121GW-Open-Firmware v1.3.5

Replacement firmware for the EEVblog 121GW, with an emulator of the meter and the 121GW Companion app.

Downloads

File	What it is
firmware-v1.3.5.zip	the firmware: install it with the Companion, or copy EEVBlog.bin to the SD card (how)
121GW-User-Manual-v1.3.5.pdf	the user manual
121GW-Open-Firmware-Emulator-v1.3.5-<platform>	the emulator: macOS (Apple chips), Windows, Linux (how to start it)
121GW-Companion-<version>-<platform>	the Companion app: Windows, macOS, Linux

What's new

New in v1.3.5 (F-1.35): current clamp mode (GitHub issue 39). A new SETUP page CLP in DCV, ACV, DCmV and ACmV (after dSP) takes the millivolts your clamp gives per ampere: off (default), 1, 10, 100 or 1000. With a setting the main display shows amperes: the same digits with the decimal point moved, the V sign replaced by A, and mA when the amperes would need more than four decimals; a current that does not fit the five digits shows OFL. The measurement, MIN/MAX, REL, HOLD, the bargraph and the sub display are not touched. The Bluetooth status frame carries the setting in byte 13 bits 7..5 (the voltage in the other bytes is unchanged, so older apps keep showing volts), the SD card log writes the main reading in A or mA, and the setting is a Bluetooth remote setting (id 0x020, bits 7..5). It is stored in bits 7..5 of EEPROM byte 0x020, which were unused; the other bits of the byte are never changed by it.

Earlier versions: the whole changelog.

121GW Companion v1.3.8

The 121GW Companion: the computer app for the EEVblog 121GW over Bluetooth (live view, graphs, recording, card files, settings, firmware and bootloader updates).

Downloads

File	For
121GW-Companion-1.3.8-windows-x64.exe	Windows 10 / 11 (installer)
121GW-Companion-1.3.8-macos-arm64.dmg	macOS on Apple chips (M1 and newer)
121GW-Companion-1.3.8-macos-x86_64.dmg	macOS on Intel processors
121GW-Companion-1.3.8-linux-amd64.deb	Ubuntu, Debian, Mint (sudo apt install ./<file>)
121GW-Companion-1.3.8-linux-x86_64.AppImage	any other 64-bit Linux

On the meter: Bluetooth on (hold PEAK), other Bluetooth apps for the meter closed. Do not pair the meter in the computer's Bluetooth settings. Free for individuals, schools and non-profits (licence).

What's new

New in 1.3.8: Export trend CSV on the LOG view no longer quits the program on macOS (GitHub issue 43). The window could not save a download, so the export opened the CSV in place of the program's page, and closing it closed the program. The program now writes the file itself, as 121gw-trend-<date>-<time>.csv in the recordings folder, and the status line names the file.

Earlier versions: the whole changelog.

121GW Companion v1.3.7

The 121GW Companion: the computer app for the EEVblog 121GW over Bluetooth (live view, graphs, recording, card files, settings, firmware and bootloader updates).

Downloads

File	For
121GW-Companion-1.3.7-windows-x64.exe	Windows 10 / 11 (installer)
121GW-Companion-1.3.7-macos-arm64.dmg	macOS on Apple chips (M1 and newer)
121GW-Companion-1.3.7-macos-x86_64.dmg	macOS on Intel processors
121GW-Companion-1.3.7-linux-amd64.deb	Ubuntu, Debian, Mint (sudo apt install ./<file>)
121GW-Companion-1.3.7-linux-x86_64.AppImage	any other 64-bit Linux

On the meter: Bluetooth on (hold PEAK), other Bluetooth apps for the meter closed. Do not pair the meter in the computer's Bluetooth settings. Free for individuals, schools and non-profits (licence).

What's new

New in 1.3.7: the current clamp of firmware 1.3.5 (F-1.35, GitHub issue 39). With a clamp ratio set on the meter (SETUP page CLP: 1 mV/A, 10 mV/A, 100 mV/A or 1 V/A), DCV, ACV, DCmV and ACmV show the clamp's current: the LIVE page, the statistics, the trend and recordings show A (or mA for small currents) with the point where the meter puts it, and OFL when the current does not fit the meter's five digits. METER SETTINGS has the row "Current clamp ratio" (firmware F-1.35 and newer). Also: the LOG view has a log trigger (GitHub issue 40: the recording ignored the meter's trigger and interval). Choose every reading (as before), interval, on change or on limit verdict; the rows follow the meter's own rules, with the interval in seconds and the change in counts of the last digit, and start with the meter's In and Ch from the last settings read. The display, statistics and trend still get every reading.

Earlier versions: the whole changelog.

121GW Companion v1.3.6

The 121GW Companion: the computer app for the EEVblog 121GW over Bluetooth (live view, graphs, recording, card files, settings, firmware and bootloader updates).

Downloads

File	For
121GW-Companion-1.3.6-windows-x64.exe	Windows 10 / 11 (installer)
121GW-Companion-1.3.6-macos-arm64.dmg	macOS on Apple chips (M1 and newer)
121GW-Companion-1.3.6-macos-x86_64.dmg	macOS on Intel processors
121GW-Companion-1.3.6-linux-amd64.deb	Ubuntu, Debian, Mint (sudo apt install ./<file>)
121GW-Companion-1.3.6-linux-x86_64.AppImage	any other 64-bit Linux

On the meter: Bluetooth on (hold PEAK), other Bluetooth apps for the meter closed. Do not pair the meter in the computer's Bluetooth settings. Free for individuals, schools and non-profits (licence).

What's new

New in 1.3.6: METER SETTINGS no longer fails with "the link is busy: settings" (GitHub issue 37). Since 1.3.4 the page reads the settings by itself when it opens and when the meter shows page Ld; when two of these reads met (on a meter with the old BLE112 Bluetooth module a read takes longer than the 2.5 s a second request waits), the second one failed. Now one settings read or write runs at a time, and a read that finds another one running waits for it and shows its result. The macOS installers are checked again when Apple's ticket service drops the connection during the check.

Earlier versions: the whole changelog.

121GW-Open-Firmware v1.3.4

Replacement firmware for the EEVblog 121GW, with an emulator of the meter and the 121GW Companion app.

Downloads

File	What it is
firmware-v1.3.4.zip	the firmware: install it with the Companion, or copy EEVBlog.bin to the SD card (how)
121GW-User-Manual-v1.3.4.pdf	the user manual
121GW-Open-Firmware-Emulator-v1.3.4-<platform>	the emulator: macOS (Apple chips), Windows, Linux (how to start it)
121GW-Companion-<version>-<platform>	the Companion app: Windows, macOS, Linux

What's new

New in v1.3.4 (F-1.34): readings sized to the converter's real speed. Measured on a meter, the measuring chip takes two conversion times plus 0.79 ms for each result whenever its chopper is on (continuity, ohms, DC volts and millivolts, currents, diode, temperature), and the averages had been sized for one conversion time. They are now sized for the measured speed: the continuity display and its beep decision every 102 ms (was 250 ms), ohms every 105 to 154 ms (was 206 to 225 ms), currents and diode every 159 ms (was 212 ms), millivolts range 0 and temperature every 608 ms (was 811 ms), and after a DC volts range change from the lowest range a value 0.34 s sooner. DC volts, the highest ohm ranges and LowZ keep their timing; where a value now averages fewer results it is at most a quarter fewer, so readings stay steady. Calibration mode keeps every count, so a calibration is taken exactly as before. The emulator now converts at the measured speed too. Also in v1.3.4: a battery type setting for rechargeable NiMH cells (GitHub issue 36). The new SETUP page after the battery voltage shows bAtAL (alkaline, the default) or bAtnH (NiMH); REL or PEAK switches, a long SETUP saves. With NiMH the low-battery symbol, the logging stop and the Bluetooth low-battery flag come at 4.7 V instead of 4.1 V, before the weakest cell of the four is driven empty; settings can still be saved down to 4.1 V with either type. After switching on, the small display shows the version and then the battery voltage for the same 2 s (for example 4.95 with the V sign), in every function but VA; a key, a dial turn or a SETUP page ends it at once. A battery under the limit gives a double beep at switch-on (silent with the buzzer off).

Earlier versions: the whole changelog.

121GW Companion v1.3.5

The 121GW Companion: the computer app for the EEVblog 121GW over Bluetooth (live view, graphs, recording, card files, settings, firmware and bootloader updates).

Downloads

File	For
121GW-Companion-1.3.5-windows-x64.exe	Windows 10 / 11 (installer)
121GW-Companion-1.3.5-macos-arm64.dmg	macOS on Apple chips (M1 and newer)
121GW-Companion-1.3.5-macos-x86_64.dmg	macOS on Intel processors
121GW-Companion-1.3.5-linux-amd64.deb	Ubuntu, Debian, Mint (sudo apt install ./<file>)
121GW-Companion-1.3.5-linux-x86_64.AppImage	any other 64-bit Linux

On the meter: Bluetooth on (hold PEAK), other Bluetooth apps for the meter closed. Do not pair the meter in the computer's Bluetooth settings. Free for individuals, schools and non-profits (licence).

What's new

New in 1.3.5: the METER SETTINGS page has no READ button any more in normal use (GitHub issue 37). The settings are read by themselves when the meter shows page Ld and every time the page is opened, and the meter's settings cannot change while page Ld is shown; a lit button made it look as if something needed checking. Only when a read fails does a "Read again" button appear, to retry.

Earlier versions: the whole changelog.

121GW Companion v1.3.4

The 121GW Companion: the computer app for the EEVblog 121GW over Bluetooth (live view, graphs, recording, card files, settings, firmware and bootloader updates).

Downloads

File	For
121GW-Companion-1.3.4-windows-x64.exe	Windows 10 / 11 (installer)
121GW-Companion-1.3.4-macos-arm64.dmg	macOS on Apple chips (M1 and newer)
121GW-Companion-1.3.4-macos-x86_64.dmg	macOS on Intel processors
121GW-Companion-1.3.4-linux-amd64.deb	Ubuntu, Debian, Mint (sudo apt install ./<file>)
121GW-Companion-1.3.4-linux-x86_64.AppImage	any other 64-bit Linux

On the meter: Bluetooth on (hold PEAK), other Bluetooth apps for the meter closed. Do not pair the meter in the computer's Bluetooth settings. Free for individuals, schools and non-profits (licence).

What's new

New in 1.3.4: updates lose less time on lost answers (GitHub issue 23). Through the two-part bootloader the wait for a missing answer follows how fast the meter has been answering, as TCP does: the average plus four times the variation, at least 1 s, at most 5 s, doubled after each missing answer. Before it was always 20 s; an update with 9 missing answers waited 180 s for them. The wait for the answer to START, which comes once the bootloader has erased the image pages, is 6 s instead of 30 s: the largest image takes 4.8 s to erase at most. The same 6 s apply to the answer to END (the bootloader's check of the written image). On page Ld the wait for an answer is 5 s instead of 20 s; every answer in the reports came within 3.5 s. The "last transfer" line now also says how long START took to be answered. The programs are built with Python 3.15 (was 3.11), bleak 3.1.0 and pywebview 6.2.1.

Earlier versions: the whole changelog.

121GW Companion v1.3.3

The 121GW Companion: the computer app for the EEVblog 121GW over Bluetooth (live view, graphs, recording, card files, settings, firmware and bootloader updates).

Downloads

File	For
121GW-Companion-1.3.3-windows-x64.exe	Windows 10 / 11 (installer)
121GW-Companion-1.3.3-macos-arm64.dmg	macOS on Apple chips (M1 and newer)
121GW-Companion-1.3.3-macos-x86_64.dmg	macOS on Intel processors
121GW-Companion-1.3.3-linux-amd64.deb	Ubuntu, Debian, Mint (sudo apt install ./<file>)
121GW-Companion-1.3.3-linux-x86_64.AppImage	any other 64-bit Linux

On the meter: Bluetooth on (hold PEAK), other Bluetooth apps for the meter closed. Do not pair the meter in the computer's Bluetooth settings. Free for individuals, schools and non-profits (licence).

What's new

New in 1.3.3: a version for Intel Macs (macos-x86_64), signed and notarized like the one for Apple chips (GitHub issue 23). Also: the battery type setting of firmware 1.3.4 (F-1.34, GitHub issue 36) in the meter settings list.

Earlier versions: the whole changelog.

121GW-Open-Firmware v1.3.3

Replacement firmware for the EEVblog 121GW, with an emulator of the meter and the 121GW Companion app.

Downloads

File	What it is
firmware-v1.3.3.zip	the firmware: install it with the Companion, or copy EEVBlog.bin to the SD card (how)
121GW-User-Manual-v1.3.3.pdf	the user manual
121GW-Open-Firmware-Emulator-v1.3.3-<platform>	the emulator: macOS (Apple chips), Windows, Linux (how to start it)
121GW-Companion-<version>-<platform>	the Companion app: Windows, macOS, Linux

What's new

New in v1.3.3 (F-1.33): continuity with a threshold and hysteresis of your own. The threshold page of the continuity function has two more choices, DNUSr (beep on a short, at or below your threshold) and UPUSr (beep on an open, at or above it: the one for intermittent connections, it sounds when the connection breaks). With either one the SETUP walk shows two more pages after bH: th, the threshold from 1 to 500 ohm in 1 ohm steps (30 ohm until you set it), and HY, the hysteresis from 0.1 to 25.0 ohm in 0.1 ohm steps (5.0 ohm until you set it): once the tone is on it stays on until the reading is that far past the threshold, so a reading near the threshold does not chatter. The 16 fixed thresholds work as before. The settings take three spare bytes of the meter's memory that share nothing with the calibration, the serial number or the other options; the 121GW Companion 1.3.1 shows and changes them.

Earlier versions: the whole changelog.

121GW Companion v1.3.2

The 121GW Companion: the computer app for the EEVblog 121GW over Bluetooth (live view, graphs, recording, card files, settings, firmware and bootloader updates).

Downloads

File	For
121GW-Companion-1.3.2-windows-x64.exe	Windows 10 / 11 (installer)
121GW-Companion-1.3.2-macos-arm64.dmg	macOS on Apple chips
121GW-Companion-1.3.2-linux-amd64.deb	Ubuntu, Debian, Mint (sudo apt install ./<file>)
121GW-Companion-1.3.2-linux-x86_64.AppImage	any other 64-bit Linux

On the meter: Bluetooth on (hold PEAK), other Bluetooth apps for the meter closed. Do not pair the meter in the computer's Bluetooth settings. Free for individuals, schools and non-profits (licence).

What's new

New in 1.3.2: the macOS disk image is signed with a Developer ID and notarized by Apple, so it opens like any other app: no "could not verify" question and no trip to Privacy & Security. Every part of the program is signed with the hardened runtime; the disk image carries Apple's ticket, so the check works offline too. The READ ME on the image now has only the install step and the Bluetooth question. Also: the Bluetooth library bleak is updated from 1.1.1 to 3.0.2 on every system (GitHub issue 23). On Windows a connection that Windows could not make within its 7 s ("Could not get GATT services: Unreachable") ended the attempt; bleak now asks again 1 s later, up to 10 times within 30 s, so one such answer no longer costs a whole new search, which the meter's update mode cannot afford.

Earlier versions: the whole changelog.