Description
Way back when we were called One Million Lights, Masitek came on board to help us out. Our students had basic electrical engineering experience and we wanted to make a SAFE solar powered light. The complexity was beyond our abilities. A great example of a community partner allowing their employees to be distracted from their “real” work to help our students and students all over the world.
This circuit uses 6 LEDs, 3 AA NiMH batteries and is solar recharged by its own 6V panel. It has battery thermal protection in the form of a thermister.
There are two different boards of the identical circuitry. The Blue board is a little bit easier because the components are more separated, while the Yellow board is much more compact.
Chris Standen and NBCC Moncton took the schematic and prototype and created professional circuit boards. These boards were wonderful, and the pads were very fine. It was a few steps higher than our soldering abilities and our soldering equipment. Our large globs of solder caused many short circuits.
We then learned how to 3D print a stencil of the circuit and made it larger to better match our formative soldering techniques and equipment. The stencil would let students trace a larger circuit on a copper plate and etch the traces with ferric chloride by single displacement chemical reaction. The remaining traces were thin and had multiple micro breaks. Our soldering techniques and equipment were terrible. Also, sometimes students would put the template backwards, which was not compatible with polarized components like Diodes and Transistors. We will need to abandon this until we have a better way to make the circuits boards and we are more sophisticated electrical technicians.
Technical
Parts list
| Digikey Code | Description | Quantity |
| LP2950ACZ-5.0NS/NOPB-ND | IC REG LDO 5V 0.1A TO92-3 | 1 |
| 445-8497-ND | CAP CER 10UF 16V X5R RADIAL | 2 |
| 365-1175-ND | LED RED CLEAR 3MM ROUND T/H | 1 |
| 1N5817-TPCT-ND | DIODE SCHOTTKY 20V 1A DO41 | 1 |
| C503B-WAN-CBADA231-ND | LED COOL WHITE CLEAR 5MM RND T/H | 6 |
| CF14JT300RCT-ND | RES 300 OHM 1/4W 5% CARBON FILM | 1 |
| 7.5KADCT-ND | RES 7.5K OHM 1/4W 0.1% AXIAL | 1 |
| 15ZCT-ND | RES 15 OHM 2W 5% AXIAL | 1 |
| 22H-ND | RES 22 OHM 1/2W 5% AXIAL | 6 |
| BC2307-ND | THERMISTOR NTC 3.3K OHM LEADED | 1 |
| NDP6020P-ND | MOSFET P-CH 20V 24A TO-220 | 1 |
| N703-F031-ND | BATTERY PACK NIMH 3.6V 2300MAH | 1 |
| Discontinued | 6V 1W solar panel | 1 |
| CWI333-ND | SWITCH SLIDE SPST 8.5A 125V | 1 |
Good News…In 2017, NAV Canada donated 8 soldering stations and sent us their technicians who taught us how to solder properly. After 2 years of dreaming and searching, we were able to receive a Voltera Machine that allows us to print on demand, in various sizes, the same Masitek Schematic.