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 and wakes the device from sleep. Power-off is done from the menu.
USB-C	Charging. Plugging into a powered-off device opens the charging screen (Section 9).

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 8). 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.
• 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 or total.
• 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.

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 or total (odometer).

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 8). 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 8).

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:

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 8) — it shows top-left on the pet screen.
• Hold A for the menu, then Dashboard to ride.

MyBuddy screen

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.

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. See Section 11.

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. Only a button press resets the timer.
• 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.)

Power off

• Menu → Power off, or from the WiFi panel.

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 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 (shown three fields at a time — press A to flip pages, B to close).
• 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.
• Tap a ride for a details pop-up; edit any value by hand, add a ride manually, or delete one.
• Download CSV to keep or analyse your whole history on a computer.

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.

Open the web flasher →

Updating in the browser

FAQ

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