General log¶
Week 1 : Preliminary concept sketch¶
Problem :
Mobile street vending is widespread globally, yet many lack reliable (and safe) access to affordable electricity especially during evening and night-time trading hours
Target user characteristics :
- Trade mostly in the evening
- Daily-based income
- Limited technical knowledge
Solution :
Plug and play, pay-as-you-go (pay amount based on usage or time for example daily, weekly or monthly) solar PV system for essential lighting and load appliances of the street, inspired by implementation in Africa.
Main features :
- Solar panel with built-in axis tracker for optimal energy capture in the morning before use during night-time trading hours.
- Smart controller that enables flexible installment payments (pay-as-you-go) without upfront cost and embedded security features.
Week 2 : Consultation at SEEED studio¶
First consultation on the final project with Matthew, the Fab Academy 2026 instructor for ChaiHuo makerspace, was done at the SEEED studio (check out @timmili_makers week 2 to get a peek)!
The following topics were discussed :
- Work breakdown ; the following upcoming sections will be organized around these four main building blocks: SBC, MCU, power supply, and payment system (see respective logs for detailed research)
- Focus will be on building a small, simple prototype first, with further expansion planned after gaining insights from the initial
- Materials required for the first prototype
Week 3 : Components acquired, initiate prototype testing¶
The following components were sourced from Taobao. Specifications on it could be seen below :
Image of the materials
| Component | Specifications / Notes | Quantity | Additional Details |
|---|---|---|---|
| Photoresistor | Light-dependent resistor, Vin : 3.3~5.5 V | 1 | Detects light intensity |
| Servo motor | Vin : 4.8–6 V | 1 | Used to adjust solar panel orientation |
| Solar Panel | Voc : 9 V, Isc : 1.23 A | 1 | Converts sunlight to electrical energy to charge battery |
| Solar voltage Regulator | Vin : 9-30 V, Output (V A): 5 V 3 A, 9 V 2 A, 12 V 1.5 V | 1 | Stabilizes voltage for MCU and sensors |
| Battery | Vout: 5V, Iout : 2.5~3A, Li-ion, 6800 mAh | 1 | Powers the system when sunlight is low |
Regarding Voc and Isc
-
VOC (Open-Circuit Voltage):
This is the maximum voltage the solar panel can produce when no current is drawn (open circuit). It represents the upper voltage limit of the panel. -
ISC (Short-Circuit Current):
This is the maximum current the solar panel can produce when the terminals are shorted together (voltage = 0). It represents the highest current the panel can deliver under full sunlight. It is used to size fuses, wires, and regulators safely.
Source: ChatGPT by OpenAI, February 2026
Updates :
- MCU
- SBC
- Power supply
- Payment system
- It was decided that the preliminary prototype should prioritize offline device activation, with the concept centered on token generation and matching to unlock the device. Further details can be found under the Details: Payment system tab.
Week 4 :¶
Test on the mcu with light direction About servo motors Connect to the same reference point!
Week 5 :¶
normal jumper wire can only at mA why cannot detect connectivity solar panel