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Bemix is a music system which plays user selected music in the Bemis bathroom. Residents can select music over a web interface and can turn the music on and off directly from the bathroom or remotely over the web.

Bemix v1.0

The original Bemix (Spring 2005) was designed to play music in the Bemis bathroom through speakers located above the drop ceiling. Users would select music through Glirnath, a web interface.

Later, a touch switch was added to provide on/off control from the bathroom. The touch-switch was hidden in a towel rack in the Bemis bathroom. When someone touched the towel rack and the faucet at the same time, the op-amp senses the change in voltage, compares it to an internal reference voltage, and amplifies it. This signal is sent to a flip flop which toggles power to the speakers.

The success of Bemix led slugs to plan its expansion into other bathrooms. But, the v1.0 hardware and software had much room for technical improvement. The touch switch was finiky and there was no way to override the touch switch from the computer. Slugs designed new hardware and software for Bemix v2.0.

Bemix v2.0

Bemix v2.0 is the current version of the Bemis bathroom music system. It will span the three central bathrooms: Bemis, shallow Goodale, and shallow Walcott. At present, we have all necessary hardware and software. It will be fully operational following the installation of Cable Trays on 4E.

The hardware is very similar to v1.0 hardware. It consists of a touch switch in each bathroom and a central logic circuit. The touch switch uses a commercial IC (QT1013?) made for this purpose for improved reliablilty. The logic circuitry is built around flip flops, one for each bathroom. Each flip flop is toggled by the remote touch switch, the computer, and a control panel which has not yet been implemented. The output is sent to the computer so that it can play or stop the music in the appropriate bathroom.

On the computer side, we are using a 700MHz PIII with three sound cards to. It will be running custom software written in python.

Bemix v3.0

Bemix v3.0 will be a complete redesign of the v2.0 hardware. It will be PIC based and will communicate with the computer over the 4E Network. This will allow a virtually unlimited number of commands to be exchanged between the bathrooms and server. In order to keep the hardware simple, we will continue to transmit analog audio from the computer to speakers in each bathroom.

The user interface, however, will be largely unchanged. It will remain invisible though the use of touch switches. Two additional features will be volume control and song selection. It is unclear what kind of interface the later will use.

Cable Trays

All low voltage wiring Bemixmust be run in a cable trays, because messy wires start fires. Our cable trays are from Reuse and currently being installed.

See Also