EucBuddy — User Manual

Device & buttons

EucBuddy runs on a small M5Stick-S3 with a screen, a battery and a USB-C port. It's driven by two buttons plus a power button.

Part	What it does
A Main button	Large front button. Short press = next / select; hold ~1 s = open menu.
B Side button	Small side button. Short press = confirm / back (context-dependent, e.g. headlight, horn or trip reset — the ride-screen action is configurable, see Section 6).
PWR Power	Side button. Turns on, wakes from sleep — and a press while the device is running switches it off (the menu's Power off does the same). Section 11.
USB-C	Charging. Plugging into a powered-off device opens the charging screen (Section 10).

Throughout this guide A is the main button and B is the side button.

M5Stick-S3 — EucBuddy runs on it

First start & pairing

Favorite wheels

Star the wheels you ride so they're always easy to find. Favorites jump to the top of the scan list and get a star ★. You can have as many as you like.

A custom name then shows in place of the Bluetooth name on the scan list, and top-left on the Dashboard instead of the vendor (e.g. "My Sherman" instead of "Veteran"). Long names scroll by themselves on the highlighted row.

The six ride screens

Once connected, a short press of A cycles six screens (default order): Dashboard → Custom 3 → Power → Trip → Stats → Custom 1 and back. You can reorder them or hide ones you don't use in the WiFi panel (Section 9). Two of the six are yours to configure — Custom 3 (three values) and Custom 1 (one value) — under Dashboard setup → Dashboard config (Section 6). Each screen is the same idea — a different headline value:

1 · Dashboard — live ride

• Big speed (colour shifts cyan → yellow → red).
• Wheel battery %, voltage and current.
• A short press of B runs your Short B action — headlight by default (if your wheel supports it), or horn. Set it under Dashboard setup (Section 6).

2 · Custom 3 — three values, your choice

• One big value on the left, two small ones stacked on the right — you pick all three.
• Out of the box it's the classic PWM safety screen: PWM % big (how hard the motor works; near 100 % = near a cut-out) with speed and voltage beside it. green <80 · yellow 80–90 · red 90+ (back off).
• Change any slot under Dashboard setup → Dashboard config or in the WiFi panel; short B = your Short B action (headlight by default).

3 · Power — battery & output

• Tall battery gauge and percentage down the left, with voltage and watts below it. The watts are what the pack is actually delivering, and take the same colours as the current below — pink drawing, cyan on regen.
• Current is the hero on the right — pink when drawing, cyan on regen — over a slim 0–100 A load bar.
• Speed and temperature sit in the footer.

4 · Trip — distance

• RIDE — distance of the current ride.
• TRIP — resettable counter.
• Press B to reset the trip (confirm popup).

5 · Stats — per-wheel stats

• TOTAL — wheel odometer.
• Ride count, top speed and peak current.
• Press B to clear the peaks (confirm popup).

6 · Custom 1 — one value, your choice

• A single value, big and centred — you pick which.
• Speed, battery, voltage, current, power, temp, PWM, trip, ride, total, ride time or energy used.
• Set via Dashboard config in Dashboard setup or the WiFi panel; short B = your Short B action (headlight by default).

Button cheat-sheet

Menu — every option

Hold A from any screen to open the main menu — an animated carousel of icons. A moves between them, B opens the one in the middle, holding A takes you back. The item you're already on is hidden, so you only see where you can go:

Dashboard setup

Choose Dashboard setup from the carousel to configure how ride screens behave. Press A to move and B to change a value. The list shows a few rows at once and scrolls as you move through it.

The six backgrounds

Same dashboard, one setting — Background repaints only the backdrop. Telemetry, colours and layout never change. Blue is the default; B steps through them and the row's live swatches show what you're picking.

The tints are lifted a few percent here so the hues survive a bright phone screen — on the device they sit much closer to black, which is exactly what keeps the telemetry crisp. The coloured frame is just this guide's swatch border.

Dashboard config — the two Custom screens

Four rows, one per slot. B steps each one through the same list of values: speed, battery, voltage, current, power, temp, PWM, trip, ride, total (odometer), ride time (TIME, mm:ss and h:mm:ss past an hour) or ride energy (ENERGY, Wh) — the last two are new, see Section 4.

Leaving the defaults alone gives you exactly the old fixed PWM screen. Whenever PWM sits in the Custom 3 main slot it keeps its safety colours and the set calib / PWM est tags described in Section 4. All four slots are also in the WiFi panel.

Settings

From the carousel pick Settings. Move with A, change with B. Names match the on-screen labels.

My Wheels — favorite wheels & PWM calibration

The carousel's My Wheels icon lists every wheel you've starred (Section 3). If you haven't starred any yet, it prompts you to hold B on a wheel in the scan list. A moves down the list, B opens the highlighted wheel; a small green dot marks wheels that already have a PWM calibration. Each wheel's detail screen shows:

Why calibrate? Wheels that don't report their real motor duty (KingSong, classic InMotion, older Begode) show no PWM until you set the two values above — then EucBuddy estimates the duty from live speed and voltage using your wheel's calibration values (marked “PWM est” on the Custom 3 screen). Wheels that already send real PWM don't need this. Calibration is stored per wheel, kept across power-offs and updates, and can also be set from the WiFi panel's Favorite EUC section (Section 9). Editing it while that wheel is connected updates the live estimate at once.

EUC health

Open the EUC health row of a wheel's detail screen to see the diagnostics that wheel broadcasts about itself. A scrolls the rows, B asks the connected wheel for a fresh reading, holding A goes back.

The header says HEALTH LIVE when the wheel is connected right now and HEALTH LAST when you're looking at the last snapshot EucBuddy saw — dimmed, so you can tell at a glance. Anything the wheel simply never sends stays Unknown rather than pretending to be OK; how much you see depends entirely on how talkative your wheel is.

Blackbox — battery map

The carousel's Blackbox icon opens a small logger that records a battery curve to the device (about one row per second — handy for tuning). Inside:

Download the CSV from the WiFi panel (Section 9).

Alerting — speed limiter & warning beeps

The carousel's Alerting icon groups the speed limiter and the on-device warning beeps. Move with A, change with B.

Option	What it does
Limiter	Master on / off for the speed limiter — off by default. While off, holding B won't arm the cap and the top-bar glyph shows a cross. Turn it on to use the limiter.
Wheel alert	While the limiter is armed, also set the wheel's own speed warning to 1 km/h below the cap. Available for KingSong and supported modern Leaperkim/Nosfet wheels. This row is grey and cannot be changed while Limiter is off.
Speed limit	The hard-cap value the limiter writes to the wheel, in km/h (5 km/h steps).
Speed alert	Beep when your speed reaches the threshold, plus Speed val — the threshold.
PWM alert	Beep when the motor load (PWM) reaches the threshold, plus PWM val — the threshold.
Batt alert	Beep when the wheel battery drops to the threshold, plus Batt val — the threshold.

Alerting menu

Speed limiter (hard cap)

First turn on Limiter — it's off by default. Then, on any ride screen (Dashboard, Custom 3, Power, Trip, Stats or Custom 1), hold B to arm the cap. If the wheel is already stationary, EucBuddy writes and verifies your Speed limit. If you request it while riding, it confirms the request, makes the limiter gauge blink green, and waits until the wheel has been stopped for about three seconds before writing it. A second confirmation beep means the cap was verified. If verification still fails after one retry while stopped, EucBuddy cancels the request and restores the original settings. Hold again after it is armed to restore the wheel's original max. EucBuddy saves the wheel's current limit before changing it, so disabling the limiter restores the rider's original setting.

If Wheel alert is on, arming also moves the supported wheel's own warning threshold to cap minus 1 km/h. KingSong's three alarm thresholds are moved together; Leaperkim/Nosfet use their separate speed-alarm setting. EucBuddy saves every affected value first and restores each one exactly when the limiter is released. Changing the option or cap while armed keeps the original snapshot safe.

The horn is a momentary wheel command, not a saved wheel setting. It is supported on Begode/Gotway, KingSong, Veteran/Leaperkim, Nosfet and InMotion; on an unsupported wheel the action simply does nothing. EucBuddy plays a short local confirmation cue as well.

The top-bar limiter glyph

A small glyph and number sit on the top bar, just left of EucBuddy's own battery. The number is the wheel's current max-speed limit in km/h (a dash while it's being read, ∞ if the wheel has no limit set); the glyph shows the state. When you arm the cap, the number becomes your Speed limit value:

Connections — WiFi & link info

The carousel's Connections icon gathers everything WiFi in one place. A moves between rows, B changes the highlighted one, holding A goes back. WiFi is off by default and EucBuddy never switches its radio on by itself.

Using Home WiFi

Home WiFi needs your network's name and password, and those are entered in the web flasher — tick Configure WiFi before you update the firmware. EucBuddy stores them and preselects Type = Home WiFi, so afterwards you only have to open Connections and set WiFi to Always.

• Only 2.4 GHz networks work — the chip has no 5 GHz radio.
• A popup reports the result: WiFi connected with the address, or WiFi failed with the reason. A failed join is deliberate about giving up — the radio goes back off and WiFi returns to Off rather than retrying and draining the battery.
• If you pick Home WiFi without having set a network, EucBuddy says No home WiFi — Set it in flasher and stays on Access point.
• A Factory reset erases the stored network along with everything else.

Weather charging screen

With Charge screen set to Weather, plugging a charger into a switched-off EucBuddy shows a weather dashboard instead of the battery animation: a clock, the temperature right now, the sky outside, and the hours ahead. Press A or B to carry on to the normal screens, or unplug to switch off — exactly as before.

• It joins your home network to fetch this, so it needs one stored (see above). This is the only time EucBuddy brings up WiFi on its own — and only ever while it is plugged in.
• The same screen is now also a menu page you can open any time, from the carousel's yellow Weather icon.
• Forecast comes from Open-Meteo, a free service that needs no account. The clock is set from public internet time servers and follows the city you pick (the default is Warsaw).
• It updates every 15 minutes. While it is still connecting you will see Connecting… or Updating… in place of the conditions.

MyBuddy — your virtual pet

MyBuddy is a little pet living inside your EucBuddy. Open it from the menu (MyBuddy).

• B — pet your buddy (it reacts).
• Your buddy grows as you ride — it feeds on zaps (1 zap = 1 km), so it counts the same whether your screen is set to km or miles.
• When two EucBuddies are close, their pets can "greet" each other over infrared.
• Give it a name in the WiFi panel (Section 9) — it shows top-left on the pet screen.
• Hold A for the menu, then Dashboard to ride.

MyBuddy screen

Weather

EucBuddy can also be a little weather station: a big clock, the temperature right now, the sky outside and what the next few hours look like. It shows up in two places — as its own screen from the menu, and instead of the battery animation while the device sits on a charger. Both need a home WiFi network stored on the device; the forecast is the only thing EucBuddy fetches from the internet.

Two ways in

• No network stored? Both routes say Weather needs WiFi — Set it in flasher and nothing else happens. Store one in the web flasher or the WiFi panel first (Section 9).
• WiFi switched off? Opening Weather from the menu asks first — B turns the radio on just for this page and puts your WiFi setting back to Off when you leave. On the charger it needs no permission: the device is on external power by definition, which is the one case where EucBuddy brings up WiFi by itself.
• While the page is open it owns the radio, so an active config panel pauses and comes back when you leave. WiFi and Bluetooth share one antenna (Section 9).

What's on the screen

The sky glyphs

The forecast's condition codes collapse into eight conditions — a finer set stops reading clearly on a 240×135 screen. Clear and partly-cloudy skies each get a second face: a sun by day, a crescent moon with stars by night, chosen from the daylight flag for your city rather than guessed from the hour. Anything the forecast doesn't name at all stays a plain ?.

Temperature colours

Cold blues through a temperate green into warm ambers, so a glance at the hue tells you the weather before you read the number. The forecast row uses the same scale.

The steps are always these Celsius values — switching to °F changes the number you read, not where the colour turns.

The forecast strip

Four horizons come from the same request — +1 h, +2 h, +4 h and +8 h. The strip shows one at a time, holds it about five seconds and slides the next one in. The quiet time on the right is the hour it actually lands on.

The strip above cycles exactly as the device does.

Your city

• The built-in default is Warsaw, and a Factory reset puts it back.
• The clock follows the city: the time offset comes down with the forecast (already adjusted for daylight saving) and is remembered, so the clock is right from the next start. Right after a change the time is hidden until the new one lands.
• Opened over EucBuddy's own hotspot, the panel has no route to the internet to search with — it saves the plain name and the device looks up the coordinates on its next fetch. Nothing to do differently; it just resolves a moment later.

While it works — and when it can't

Until there is something real to show, the screen shows no readings at all rather than a half-filled dashboard: an animated mark, what it's doing, and why if it failed. It keeps trying — a refresh every 15 minutes, a retry about a minute after a failure — and never quietly swaps itself for the battery view.

WiFi config panel

EucBuddy can host its own WiFi hotspot with a config panel in your phone's browser — every setting with a bigger screen and a keyboard. WiFi is off by default.

In the panel you can set: battery / device ID / firmware (read-only), the MyBuddy name, brightness, sound, auto-sleep, Only-EUC, battery readout (% / V), flip screen, Begode voltage, battery-map logging (with the CSV download — Section 6), and a power-off button.

The Dashboard setup card matches the device menu: configure Short-tap B, Hold-B, what Custom 1 shows, all three Custom 3 slots (main / upper / lower), the dashboard background, units, and the temperature unit in one place.

The Speed limiter & alerts card mirrors the device's Alerting menu: master limiter, cap, EucBuddy speed/PWM/battery warnings and the optional in-wheel speed warning. That last switch is greyed out until the limiter master is enabled; changing it while the cap is armed uses the same safe save-and-restore behavior described in Section 6.

The Home WiFi card holds the network EucBuddy joins in Home WiFi mode, and the one the weather screen needs (Section 8): type the network name and password and press Save WiFi — so you can set or replace it without re-flashing. The password is written to the device but never read back to the page; only the network name comes out again. Only 2.4 GHz networks work.

Forget this network (same card, with a confirmation) erases it — and puts back what depended on it: the link Type returns to Access point and Charge screen to Battery, since neither could work without a network. The link you are reading the panel over is deliberately left alone; the change applies at the next start.

The Weather card sets your city — start typing and pick it from the live search — and which forecast steps the strip cycles through: +1h, +2h, +4h, +8h, all four on by default, none = no strip. See Section 8. (Opened over EucBuddy's own hotspot the page has no route to the internet to search with, so it saves the plain name and the device looks the city up itself.)

It also has a Favorite EUC section: give each favorite a custom name (next to its Bluetooth name), set its PWM calibration (spin km/h + volt V — the same values as the on-device My Wheels screen, Section 6), or remove a favorite with the ✕ button. See Section 3.

A Dashboards section lets you drag the six ride screens into the order you want and untick any you don't use — the device's screen cycle and dots update to match (at least one stays on). The default order is Speed → Custom 3 → Power → Trip → Stats → Custom 1 (“Speed” is the main Dashboard). What the two Custom screens actually show is set in the Dashboard setup card described above.

And a Rides section with your full ride history: tap any ride to see its details, edit values by hand, add a ride, delete one, or download everything as CSV. Every entry now also lists its ride time and the watt-hours used, and both can be edited by hand (type the time as mm:ss — for example 12:34 — as h:mm:ss for a long ride, or as plain seconds). Leave a field empty to say that value was never measured; it then shows as a dash instead of a misleading zero. Bad input is refused with a message rather than silently saved. See Section 12.

Downloads

Both CSV exports — Rides and the battery map — are meant to be run from the panel and simply work now:

• The battery-map button fetches the file in small verified pieces and shows “Downloading … %” as it goes, retrying a piece by itself if the WiFi hiccups. A large log no longer stalls part-way through on some phones.
• Using the panel counts as activity, and a download in progress holds the device awake for the whole transfer — auto-sleep can't shut the hotspot down mid-file.
• If something does go wrong (busy device, empty log), you get a clear message instead of an empty or truncated file.

Charging

Plugging USB-C into a powered-off device opens a dedicated charging screen: a battery animation, the percentage and the voltage, dimmed so it can sit on a desk.

Battery, sleep & power-off

Device battery

• EucBuddy's battery is shown top-right (% or V — the Battery option).
• The percentage is a smoothed estimate tuned to the battery's real discharge curve, so it stays steady and counts down evenly instead of jumping around or dropping fast under load.
• At a low level the device beeps a warning.
• At a critically low level it powers off with a "battery depleted" notice (except on the charging screen) — plug in USB-C.

Sleep & wake

• After the inactivity timeout (Auto-sleep) the device sleeps. A button press resets the timer — riding doesn't. Using the WiFi panel counts too, and a CSV download keeps the device awake until it finishes (Section 9).
• Wake it with the PWR button.
• If it sleeps while connected to a wheel, it tries to reconnect on wake and resume your trip without resetting the counter.
• It also comes back to the ride screen you were last on — not the first one — after a connected sleep or reconnect. (If you'd since hidden that screen, it falls back to the first one.)

Cancelling the reconnect

While EucBuddy is reconnecting after a wake you'll see “Reconnecting” with B = cancel reconnect along the bottom. Useful when you've walked away from that wheel, or want to hop onto a different one straight away.

• Press B — a “Cancel reconnect?” popup appears. A second B stops trying and takes you back to the scan list; A closes the popup and carries on. Ignore it and it disappears by itself after 10 seconds, reconnecting as usual.
• The reconnect keeps working underneath the popup — deciding to continue costs you nothing.
• A button you were already holding when the screen appeared is ignored, so waking the device with a long press can't cancel anything by accident.
• Cancelling doesn't throw your ride away. Pick the same wheel from the scan list within about ten minutes and the ride carries on where it stopped; pick a different wheel and the old ride is closed and saved first.

Power off

• Press PWR while the device is running — the screen goes dark and it switches off. Press it again to start up.
• Or menu → Power off, or the WiFi panel's power-off button. All three do the same thing.
• Switching off while connected to a wheel keeps your place: the next start reconnects to that wheel and resumes the ride, exactly like waking from sleep.
• On a charger the device cannot cut its own power while USB is feeding it, so it goes dark and quiet instead. A or B brings it back; pull the cable and it is properly off.

Rides — your ride history

EucBuddy logs every ride automatically. Each entry records the wheel, start & end battery, the voltage range (min–max), top speed, peak current, max PWM (highest motor load — see Section 4), distance, the ride time, the energy used (Wh), the odometer at the start, how many times the device slept mid-ride, and the max temperature. A ride is saved whenever you disconnect or the wheel goes out of range.

On the device — the Rides viewer

• Open it from the carousel (Rides). It works like MyBuddy — a separate screen.
• A scrolls the list (newest first); B opens a ride's details — three big fields at a time across four pages (press A to flip pages, B to close). Time and Energy sit on page 3, next to distance.
• Hold B to delete — all rides from the list, or this ride when its details are open (each asks to confirm). Hold A for the main menu.

In the WiFi panel

• The Rides section lists everything with room to scroll back through older rides. Each row shows battery, top speed, peak current, distance, time, Wh, sleeps and max temperature at a glance.
• Tap a ride for a details pop-up; edit any value by hand — including ride time (mm:ss, or h:mm:ss past an hour) and energy — add a ride manually, or delete one. Clearing a time or energy box marks that value as “not measured”.
• Download CSV to keep or analyse your whole history on a computer — the export now carries ride_seconds and energy_Wh columns as well.

Firmware updates

New firmware adds wheel support and features. Updating happens in your browser — no software to install.

Step	Do this
1	Open the flasher page in Chrome or Edge (on a computer).
2	Connect EucBuddy with a USB-C cable.
3	Click and follow the prompts — the rest is automatic.

Your settings and remembered wheel are kept across updates.

The flasher also has an optional Configure WiFi tick box. Fill in your home network's name and password there and EucBuddy stores them, so it can join your own network instead of making its own hotspot — see Connections in Section 6. The same box has a City field with live search for the weather screen (Section 8) — optional, and changeable later in the WiFi panel. Nothing you type there is sent to our servers; it goes straight to the device over USB.

Open the web flasher →

Adding ride time and energy changed what a stored ride looks like, so the first start after that update clears the ride history once. Settings, favorites, names, PWM calibrations and the lifetime counters are untouched. Want to keep the old rides? Download the CSV from the WiFi panel (Section 9) before you update.

Updating in the browser

FAQ

Questions? Message us on facebook.com/eucbuddy — happy to help.