GUIDE - NRF5 / NRF51 / NRF52 for beginners
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@monte said in GUIDE - NRF5 / NRF51 / NRF52 for beginners:
@NeverDie are you saying it is only programmable with j-link? Won't stlink/blackmagic work?
:face_palm: Yes, you're right. Either of those should work. I happen to be using j-link, so that gave me tunnel vision, but if either or those were the basis, then problem solved!
BTW, I just now checked, and the module I'm using literally does fit on a dime:
$2.50 each. -
@monte said in GUIDE - NRF5 / NRF51 / NRF52 for beginners:
@NeverDie sorry, where did you buy them? I don't see them anywhere :(
https://www.fanstel.com/buy/bt832f-low-cost-longer-range-bluetooth-50-module-cjtrx-8shlz-r7a7z
Presently sold-out of this particular model, but if you watch for it, it seems to come back into stock fairly often. When I was buying they had only 10 in stock, so I bought all ten. Then the next day they had another 15 in stocki, so I bought all 15. Then they were out of stock for a while, but then recently they re-stocked. Apparently that didn't last, because now they are already out of stock again.
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@monte said in GUIDE - NRF5 / NRF51 / NRF52 for beginners:
@NeverDie sorry, where did you buy them? I don't see them anywhere :(
https://www.fanstel.com/buy/bt832f-low-cost-longer-range-bluetooth-50-module-cjtrx-8shlz-r7a7z
Presently sold-out of this particular model, but if you watch for it, it seems to come back into stock fairly often. When I was buying they had only 10 in stock, so I bought all ten. Then the next day they had another 15 in stocki, so I bought all 15. Then they were out of stock for a while, but then recently they re-stocked. Apparently that didn't last, because now they are already out of stock again.
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@monte There are $1.59-$2.39 nRF52805 Minew modules on Alibaba: https://minewtech.en.alibaba.com/search/product?SearchText=nrf52805
The size is just a couple mm larger than the the dime sized BC805M (above photos). I've never ordered from Alibaba so I can't really say how well that may or may not go. i.e. maybe it's a good deal, or maybe it's clickbait pricing and they hammer you on shipping. For instance, unlike Aliexpress, I don't see a rapid way to place an order, which is kinda weird given that the minimum order is just quantity 3. I assume one has to send the seller an RFQ indicating the quantity desired, and then the seller responds with a price that includes shipping? Anyone know if that's how it works? Obviously I have no idea where the breakpoint is, but maybe if you were to order 20 or 30 you'd come out ahead vs ordering from Aliexpress. -
@monte There are $1.59-$2.39 nRF52805 Minew modules on Alibaba: https://minewtech.en.alibaba.com/search/product?SearchText=nrf52805
The size is just a couple mm larger than the the dime sized BC805M (above photos). I've never ordered from Alibaba so I can't really say how well that may or may not go. i.e. maybe it's a good deal, or maybe it's clickbait pricing and they hammer you on shipping. For instance, unlike Aliexpress, I don't see a rapid way to place an order, which is kinda weird given that the minimum order is just quantity 3. I assume one has to send the seller an RFQ indicating the quantity desired, and then the seller responds with a price that includes shipping? Anyone know if that's how it works? Obviously I have no idea where the breakpoint is, but maybe if you were to order 20 or 30 you'd come out ahead vs ordering from Aliexpress. -
@NeverDie I contacted alibaba sellers a few times for quotes, but never got to buy anything:) The process and shipping costs kills any wish to try and buy if anything less then 20-50...
Reporting back: Yeah, I just now contacted them. The price they're quoting now is $3.89 per module and they want $35 shipping. They said "Mass production is about 2.5-2.2 USD", which is higher than what their Alibaba listing says for quantity 3 sample pricing, which they now say is 2 years out date and should be ignored. Checking, I see that the quoted pricing is actually slightly worse than the $3.82/unit in their Aliexpress store. What a joke. I mean, given that this is allegedly the manufacturer talking, who can't be bothered to keep their own Alibaba listing updated even though it's allegedly two years out of date.... I guess the pricing indicated on Alibaba means nothing, which certainly explains a lot.
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One shortcoming of the nRF52805 that I just ran across: it has no LPCOMP. I'm surprised, as it's rather basic functionality.
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On the other hand, the nRF52805 does have PORT DETECT, which appears can provide the basic wake-up functionality at no penalty to current consumption. i.e. total sleep current remains at 0.8ua with full memory retention. AFAIK, that's still better than any of the other nRF52xxx chips Nordic has so far made, and in that one respect also better than what the nRF5340 can achieve. That compares to 0.5ua current draw when the nRF52805 is in OFF mode, with no memory retention, but where PORT DETECT could still be used to wake-up the nRF52805. So, the interesting question remains: how many mah are consumed by going from stone-cold 0ua OFF to full-on? Knowing that, one could compute the tradeoff of going that route vs sleeping at 0.8ua or 0.5ua. If the stone-cold OFF interval is long enough, it will win, and so the only unknown (currently) is how long that interval needs to be to reach a break-even point, and beyond that the energy savings pile up.
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On the other hand, the nRF52805 does have PORT DETECT, which appears can provide the basic wake-up functionality at no penalty to current consumption. i.e. total sleep current remains at 0.8ua with full memory retention. AFAIK, that's still better than any of the other nRF52xxx chips Nordic has so far made, and in that one respect also better than what the nRF5340 can achieve. That compares to 0.5ua current draw when the nRF52805 is in OFF mode, with no memory retention, but where PORT DETECT could still be used to wake-up the nRF52805. So, the interesting question remains: how many mah are consumed by going from stone-cold 0ua OFF to full-on? Knowing that, one could compute the tradeoff of going that route vs sleeping at 0.8ua or 0.5ua. If the stone-cold OFF interval is long enough, it will win, and so the only unknown (currently) is how long that interval needs to be to reach a break-even point, and beyond that the energy savings pile up.
@NeverDie Oh I've been running around 20 NRF52805 nodes for the past ~2 years https://forum.mysensors.org/post/108893. They've been working very well for me.
edit:
PRs to get working with mysensors
https://github.com/sandeepmistry/arduino-nRF5/pull/442
https://github.com/mysensors/ArduinoHwNRF5/pull/12 -
Reporting back: I did the measurements, and it takes an nRF52805 about 750uSec to go from cold-start to turning on an LED, at an average current drain of about 330ua just prior to the LED turning on. Of course, the 805 may have to spend additional time and current to re-establish a particular context, but ignoring that, the measurements suggest a breakeven point between cold-start vs sleeping with the RTC turned-on and full memory retained (roughly 1.5ua current draw) is approximately 200ms. The downside is that it would require additional hardware to benefit from the arbitrage, but if so desired it could be done. In fact, just knowing that's it's possible makes me want to try it! :sunglasses:
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@NeverDie Oh I've been running around 20 NRF52805 nodes for the past ~2 years https://forum.mysensors.org/post/108893. They've been working very well for me.
edit:
PRs to get working with mysensors
https://github.com/sandeepmistry/arduino-nRF5/pull/442
https://github.com/mysensors/ArduinoHwNRF5/pull/12@ncollins Impressive! Looks as though you even modeled the exact shape of the coincell holder. And you apparently designed the 3D printer snap enclosures as well. Even just the 3D printed enclosure modelling is quite a task all by itself. I hope to one day evolve into doing that too, but for now the Hammond enclosures are going to be my short-term solution. The smallest Hammond is still not as small as what you've managed to produce, but at 36mm wide for an off-the-shelf ABS enclosure, it's too wide by only about 10mm. Still.... one day I want to 3D print an enclosure to be as small as possible.
