Do you happen to have a board or two left over that I could buy from you.
I'm looking for testing this module with an external antenna before integrating it in our project (https://github.com/NathanB49/Utilipi/tree/dev_V2)
@tekka unbelievable !!! I tried with NRF24 and arduino nano, it's working like a charm !!!
If I use the same sketch, on a pro mini using one of my ftdi as serial interface the Tx don't go threw anymore !!!
Ftdi use a 1047 chip
Arduino nano use a CH340 for which I had to install a Chinese driver for it !?!? !!!!
Small update here. I've been working on the routing part. it's been years since i played with the nets, and wires on Eagles ... Oh boy, its a mess ! and while placing, moving components, i was thinking , wow, the Balun filter, the NRF24L01 are going to be impossible to hand solder correctly ! and I don't really want to buy a microscope, a $300 soldering station, ...
So I looked around and found something interesting so I post it here, if some makers don't know about it, and are afraid of SMD soldering : OSH also make stencil for you, Kapton stencil for $5 ! https://www.oshstencils.com/index.php
then it's a peace of cake or is it ? https://www.youtube.com/watch?v=1RMtOAHbfvU
Has anyone tried it before ? I'll definitely try it
So after some reading, phoning, thinking, again and again about FCC/CE Certification here is the plan.
I'm not going to go for the FCC Certification, as it's way too expensive, but I'll run the test myself for CE compliance.
When FCC needs to be done by US agencies, the CE can be self-certified : you run the tests with the appropriate tools, make sure your design respects the requirements, and if so, keep the results in case anyone asks anything.
Now pretty much everywhere, I read that if your product is CE compliant, then your chance of getting the FCC on the first run is very high. Dropping the cost to a "small" $5k or so
So first, CE self certification, and then if needed/wanted/asked/ ... FCC, IT, ... other certifications. Meaning so US selling first just Europe. Are there many US folks using Mysensors ?
To run the test, I'm working with my University which has all the tools, and knowledge to assist me. Could be an interesting project to run with some student ... will see !
So regarding the design, zero risk must be taken regarding the RF part :
I share a great guide from TI about antenna design : http://www.ti.com/lit/an/swra161b/swra161b.pdf
Now I want to try the Inverted F antenna presented in my early post, a Di pole antenna (no more Balun Filter), and Chip antenna and compare them the standard Meandered Inverted-F Antenna (MIFA) we all have on our NRF board !
Indeed what you are pointing out is the Achilles heel of the project ! I haven't mention it because I haven't done my research on the subject. Their might be some solutions I will post on that later on.
And you are right once again, I haven't investigated all the details ... **yet **
It's all a project is about, isn't it ? You have an idea, a goal, and then you investigate step by step to see whether you have a good chance of success or not. I use "good chance of success", because in every project you take some hypothesis, you take some risks, because success is never 100% sure.
At the beginning of the project, the chance of failure are very high, but its ok because the investment in very low (just time so far). And the more I'll progress, the lower the risk will be (if I did the investigation work properly) and then it will be ok to invest a little more.
It's also one of the reason why I post in here all of my project, this (all the comments, and feedback) helps me (and the Mysensors community) to evaluate the chance of success Vs the chance of failure. You guys can point out weak point and so on and so forth.
So I'm pretty glad you mentioned that, it shows me my project is of interest.
As mentioned, I will post on that specific crucial part once I'm done evaluating all of my options.
@scalz Yes, I know I'm not inventing anything, everything that I propose already exist
the only, and MAJOR difference is the price : I'm following a design to cost process. What does it means : I take available hardware/schematics : NRF, Arduino (Sensebender, and other good board), ... and I try to redesign and make it as cheap as possible.
The nrf51822 is indeed the killer, BUT it's not working yet with MySensors
And I totally agree with you, if you work in HW and if you are not focused on the future (new chip, new protocols, new project, ...) then your project life expectancy is very little
I obviously won't lunch mass production, so I'm running the process with 400 boards batch. So far, only based on hypothesis, meaning its pure fiction, meaning there is a margin of error in my calculation. The more I will progess, the more the margin of error will be important, and the better I will fine tune the final price.
And I'm pretty sure that if we talk about bigger production batch, then the cost of a simple board could be as low as a couple of $
Look at the low cost airline company, they didn't invent anything, they just optimized everything to drive cost down, and now they are very successful company.
Look at the new Raspberry Zero (produced in EU) : given away for free with a magazine, and then sold for $5 !!
I give out those example to illustrate that innovation is not always the key to success and to illustrate that the cheaper you go, the wider spread it will be ! (no need to add : if the quality is here)
And just to be clear, I'm not doing this to earn money, because low cost, and small batch are usually not big money maker.
Now clearly, if you tell me you will manufacture your Mytinycamel, and sell it under $7-10 fully equipped (board + radio) then I'll reconsider the project. and don't worry, if I didn't want to be challenged on the project I won't be here talking about it !
"Too bad we didn"t met when I started my projects..." => It's maybe not too late !? If we are after the same goal, we can maybe add our skills ...
@ahmedadelhosni Idk what to tell you, I guess Temp sensor is quite common, and fun thing to have inside and ouside.
Many people like to know what is the weather ouside, and the can also use inside temp sensor to control their heating/cooling system.
@tbowmo I will do my best to please the most ! I'm thinking about the footprint options. I'm also thinking about production option in one batch. If you think about it, in 400 boards, if you use the same Stencil, you can in case 1 populate the full board (EEPROM, temp sensors, ...), in case 2 only temp, and in case 3 the minimum. It's a minor program update to disable one or 2 ref. And then you have 3 types of complete board with three price to make everyone happy. I obviously won't be able to do that with chinese supplier, so I'll talk about that with the French supplier.
I'm actually doing all the quotation with various hypothesis because I don't have yet any design file. I'm working on it. So I have not made a choice on specific ref for the RF part (only the couple of inductance and capacitor for the impedance matching are critical). The PCB will be 1mm thick, and the cooper trace 1oz. There will be no ground plan under the antenna.
Thanks for sharing the MYSX connector, I'll take that into account too. Is there an eagle lib for it ? (I know it's standard dual row pin header, but the pin assignation could be useful to have directly via a lib)
Thanks I'll read that carefully.
@Anticimex still thinking about the ATSHA204 and the HW security vs SW security.
If you have a node with the ATSHA204, does the GW needs to have it on board to ?
BTW do you have the link to the security thread so I can update my knowledge on that side ? please