A solar-powered, grid-independent charging station for everything from earbuds and phones to pedelec batteries (provided you carry the charger). Devices can be securely locked with a code or an RFID card and later retrieved using the same method. All powered by an ESP32, a few relays, an inverter and other common electronics.
The original idea behind the SolarDock was to build a carport-like box for pedelecs with charging capabilities through solar. As we had limited time to build the dock within the program, we sized the idea down to a box roughly one meter wide and half a meter long and tall. Additionally, the BOSCH-only idea (BOSCH proprietary pedelec plug) was scrapped and a regular inverter was put in place. Lastly, the concept of a central server-driven management system for the SolarDocks which communicated via an LTE-module was, in favor of time, replaced by a simple website the ESP32 hosted locally.
Three teams were building a SolarDock each, completing three docks in two weeks. This not only includes the wood construction, but also all wiring, programming and CAD models required to finish the project. Each team consisted of roughly 6-7 people.
First of all, the idea of only one locker was immediately replaced and all teams built their SolarDock with two lockers. In addition to that, two teams decided to add a touchscreen as an additional method to lock and unlock a locker.
| Image | Description |
|---|---|
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SolarTech: horizontally split lockers with RFID, touchscreen and WiFi (code in this repository is from this SolarDock) |
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Ladestark: vertically split lockers, same unlocking mechanisms as SolarTech's dock; possibility to view inverter power |
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MINTEES: horizontally split, angled panel mount and only RFID unlocking; however the only dock not based on this code |
These drawings were made before work started, meaning many things were changed during the construction process. However, these images still serve as a good baseline for understanding the general layout of the dock.
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- Solar panel 100W/12V
- MPPT 10A/12V
- ESP32 board with four relays
- additional relays
- MRFC522 RFID module
- electromagnetic door lock
- any kind of 12V inverter
- lead-acid solar battery 100Ah/12V
- 12V lamp(s)
- microswitches as door detectors
- optionally a CYD (cheap yellow display) based on the ESP32 for touch unlock
- optionally DC disconnects to turn the device of
No exact links are provided by intention, as the places to gather those resources differ from country to country. Furthermore, none of these components are definitive. For example, one could replace the ESP32 board with relays with one without relays and instead simply connect those to the GPIO-pins directly.
- The inverter requires a button press to turn on after providing power. The inverter button relay triggers that programmatically.
- The relays not connected to the inverter are connected to the MPPT 12V bus.
- The lamps have been combined to one relay.
- The buttons are configured as
INPUT_PULLUP. - The RFID module communicates via SPI.
- The touchscreen communicates via WiFi and does so by subscribing to the same websocket and sending the same requests the locally hosted website uses to receive status updates and to lock/unlock.
This should not serve as a guide to wiring this project, there are many things wrong with this installation. Luckily, only 12V is ever passing through those wires. The image should only provide a rough image to understand what the wiring might look like.
| Pin | Var | Description |
|---|---|---|
| 32 | LOCK_1 | relay 1 on ESP board for lock 1 |
| 33 | LOCK_2 | relay 2 for lock 2 |
| 25 | LAMP_SHARED | relay 3 for both lamps |
| 26 | INVERTER_POWER | relay 4 for inverter power button |
| 13 | INVERTER_RELAY | external relay for inverter power |
| 27 | SWITCH_1 | door detector 1 |
| 14 | SWITCH_2 | door detector 2 |
| 21 | RFID_SS | RFID chip select (SDA) |
| 4 | RFID_RST | RFID reset |
| 5 | SPI_MISO | RFID MISO |
| 18 | SPI_MOSI | RFID MOSI |
| 22 | SPI_SCK | RFID SCK |
The source code in this repository is licensed under the MIT license.
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