Editor's note: The following is Planet Analog's first in a series of Design Challenges. This one was sent to me by a reader/design team interested in using GPS in a particular application. We are looking for design ideas to solve this challenging GPS design. We ask you, our readers, to comment on this challenge and suggest possible solutions.
This effort is meant to stimulate the creative juices of the Planet Analog Community as well as solicit any responses from IC companies or related software or even module suppliers that may have solutions or close solutions that can be modified to fit the application.
This series is also meant as a tutorial to Planet Analog readers by fellow readers who can act as mentors to stimulate and guide your design ideas.
GPS minimum specifications:
GPS chip: Best available — SiRFstarIV looks like good possibility
GPS sensitivity: -163dBm
Tracking: Indoor & Outdoor
Accuracy: 3 meters
GPS Start (Hot): 1 second
Battery: 3.7V lithium Ion or lithium polymer or other light weight rechargeable
Battery Charging: port for charging and setting up GPS
SIM Card: Nano
Networks: GSM networks
Operating Temp: -40°C to +85°C
Certification: FCC & CE Certified
Size: 25mm x 25mm x 15mm or 25mm diameter x 15mm
Antennas: On board GPS antenna and communications antenna
The unit will likely be dormant for up to one year. The reader's thoughts are possibly a reed switch on the unit. The unit will be placed on a magnetic field so there is no power consumption until the unit is removed from the magnetic field. Once removed from the magnetic field it needs to wake up on motion of two minutes and be able to track three to four days or more.
GPS should be capable of setting up Geo-Fence parameters manually, by dragging the fence to specific needs. GPS should be capable of triggering an email, ringtone, or SMS when the device wakes up, leaves, or enters the designated area. It should then send position to a server or cellphone every five minutes or less.
Additional batteries, if required, should be no more than 6 mm or 7 mm square or round, to increase time of operation.
New technology indicates that batteries can now be made on 3D printers for more capacity and minimal size.
It must be possible to charge the battery while unit is in motion.
Software package should monitor GPS units online, then live track and record location of GPS unit when activated. The GPS and/or the software should be able to notify monitoring computers and cellphones by SMS or email when activated.
Apps for iPhone and Android are needed for monitoring GPS movement.
The least expensive monthly charge is desired for providing cellphone or data service since the unit will likely be dormant for extended periods of time.
The following is a flow chart for operation of the device in the particular application:
Please feel free to ask any questions on Planet Analog in the comments section so all readers will benefit from complete information and answers by the design team. The team will answer any questions and add any insights in the comments section of Planet Analog, as well.