Hello all,
I am working on a project consisting on controlling the light intensity of a series of light bulbs using wireless sensor nodes. To do this, I have built an experiment with five light bulbs, each of them connected to an analog dimmer. These analog dimmers are controlled by the wireless nodes. These wireless nodes have a DAC which gives up to
3V on their output. Since the analog dimmers require an input from 0 to 10 V, I built an inverter-amplifier circuit between each node and each dimmer, using operational amplifiers.The nodes are connected through a USB cable into USB Hubs which are in turn connected to the wall socket.
The operational amplifiers are supplied with +15/-15/mass by a regulable tension source, which is in turn also connected to a wall socket.
The idea is to control each of the light bulbs indepently, telling to each node per radio to change its DAC output. But, if I want to set a node's DAC to a determined voltage while keeping the others to zero, the voltage divides itself among all nodes.
It seems that there is no galvanic isolation between the node and its USB connector, so that a circuit is being formed through the masses.
Could anyone give me some suggestions to help solve this problem?
Thank you very much,
- J.