Centrifuge electronics
01A clear role
for every board.
RP2350 display + ESP32-S3 supervisor
+ your existing motor drive.
Recommended starting architecture · Additional protection, hardware and validation required
The user confirmed that the existing controller provides motor drive and speed regulation only. The new electronics must manage the centrifuge. This deck is a feasibility and architecture proposal, not a finished design or compliance declaration. HMI means human–machine interface. Requirements come from the client email dated 14 October 2026; private addresses are omitted.
24 requirements. Five parts of the product.
02The client is asking for a complete instrument interface and its supporting systems.
Operator interface
7-inch screen · resolution · visibility · gloves
Requirements 1–4Connections
Ethernet · serial · USB · Wi-Fi diagnostics
5–8, 19Controlled operation
Recipes · roles · passwords · service reminders
9–12, 24Records & recovery
Logs · alarms · time · graphs · exports · backup
13–18Product qualification
EMC · vibration · IP66 front · temperature/humidity
20–23All 24 numbered email requirements are represented. Requirement 22 is labelled “Front static protection” in the email, but its specification is an IP66 minimum target subject to mounting and installation. The underlying requirement is preserved here as front ingress protection.
What the RP2350 board provides
03800 × 480 · capacitive touch
RS-485 · CAN · UART · USB
microSD · LVGL examples
Meets the minimum display resolution.
The client prefers 1024 × 600 or higher.
- ConnectivityAdd Wi-Fi and Ethernet hardware.
- Persistent timeBudget a battery-backed RTC.
- Application firmwareBuild users, recipes, records and reports.
- Physical suitabilityVerify gloves, sealing, EMC and vibration.
Waveshare advertises a 7-inch 800×480 panel, 345 cd/m² brightness and 170° viewing angle. The published schematic does not show a dedicated battery-backed RTC, Ethernet or Wi-Fi. The wiki links a PCF85063 datasheet, which by itself does not prove that the chip is fitted. Confirm the delivered board revision. Host capability does not prove a finished, powered USB pendrive-export implementation.
The proposed architecture
04The ESP32 supervises the machine. The existing drive regulates the motor.
Conceptual connections, not a wiring schematic. For short internal links, UART can carry framed messages; use suitable transceivers/isolation where the electrical environment requires them. Use the motor drive’s supported protocol, such as RS-485 or CAN. Keep external customer communications separate from the internal control link when needed. The independent protective path must also enforce lid-release permission; its implementation is to be established by the machine risk assessment.
Assign one owner to each responsibility
05Presentation
- Touch and keyboard input
- Recipe and login screens
- Live and historical plots
- Alarms and actual status
Requests a change.
Displays the accepted result.
Machine application
- Run sequence and sensors
- Permissions and recipe limits
- Logs, reports and backups
- Network and USB services
Validates the request.
Owns the operating state.
Speed regulation
- Motor switching/control loop
- Speed and ramp commands*
- Actual-speed feedback
- Local drive protections
Executes valid commands.
Reports speed and faults.
*Confirm which ramp, braking and protection functions the drive actually exposes.
Do not duplicate authoritative recipe or user databases on both processors. The display can cache presentation data and recent trend samples. The supervisor must enforce the same role and command rules for local and remote requests. Keep control tasks bounded and separate from slower network, storage and report tasks. This architectural separation alone is not a safety guarantee.
A centrifuge run, step by step
06The ESP32 supervises every transition. The display shows what is actually happening.
Ready for an authorised run
Select the recipe and rotor. The supervisor checks the user’s permission before accepting Start.
Illustrative sequence and speed profile. Timer start, stopping policy and release threshold must be specified.
Click a numbered stage to explore its responsibilities. Stage ordering is a proposal, not validated firmware. Safe lid release requires a validated safe-speed/standstill condition and the protective path; elapsed time alone is not proof. Rotor-dependent speed limits, RPM/RCF conversion and a decision on when the run timer starts must be defined. Protective faults can interrupt the normal sequence.
From measured data to a usable report
07Store the original run record on the supervisor’s storage. Create exports from that record.
Reliable time
Battery-backed RTC; record time changes.
Recoverable records
Handle power loss, full storage and USB removal.
Requirements 13–18 and 24. Local PDF-to-pendrive export must work without a PC or internet if that is the client expectation. Prototype a fixed report template on the MCU before committing to complex layouts. A browser print-to-PDF feature would not meet standalone export. Choose retention, sample rate, storage endurance and power-loss handling. Alarm history and an audit trail of user/configuration changes serve different purposes.
Design the fault response explicitly
08A slow report or lost display must not block machine supervision.
The supervisor detects the loss.
Follow the agreed continue-or-controlled-stop policy. Retain lid protection and record the event.
Overspeed response
Drive inhibit
Safe lid-release permission
UI or application software fails.
Conceptual safety allocation. Protective circuitry and stopping behaviour require machine-level engineering and tests.
Do not treat an ESP32 or a watchdog alone as a complete safety system. A motor drive board is not necessarily a complete centrifuge controller. Specify the independent protective functions through risk assessment. Stopping is not always immediate power removal; braking and coast-down behaviour must be engineered. Wi-Fi diagnostics should default to monitoring, with locally enabled, time-limited service access and no route around interlocks.
What goes on the supervisor board
09Start with an ESP32-S3 module and design the surrounding hardware for the instrument.
Suggested additions, not a released BOM. ESP32-S3 requires external Ethernet hardware. GPIO allocation, interfaces, memory, power budgets and device drivers must be checked together. Reserve dedicated ports for customer connectivity and machine-control links as necessary. The actual chamber temperature requires an external sensor; the MCU die-temperature sensor is not a chamber measurement. Add refrigeration outputs and safeguards only where the model needs them.
Requirement coverage · 1–12
10Hardware capability is only one part of fulfilling the requirement.
| # | Client requirement | Assessment | Proposed response |
|---|---|---|---|
| 1 | 7-inch industrial colour touch | Hardware + qualification | RP2350 screen; qualify finished assembly |
| 2 | 800×480 min; 1024×600 preferred | Minimum met | RP2350 is 800×480; preferred size unresolved |
| 3 | Lab visibility / viewing angle | Validate | Test panel in intended lighting and mounting |
| 4 | Operation with intended gloves | Validate | Test actual gloves; change panel if necessary |
| 5 | Built-in Ethernet port | Add hardware | Supervisor + Ethernet controller and RJ45 |
| 6 | RS-232 and/or RS-485 | Interface + software | RS-485 available; RS-232 transceiver if needed |
| 7 | Authorised USB export / backup | Develop + validate | Supervisor USB host, power and access checks |
| 8 | Wi-Fi / Android diagnostics | Add + develop | ESP32 network service with authentication |
| 9 | Recipes and selectable colours | Develop | Supervisor stores recipes; display renders |
| 10 | Protected recipe changes | Develop | Supervisor enforces permissions and versions |
| 11 | Operator / supervisor / service roles | Develop | One role model for local and remote access |
| 12 | Passwords and failed-login handling | Clarify + develop | Implement agreed policy; clarify Part 11 scope |
Traceability to the 24-item client email. “Develop” means proposed custom work, not a supplied or validated feature. The formal meaning of “industrial” and the 21 CFR reference require agreement. Hardware facts are based on the vendor page and schematic.
Requirement coverage · 13–24
11Records, recovery and environmental suitability need their own acceptance criteria.
| # | Client requirement | Assessment | Proposed response |
|---|---|---|---|
| 13 | Cycle records and PDF on USB | Develop + prototype | Persistent records; standalone PDF export |
| 14 | Time-stamped alarm history | Develop | Supervisor records code, description and state |
| 15 | Clock retained after power loss | Add hardware | Battery-backed RTC; verify retention |
| 16 | CSV export over USB | Develop + validate | Export selected records with permissions |
| 17 | Live / historical graphs and saving | Develop | Supervisor stores; display renders trends |
| 18 | Application and configuration recovery | Develop + validate | Versioned backup and recoverable updates |
| 19 | Restricted remote diagnostics | Develop + validate | Authenticated service mode, disabled/restricted |
| 20 | EMC evidence for centrifuge use | Engineer + test | Power, layout, shielding and system testing |
| 21 | Vibration resistance | Engineer + test | Mounting, connectors and assembly tests |
| 22 | IP66 minimum front target | Engineer + test | Sealed front assembly; verify installed result |
| 23 | Temperature / humidity range | Specify + qualify | Agree range, then qualify the full assembly |
| 24 | Expiry / calibration / service reminders | Develop | Persistent counters, history and reliable time |
The email asks for PDF export on a USB memory stick as well as CSV; both are retained. For environmental items, no compliance is inferred from use of either MCU. Requirement 22 specifies an IP66 minimum front target subject to mounting and installation. Formal Part 11 scope is not established by the wording “21CFR password combination.”
Three implementation choices
12RP2350 display + ESP32-S3 supervisor
Separate graphics and machine application. Add Ethernet, RTC, storage and protection.
for the proposed display
Integrated ESP32 display + motor drive
Fewer application processors. UI, records, network and machine tasks share resources.
more concurrency to validate
Industrial HMI + machine supervisor
Compare documented glove, enclosure and environmental performance from suppliers.
if evidence and delivery dominate
Option B example: Waveshare ESP32-S3-Touch-LCD-7B is specified at 1024×600 with Wi-Fi and 8 MB PSRAM. These do not automatically solve Ethernet, industrial qualification or safety. Check pin multiplexing and simultaneous interface availability before selection. Option C is a procurement category, not a verified supplier recommendation. There are no researched cost or schedule estimates in this deck.
Prove the uncertain parts first
13Use a small prototype to answer the questions that could change the hardware choice.
Display & touch
Actual gloves, lab lighting, mounting and screen content.
Decision: keep this panel?Concurrent workload
Live plots + logging + Wi-Fi + USB/PDF export.
Decision: enough resources?Fault behaviour
Unplug links, stall tasks, interrupt power and verify lid protection.
Decision: safe and recoverable?Product evidence
Agree IP66, EMC, vibration and environmental acceptance tests.
Decision: what can be promised?These are recommended validation activities, not tests already performed. Critical real-time behaviour and protective functions need a risk-based test plan. The prototype must include simultaneous workloads; separate successful demos do not establish concurrency. Confirm log sample rate, retention, number of users/recipes, standalone PDF content, service-access permissions and environmental limits.
Recommended direction
14FOR THIS CENTRIFUGE
Keep the screen focused.
Give the machine one supervisor.
Add independent protection and qualify the finished product.
The display alone cannot satisfy the full client specification.
This recommendation incorporates the user’s confirmation that the existing board handles motor drive and speed only. It is a starting architecture for detailed engineering. It does not claim that the combined boards already meet all requirements or that any product certification has been achieved.
Sources & decision boundaries
15Source material
Client email: 24 requirements
14 October 2026
User clarification:
Existing board handles motor drive
and speed control only.
Vendor and official documentation links are available in the notes for each relevant slide.
How to read this deck
- Published hardwareCapabilities described by the manufacturer.
- Proposed architectureEngineering recommendations to develop.
- Unproven suitabilityItems requiring physical tests or evidence.
Only sources relevant to the technical recommendation are listed. The source email is not embedded to avoid including unnecessary correspondence and personal contact details. No prices, delivery estimates, certification claims or measured performance results have been invented.