this is a fairly involved and time-consuming project and requires some knowledge of programming in Arduino, and skills in SMD soldering.

There is an information page for it in my portfolio website here, and you can also find a direct link to the build guide I put together here.

Step 2: Parts and Equipment Needed

The Circuit Schematic contains part labels for all discrete electronic components used in this project. I purchased these components from LCSC, so entering those part numbers in the LCSC search bar will show the exact components needed. The build guide document goes into more detail, but I'll summarize the information here.

UPDATE: I've added an Excel sheet of the LCSC order list to the GitHub page.

Most of the electronic parts used are SMD, and this was chosen to save space. All passive components (resistors, capacitors) have a 1206 footprint, and there are some SOT-23 transistors, SMAF size diodes, and SOT-89 LDO, and an SOIC-8 555 timer. There are custom footprints made for the inductor, switch and the buzzer. As mentioned above, the product numbers for all of these components are labeled on the schematic diagram, and a higher quality PDF version of the schematic is available at the GitHub page.

The following is a list of all the components used to make the full assembly, NOT including the discrete electronic components to be ordered from LCSC or a similar supplier.

  • PCB: Order from any manufacturer using Gerber files found in my GitHub
  • WEMOS D1 Mini or clone (Amazon)
  • 2.8" SPI Touchscreen (Amazon)
  • SBM-20 Geiger tube with ends taken off (many vendors online)
  • 3.7 V LiPo charger board (Amazon)
  • Turnigy 3.7 V 1S 1C LiPo battery (49 x 34 x 10mm) with JST-PH connector (HobbyKing)
  • M3 x 22 mm Countersunk screws (McMaster Carr)
  • M3 x 8 mm hex machine screws (Amazon)
  • M3 brass threaded insert (Amazon)
  • Conductive copper tape (Amazon)

In addition to the parts above, other miscellaneous parts, equipment and supplies are:

  • Soldering iron
  • Hot Air soldering station (optional)
  • Toaster oven for SMD reflow (optional, either do this or the hot air station)
  • Solder wire
  • Solder paste
  • Stencil (optional)
  • 3D printer
  • PLA filament
  • Silicone-insulated stranded wire 22 gauge
  • Hex keys

Step 3: Assembly Steps

1. Solder all SMD components to the PCB first, using your preferred method

2. Solder the battery charger board to the pads SMD-style

3. Solder male leads to the D1 Mini board and to the bottom pads of the LCD board

4. Solder the D1 Mini board to the PCB

5. Cut off all protruding leads from the D1 Mini on the other side

6. Remove the SD card reader from the LCD display. This will interfere with other components on the PCB. A flush cutter works for this

7. Solder through-hole components (JST connector, LED)

8. Solder the LCD board to the PCB AT THE END. You won’t be able to de-solder the D1 Mini after this

9. Cut off the bottom-side protruding male leads from the LCD board on the other side of the PCB

10. Cut two pieces of stranded wire around 8 cm (3 in) long each and strip the ends

11. Solder one of the wires to the anode (rod) of the SBM-20 tube

12. Use the Copper tape to attach the other wire to the body of the SBM-20 tube

13. Tin and solder the other ends of the wires to the through-hole pads on the PCB. Make sure the polarity is correct.

14. Upload the code to the D1 mini with your preferred IDE; I use VS Code with PlatformIO. If you download my GitHub page, it should work without needing any changes

15. Attach the battery to the JST connector and power on to see if it works!

16. 3D print the case and the cover

17. Attach the brass threaded inserts into the six hole locations in the case with a soldering iron

18. Install the assembled PCB into the case and secure with 3 8mm screws. Two on top and one on the bottom

19. Place the Geiger tube on the empty side of the PCB (towards the grill) and secure with masking tape.

20. Insert the battery over the top, sitting over the SMD components. Guide the wires to the gap at the bottom of the case. Secure with masking tape.

21. Install the cover using three 22 mm countersunk screws. Done!

The voltage to the Geiger tube can be adjusted using the variable resistor (R5), but I've found that leaving the potentiometer in the default middle position produces just over 400 V, which is perfect for our Geiger tube. You can test the high voltage output using either a high-impedance probe, or by building a voltage divider with at least 100 MOhms of total impedance.

Step 4: Conclusion

In my testing, all features are working perfectly in the three units I've made, so I think this is going to be pretty repeatable. Please post your build if you end up making it!

Also, this is an open-source project so I would love to see changes and improvements made to it by others! I'm sure there are many ways to improve it. I'm a mechanical engineering student and I'm far from an expert in electronics and coding; this just started as a hobby project, so I'm hoping for more feedback and ways to make it better!

UPDATE: I'm selling a few of these on Tindie. If you'd like to buy one instead of building it yourself, you can find it at my Tindie store for sale here!

4 People Made This Project!

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55 Comments

0
blazkowicz0
blazkowicz0

1 year ago

Great project. Well designed and documented.
I made a single Side PCB- no SMD parts...
See Picture.
Thanks for sharing

GC-20.JPGIMG_1944.JPG
0
ladislav02
ladislav02

Reply 10 months ago

Hello,
could you please send me your design of PCB, I don´t like SMD :-)
Thank you very much.

0
Андрей 126
Андрей 126

Reply 24 days ago


Здравствуйте, не могли бы вы поделиться своей печатной платой, большое вам спасибо.

0
andrey_markovskiy
andrey_markovskiy

Reply 1 year ago

Hi! Could you share PCB and parts, that you used?

0
prabhat_
prabhat_

Reply 1 year ago

That looks awesome! Thank you for sharing your build!

0
bcamel541
bcamel541

Question 1 year ago

Hello! I recently assembled all components with the exception of the Geiger tube itself. One thing I noticed was a high pitched whine emitting from the assembly. Is this normal? Do you know what might be causing it? (Perhaps not having the tube connected results in this...). I look forward to your reply. Thanks.

0
josjlandon
josjlandon

Answer 1 year ago

i was having this same issue and it ended up being the piezo speaker.. discovered it by covering the speaker hole and then removing speaker

0
prabhat_
prabhat_

Answer 1 year ago

The high-pitched whine comes from the high voltage MLCC capacitor (which is piezoelectric) and it's normal.

0
joedol48
joedol48

11 months ago

Nice build. I've assembled 5 boards, and still having same voltage on each : only 230V...i guess 400v would be better
... and when turning variable resistor, it changes, but not so much.
And ideas will be appreciated.

Thanks.

0
schlabic
schlabic

Reply 10 months ago

Hi joedol48,

Please see the end of my comment, which is about some of the problems I've encountered. The last paragraph is regarding how measuring with a regular type voltmeter gives a low reading.

schlabic

0
josjlandon
josjlandon

Reply 5 months ago

i use a 1 gigaohm resistor inline with the positive on the voltmeter and if the input imp is 10M then times the display by 100

0
schlabic
schlabic

10 months ago

I hope I can save someone else a few hours of grief.

First of all, this is a nice design. But after having PCBs made and building one that sort of worked and now building a second one with fixes, these are some design errors:

1) The polarity stripe for polarized capacitor C4 printed on the PCB is backwards, so make sure to reverse it.

2) The D1 Mini's output D0 basically gets shorted when it goes high because there is no resistor in between D0 and transistor Q4 that goes to the piezo speaker. I found this out when I built the unit with a D1 Mini that was already programmed with a program that held D0 high. This may not be obvious because of how short the duration of the audible clicks are. Fixing this should help power consumption especially when the CPM are high. Unfortunately, it fried my first D1 Mini before I figured out the problem. This may be why one commenter said his unit buzzed and why another said he removed the piezo. Before my first D1 Mini fried, it made a weird buzzing sound. I left the D0 pin out and am going to investigate what size resistor to kludge in between the D1 Mini's D0 hole and and the PCB's D0 hole.

3) The U5 voltage regulator is a 3.0V unit instead of a 3.3V. In my case, that made the display stay blanked out whenever I tried to turn on the unit when it was in last turned off in a setting that used wifi. I were to order them from LCSC again, I'd order the 3.3V version. The D1 Mini nominal voltage is 3.3V

4) As another commenter noted, the wrong part number is shown for D1 on the schematic, so use the BOM.

In addition to the kludge mentioned in 2), I'm also kludging in the outputs OUT+ and OUT- of the TP4056 board by routing them with wire to the B+ and B- on the PCB and soldering the battery leads to the B+ and B- of the TP4056 board instead of the PCB. That way the battery will be protected from undervoltage.

I'm also leaving the "LED" pin out of the LCD display and bypassing it with a switch so I can turn off the display for extended periods using wifi with ThingSpeak.

Also, note that if you measure the 400V with a regular voltmeter, it will read significantly lower. I'm still trying to figure out a way to measure and compensate for that. There are a few posts about how to read geiger tube voltages if you do a web search.


:


0
josjlandon
josjlandon

Reply 5 months ago

tantalum polarity stripe is on the positive side
other than that thank you for the info on the D0 this is a well designed geiger on the software side but the pcb not so much.. i have also re designed it to get rid of the unnecessary lcd PCB and the tp4056 error.. with the wemos mini it has a 3v3 regulator so i dont understand the purpose of the other

0
sapatsidis
sapatsidis

Question 8 months ago

Cannot find esp8266wifi lib. from platformio.
Any suggestions?

0
sapatsidis
sapatsidis

Question 8 months ago

Hello
Can someone give us the libraries?
We can't find any.....

0
yakimov.andy
yakimov.andy

9 months ago

Hi! Could you make the firmware in .bin format for nodemcu flasher? Please... I tried to compile with Visual Studio Code several times, selecting different versions of libraries, and I have a white screen, a flashing LED on the WEMOS D1 Mini board and a bip...bip...bip... in buzzer.

0
sapatsidis
sapatsidis

1 year ago

Maby the best so far diy geiger I ve seen!!!
Could you help us with a guide for programming the boards?
Regards.

0
prabhat_
prabhat_

Reply 1 year ago

You can program it just like any other esp/Arduino board. If you're using the Arduino IDE, make sure all the required libraries are installed.