Stop babysitting the fruiting room
A fogger that quits at 2am dries back the pins and aborts the flush. LoopString texts you before it does.
What actually loses a flush
A few bad hours ends a flush
A humidifier that runs dry or a fogger that quits for a few hours dries back the pins for good — and you find out at the morning check. LoopString texts you the moment humidity leaves the band, not the next morning.
Are you exchanging the air, or just moving it?
Weak fresh-air exchange is the quiet killer: pins stretch into stems with stunted caps, clusters abort, and the room starts to smell off. LoopString watches CO₂ in every room and fires the FAE fans before the air goes stale.
What did each room actually live through?
When a flush comes out short, the whiteboard and the spreadsheet can’t tell you what the room actually did that week. LoopString logs every fruiting room on its own, so you can see exactly what a flush lived through instead of reconstructing it.
How LoopString Solves It
Humidity that holds overnight
The humidifier cycles against your target band on the Pi itself, holding RH tight through pinning and fruiting. There is no cloud round-trip to fail, so a dropped connection never stops the room.
FAE that fires on the air, not a guess
Watch CO₂ climb across the flush and trigger fresh-air-exchange fans on a threshold or a schedule — so you stop circulating the same stale air and start actually exchanging it.
A text before you lose the flush
SMS and in-app alerts fire the moment temperature, humidity, or CO₂ leaves the range you set. The 2am failure reaches you at 2am, while you can still save the room.
Colonization and fruiting on autopilot
Recipes move each room between stages for you — higher CO₂ and no FAE while colonizing, then fresh air and humidity for pinning and fruiting. No sticky notes on the rack.
See what your best flush actually saw
Every reading is logged, so you can line your conditions up against the weigh-out and repeat the runs that hit — instead of guessing why one block beat another.
How It Works
Flash the card and boot the Pi
Write the LoopString image to an SD card and power up. The first-boot wizard links the Pi to your account in about five minutes.
Plug in your sensors
Connect a temperature-and-humidity sensor, a CO₂ sensor, and a relay board for your humidifier and FAE fans. Screw terminals, no soldering.
Pick the fruiting-chamber template and go
Start from the Mushroom Fruiting Chamber template, check the room targets, and turn it on. Then watch every room from your phone.
Pre-Built Template
Mushroom Fruiting Chamber
A complete fruiting-chamber setup: humidity held to your target band, FAE fans on a CO₂ threshold, temperature watched, and alerts on the windows that actually lose a flush. Estimated hardware: ~$80.
- Temperature + humidity sensor (DHT22 or SHT31)
- CO₂ sensor (MH-Z19)
- Relay board for the humidifier and FAE fans
- Humidity held to a 90–95% band through fruiting
- FAE fans fire when CO₂ climbs past your ceiling (default 2000 ppm)
Hardware You'll Use
DHT22
Temperature & humidity sensor
GPIOMH-Z19
CO₂ sensor for the fruiting room
UARTSHT31
Higher-accuracy temperature & humidity (I²C alternative)
I²CRelay HAT
Switches the humidifier, FAE fans, and heater
GPIO
Join growers who stopped checking the room at 2am
Free tier supports one device and up to 8 sensor slots — enough for a complete single-chamber setup.
Frequently asked questions
- Can LoopString control temperature, humidity, CO₂, and FAE for mushrooms?
- Yes. It reads temperature, humidity, and CO₂ and drives humidifier, fan (fresh-air exchange), and heater relays on the Pi to hold your fruiting conditions, switching targets between colonization and fruiting.
- Can I program different stages for colonization and fruiting?
- Yes. Recipes and schedules move the environment between stages automatically — higher CO₂ and no FAE during colonization, then fresh-air exchange and humidity for pinning and fruiting.
- How does it keep humidity high without runaway condensation?
- The on-Pi loop cycles the humidifier against a target band and coordinates FAE fans, and threshold alerts flag if RH or CO₂ leaves the range you set for the current stage.
Ready to stop losing flushes overnight?
Start free — no credit card required.