CONCEPT DESIGN · 14 OCTOBER 2026 · NOT A FABRICATION DRAWING
A DIY feeder for a large sulcata
Shaded outdoor installation with household AC, an ESP32 controller and McMaster T-slot framing. The recommended fresh-food mechanism uses fourteen independent tipping trays: seven greens portions and seven vegetable portions. Dry pellets and water have separate dispensers.
Functional schematic only. Chutes merge near the dish, with a separate water nozzle. Provide a separate clean drinking-water dish continuously.
For sulcatas, this is supplemental feeding alongside grass/hay; omit routine apple portions. Weekly capacity does not prove seven-day freshness or eliminate daily animal checks and dish cleaning. The initial refill interval should follow monitored storage tests, not an assumption that all produce lasts a week.
Mechanisms
Fresh food: broad food-contact trays in two banks with individual pivot linkages. Tip each tray past vertical, then return it home; keep its swept path clear of every other tray and the fall corridor. Use removable stainless-steel or suitable food-contact plastic liners. Prototype wet greens and sticky slices after several days of refrigeration. Wide openings and short, steep chutes reduce snagging; they do not guarantee release.
Pellets: keep the hopper dry. An upper gate fills a small chamber, closes, then a lower gate empties that chamber. Mechanically prevent both gates opening together. Chamber size caps a release even if the lower gate stays open. Soften Zoo Med pellets before the tortoise can access them; dispensing dry pellets and immediately spraying them does not establish adequate softening. Use a removable internal preparation cup: dose dry pellets and water into it, wait for a recipe-specific softening interval confirmed with the actual pellets, then tip the cup into the plate. Clean this cup daily; do not store a week of wet pellets. Mazuri directions depend on the exact formula.
Water: use a peristaltic pump and tubing explicitly rated for drinking water, an opaque removable reservoir, and an outlet above the plate with an air gap. Place the reservoir below the outlet or add verified anti-siphon protection. A slow dosing pump may be unsuitable for large water volumes. Provide independent run-time cutoff and maximum daily dose. Adding water does not clean a dirty dish.
Cooling integration
Use compressor refrigeration. A front-opening appliance with a purpose-built insulated replacement door and outlet is a plausible integration route; final appliance selection and tray geometry remain unresolved. Do not drill the appliance shell or cut refrigerant lines. Preserve compressor ventilation, condensate management and the original refrigeration orientation. The chute hatch must seal between feeds and have position feedback. Measure the warmest stored-food location, not just the fridge thermostat.
Cold fresh-food cabinet, dry actuator enclosure and ventilated weather-protected battery/compressor space are distinct zones. A gasketed electronics box is suitable for controls; sealing the battery or compressor into that same box would trap heat. An outdoor roof needs side protection against wind-driven rain.
Candidate sourcing specification
| System | Starting specification | Before purchase |
|---|
| McMaster frame | 40 × 40 mm, 8 mm slot T-slot family, gussets, shelf supports, panel brackets, anchored feet | Use one compatible rail/nut/bracket family; size after tray and fridge layout |
| Amazon controls | ESP32 board; DM542T motor drivers; MCP23017 slow I/O; RTC; separate regulated servo and logic supplies | 3.3 V logic compatibility, safe power-up behavior and actuator stall-current budget |
| Fresh-food actuation | 14 slide motors and 14 geared tipping motors with brackets and feedback; plus outlet hatch actuator | Torque test with a wet loaded tray and cold mechanism; inspect condensation resistance |
| Pellet actuation | 2 gate actuators, dose chamber, dry hopper and tipping hydration cup | Actual pellet size, bridging, gate interlock and maximum possible discharge |
| Water | 24 V peristaltic pump, drinking-water tubing and removable tank | Flow rate, tubing lifetime and independent electrical cutoff |
| Feedback | Two temperature probes, home sensors, plate-presence sensor, outdoor camera | Cold/hot test, jam detection and recovery after interrupted dispense |
| Electrical | GFCI supply, fuses, motor drivers, glands, drip loops, backup battery | Power transfer test, no auto-repeat after reboot, battery temperature/ventilation |
Engineering estimates
Control behavior
Remote commands and a locally stored schedule share the same interlocks. Check temperature history, dish presence, hatch state, remaining portions and dose limits before dispensing. Store each command and outcome in nonvolatile memory. After uncertain power interruption, flag the portion for inspection instead of automatically repeating it. Disable actuator outputs during boot. The camera supports observation; it cannot prove food safety or guarantee that the tortoise ate.
Prototype sequence
- Measure the actual volume and weight of one normal greens portion and vegetable portion.
- Build one tipping tray and removable chute. Test real chilled food repeatedly.
- Select the appliance and create the internal tray, clearance and replacement-door layout.
- Build the braced frame and add pellet and water systems.
- Run a supervised seven-day temperature and release test, including warm weather.
- Test loss of Wi-Fi, power transfer, missing dish, stuck tray, open hatch and interrupted commands.
Source references