Formada3D Hydroponic pH / EC controller enclosure and probe holder arm: O-ring lid, BNC and gland ports (ASA)
An enclosure and probe holder for DIY nutrient monitoring and dosing builds (ESPHome-style controllers). The box takes an ESP32-DevKitC-size board and two 42 x 32 mm pH / EC signal boards on standoffs, has two BNC bulkhead holes for the probe cables and two PG7 cable-gland holes, and closes with an O-ring face-sealed lid on four M3 inserts. The probe arm clamps over a reservoir or bucket rim and holds a 12 mm pH probe, a 12 mm EC probe and a 6 mm temperature probe at any depth, gripped by O-rings in the bores so there are no screws on the glass. Enclosure only: no electronics and no electrical function. Black ASA for greenhouses; printed to order in our Melbourne workshop.
From A$8 for the probe holder arm. Printed to order in Melbourne and shipped Australia-wide; we confirm the final price and lead time before anything is printed.
On the quote page choose Request a quote (no file needed) and name this part and the option you want.
Order status. Every fit comes from published drawings. Check that your BNC bulkhead has a D-flat (Amphenol 31-10 style); a round-only bulkhead needs a lock washer. The lid is designed for an O-ring face seal but has not been tested to an IP rating.
What does it look like in use?
Renders are computer images of our own design, made from the same model we print. This family is made to order: real photos of our first prints are coming.
Specifications: material, size and what it fits
| Spec | Detail |
|---|---|
| Material | ASA (black, UV and heat resistant for greenhouses), 0.24 mm layers, 3 walls, 15 % gyroid, no supports. PETG on request for indoor tents |
| Enclosure | 119 x 105 x 36 mm box + lid. Corner-post cradle for an ESP32-DevKitC V4 (48.26 x 27.94 mm, held with foam tape), four standoffs (2.1 mm pilots, M2.5 self-tap) for each of two 42 x 32 mm signal boards (holes 35 x 25 mm), two BNC bulkhead D-holes (9.5 mm, 8.7 mm across the flat), two PG7 gland holes (13.0 mm) |
| Lid seal | O-ring face seal for an AS568-048 O-ring (120.24 x 1.78 mm), lid on 4 x M3 heat-set inserts. Splash-resistant design; not tested to an IP rating |
| Probe arm | 136 x 26 x 16 mm, hooks over rims up to 16 mm thick with an M5 thumb screw. Bores for two 12 mm probes (12.8 mm with 12 x 2 mm O-rings) and one 6 mm temperature probe (6.4 mm with a 6 x 1.5 mm O-ring); probes slide to any depth |
| Fits | DFRobot Gravity-style pH and EC probes (12 mm bodies) and V2 signal boards, Atlas Scientific consumer probes (12 mm), ESP32-DevKitC V4, Amphenol 31-10-style D-flat BNC bulkheads; all from the makers' published drawings. Generic 6 mm stainless temperature probes |
| Not included | Electronics, probes, BNC bulkheads, glands, O-rings, 4 x M3 x 5.7 inserts, 4 x M3 x 10 countersunk screws, M5 thumb screw and nut |
| Weight | About 126 g in ASA for box, lid and arm |
DFRobot, Gravity, Atlas Scientific, Espressif, ESP32 and Amphenol are trademarks of their owners, named only to describe fit. This enclosure is our own design and is not affiliated with or endorsed by them.
How much does it cost?
Guide prices for printed parts, in Australian dollars. Shipping is extra; we confirm the final price, including any business minimum, before printing. Bulk and custom sizes are quoted per job.
| Option | From |
|---|---|
| Probe holder arm, ASA | A$8 |
| Enclosure: box + lid, ASA | A$32.95 |
| Enclosure + probe holder arm, ASA | A$39.95 |
| PETG for indoor tents | Quoted on request |
Who it's for
Hobby hydroponic growers automating pH and EC monitoring or nutrient dosing, makers building ESPHome controllers, and schools running sensor projects.
Safety & use
Installation & use. Designed for the uses described on this page only. Fixings are not included: use the sizes listed, check they are tight before use, and check the parts regularly for wear or damage. Not for safety-critical or overhead load-bearing use. Damage caused by misuse, modification or overloading isn't a fault in the product.
Electronics. A plastic enclosure with no electrical function. Boards, probes, pumps and power supplies are your own: fit and use them to their makers' instructions, keep mains-powered parts out of the box, and keep the box above the reservoir where a spill cannot reach it.
Sealing. Splash-resistant design with an O-ring lid; not tested to an IP rating. Do not submerge it or rely on it where water getting in would be dangerous or costly.
This doesn't affect your rights under the Australian Consumer Law.
Common questions
What fits inside?
An ESP32-DevKitC-size board on a corner-post cradle and two 42 x 32 mm pH / EC signal boards (such as DFRobot Gravity V2) on standoffs, with two BNC bulkhead holes for the probe cables and two PG7 gland holes for power and pump wires.
Is it waterproof?
It is a splash-resistant design with an O-ring face-sealed lid, but it has not been tested to an IP rating, so we do not claim one. Mount it above the reservoir, not in it.
Which probes does the arm hold?
Two 12 mm probe bodies (pH and EC, such as DFRobot or Atlas Scientific consumer probes) and one 6 mm stainless temperature probe. O-rings in the bores grip the probes so they slide to any depth with no screws on the glass. The arm hooks over rims up to 16 mm thick.
Does it include electronics?
No. It is an enclosure and a probe holder only: no boards, probes, connectors, glands, inserts, screws or O-rings are included, and it has no electrical function. The sizes you need are listed in the specifications.
How do I order?
Use Get a quote and choose Request a quote, naming the enclosure, the arm or both, and ASA or PETG. We confirm the price and lead time before anything is printed.
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Last updated 15 October 2026.