GroundsKit

How it fits together

GroundsKit, part by part

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.

See the 3D CAD designShow the concept

Real-time 3D render · drag to rotate · final design may varySwipe sideways to rotate

1. 01

   The whole GroundsKit

   A post by the shed hears wet-spot pucks, tarp tags and rain, and sends RTK corrections and the wet map to the striper.

2. 02Brain

   XIAO ESP32S3 in the GroundBase

   The brain: it runs the groundbase firmware program

3. 

   03

   Wet-spot puck

   Reads soil wetness and standing water, flush in the turf

   RAK3272S receiver · LoRa radio, 915 MHz · Wetness vs baseline, standing water

4. 

   04

   Tarp cover tag

   Sees the tarp pulled on or off, and rain on it

   RAK3272S receiver · LoRa radio, 915 MHz · Cover on/off, rain on cover

5. 

   05

   Rain gauge

   Counts rain on the post, about 0.28 mm a tip

   XIAO ESP32S3 in the GroundBase · GPIO pin (reed switch) · Bucket tips

6. 

   06

   LoRa receiver

   Hears every puck and tag around the field

   XIAO ESP32S3 in the GroundBase · UART (AT commands) · Node reports

7. 07

   RTK base station

   Fixed GPS on the post makes the corrections

   XIAO ESP32S3 in the GroundBase · UART (UBX, RTCM3) · Corrections, fix state

8. 08

   Link to the striper

   Carries corrections and the wet-spot map to the handlebar

   XIAO ESP32S3 in the GroundBase · UART to 915 MHz radio · RTCM3 + wet-spot map

9. 09

   Striper handlebar screen

   Guides the walk, opens the paint valve, holds wet lines

   Waveshare ESP32-S3 display · 915 MHz radio link · Paint plan, puck positions

10. 10

    All connected

    8 key parts, one program, and your phone

How the parts connect

GroundsKit, wired up

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

What controls GroundsKit

for (;;) {
    node_msg_t m;
    while (rak_read(&m))                         // UART2: RAK3272S AT +EVT:RXP2P
        ground_update(&m);                       // puck wetness / water, tag on/off / rain
    ground_add_rain(rain_tips_take());           // GPIO ISR, 0.28 mm a tip

    size_t n = f9p_read_rtcm(buf, sizeof buf);   // UART1 from the base ZED-F9P
    sik_write(buf, n);                           // UART0 to the 915 MHz radio
    if (sik_idle_ms() > 800)
        sik_write_map(ground_wet_map());         // puck x/y + state, about 60 bytes

    if (every_ms(15 * 60 * 1000))
        mqtt_publish_ground_page(ground_page()); // Wi-Fi to the shed router, TLS
    vTaskDelay(pdMS_TO_TICKS(20));
}

To your phone

How the data reaches GroundsKit app

Phone or laptop browser; run screen on the handlebar

1. GroundBase post
2. Wi-Fi to the shed router
3. IEMI cloud
4. MQTT over TLS
5. GroundsKit app

Key specs

Targets for production units; they may change during development.

Pricing

Target pricing. Bought separately, SmartLine Guide ($2,490 + $29/mo) and a FieldFlag station with the GroundCheck kit ($699 + $349 + $299/yr) add up to $3,538 + $647 a year. Extra wet-spot pucks $49, tags $39. Parts cost about $1,200 per kit (est.).

Indicative launch pricing in USD, excluding taxes and shipping. Final pricing is confirmed before any balance is charged.

1. 28 Oct 2026, 01:00LatestOne school athletics product, as the smart finish posts themselves.

   • Still part of AthleticsOne, now redesigned as smart finish posts: https://iemilabs.com/products/athleticsone/

   See it in 3DFull research and design

2. 27 Oct 2026, 21:55Schools want one product for heat, lightning, wet fields and race timing, not one per job.

   • GroundsKit page now links to AthleticsOne: https://iemilabs.com/products/athleticsone/

   See it in 3DFull research and design

3. 27 Oct 2026, 15:27After rain the groundskeeper must decide whether to mark lines and whether a field is playable: paint makers say to let the field dry fully before striping (Krylon, Rust-Oleum), parks departments post open or closed by 7 am (Montgomery Parks, Rainout Line), and Canberra and Moreton Bay check wet spots with sensors because damage happens under the surface. Our SmartLine Guide and a FieldFlag station with GroundCheck cost $3,538 + $647 a year together.

   • New product GroundsKit: one post by the shed is the GPS base for the striper and the receiver for wet-spot pucks, tarp tags and a rain gauge, with one brain (XIAO ESP32S3), one radio link and one app
   • Checked first: the striper visits once or twice a week but the pucks report every 15 minutes, so the striper cannot be the receiver; the receiver moved into the GPS base instead
   • Reused CAD parts unchanged: the SmartLine mast clamp, antenna puck, handlebar display, control box (printed twice, the second as the GroundBase box) and valve bracket, and the GroundCheck pucks and cover tags. New: a post-top antenna socket and a post saddle. 15 printed parts, each one solid, every bought part fits
   • 3D view: a school field with the striper on the touchline, the GroundBase post by the shed with its antenna and rain gauge, a puck flush in the turf and a tag on the rolled infield tarp
   • Program: 4 new checks pass, such as holding only the line next to standing water and showing a silent puck as missing, never dry
   • Dropped: SmartLine's tripod and its set-up each time, GroundCheck's own receiver box and cable, and the need to buy a heat station first; heat and lightning stay with FieldFlag
   • Hardware: parts about $1,200 a kit (est.); priced $2,890 + $39 a month against $3,538 + $647 a year for the two separately; product page, parts list, how-it-works and design notes added

   See it in 3DFull research and design

4. 27 Oct 2026, 15:27After rain the groundskeeper must decide whether to mark lines and whether a field is playable: paint makers say to let the field dry fully before striping (Krylon, Rust-Oleum), parks departments post open or closed by 7 am (Montgomery Parks, Rainout Line), and Canberra and Moreton Bay check wet spots with sensors because damage happens under the surface. Our SmartLine Guide and a FieldFlag station with GroundCheck cost $3,538 + $647 a year together.

   • Combined into GroundsKit (https://iemilabs.com/products/groundskit/); SmartLine Kit itself is unchanged

   See it in 3DFull research and design

5. 27 Oct 2026, 15:27After rain the groundskeeper must decide whether to mark lines and whether a field is playable: paint makers say to let the field dry fully before striping (Krylon, Rust-Oleum), parks departments post open or closed by 7 am (Montgomery Parks, Rainout Line), and Canberra and Moreton Bay check wet spots with sensors because damage happens under the surface. Our SmartLine Guide and a FieldFlag station with GroundCheck cost $3,538 + $647 a year together.

   • Combined into GroundsKit (https://iemilabs.com/products/groundskit/); FieldFlag itself is unchanged

   See it in 3DFull research and design