One sideline station per practice field: heat number, lightning clock, sprint timing and referee flag buzz
Software: $299 per field per year
Concept, not for sale yet. Tell us if you want it; that decides what we build.
Rate this idea and tell us what to change
Drag to rotate · right-drag to move · scroll to zoom · click a part for its size and placeSwipe to rotate · pinch to zoom · two fingers to move · tap a part for its size
How it fits together
Scroll or tap a part. Press “See the 3D CAD design” to watch the model, built from our CAD, light each part up and show how it connects.
Real-time 3D render · drag to rotate · final design may varySwipe sideways to rotate
01
The whole FieldSide
One fence-post station works out the heat number, hears lightning, lights the sideline digits and is the radio hub for flags and sprint poles.
02Brain
LilyGO T-SIM7080G-S3 (ESP32-S3 + LTE-M)
The brain: it runs the fieldside-station program
03
Shade air and globe
Reads shaded air, humidity and the black globe's sun heat
LilyGO T-SIM7080G-S3 (ESP32-S3 + LTE-M) · I²C + SPI (MAX31865) · Air °C, RH, globe °C
04
Ultrasonic wind sensor
Measures wind speed on the post top, no moving parts
LilyGO T-SIM7080G-S3 (ESP32-S3 + LTE-M) · RS485 Modbus (address 1) · Wind speed
05
Lightning detector
Hears strikes up to about 40 km and starts the 30-minute clock
LilyGO T-SIM7080G-S3 (ESP32-S3 + LTE-M) · SPI + interrupt pin · Strike distance, interrupt
06
TAP spot
Athletes tap wristbands in for heat-acclimatization days
LilyGO T-SIM7080G-S3 (ESP32-S3 + LTE-M) · I²C (4 wires) · Wristband IDs
07
Sideline digits
Shows heat number and colour, lightning countdown or last split
LilyGO T-SIM7080G-S3 (ESP32-S3 + LTE-M) · One data line, 2 m cable · Digit colours
08
Referee flags and band
Flag press buzzes the referee; station adds a lightning stop buzz
XIAO ESP32-C3 · ESP-NOW radio · Flag events, stop alerts
09
Sprint timing poles
Each pole times the torso crossing; the station keeps the clocks
XIAO ESP32-C3 · ESP-NOW radio · Crossing times, clock sync
10
All connected
8 key parts, one program, and your phone
What it is
A solar sideline station with one brain that does the heat, lightning, check-in, sprint timing and referee flag jobs for one practice field.
What it does
Who it's for
High-school athletic directors and athletic trainers, and clubs that share one field.
How the parts connect
Every part, what links it to the brain, and how the data reaches your phone. A solid line is a cable; a dashed line is a radio link.
The program
for (;;) {
if (minute_tick()) {
s = read_heat(); // SHT45 I2C, MAX31865 SPI, wind RS485
wbgt = liljegren_wbgt(&s); band = band_for(wbgt, ruleset);
}
if (as3935_irq() && strike_km() <= 16) {
clock_restart(30 * 60); // NFHS 30-minute rule
espnow_send(BAND, STOP_LIGHTNING); // referee's wrist buzzes
}
evt_t e;
while (espnow_pop(&e)) // flags and sprint poles
e.kind == POLE ? splits_add(&e) : band_relay(&e);
tag = pn532_poll(); // TAP spot
if (tag) roll_tap(tag);
digits_show(clock_running() ? clock_left() : split_fresh() ? last_split() : wbgt, band);
if (band_changed() || uplink_due()) sim7080_mqtt_publish("fs/dev/tele", pack());
vTaskDelay(pdMS_TO_TICKS(20));
}To your phone
Coach, trainer and AD phone or laptop browser
One screen for each job FieldSide does.
Heat bandMid-practice on field 2 the heat number climbs. The station moves the band from Yellow to Orange and texts the coaches.
LightningA storm builds to the west. The station hears a strike 9 km away, starts the 30-minute clock and buzzes coaches and the referee band.
Sprint timesCoaches set four poles in a lane. Each athlete runs 30 m, and the split lights up on the sideline digits and in the app.
Referee flagsOn match day the assistant referees raise their flags. The referee wrist band buzzes, and the station logs each flag with the match time.
App screens with sample data. The interface is in development.
| Heat reading | WBGT 87.4 °F, band Orange | Every 30 min in practice |
|---|---|---|
| Lightning clock | Strike 9 km, 28:15 left | During a stop |
| Sprint split | #14 0-10 m 1.82 s | Each run |
| Flag log | Left AR raise 61:04 | Each flag, match days |
| Acclimatization day | Band 17, day 3 | Each tap |
The station stores wristband and bib numbers, not names. Names live only in the trainer's roster. No camera.
CAD design · Design rev A, 27 Oct 2026: CAD, fit checks and assembled 3D model done; not built
| AI processor | LilyGO T-SIM7080G-S3: ESP32-S3 + SIMCom SIM7080G LTE-M/NB-IoT + GNSS |
|---|---|
| Sensors | Sensirion SHT45 in a printed radiation shield · PT1000 in a 150 mm black globe (MAX31865) · Renke ultrasonic wind sensor (RS485) · SparkFun AS3935 lightning detector · PN532 tap reader under the door · TFmini Plus + TF-Luna LiDAR in each sprint pole · LIS3DH + thumb button in each flag grip |
| Connectivity | LTE-M to the cloud · ESP-NOW to flags, referee band and poles · Own Wi-Fi hotspot at the lane |
| Power | 30 W solar + 12.8 V 12 Ah LiFePO4: about 2.8 days with the display lit 4 h a day, 43 days without (est.) |
| Enclosure | White ASA fence-post box, arm and shield; black ASA digit modules; yellow flag grips; orange pole heads |
| Dimensions | Station 260 x 248 x 114 mm; digits 4 x 176 x 250 mm; flag grip 34 x 220 mm; pole head 120 x 60 x 43 mm |
| Weight | ~3.5 kg station with battery (est.) |
| Ingress rating | IP65 target for the station (est.) |
| Heat | WBGT band every minute, coach alerts, heat log |
|---|---|
| Lightning | 30-minute clock from its own detector |
| Check-in | Wristband tap for acclimatization days |
| Sprints | 4 poles, 3 splits a run |
| Referee | Flag buzz on the band, lightning STOP buzz |
| Mount | 2 U-bolts on a 1-5/8 to 2-7/8 in fence post |
|---|---|
| Power | 30 W solar, no mains |
| Radio range | About 70 m to the far touchline (untested) |
| Data | LTE-M SIM included |
Targets for production units; they may change during development.
Hardware: $999–$1,690 station + display, or full field kit
Software: $299 per field per year
Target pricing: $999 for the station and display, $1,690 for the field kit (station, display, flag Set, 4 sprint poles, 100 wristbands) + $299/yr. Bought separately for one field, FieldFlag with StrikeClock, RollCall and display ($1,496 + $299/yr), an OffsideFlag Set ($249) and a SplitPole Squad Kit ($649) add up to $2,394 + $299/yr. Parts cost about $1,290 per field kit at qty 1 (est.).
$999
Heat, lightning and check-in for one field.
$1,690
Every job on one field.
Custom
Many schools, one dashboard.
Indicative launch pricing in USD, excluding taxes and shipping. Final pricing is confirmed before any balance is charged.
Community
FieldSide is in development. Rate the idea, tell us what to change about the features, specs or price, and we'll build it with your feedback.
How much people want it
–
No ratings yet
Follow FieldSide
Get build updates and first access when pre-orders open.
No comments yet. Tell us what you'd want from FieldSide.
Questions
Tell us what this would save you, or ask anything. We reply within two business days.
A member of the IEMI Labs team will reply within two business days.
From the product lab · ideation phase
It does the job of FieldFlag (heat band, coach alerts, lightning clock, tap-in and sideline digits, with HeatFlag's heat sensors), OffsideFlag (flags that buzz the referee) and SplitPole (sprint timing poles). Bought separately for one field those are $2,394 + $299 a year; FieldSide is $1,690 + $299 a year.
No. It measures heat and hears lightning, shows the band and the clock and alerts people. The athletic trainer or coach decides. It is not UIL, GHSA or NFHS approved.
No. The detector chip estimates the distance to strikes it hears, up to about 40 km. It is an extra warning, not a replacement for a weather service, the forecast or your own eyes and ears.
The referee crew on match days. Referees often bring their own flags, and leagues must allow electronic flags. The station listens to the flags, logs them and can buzz the referee STOP for lightning.
No. It is a concept in design. Specifications are targets. We are not taking orders, reservations or deposits, and it has no ship date yet.
IEMI's one product for school and club athletics: the pair of finish posts, made smart, with one brain and one app.
From $2,090 $2,090 for the pair of smart finish posts with the starter unit
Details
IEMI's one cricket product: a smart wicket pair at Law 8 size, with every sensor inside the stumps.
From $1,990 per CricketOne
Details
IEMI's one football product: a pair of legal full-size goals with cameras, computers, batteries and radios inside the posts and crossbar, and a referee wrist unit.
From $4,690 per pair of smart goals with sockets and the referee wrist unit
DetailsFieldSide
Concept · target $999