We may need a low power industrial 8-bit MCU with Configurable Logic Circuits (CLCs) like some of the PICs have. When the NFC power is present we can wake the MCU up by connecting an interrupt pin to the Field Detect pin on the NTAG 5 and perform configuration. Then at all other times the MCU is in a permanent sleep state and the CLCs just do simple gate operations to drive the LED segments.
I was kind of hoping we could find an RTC with a simple built in driver to run the LEDs (like a purpose built one for a watch or something). That way we wouldnāt need an MCU at all and the RTC could just be set by I2C commands over the NTAG 5s transparent master channel. That might require some hit or miss sourcing from Alibaba though. China holds all the purpose built chips for their internal industry activity.
Depending on how low you want to go, you can turn off a lot of the features in the smaller microcontrollers. This can significantly lower their power consumption. Iām really not sure if we can get an attiny85 low enough but it is certainly worth investigating, and I have several lying around.
The NRC representative got back to me. They require a $8400/year R&D license fee
Iām so fucking tired of gatekeepers. It would be one thing if they just said āno, you canāt do thisā. Theyāre not saying that though. You can do whatever you want, as long as you pay the vig.
We either need to: find a way around licensure (Iām talking it over with Chris), find another company where we can pay a smaller fee and theyāll handle shipping, poke a hole in the regulation (not likely), find another source overseas (not likely and also probably illegal because we didnāt pay )
or
We could use another power source, like NFC power and a larger capacitor bank. That will inevitably result in the RTC needing to be reset often though.
EDIT: Chris just got back to me and said that thereās something wrong here, it should only be a one time fee. Heās reviewing my correspondence with the NRC rep to see if thereās anything erroneous or fishy.
Iām sure this has been discussed, but how will you update the time?
I was thinking if itās via nfc could we use the coil as an alternative to power the implant? that way we could quickly charge it whenever we get out our phones, or have a coil in your desk etc.
My understanding is that there will be an NFC/I2C interface which can provide power and be used to set the time. I am working on testing that with a small microcontroller at the moment. The problem is that it doesnāt keep time the way an RTC with battery would. When you take away power the RTC dies. You can store power to keep it running, but short of batteries options are limited.
The original plan was an RTC to keep the time, a micro controller to run the display and a 7 segment LED. This would be supplemented with an NFC to I2C interface to set the time using your phone.
Still negotiating with Chris Thomas of Widetronix. I need them to provide me with some documents that prove the amount of radioactive tritium in the betavoltaics is not sufficient to require a radioisotope license. One of the regulators in my state hinted as much in an email thread, but they really want me to pay the vig. Iāll keep you posted, thereās just been unexciting email arguments for the past couple months.
Beuracracy. I swear, half my job is convincing people to sell me something. Like just shut up and take my money. I suffer through all the hardships of this capitalist hellhole, at least let me enjoy the supposed benefits of a laissez-faire market. Christ.
Yeah I get that, even trying to figure out what you want without knowing someone is almost impossible. Iād love to get in on the action when thereās something for me to do
Several check-ins later and Chris seems unwilling to respond to me. I guess he wants me to sort out the licensure and get back to him then
I reached back out to my local regulatory representatives. Initially one said that the betavoltaic cells may be exempt, so Iām pushing that angle. Otherwise Iām looking at $8400/yr for the Research & Development license. Iām also pressing to get a cheaper license or at least make it not yearly.
If you do have to pay for licensure, is there any way someone could donate to help with the costs? I canāt donate $8,400 but I could donate something.
I considered that, because $8400 is a somewhat attainable sum. There would also be the cost of the betavoltaics which would probably bring the total to an even $10k if we wanted ~100 of them.
It would be a matter of trust though, since I would be the license holder. Thereās also the question of whether I would go to federal prison if I were to redistribute these once they were acquired.
Ugh. Turns out thereās no way in hell youāre going to be able to do something useful below the 1 milliCurie non-regulated threshhold. Even the smallest betavoltaics that Widetronix produces in the microWatt range will be several hundred milliCurie or several Curie.
Hereās some data on Tritium via Wiki:
āTritiumās specific activity is 9,650 curies per gram.ā
We also wouldnāt qualify for the $480 āGeneral Licenseā because of the relatively high concentration of radioactive material. Chris did tell me a bit about a medical device company that is navigating the betavoltaics path with the NRC, which was very interesting. He was nice enough to offer to call me next time they have SMT scale units in house so I can come up to Ithaca and test out some prototypes with them.
Iāll have to think on this. I may have to wait until Grindfest 6 to locate enough support to actually get this going. The idea of monetary contributions is nice and all, but I definitely canāt make any guarantees so a kickstarter is kind of out of the question. Plus I really need like dedicated grinders to help me get this across the finish line. Itās not a one person job.
A few things I thought of:
How are we planning to activate the implant, if we use a magnet implant would we have to hold the magnet there for the entire display duration, and would we be able to have multiple sensors for multiple functions, like date and time separately?
How much progress has been made towards programming the implant?
Do we know the approximate amount of power generated and used? Can we figure out how often the implant can be used?
Do we know what kind of chips we would use for this question mark would we name custom silicone?
No additional programming has been done by me. We donāt have any real hardware at the moment to program. If we have sufficient power then the idea would be that however it is triggered it would then display the time and stop.
You would want to trigger it, it displays and then sleeps.
Iāve been focusing on acquiring the betavoltaics, so I havenāt done much part sourcing. If we canāt acquire betavoltaics for the foreseeable future without significant investment, we may need to seek out an alternative power source. I really donāt think continuously topping it off from your phone is viable, because at that point why not just use the phone.
If anyone has any ideas Iām all ears. We can always try and source a low power/profile RTC module and work up from there, but without some form of battery, generator, or energy harvesting, we donāt really have a path forward.
If anyone is independently wealthy and wants to see this through though, you could easily pay for an R&D license from the NRC and order some custom betavoltaics from Widetronix. I will certainly help
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