Hand Hygiene

Ted sent along this link to a redesign of the telos.  This one uses the CC1101 and has some new power management capabilities.

We’d talked about the possibility of making an adapter for the USB, USB to miniUSB, but it took us a while to design the miniature circuit board to do it.  Finally I got around to it (my first board design, actually).  The prototypes cost $15 for half a dozen.  Looks like it would work just fine on telosb board without any chips on it.  I checked the connections and everything seems fine.  We could save a bit of space in the next badge design using these without having to go with the full redesign of the teleosb board.

In case we want to add an accelerometer to the mote at some point, this would be handy.

Information and recommendations on lab computers on google docs:

http://spreadsheets.google.com/ccc?key=0AmGN0bxAc29ydGlTdC1sRmZkTVlRUWdsWW1JRGFKcUE&hl=en

We’ve set up 20 Foam bottles and 7 puck and they are ready for their experiment.

Note the USB at the bottom of the bottle.

Michael Ireland finished building the Kit IR Light Fence / Door Minder DIY Kit (kit 130 from kitsrus.com) and putting the two parts in a box and powering them with a 9V battery.  He took the output relay and connected that to the mote, which is programmed with the same software we are using for the pucks.  When the light signal is broken or reconnected, the mote sends out an RF beacon.  There is a quarter at the bottom for a sense of scale.

We’ve talked shrinking this down and combining the two parts into one box and using a reflector on the other side.  The circuit draws about 24mA @ 9V, so it aught to last on the order of 20 hours.

Currently the pucks are being directly soldered to the motes within them. While this is a sufficient solution for investigative and research purposes, it is desirable to have the puck removable for field serviceability. One potential solution from Molex is shown here. The 3-position connector is very slim and fits beneath the mote. More room could be added to the molding in the future to accommodate the connector further or to provide for a friction fit for the connector to hold it in place.

Molex PN’s: 2X Housing: 0050579003, 3X F term: 0016020096, 3X M term: 0016020108

Note: This connector setup is not polarized and could be installed backward. With more room, a locking, polarized connector would be desirable. I believe this is possible within the same family of Molex connectors. For now, our space constraint precludes this.

The eZ430-Chronos is a “customizable development environment within a sports watch.”  Pretty cool

We were thinking that we might want to add a solar cell to the room motes so the batteries wouldn’t have to be changed. 

Joe got a 2.75″x4.25″ PowerFilm MPT6-75 solar cell.  In the lab lighting, we got .23 mA at a voltage sufficient to recharge the battery.  When we put it directly in front of a 175W grow light we got about 25mA. 

Typically a mote consumes about 25mA (at 3.3V) when it is on and broadcasting and a few microA when it is sleeping. The utility of adding the solar panel depends on the duty cycle, the ratio of time spent broadcasting and sleeping.  If the duty cycle is < 1% the solar panel would just about make up for the power consumed by the mote.  If you account for the time when the inside lights are out, the duty cycle should be < 0.5%.