This project is for a variable power supply circuit design which can be controlled with a standard micro-controller capable of communication over GPIO, PWM, ADC, I2C, SPI, or UART.
The particular communication type is up to the winning bidder, but we would suggest GPI or I2C.
The unit must be as small as possible (aiming for the size of a thin A5 book) and capable of giving variable output on up to 6 channels.
Each channel must be able to be controlled separately using digital pots and provide between [url removed, login to view] and 16v output up to 3A.
I would suggest the use of the LM2596 or equivalent high efficiency, low heat output variable controller.
The unit will receive power from a 14.4v-16v power source and must be able to run all 6 channels off this power source.
In order to qualify for this project, you MUST include the phrase "vegetables are tasty" in your bid.
If you are reading this, congratulations, you are one of the few that actually reads descriptions, haha.
The unit should have a BOM under $100. Over this amount is alright, but you should be able to explain why the cost has increased.
Each channel is controlled individually meaning each channel could potentially have a different voltage and amperage.
For the aims of this project, each channel should display basic diagnostics on a LED screen with regards to the current voltage, amperage etc.
The user should be able to cycle through each of the channels and view these diagnostics without changing the layout of the circuitry.
Here's an example of what I mean, but obviously it must be on a single LED screen and capable of displaying all 6 channels:
[url removed, login to view]
The entire circuit must also be tied to a series of switches.
Each switch will turn a single channel on and off (a total of 6 switches).
These must be a physical button AS WELL AS digitally controlled.
A final master switch will turn the entire unit on or off.
When the master switch is turned off, the unit will bypass all of the circuitry and simply pass through the current from the attached power source (~14.4v-16v).
This will need to be a single - and + VOUT that can then power another device as if the circuit itself was never there.
When the master switch is turned on, the channels which are active will begin to output the charge that they have been designated.
The channels MUST be able to keep their information in non-volatile memory so that they can maintain their settings even when the unit is off and the battery is removed.
There is the requirement for a basic analog user interface.
The user should also be able to control it via the microcontroller, but in this case they also need to be able to select the channel, select the voltage/amperage and increase or decrease this value for each channel.
More detail on this can be provided.
Standard protections you expect for a power supply MUST be included (fuse, over-current etc.)
The voltage must be VERY stable. Deviation should not be greater than 0.01V.
A very basic idea of the completed circuit is:
C1 C2 C3
^ ^ ^
VIN (14.4-16v) --- >> CIRCUIT --->> VOUT (14.4-16v)
v v v
C4 C5 C6
There will NOT be an upfront milestone for this project; please do not ask for one.
Your deliverables will be:
-- A schematic of the completed circuit
-- An engineering drawing showing the populated circuit and approximate dimensions of the finished unit
-- A BOM showing where to get each unit, the quantity required for the circuit and the price per unit
-- A technical summary showing noise, ripple, power efficiency, voltage drop etc. of the circuit.
-- A sample of the completed circuit, fully working. We will pay for shipping of this prototype to our office.
Please ignore the schematic diagram.