Day 2 Flowering
Cap Junkys up front and ginger kush in back. The CJ on the right is going to be the runt of the litter
Hmmm, nice. You're a Jedi and stuff.
Ok now do this:
A
levitated root pod (3–6 in dia) suspended in an active electromagnetic cradle beneath a rotating trellis arm + SCROG net. The root pod levitates and slowly rotates (0.5–3 RPM) so the plant experiences gentle passive centrifugal tension and even canopy exposure; the SCROG net is supported by a low-friction circular ring that rides on magnetic bearings so the net can be tensioned and rotated with the arm. Roots live inside a sealed, replaceable “root pod” that receives water/nutrients through a flexible tether that carries fluid, power, and sensors. Control is via a
Raspberry Pi (high level) + ESP32/STM32 microcontroller for the fast mag-lev feedback loop (PID). Sensors monitor height, pod orientation, temp/RH, media moisture, pH and EC; automated dosing and a fail-safe mechanical cradle catch the pod if levitation fails.
System architecture (high level)
- Levitated root pod (LRP)
- Hollow cylinder 3.5" dia × 3" tall (you can scale 3–6"). Contains mesh basket for media and roots.
- Magnetic coil assembly below + position sensors above/below for vertical stabilization.
- Magnetic bearing / cradle
- Active electromagnetic suspension (electromagnets + hall/optical position sensors) combined with permanent magnet pre-bias to cut power draw.
- Backup mechanical catch ring (spring steel) that deploys within 20 ms on power loss.
- Rotating SCROG support
- Circular aluminum ring (approx 24–36" dia depending on final plant size) mounted on low-friction mag bearings (or high-quality ball bearings if cheaper).
- SCROG net attaches to ring with adjustable clips; ring rotates with a slow gearmotor or passive airflow drive.
- Tether (umbilical)
- Flexible braided cable carrying: low-pressure tubing (1/8"–1/4") for nutrient feed + drain, two thin power conductors (for sensors/pod lights if needed), and data bus (I2C/1-wire or UART). Routed through a slip-ring or rotary joint so ring rotation isn’t a problem.
- Control electronics
- Fast PID loop on microcontroller (ESP32 or STM32) reading position sensors (optical/ultrasonic or Hall arrays) and driving PWM current to coils via MOSFET H-bridge / current driver.
- Raspberry Pi handles UI, logging, scheduling, sensor fusion, nutrient dosing rules, and web UI.
- Sensors & actuators list (monitored)
- Pod vertical position (µm-mm resolution) — magnetic Hall array or optical distance sensor.
- Pod tilt/rotation — 3-axis IMU in pod optional.
- Media moisture, pH, EC in reservoir (inline probes).
- Tent temp/RH, CO₂ optional.
- Flow sensor on nutrient line, peristaltic pumps for dosing, solenoid drain valve.
Design choices & why
- Active electromagnetic suspension (AES) chosen because passive diamagnetic levitation at hobby scale needs exotic materials and huge static fields. AES gives precise control, reasonable power draw when combined with permanent magnet pre-bias, and predictable failure modes (which we can safely catch).
- Ring + tether + slip-ring architecture chosen to separate rotation from levitation (keep control simpler). Tether supplies everything and slip-ring prevents messy twisted lines.
- ESP32 for fast loop because it’s cheap, fast, Wi-Fi capable, and has enough ADC/DAC/PWM channels for coil drive and sensors. Pi handles data logging and UI.
Mechanical design — dimensions & parts (practical build)
I'll pick a target canopy ring
30" outer diameter (OD) — good for 1–2 full plants training SCROG style. Scale up/down later.
A. Levitated Root Pod (LRP)
- Outer dia: 3.5 in. Height: 3 in. Inner basket: perforated PETG cylinder 3.0 in ID.
- Pod flange: 0.25" thick, 4" OD collar so magnets/coil can interact.
- Pod weight (dry + media): aim ≤ 8 oz (0.5 lb). Keep mass low — lighter mass = easier levitation.
Materials: PETG or ABS 3D printed basket + 6061 aluminum collar.
B. Electromagnet cradle
- Permanent magnet pre-bias ring: Neodymium ring magnets embedded in cradle (Halbach-ish partial array) to create an upward bias. This supports some weight statically so coils run at modest current.
- Coil stack: 3–4 coils arranged symmetrically under the pod flange, wound on soft-iron bobbins. Each coil is driven by a current source (PWM + current sense).
- Position sensors: 3 Hall sensors spaced 120° under the pod flange to measure distance (or an IR time-of-flight sensor with mm precision). Use redundancy.
Cradle frame: 3D printed mounts + 1/8" steel base plate.
C. SCROG ring & rotation
- Ring: 0.08" aluminum sheet ring 30" OD, 22" ID (1" wide track for clips). Supported by 4 magnetic bearing pads (or radial ball bearings) on columns anchored to base.
- Rotation motor: 24 V DC gearmotor with encoder, geared for 0.5–3 RPM under load. Use reduction to increase torque and smoothness.
- Slip-ring: 6–12 channel mini rotary electrical slip ring and a fluid rotary union for nutrient line (miniature 1/8" rotary union).
D. Umbilical
- Flexible braided tubing bundle, length ~12–18 in slack, passes through rotary union. Include quick-disconnect couplings.
Electronics & control (detailed)
1) Coil drive
- Each coil: driven by MOSFET H-bridge or dedicated current-regulated driver (e.g., TI DRV series) controlled by PWM.
- Current sense resistor + op-amp for closed-loop current control.
2) Control topology
- Fast control loop on ESP32 running at 1 kHz (or at minimum 200–500 Hz)
- Read Hall sensors (position) → compute error = setpoint − position → PID → set coil currents.
- Safety interlock: if error grows > threshold or lost sensor, drop current and engage mechanical catch.
- High-level Pi tasks:
- Logging (position, current, pH, flow)
- Web UI and alerts
- Dosing schedules (peristaltic pump control)
- Overhead camera capture (optional), yield prediction
3) Sensor specifics
- Position sensor: Melexis or Allegro linear Hall sensors (digital readout) or VL53L1X ToF for mm. Use three sensors for redundancy and tilt detection.
- Flow: small turbine or Hall flow sensor inline.
- pH/EC: industrial inline probes (BNC pH probe + controller) or cheap hobby probes (calibrate often).
- Temp/RH: SHT35 or BME280 sensor.
4) Power
- 24 V DC supply for motors and coils; split regulated 5 V/3.3 V for logic. Size PSU for peak coil current: estimate coils total peak ~10–30 A depending on design — design conservatively; include current limiting. Use MOSFETs with heat sinks.
Control pseudocode (high level)
loop @ 500-1000 Hz:
read_positions = [S1, S2, S3]
pos = average(read_positions)
error = setpoint_height - pos
d_error = error - prev_error
integral += error * dt
output_current = Kp*error + Ki*integral + Kd*d_error/dt
limit output_current to safe_range
compute per_coil_currents based on output_current and tilt_correction
write currents to coil_drivers
if abs(error) > fail_threshold or sensor_fail:
engage_mechanical_catch()
alarm()
High-level tasks (Pi) run asynchronous to tune setpoint over day/night cycles.
SCROG net specifics & trellis integration
- Net mesh: 1.25" squares is common; for autoflowers smaller mesh (1–1.5") works better.
- Net mounting: elastic clips on ring; allow vertical adjusters to raise net as canopy fills.
- Training approach: start at 6–8 nodes under the net, weave branches horizontally, maintain canopy height at setpoint 0–2" above net.
- Tensioning: use turnbuckles at four quadrant points to keep net planar. Ring rotation will gently shift canopy relative to light for uniform exposure.
Fail-safe & safety systems
- Mechanical catch — spring steel cradle under pod that drops into place if coil current drops below threshold.
- Redundant sensors — at least 2 independent position sensing technologies (Hall + ToF).
- Overcurrent & thermal protection — fuses and MOSFET thermal shutoff.
- Water isolation — all electronics sealed behind splash shields and conformal coat where possible. Umbilical connectors are dripless quick connects.
- Manual lock — manual positive lock to put system into service/maintenance mode.
Bill of Materials (approximate, hobbyist parts)
(Prices are ballpark; you’ll shop for exact parts)
Mechanical
- 30" aluminum ring (custom cut) — $40–120 (metal shop/DIY)
- 6061 aluminum pod collar, PETG basket — $20 (3D print + machine)
- Neodymium ring magnets & small block magnets — $60
- Steel base plate & cradle parts — $40
Electronics
- ESP32 dev board — $8–15
- Raspberry Pi 4 (4GB) — $60–100
- MOSFET drivers / H-bridge modules (x3–4) — $40–120
- Hall sensors (x6) / VL53L1X ToF modules (x3) — $20–80
- 24 V DC 10–30 A PSU — $80–200 (depends on coil currents)
- Peristaltic pumps (2-3) — $30–60 each
- Slip ring (electrical) — $50–120
- Rotary fluid union (1/8") — $60–150
- Flow sensor, pH probe, EC probe + BNC controller — $100–300
Mechanical drive
- Gear motor with encoder (24 V, low RPM) — $40–80
- Bearings / columns / fasteners — $40
Misc
- Tubing, quick disconnects, wiring, heat sinks, enclosures — $100
Estimated total:
$700–$2,000 depending on quality and power sizing.
Assembly steps (practical)
I’m giving a clear build sequence so you don’t have to keep asking stuff.
- Fabricate pod & cradle — 3D print basket, machine aluminum collar, assemble ring magnets in cradle base.
- Wind coils / mount coil drivers — test coil resistance and temperature with dummy loads before pod present.
- Install sensors — mount Hall sensors and ToF sensors; route wiring to controller.
- Set up power — connect PSU through fuses to coil drivers and motor driver.
- Mount SCROG ring & motor — test rotation and encoder feedback. Install slip ring & fluid rotary union.
- Connect umbilical — assemble tubing and cables through rotary union to slip ring. Test for leaks.
- Deploy software — flash ESP32 with PID loop; Pi for logging/UI. Start with very low coil currents and tune.
- Tuning — gradually increase setpoint while monitoring sensors and temperatures. Tune PID gains slowly.
- Safety test — simulate power loss and verify mechanical catch deploys in <50 ms.
- Planting — start with small clone in LRP and run conservatively for first week.
Tuning guidance & troubleshooting
- Start PID with P small, I=0, D small. Increase P until you see faster response, then add small I to remove steady error, then D for overshoot control.
- Watch coil temps — if coils get hot, increase permanent magnet pre-bias or add heatsinks.
- If pod tilts, check sensor calibration and apply tilt compensation by differential coil currents.
- If rotation causes tether twist, check slip ring channels and lengthen tether slack.
Optional advanced upgrades
- Wireless IMU in pod for micro-motion logging.
- Computer vision canopy mapping with Pi Camera + OpenCV for automated net height control and LST suggestions.
- CO₂ control and automated VPD schedule integration.
- Full CAD package: export as STEP files for CNC cut ring and 3D printable cradle—if you want, I can generate dimensioned CAD drawings or a printable BOM.
Numbers you can trust (worked step-by-step)
I ran conservative power scenarios so you can plan wiring, breakers, and whether to sweat 110 vs 220.
Assumed system power consumption scenarios (realistic ranges):
- Low: 150 W — well-biased magnets, minimal pumps, tiny motor, electronics only.
- Typical: 300 W — modest coil use, motor running slowly, pumps and Pi + peripherals.
- High (peak-ish): 600 W — heavier coil duty, more pumps, higher motor torque (rare continuous).
For each: current draw and energy use.
- Low (150 W)
- Current @ 110 V = 150 ÷ 110 = 1.36 A.
- Current @ 220 V = 150 ÷ 220 = 0.68 A.
- Energy/day = 150 W × 24 h = 3.6 kWh/day → 108 kWh / 30-day month.
- Typical (300 W)
- Current @ 110 V = 300 ÷ 110 = 2.73 A.
- Current @ 220 V = 300 ÷ 220 = 1.36 A.
- Energy/day = 300 W × 24 h = 7.2 kWh/day → 216 kWh / 30-day month.
- High (600 W) — rare continuous case
- Current @ 110 V = 600 ÷ 110 = 5.45 A.
- Current @ 220 V = 600 ÷ 220 = 2.73 A.
- Energy/day = 600 W × 24 h = 14.4 kWh/day → 432 kWh / 30-day month.
(If you want exact math for another power level, I’ll compute it — but those cover the likely envelope.)
Practical electrical advice
- 110 V is fine for our expected loads (most hobby setups under ~1 kW). You’ll typically draw ~1–6 A depending on how aggressively the coils run. A standard 15 A circuit is more than adequate for these numbers — but remember other devices (lights, other gear) on the same circuit matter.
- If you start designing for continuous >1 kW, or multiple systems on the same circuit, use 220–240 V to halve line current and reduce wiring losses.
- Breaker & wiring: for peaks approaching 6–7 A you’re fine with 14 AWG/15 A wiring; if you might hit >10 A regularly, step up to 12 AWG/20 A.
- GFCI required — because this is in a tent with water. Put the system on a GFCI-protected outlet or breaker. Do not skip this.
- Isolation / safety: use a UL-rated SMPS + proper fusing. Keep all coil drivers and mains wiring inside an enclosure, away from water.
How to make it power efficient — real engineering tricks
These are practical, high-impact items you should implement:
- Permanent-magnet pre-bias the levitation (big win).
Embed a permanent magnet arrangement to carry most of the static weight. Coils then only need to supply small corrective forces. That often cuts coil power by 50–90% compared to holding everything electromagnetically.
- Use an efficient switching power supply (SMPS).
Pick a quality 24 V SMPS with >90% efficiency at your load (Mean Well or equivalent). Linear supplies are wasteful — don’t use them.
- Efficient coil drivers (current-mode switching).
Drive coils with a switching current regulator (not brute-force resistive/current-waste). MOSFET PWM + current feedback is fine; use synchronous drivers when possible to reduce losses.
- Keep control loop lean and event-driven.
Don’t run coils at high duty 100% of the time. Use PID with deadband and low-power cruise modes. e.g., after stable levitation, reduce loop bandwidth and coil current to cruise levels; only ramp up for disturbances.
- Mechanical failsafe + passive support.
The more load carried by passive hardware (magnets, mechanical cradle), the smaller the active power budget. Design so coils fight only small offsets, not total weight.
- Energy recovery for rotation (regenerative drive).
If you use a DC motor to rotate the ring, include regenerative braking—return minor energy to a buffer (supercap or battery) instead of wasting it as heat during slowing.
- Use low-friction bearings / mag bearings where possible.
Less torque needed → smaller motor → lower power.
- Scale pumps and only run them when needed.
Use small peristaltic pumps and run them intermittently. Flow sensors and smart dosing avoid continuous pump duty.
- Sensor & electronics efficiency:
Put ESP32 / Pi into low-power modes where possible. The Pi can be used mainly for logging/UI and can sleep peripherals or be woken on schedule (or replaced with a lower-power SBC if you want ultra-low draw).
- Treat heat as useful energy.
Any waste heat can warm your grow room slightly — recover via conduction rather than dumping into ventilation if you need that heat. (Don’t overheat the tent.)
Green / renewable options
- Solar + battery: to offset a typical 300 W continuous system you need roughly 1.8 kW of PV (assuming ~4 sun-hours/day). That’s enough to cover ~7.2 kWh/day. If you want a rough sizing: panel_watts ≈ daily_kWh ÷ sun_hours.
- Example: 7.2 kWh/day ÷ 4 h ≈ 1,800 W of panels (about 5–7 panels depending on panel wattage). You’ll also want an inverter and battery to cover night operation.
- Battery buffer / supercaps for peak coil draws — lets you size the SMPS for average rather than peaks, reduces stress and improves efficiency.
- Time-shift heavy loads (pumps, dosing) to cheaper grid times if you have TOU billing — save money though not grid-green by itself.
Quick cost estimate for electricity (so it stings less)
Using U.S. average electricity price ≈
$0.15 / kWh (change per your local rate):
- Low (150 W) → 108 kWh/mo → $16.20 / month.
- Typical (300 W) → 216 kWh/mo → $32.40 / month.
- High (600 W) → 432 kWh/mo → $64.80 / month.
Final practical checklist to keep it green + safe
- Design strong permanent-magnet pre-bias.
- Use an efficient 24 V SMPS (≥90%).
- Use switched current drivers and small deadbands.
- GFCI-protected outlet and splashproof enclosures.
- Proper breaker/wire sizing (12 AWG/20 A if you expect >10 A peaks).
- Add supercap/battery buffer for coil peaks and regen.
- Run pumps intermittently, not continuously.
- Consider solar + battery if you want to offset ongoing operating cost.
Do cannabis roots excrete waste?
Why do roots release these compounds?
Waste removal
Is this harmful to the plant or soil?
Summary
www.thcfarmer.com
GREEN LIGHT: These Plants Are Ready to Flip TODAY.
1. Canopy Health: Excellent
2. Structure: Perfectly Set for a 4×4 Flip
3. CO₂ Bag Placement: Excellent Placement
4. Climate + Structure Together = GO
NEXT STEPS (TONIGHT @ 4PM)
3. You’re reading the plants — not just following steps
