TL;DR
A project developer is testing a rooted Redmi 13C 5G and a Huawei Mate 30 5G as alternatives to a Raspberry Pi-based setup for a camera and lighting project. The phones cost about ¥300–500 second hand and already include features that add cost to the Pi build, but camera performance and the availability of many matching used devices remain open questions.
A developer is testing whether used Android phones can replace a more expensive Raspberry Pi setup for a project that needs a camera, GPS, storage and a controller for lights. The early comparison puts a used Redmi 13C 5G or Huawei Mate 30 5G at about ¥300–500, while a Raspberry Pi build with a camera, GPS and storage is listed at about ¥1,483 before other components.
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The developer, writing at so.long.thanks.fish, says they had been designing adapter boards around a Raspberry Pi, an Arducam 64MP camera and a GPS module. As parts accumulated, they began considering phones they already had: a Redmi 13C 5G and a Huawei Mate 30 5G. Second-hand listings for phones of this kind on Taobao were roughly ¥300–500, or about $45–75 using the report’s stated conversions.
In the report’s parts comparison, the Redmi’s camera produces 50MP JPEGs, while the Mate 30 has a 40MP main camera and a telephoto lens. Both phones also have GPS, built-in storage, a clock, a battery, a touchscreen and mobile connectivity. Their USB-C ports can connect to a custom board for controlling lights and other sensors. The Pi comparison lists a Raspberry Pi 4 with 4GB of memory, the camera, a GPS HAT and a 64GB microSD card for about ¥1,483.
The report estimates a more fully equipped Pi setup at about ¥2,317, including a touchscreen, backup power and a 4G HAT that supplies cellular connectivity and GPS. The phone models are 5G devices. These figures are illustrative listings from November 2026, not a standardized market survey; neither total includes the custom controller board, SIM or data plan, or enclosure. The developer says the Redmi has been unlocked and rooted, its camera tested, and scheduled sleep and wake behavior tried. The Huawei is harder to root, but can run a kiosk app.
What the Phone Already Includes
The comparison matters to makers and installation developers because a phone combines several parts that might otherwise be bought separately. A camera, GPS, battery, display and mobile connection are already in the device, which can reduce component costs and simplify assembly for a project that can use Android and communicate with external hardware over USB-C.
The same idea could apply to digital artworks or installations, the developer suggests. Instead of shipping a Raspberry Pi or Mac mini configured for a display, a maker might send a prepared phone that runs a kiosk application. A phone with mobile data and remote access could also make support possible without relying on a venue’s Wi-Fi or network permissions. Those are proposed uses, not results from a deployed installation described in the report.
There are trade-offs. The phone’s integrated hardware is convenient, but its software, connectors, battery condition and camera behavior may be harder to standardize than a purpose-built board. The reported price gap is a parts estimate; it does not establish that a phone will be cheaper over the life of a finished project.
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From Pi Parts to a Used Handset
The project requires a high-resolution camera, GPS, storage and a microcontroller to operate lights. The developer was planning a Raspberry Pi-based system and is also trying an ESP32-P4 board, which the original report says will be covered separately. The phone is being explored as another route, rather than presented as a completed replacement for every use of a Pi.
The listed prices use mid-market currency rates dated 10 November 2026 and are rounded in the comparison. The fully equipped Pi estimate uses a cellular HAT’s GPS instead of adding the separate GPS HAT, and includes a 4G modem; batteries for its UPS setup are additional. The report compares particular used phones and example component listings, so prices and equipment choices may vary.
““I’m working on a project that needs a high resolution camera, GPS, storage, and a microcontroller to control some lights.””
— The developer, writing at so.long.thanks.fish
Camera Quality and Phone Supply
The camera comparison is not complete. The developer has made a stand to photograph the same target with the Redmi and the Arducam side by side, but the report does not provide results. The phones’ stated megapixel counts alone do not show how much detail either camera will capture in the intended conditions.
Reliability at scale is also unresolved. The developer says it is easy to find two suitable used phones, but obtaining a few hundred matching devices with healthy batteries and predictable camera behavior would require more work. The report does not establish how well the setup performs over long periods, what software limitations might arise, or whether the cost advantage persists after configuration and maintenance.
Planned Tests and Project Updates
The next reported test is a side-by-side comparison of the Redmi’s camera with the Arducam using the same target. That should help establish whether the phone camera is suitable for the project beyond its advertised resolution. The developer also says more details on the broader project and the ESP32-P4 trial will follow in separate posts.
For now, the phone remains an early hardware option, not a demonstrated universal replacement for a Raspberry Pi. Its usefulness will depend on the camera test, the needs of the controller board and, for larger deployments, whether consistent used devices can be sourced.
Key Questions
How much does the used-phone option cost?
The report cites second-hand prices of about ¥300–500 for phones like the Redmi 13C 5G and Huawei Mate 30 5G on Taobao, equivalent in its table to roughly $45–75. Actual prices and condition can vary.
What does the Raspberry Pi comparison include?
The core estimate is about ¥1,483 for a Raspberry Pi 4 with 4GB of memory, an Arducam 64MP camera, GPS HAT and 64GB microSD card. The report’s fuller configuration is about ¥2,317, plus batteries for the backup-power setup.
Has the phone camera been shown to outperform the Arducam?
No. The developer has tested the Redmi camera but says a same-target comparison with the Arducam is still planned. The stated megapixel count does not settle which captures more useful detail.
Can a used phone replace a Pi in every project?
The report does not establish that. A phone may suit projects that can use its built-in hardware and Android software, but requirements for connectivity, control, reliability and sourcing may favor a dedicated board.
What is the main issue with using phones at scale?
The developer identifies the supply of hundreds of matching phones with healthy batteries and predictable camera behavior as unresolved. Finding a small number of used devices is easier than guaranteeing a consistent fleet.
Source: so.long.thanks.fish
