Custom Firmware for the FNIRSI GC-01 Geiger Counter

The FNIRSI GC-01 is currently among the best-selling Geiger counters of amazon.com, but its original firmware lacks many features, in particular pulse clicks and data logging!

So I decided to port Rad Pro, a custom firmware for Geiger counters I did last year, to the FNIRSI GC-01.

In this instructable I will teach you how to install Rad Pro on your FNIRSI GC-01.

With Rad Pro, your FNIRSI GC-01 will be able to:

• Measure instantaneous radiation rate.
• Measure average radiation rate for performing surveys.
• Measure cumulative dose.
• Set up user-adjustable rate and dose alarms.
• Plot radiation rate history (10 minutes, 1 hour and 24 hours).
• Log data to the built-in flash memory or live on a computer, optionally sending the data to the gmcmap.com, radmon.org and safecast.org radiation monitoring websites.
• Generate true random data: secure passwords (alphanumeric, full ASCII), random hexadecimal and decimal numbers, dice throws (4-sided, 6-sided, 8-sided, 12-sided and 20-sided) and coin flips.

To install Rad Pro on your FNIRSI GC-01 Geiger counter, you will need the following tools and components:

• A USB-C data cable
• A Philips screwdriver

Follow these steps to start installing Rad Pro:

• Turn off the device.
• Remove the screws holding the back case and open the device.
• Disconnect the large battery.
• Take note of the MCU (microprocessor) installed in your device: CH32F103R8T6 (WCH) or APM32F103RBT6 (Geehy). The picture above should help you identify the MCU. WARNING: Rad Pro does not work on devices with a CACHIP microprocessor.
• Take note of the type of Geiger tube: the markings on the glass should be either J321 (as in the picture above), J305, M4011 or J614. If you have an unmarked tube measuring 55 or 65 mm long, you probably have a J614 or J613 tube, respectively.
• Also, take note of the type of LCD display: the marking on the ribbon cable should be “CL24CG1045-40B”, “ENH-TV0240b026” or “GMT024-05 V2.0”. If it does not match any of these, please create an issue.
• Close the device.

Download the radpro-fnirsi-gc01-[mcu]-x.y.z-install.bin firmware file from the Rad Pro releases.

[mcu] is the type of microprocessor of your device: ch32f103r8t6 or apm32f103rbt6.

Next:

• Connect the device to a USB 2.0 port of a Windows computer using the USB data cable. WARNING: Installation from macOS or Linux may fail. WARNING: Installation from a USB 3.0 port may fail.
• Power on the device. A USB drive should become available.
• Drag the firmware file onto the USB drive. The device should restart with Rad Pro installed.

Some devices require that you keep the power button pressed from power on until the firmware is copied to the USB drive and the device restarts. Some other devices require that you press the right/settings key while pressing the power key for the USB drive to become available.

If something goes wrong, press the reset switch next to the USB connector of your device and repeat the previous procedure. You can recover your device with the original firmware.

If you are unable to install Rad Pro on your device, or your device becomes unresponsive, follow the FNIRSI GC-01 alternative installation instructions.

Go to Rad Pro's settings, select “Geiger tube”, “Conversion factor”, and select the option that matches the Geiger-Müller tube installed in your device.

Within the “Geiger tube” settings, select “HV Profile” and choose an appropriate HV profile: “Energy-saving” is best for measuring background levels of radiation; “Factory default” is the profile from the original firmware and consumes considerably more power.

If the “Energy-saving” does not produce any tube counts, you will need to setup a custom HV profile to reduce power consumption.

If your device produces spontaneous key presses by itself, select the “Energy-saving” HV profile or use a custom HV profile to fix this problem.

Last, read the user's manual for learning how to use Rad Pro.

If you like Rad Pro, consider watching the project to get notified when new releases are out. Also, show your support by starring the project on GitHub.

The keys are mapped as follows:

• Power on/off: long hold of the ok/power key.
• Switch measurement mode: the up and down keys.
• Switch measurement secondary view: the ok/power or left/back key.
• Reset measurement: long hold of the left/back key.
• Enter settings: the right/settings key.
• Go up/down: the up and down keys.
• Select option: the ok/power or right/settings key.
• Go back: the left/back key.

FNIRSI GC-01 with a CH32F103R8 (WCH) microprocessor

On the FNIRSI GC-01 with a CH32F103R8 microprocessor, you must enable “Data mode” in the Settings to establish a USB data connection. To save power, disable “Data mode” when you are finished.

Data logging can store up to 7091 data points. At normal radiation levels (20 cpm), this allows for 147 days of data at 60-minute intervals, 24 days at 10-minute intervals, 4 days at 1-minute intervals, 19 hours at 10-second intervals and almost 2 hours at 1-second intervals.

The HV profile settings are:

• Factory default: 9.207 kHz frequency and 75% duty cycle.
• Energy-saving: 5 kHz frequency and 1.5% duty cycle.

FNIRSI GC-01 with a APM32F103R8 (Geehy) processor

On the FNIRSI GC-01 with an APM32F103R8 (Geehy) processor, the USB data connection is always available.

Data logging can store up to 61793 data points. At normal radiation levels (20 cpm), this allows for 1287 days of data at 60-minute intervals, 214 days at 10-minute intervals, 42 days at 1-minute intervals, 7 days at 10-second intervals and 17 hours at 1-second intervals.

The HV profile settings are:

• Factory default: 47.058 kHz frequency and 50% duty cycle.
• Energy-saving: 5 kHz frequency and 1.5% duty cycle.