CricketOne user manual

For the P1 prototype set, 30 Oct 2026. This manual describes how the finished set is meant to work. Some features arrive as the match software is finished (phase 3); each such feature is marked (coming). To build the set, see the build guide.

1. In the box

Item	How many
Smart stumps: 3 for the striker’s end, 3 for the bowler’s end	6
Bails with magnets	4 (+ 2 spare)
6-port USB charger with one lead for each stump	1

Each stump has a number on its cap:

SL, SM, SO: the striker’s end, leg, middle and off;
FL, FM, FO: the far (bowler’s) end.

SM, the striker’s middle stump, is the brain of the set.

2. Safety first

Each stump holds three LiFePO4 battery cells, one of the safest battery types. Even so:
- charge only between 0 and 45 °C;
- don’t charge a stump that is wet, cracked or hot;
- keep stumps out of fire, and never open a cell.
A hard ball can break a stump. A cracked stump goes back to us, not back on the field.
Stumps and bails fly when they are hit, as normal stumps do. Wear the usual protection.
The P1 prototype is not yet sealed against rain. Bring it in when it rains (section 8).

3. Charging

Plug each stump’s USB lead into the 6-port charger, and the charger into the mains.
A full charge from empty takes about 8 hours (est.). Charge the night before a match.
A full stump runs a full day of play, about 14 hours (est.).

4. Setting up for a match (about 5 minutes)

4.1 Pitch the wickets

Push each stump’s spike into the ground like a normal stump:
- the line on the tube faces down the pitch, toward the other wicket;
- push until the base sits on the grass: only the solid spike goes in.
Put SL, SM, SO at the striker’s end and FL, FM, FO at the bowler’s end. The leg and off sides follow the batter.
Check the wicket with the usual gauge: 9 in (228.6 mm) wide, 28 in (711.2 mm) high. The stumps are made to Law 8 sizes.
Put two bails on each wicket:
- the long end goes on an outer stump;
- the short ends meet over the middle stump;
- either way up is fine.

4.2 Switch on

The stumps wake when they are pitched; on the P1 stumps, that is when the battery is connected and charged. (coming) You can also wake them from the app.

Each stump’s lights show what it is doing:

Lights	Meaning
a slow blue sweep	starting up, finding the other stumps
two white flashes from both wickets	the clock check: the wickets flash at each other to line up their clocks; keep the pitch clear for 5 seconds
a short green glow	ready

4.3 Calibration (automatic)

Each camera finds the far stumps and the creases in its first half-second, and checks its aim again between every ball. You don’t need to do anything.

If a stump is knocked over and pitched again, it re-aims before the next ball. Its calls show as unsure until both wickets are standing again.

4.4 Choose the match mode in the app (coming)

Umpires assisted: league matches. The stumps suggest each call and show the evidence; the umpires decide.
Stumps decide: club, school, junior, friendly and net games. The stumps make the sure calls themselves.
No official: no umpire at all. Sure calls are made by the stumps; unsure calls go to the two captains on the app.
Leg-side wide rule: the league’s own rule (the leg-stump line, or the MCC Law 22 reach test).

5. During play: what the stumps tell you

You see	You hear	It means
The struck wicket glows red	one long tone	Out: bowled, run out, stumped or hit wicket
Green at the wicket	one short tone	Not out: a close run-out or stumping, the batter was in
Amber, steady	two quick tones	No-ball: front foot or back foot
Amber, flashing	none	Wide
All six stumps blue	none	Over complete: six fair balls
White pulse	none	LBW evidence ready in the app; the umpire decides
White, steady	two short tones; the app notifies	Unsure call or “check count”: a person must decide (section 6)

The no-ball signal comes before the ball reaches the batter, so the batter can play a free hit.

On your phone and watch

The CricketOne app shows each call on the umpire’s, scorer’s or captains’ phones. Turn on the app’s notifications to get a buzz on your own smartwatch. Unsure calls are answered in the app (section 6).

6. Unsure calls

The stumps make a call themselves only when they are sure: the measurement is clearly on one side of the line. When it is close, hidden behind a player, or the light is poor, they don’t guess:

The stumps show steady white with two short tones, and the app notifies the umpire, scorer or captains.
With an umpire: the umpire gives the decision as normal and taps it in the app (or the scorer enters the umpire’s signal). The clip is in the app.
With no official: both captains get the ball on the app, with the clip and the track. If they can’t agree, the batter stays in (club custom; your league can change this).
Over count: if a ball in the over was unsure, the stumps show “check count”. Answer on the app and the count carries on.

What the stumps can’t see:

catches in the deep, and very thin edges;
run-outs where the bat is grounded far wide of the stumps.

The umpire or captains decide these as usual. LBW is always evidence only; the umpire decides.

7. After play

Lift the stumps out and wipe them with a damp cloth. Wipe the camera windows with a soft lens cloth, never anything rough.
Put them on charge (section 3).
Storing for more than a few days: charge to about half, and keep the set in a cool, dry place (0-35 °C). P1 stumps keep using a little power when stored, so for long storage ask your builder to unplug each battery.

8. Weather and care

Heat: the white shell reflects sun, and the stump checks its own temperature. Above 60 °C inside (est.), the cameras slow down and calls show as unsure, instead of stopping.
Cold: plays down to 0 °C. Don’t charge below 0 °C.
Rain: the P1 prototype has O-ring seals but a charging lead through the side of the tube, so bring it in when it rains. (coming) P2 is sealed to IP67 with charge pads and a breather vent, and plays in rain. To clean a stump, wipe it or rinse it gently; never point a hose or pressure washer at it.
Low sun straight down the pitch can dazzle one end. The other end carries the ball track, and anything it can’t see shows as unsure.
Floodlights and dusk: LBW evidence and close calls are more often unsure.

9. Your data and privacy

Video stays inside the stumps. Only 10-second clips around calls are kept, for 30 days.
No face recognition.
Junior matches need a parent’s consent screen in the app (GDPR, COPPA).
Every call is signed by a security chip in the stumps, so a call log can’t be changed afterwards.
(coming) Theft lock: the set works only at its home ground unless the owner unlocks it.

10. Troubleshooting

Problem	What to do
A stump stays blue and never turns green	It can’t find the others. Check SM is pitched and on; stumps need to be within Wi-Fi range (about 75 m)
“Clocks re-syncing” in the app	Calls that need both wickets show as unsure for a few seconds; play on
A wicket keeps showing unsure	Check the far wicket is standing, the bails are seated, and the camera windows are clean
A bail falls off by itself	Check the magnets are flush with the bail ends and the grooves are clean
No lights on one stump	Charge it. If it still shows nothing, it goes to the builder

11. Specifications (P1 prototype)


Stump	711 mm above the ground plus a 102 mm solid spike (813 mm overall, like a match stump), 38.1 mm across (Law 8); clear tube with white printed ends
Cameras	one per stump, 1 MP global shutter, up to 180 frames a second
Calls	bowled, run-out, stumped, hit wicket, no-ball, wide, over count; LBW evidence
Battery	3 × LiFePO4 per stump, 24 Wh, about 14 h of play (est.)
Radio	Wi-Fi between the stumps and to the app
Price target	$1,990 for the set (extra pair of stumps $1,490)

Numbers marked est. are design estimates. The field tests will measure them and update this manual.