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Need Advice About A Roadtest: Amber Pi Design Kit

rscasny

Greetings. I wanted to get the advice of any top member regarding a roadtest I am getting ready to launch.

 

Let me start by saying, most roadtests begin with a meeting with the sponsor who indicates an interest in sponsoring a roadtest. My boss gives a high level view of the roadtest program, and then I fill in the details, schedules, gathering information, etc. One of the things we always point out is that the products we roadtest have to be global (they can be used in N/SA, Europe, Asia, etc.)image

 

I met with WURTH ELEKTRONIK about its Amber Pi Design Kit. AMBER PI is an expansion board for the Raspberry Pi 3B that gives the Pi a sub-1GHz RF interface. The included sensors (temperature, humidity, pressure, motion) and RF dongle which runs as remote station for the AMBER PI.

 

It seemed like a good product to roadtest. It has an IoT angle, and it seemed like a product that would appeal to both makers and professionals alike. As usual, the sponsor sends me the kits so we can ship them out to the roadtesters. Well,when I opened the box, I soon learned all the kits were for use at 868MHZ (Europe) only. I didn't see that as a problem because often times there are separate part numbers for a 915MHZ product and an 868MHZ product. This time, however, there was not one for 915MHZ. I contacted the tech support line which said : "yes, unfortunately the Amber Pi is only available with the 868MHz RF module." This poses a problem since I need to open the roadtest to North America, at the very least.

 

After some quick research, I see that while the company does not make an Amber Pi with a 915MHZ radio module installed, it does sell aimage

915 MHZ radio module separately. So the radio module would need to be swapped out.

 

Question In Need of Advice

I could very well purchase some 915MHZ radio modules and provide them to the North America roadtesters. So, they would have to swap out the radio modules. I guess if this was a quick pull out/plug in task, I wouldn't be writing this discussion. But it appears that the module is soldered in. I took a close up picture of it (pictured below) for you to see. If I'm wrong, say the word. End of story.

 

But if it requires to be desoldered/soldered, then I am somewhat concerned for a couple of reasons:image

 

-- it changes the nature of the roadtest to include the modification task instead of just focusing on the rapid prototyping capability

--What if there is damage to the radio module during the swap out.

--The swap increases the complexity of the roadtest to the point where it is possible that a roadtester may not complete the roadtest/review

 

Now, I guess I could request from the company to custom build 915MHZ versions. Moreover, since they sell it with a separate 915MHZ radio module, perhaps the swapout should be roadtested to see if it is as easy to do as is implied by the supplier tech support line.

 

So, I am looking for some advice. I want to make sure the roadtest is fair and straightforward for both the supplier and the roadtester.

 

Any comments you have would be appreciated.

 

Randall

  • in reply to dougw

    I put that......______on everything!  love chip quik

  • To All,

     

    thanks to everyone who participated in this discussion.

     

    I've been discussing your comments with the supplier.

     

    Happy Conclusion: I was told today they are providing me 2 kits with the 915MHZ radio module installed.

     

    I will be creating the roadtest page shortly.

     

    Thanks.

     

    Randall

  • in reply to Gough Lui

    I'd have to agree that desoldering this without damaging the headers isn't an easy task. It's certainly possible, but not easy.

  • It appears my response might be late to your game.

     

    I see the problem as an exercise in managing risk. My take is that you define the RoadTest options and let the vendor decide what works for them.
     

    RoadTest restricted to the markets supported by the equipment without modifications.

    RoadTest expanded markets only if equipment can be supplied by vendor.

    RoadTest expanded market with equipment modified on delivery.
     

    My reasoning is taking the perspective that the RoadTest is a supplier, that is responsible for providing results within specified parameters. Depending on what option is selected the specified parameters change. If you decide, you assume all the risk.
     

    It appears from following the comments regarding RoadTest applicant selection, that you report back to the vendor on the results of RoadTest. I seem to recall missing RoadTests is a poor performance indicator that vendors frown on.
     

    Speaking from the Element14 community, I believe there are RoadTesters capable of handling the modification successfully. You want to sell the capabilities of the option  but it does increase the risk to a poor performance indicator. You can limit the exposure by limiting the number of outside of Europe RoadTest.
     

    Depending on the parameters of the RoadTest (i.e. option) there is varied risk. How do you manage the risk and still provide the vendor the RoadTest results? You need to clearly define the risks for each option. You still have the risks but you transfer that risk outcomes to the vendor.

  • There is a DIY method to remove these.

    Strip the isolation of home wiring cable and fold it so that it becomes a r3ctangular form that touches all soldered castellations, but also has a folded circle or spiral pointing upwards that fits snug around the solder tip.

    In combination with a preheater this allows you to melt all solder points in one go and lift the board without force.

  • thanks for everyone's input.

     

    This is what I am leaning to do:

     

    1. Open the roadtest for the 868MHZ Amber Pi Design Kit Roadtest

    2. Order a few of these 915MHZ radio modules and sponsor projects where they get a Amber Pi and a radio module and their job is to install the 915 module, document there steps, etc.

     

    Randall

  • in reply to ravi_butani

    I don't think that's necessarily a great idea. For one, it comes with the EU 868MHz module by default (from my understanding of what is written) but for RoadTesting outside EU, the 915MHz module is more appropriate.

     

    This is because the "900MHz" band is not quite as "standardised" across the world as the 2.4GHz band is (more or less). Different countries have different restrictions on the use of 900MHz frequencies. I took this snapshot from the present 802.15.4v document just to illustrate the point:

    image

     

    Using the "other" (i.e. 868MHz) module outside of EU will likely cause interference to licensed services and should not be encouraged. If you did that in Australia, you'd be interfering with the CMTS (Commercial Mobile Telephone Service) base stations, specifically Telstra NextG (3G-850MHz) band. Likewise, even 915MHz comes in several sub-bands - something I mentioned in my recent RoadTest of the IDT Wireless Sensor Cube because it could not operate with its included software in a legal way in Australia (using a frequency in the Optus 900MHz CMTS band instead, with potentially stiff penalties if caught).

     

    - Gough

  • One more solution...

    As you are providing both 915MHz already on Amber Pi and 868MHz stand alone module... You can just Ask roadtester to come up with standalone or something more creative application with or without Raspberry Pi using 868MHz module with DIY PCB...

  • I don't think this is a task you should leave to the reviewers.

     

    On the one hand, it may be nice to see how "easy" such a task will be, but on the other, there is a good deal of risk. Just looking at the board, I don't think it's going to be an easy road to desolder and resolder the module. For one thing, the through-hole header pin connections are so close to the module that it's going to be a pain to try and heat up the module without melting the plastic at the bottom of the pins. You'd also need a decent amount of equipment - an under-board heater and a hot air gun look to be necessary and I've only got one of the two (the hot air gun) so it's more than likely that I'd roast the top side of the module coming out and perhaps that of the module going in. That might kill the module or an inadvertent bump may dislodge some support components (e.g. antenna matching components). While the pads are castellated, which would in-theory mean that it can be soldered without hot air ... the closeness of the through-hole headers would mean that it would be hard to get the iron at the right angle to do it - assuming you had a fine-enough tip. Thus it would be best to do it with hot air, solder paste (or solder and flux) with the same issues noted before.

     

    I would suggest either the vendor start selling modules with the 915MHz modules pre-populated and then review them, review only the 868MHz modules in EU countries only. If somewhat daring, perhaps request boards without any modules populated and have the modules separately supplied with the RoadTester to populate at their own risk (expect some failures).

     

    There's also the question if the modules are software-compatible - while they may be footprint compatible, the 868MHz band has a different amount of bandwidth (and consequently, different number of channels) available. If the software does not correctly identify the module and program it properly, there's a chance that the correct module still will not operate properly?

     

    - Gough