We are growing fluid-based bacteria within a beaker, and need to pump in an amount
of growth medium (for the bacteria) in response to the density of bacteria growing within the
beaker. The objective is to maintain a constant density of bacteria within the fluid, so when the bacteria proliferate more growth medium will be pumped in and excess fluid will be allowed to flow out of the system and thrown away. As the bacteria proliferate the liquid darkens, so a light sensor is needed to sense this change. I need a device that will turn on a switch once the light level in the beaker reaches a certain threshold in the beaker - signalling the pressence of excess bacteria. This switch would be connected to a pump which would input growth medium.
The pump already exists, but I need to design the control mechanism that will operate the switching device. I imagine that the NI software could be used for this task, but i don't know how, or what devices to use.
The pump could be turned on at a certain light level or it could operate on a cycle as described below:
1) Bacterial growth sensor (either submerged, or through the beaker, or within
the sides of the beaker) checks the light level within the bacterial growth
beaker.
2A) If the liquid is DARK, the pump is turned on and quickly releases a small
amount of fluid growth medium. Just the brief length of time that the pump will be
turned on will be sufficient because the the pumping flow-rate can be controlled
using a knob on the pump, which is manually adjustable.
3A) The system would then return to (1).
or
2) If the liquid is CLEARER, the photosensor waits a specified small amount of
time and returns to (1).
