One last crucial robotic board in the C3 robotic kit needs addressing.
TomatoCube 9v Power Board:
In order to keep our mobile robot autonomous, we need a power source onboard. With the advancement of battery technology, we are never short of choices when it comes to robot building.
Taking into lots of factors, we finally decided on the 9v PP3 battery form factor. Although this might not seem like a common choice among mobile robot builders, we found it convenient for the following reason:
- Good capacity to weight ratio - Lightweight.
- Charging circuitry build within each battery.
- 9v supply, do away with a step-up converter or multiple AA batteries.
- Easily swappable for traditional 9v alkaline battery found from your Mom-and-pop or convenient stores. (In case you run out of juice in the middle of class)
- Easy to replace (Lithium battery has a lifespan)
Here are some of the connections found on the 9v Power Board.
- 1x 9v PP3 battery clip
- 1x JST connectors 5v DC output.
- 1x Main Power Toggle Switch.
At the heart of the 9v Power board is MP1584 DC-DC step-down IC (sometimes known as a 'buck' converter). The MP1584 is suitable for current requirement of up to 3A max (which I wouldn't recommend pushing to the limit), but we just utilize it around 1.5A with peaks of up to 2A for extended operation.
Technical specification:
- Input Voltage: 4.5 – 28V
- Maximum Output Current: 2A (peak)
Output Current: 1.5A (continuous)
- Switching Frequency: 1MHz
- Output ripple: 30-50mV (measured)
- Efficiency: 80-90%
Body parts found in the box:
- 2 pieces of custom laser cut acrylic sheet.
- 2 prices of PLA printed Stepper motor mount.
- 2 Stepper motors with custom wheels.
- 1 PP3 velcro battery strap strip.
- Misc screws & nuts.
