The first purchase of electronic components was to gather all the main components required to deliver the initial milestones and prove that the basic functionalities of the system work as intended.
In week 10 when the first milestones were completed and a bread-boarded version of the prototype was successfully built, in order to achieve the next milestones, slightly more budget was required. This next milestone involved introducing power electronics to make the device portable and rechargeable, also a PCB to prototype the system. It was predicted that up to £150 would be required to deliver the next milestones. Therefore as about £100 was left after the original purchase, an extra budget of £50 was applied for and granted, enabling the project to reach the next stages.
| Item No. | Item Description | Supplier | Model | Part No. | Link | Qty | Unit Cost (£) | Total Cost (£) |
|---|---|---|---|---|---|---|---|---|
| 1 | 3.3V LDO | Mouser | LDO Voltage Regulators 3.3V 500mA Positive | 355-4128 | https://uk.rs-online.com/web/p/voltage-regulators/3554128 | 5 | £1.43 | £7.17 |
| 2 | 32GB MicroSD card | Amazon | SanDisk Ultra 32 GB microSDHC Memory Card + SD Adapter with A1 App Performance Up to 120 MB/s, Class 10, U1, SDSQUA4-032G-GN6MA , Red/Grey | 750-4802 | https://uk.rs-online.com/web/p/sd-cards/7504802 | 2 | £9.13 | £18.26 |
| 3 | Recharge IC | Digikey | Adafruit Universal USB / DC / Solar Lithium Ion/Polymer charger - bq24074 | 4755 | https://www.digikey.co.uk/en/products/detail/adafruit-industries-llc/4755/13231325 | 2 | £12.09 | £24.18 |
| 4 | Solar cell | Digikey | 6V 2W Solar Panel - ETFE - Voltaic P126 | 5366 | https://www.digikey.co.uk/en/products/detail/adafruit-industries-llc/5366/15998627?s=N4IgTCBcDaIIYBM4DMBOBXAlgFwAQFYBmANmJAF0BfIA | 1 | £20.16 | £20.16 |
| 5 | Battery | RS | Lithium Ion Polymer Battery - 3.7v 1200mAh | 144-9405 | Link | 2 | £14.05 | £28.10 |
| 6 | MicroSD breakout | Digikey | MicroSD card breakout board | 254 | https://www.digikey.co.uk/en/products/detail/adafruit-industries-llc/254/5761230?s=N4IgTCBcDaIIYBM4DMBOBXAlgFwARgFYAWEAXQF8g | 2 | £6.06 | £12.12 |
| Total: | £109.99 |
This extra budget enabled the project to take the product portable and deliver the final planned milestones.
Now the prototype is designed and an accurate list of all the parts required to build the product is available. At this stage, it can be estimated how much it might cost to manufacture the product in bulk, to start considering whether it can be a profitable investment or not. And if the product did reach the market, approximately how long it would take to pay off all of the investment costs.
Estimated Cost of the parts for the central hub/sensor.