I have been thinking about getting a USB Passthrough - checking out what's available and reading the reviews, and this is looking like an area of e-cigs that desperately needs the attention of some competent engineering. So I have been kicking around some ideas and I wanted to throw out some concepts that I would be interested in prototyping. I would like some feedback from other vapers, especially those who have used a wide variety of different hardware to tell me what features would be valuable to you.
I am thinking of doing this as an open source (GPL), open hardware design where the technology would be free for anyone to duplicate and improve upon. Here's what I have in mind:
- High reliability: This design will be built to last and will not rely on overtaxing of an undersized battery. A higher voltage, higher capacity power source, whether stored internally or provided by external supply, will be used.
- Safe for PC use: The fact that some existing PT manufacturers recommend using a wall wart for "safety" tells me they have no clue how to engineer these correctly. Current regulation and overcurrent protection are solved problems and a suitable implementation (eg regulation and/or polyfuse) will be used to make this safe for use on an expensive PC. Possibly even support low current (100mA) mode to allow operation from unpowered hubs or laptops running from their internal batteries.
- Programmable: The unit will be configurable for any type of atty or carto (used with suitable mechanical adaptor). An internal switching regulator will output a steady power level that is configurable by the user. This may be constant volts, watts, or current.
- Informative: feedback from the unit will tell the user valuable information about their atty/carto such as resistance of the coil and power being consumed. Carto reconnects will be automatically detected and used to reset a "juice tracker" which will estimate the amount of juice remaining based on watt-seconds of use.
- As you can guess the above two features suggest that the USB port will also be used for its communication capabilities. A software app on the host pc/mac would be used to configure and monitor the device.
- Automotive use. A 12-15VDC input will allow the device to be used with a car accessory outlet. [edit: never mind you would just use a 5v adaptor]
- Easy to build. The electronics will use readily available components that can be assembled with no more than hand SMT techniques. [edit: never mind the USB charge controller, eg bq2407x, would probably have to be reflowed]
- Cabling to the PC will use standard USB connectors. Cabling to the mouthpiece will probably also use (mini) USB connectors even though that won't actually be a USB interface. Such a cable would be ideal for this since in addition to its small sturdy connectors, the wires inside include both a high current pair and a data pair. The data pair could be wired straight across the atty allowing for accurate current readings that are not encumbered by the the voltage drop across the power pair.
Looking for more ideas and feedback on these. If this sounds like an overkill solution be assured that is largely the point of it. But also with proper design all of the above features can be implemented at a low hardware cost.
I am thinking of doing this as an open source (GPL), open hardware design where the technology would be free for anyone to duplicate and improve upon. Here's what I have in mind:
- High reliability: This design will be built to last and will not rely on overtaxing of an undersized battery. A higher voltage, higher capacity power source, whether stored internally or provided by external supply, will be used.
- Safe for PC use: The fact that some existing PT manufacturers recommend using a wall wart for "safety" tells me they have no clue how to engineer these correctly. Current regulation and overcurrent protection are solved problems and a suitable implementation (eg regulation and/or polyfuse) will be used to make this safe for use on an expensive PC. Possibly even support low current (100mA) mode to allow operation from unpowered hubs or laptops running from their internal batteries.
- Programmable: The unit will be configurable for any type of atty or carto (used with suitable mechanical adaptor). An internal switching regulator will output a steady power level that is configurable by the user. This may be constant volts, watts, or current.
- Informative: feedback from the unit will tell the user valuable information about their atty/carto such as resistance of the coil and power being consumed. Carto reconnects will be automatically detected and used to reset a "juice tracker" which will estimate the amount of juice remaining based on watt-seconds of use.
- As you can guess the above two features suggest that the USB port will also be used for its communication capabilities. A software app on the host pc/mac would be used to configure and monitor the device.
- Automotive use. A 12-15VDC input will allow the device to be used with a car accessory outlet. [edit: never mind you would just use a 5v adaptor]
- Easy to build. The electronics will use readily available components that can be assembled with no more than hand SMT techniques. [edit: never mind the USB charge controller, eg bq2407x, would probably have to be reflowed]
- Cabling to the PC will use standard USB connectors. Cabling to the mouthpiece will probably also use (mini) USB connectors even though that won't actually be a USB interface. Such a cable would be ideal for this since in addition to its small sturdy connectors, the wires inside include both a high current pair and a data pair. The data pair could be wired straight across the atty allowing for accurate current readings that are not encumbered by the the voltage drop across the power pair.
Looking for more ideas and feedback on these. If this sounds like an overkill solution be assured that is largely the point of it. But also with proper design all of the above features can be implemented at a low hardware cost.
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