Serial Output

ESPGeiger has a software Serial interface allowing simple UART communication.

The default baud is 115200

Each command should be terminated with \r\n

Note that Serial commands are disabled on ESPGeiger-Log builds. This is due to the Serial RX pin being in use for the user input button.

Commands

Command	Description	Example
reboot	Reboot ESPGeiger	reboot
resetwifi	Erase WiFi credentials and drop into setup mode	resetwifi
resetnet	Clear net.* prefs (static IP/gw/sn/dns) and reboot to DHCP. Recovery hatch when a bad static IP makes the web UI unreachable.	resetnet
get <module>.<key>	Read any pref. Sensitive values (passwords, keys) print as ***.	get sys.ratio
set <module>.<key> <value>	Write any pref. Validation (pattern/range/type) runs before the value sticks; live-apply prefs take effect immediately, reboot-required prefs need a reboot.	set sys.ratio 151.0
cpm	Return current CPM value
usv	Return current μSv/h value
show	Enable 1-second CPM output
show N	Enable periodic output every N seconds (1-65535). Implies CPM.	show 5
show 0	Disable periodic output (clears every field toggle)	show 0
show off	Same as show 0	show off
show cpm	Toggle CPM line inclusion in periodic output	show cpm
show cps	Toggle CPS on periodic output
show usv	Toggle μSv on periodic output
show hv	Toggle HV on periodic output (ESPGHW only)
hv	Return current live HV value (ESPGHW only)
target	Set target CPM value for Test builds only	target 1234

Setting prefs

Use get and set for every persisted pref. get with no <module>.<key> echoes nothing. The names match the /egprefs JSON dumps and the pref keys on the Configuration page.

Common examples:

Was	Now
ratio 151.0	set sys.ratio 151.0
duty 50	set espghw.duty 50
freq 6000	set espghw.freq 6000
vratio 1000	set espghw.ratio 1000
voffset -10	set espghw.offset -10

Example Output

show 1 enables a line every second, CPM only by default:

CPM: 30
CPM: 32
CPM: 28

show 5 for every 5 seconds:

CPM: 30
CPM: 32

Toggle additional fields with show cps / show usv:

CPM: 30 CPS: 0.50 uSv: 0.20
CPM: 32 CPS: 0.53 uSv: 0.21

With show hv enabled on ESPGeiger-HW:

CPM: 30 CPS: 0.50 uSv: 0.20 HV: 412
CPM: 32 CPS: 0.53 uSv: 0.21 HV: 413

Toggle CPM off with show cpm for CPS-only output:

CPS: 0.50
CPS: 0.53

Turn it all off with show 0 - periodic output stops and the regular log verbosity returns.

Output format

The default output uses ESPGeiger’s own labelled style, but the firmware can also emit lines in any of the protocols it supports on the input side. This is useful for piping data into existing tools that expect a particular counter’s wire format, or for chaining ESPGeiger to a parent device that thinks it is talking to a real GC10 / MightyOhm.

Set the format via the sout.format pref. Three contiguous IDs on the output side - separate from the input-side protocol IDs (which are stable across versions for backwards compatibility).

set sout.format N	Wire format	Default baud
0	Labelled (default), driven by show cpm / cps / usv / hv	unchanged
1	MightyOhm	9600
2	User template, see below	115200

When sout.format is non-zero the show field toggles are ignored. Output still only runs when show N (or show 1) has set a non-zero period.

Examples:

set sout.format 1       # MightyOhm
show 1                  # 1 line/sec

produces:

CPS, 0, CPM, 28, uSv/hr, 0.16, SLOW
CPS, 1, CPM, 30, uSv/hr, 0.17, SLOW
CPS, 0, CPM, 30, uSv/hr, 0.17, SLOW

The CPS field is the literal count in the most recent second, not an average. At background levels (~30 CPM) most seconds read 0 with the odd 1, which is also how a real MightyOhm behaves.

The mode tag at the end of each line switches automatically:

• SLOW when CPS is 0-15 (typical background up to roughly 900 CPM)
• FAST when CPS is 16-255 (active source, faster sampling on the original hardware)
• INST when CPS exceeds 255. CPM is reported as CPS * 60 since the 8-bit sample buffer on a real MightyOhm overflows in this regime.

User template (format 2)

Format 2 emits whatever string you put in the sout.tpl pref, with {var} placeholders substituted on every line. Useful when you need to pipe data into a logger that expects its own line shape.

set sout.format 2
set sout.tpl cpm={cpm}|cps={cps}|usv={usv}
show 1

produces:

cpm=28|cps=0.50|usv=0.16
cpm=30|cps=0.53|usv=0.17

Variables

Name	Meaning
{cpm}	1-minute CPM (integer)
{cps}	Counts per second, rolling float
{cps_i}	Counts in the most recent whole second (integer)
{cpm5}	5-minute CPM rolling average
{cpm15}	15-minute CPM rolling average
{usv}	Dose rate in microsieverts per hour
{tc}	Lifetime total clicks
{ut}	Uptime in seconds
{id}	Six-hex chip id
{name}	Friendly name (or hostname)
{rssi}	WiFi RSSI in dBm
{mem}	Free heap in bytes
{mode}	MightyOhm-style mode tag SLOW / FAST / INST
{hv}	Measured HV in volts (ESPGeiger-HW only)
{t}	Temperature in user-preferred unit (env.unit)
{h}	Relative humidity %
{p}	Pressure in hPa

Unknown placeholders render verbatim as {whatever}, so misspellings are visible on the wire. Sensor variables ({hv}, {t}, {h}, {p}) render as empty strings when the relevant hardware is absent.

Visit /vars.json on the device to see the current rendered value of every variable - handy when authoring a template and checking that the field you want is actually populated on your build.

Escapes

Backslash escapes work inside the template:

Sequence	Meaning
\n	Newline (0x0A)
\r	Carriage return (0x0D)
\t	Tab
\\	Literal backslash
\{ \}	Literal brace

If you leave off the trailing newline the firmware adds one for you. Multi-line templates are fine - e.g. cpm={cpm}\ncps={cps}\n emits two lines per emit period.

Notes

• Template max length is 128 characters; rendered line also caps at 128 bytes per emit.
• MightyOhm output (format 3) stays its own special case because the mode tag (SLOW/FAST/INST) and CPM extrapolation in INST mode can’t be expressed as a static template. For a MightyOhm-like line with your own labels, combine {cps_i} + {cpm} + {mode} - note that in the INST regime the CPM won’t match MightyOhm’s wire-exact behaviour.

Baud rate

Set sout.baud to override the serial baud rate at runtime. The change applies immediately on platforms that have a real UART (ESP8266 and classic ESP32 builds). On ESP32-S3 native USB builds the baud is virtual and the option is a no-op.

set sout.baud N	Effect
0 (default)	If sout.format is set to a known protocol, use that protocol’s native baud. Otherwise keep the framework default (115200).
Any non-zero value	Force this baud regardless of format.

After changing baud, reconnect your serial monitor at the new rate so it can decode the wire.

Examples:

set sout.format 1       # MightyOhm: drops baud to 9600 automatically
set sout.baud 19200     # override to 19200 regardless of format
set sout.baud 0         # back to format-default (or framework default)

The sout prefs (format, baud, interval, flags) are command-driven and do not appear on the Config page.