Martin Harris - Moderator

Thanks for the ideas Brian. I established an input range of 3.9 - 6V which would work using an adjustable power supply connected direct to the board so I can discount battery or connector issues. Funnily enough, I did wonder about the ground connection and tried a link across the board but that made no difference. It’s so strange that I’ve had these problems and I’m perfectly prepared to find that I’ve done something incorrectly but I’m at a loss to see what that could be with such simple circuit connections. I’ve built two examples (both from the instructions, not copied) and they both show exactly the same characteristics, despite one Arduino having been programmed and tested by Phil. The only unknown is the OLEDs - which were sourced separately but physically identical although those more informed than me can’t see any way it might affect these symptoms. It would be interesting to discover whether anyone else has built one from currently available components and how they got on. I believe 99% of us are using Chinese clones of Arduinos so there might be some differences from older versions? FF - thanks, it seems like the shielding on microwaves isn’t totally effective then…

I’ve gone with a vape battery - luckily my daughter is staying with us this week and had just finished one - what a waste, lasts a week or so but unrefillable apparently but with a 650 mAh LiPo cell and neat little USB C charger module, complete with LED charge state display. Unfortunately, I damaged the display during the excavation of the module which seemed to disable its charging function so went with a simple charge jack. While 2S would probably be better, it seems happy to work for several hours while maintaining sufficient voltage to function effectively and there are no balance charging considerations (although my ISDT charger gets a little excited by the prospect of doing an unbalanced charge!) I may modify the case design to incorporate a charger module and display once I’ve worked out its switching arrangement (some sort of suction operated switch in the discarded parts of the vape, but I don’t recall any wiring) - I’ve got my name down on the next vape!

Maybe a solution now but not really an explanation. It doesn't complete the boot sequence using a 2S Lipo - or a 2S LiFe for that matter but it does on a 1S Lipo with and without pull up resistors! I've left the new test assembly running in the kitchen for several minutes and it seems happy. I can see a couple of ways forward now but it does seem so odd that I've had these problems with the standard 9V power source. There seem to be two issues here - but are they related? First is the boot up - not a problem for anyone else and seemingly relating to the absence of pull up resistors to SCK and/or SDA. Second is freezing which seems to happen mostly, but not exclusively, in the kitchen where I'm seeing much reduced signal amplitude displayed when operating on the PP3. The only common factor which hasn't been eliminated - but one that doesn't seem to be considered a possible source of the problems - is that the display that I sourced from a separate supplier is physically identical to the first one. Worse in the kitchen...no, the microwave hasn't been in use while I've been testing but that does raise a separate concern...has anyone seen activity from one registering on the scanner or is mine leaking?

I don’t know if it helps but I knocked up a quick test assembly with my original Arduino and the new display. Guess what? It behaved almost the same and I’ve tried a Duracell on both too. I’m sure it’s wired as shown on the mode-zero site but in case I’ve suddenly developed colour blindness or electronic dyslexia, I’ve attached a photo of the test version and a video of it failing to initialise. A 10k pull up resistor to VDD got it further through the sequence but I didn’t bother trying to find the “magic” value(s) for this one. IMG_3997.mov P.S. I know the Duracell is out of date but it was still sealed...

I was referring to the direct board to board mounting method which I believe uses A6 linked to 0V and A7 bridged to 5V to feed power to the OLED. I’m using fresh Procell (industrial Duracell) PP3s and seeing a steady 5V at the 5V pin. On the first attempt, I established that it would work on any input voltage between 3.9 and 6 volts.

Weird, isn't it! I'll put another one together tomorrow with my "spare" bits. Could there be any difference connecting it via the spare pin method for direct mounting of the display on the Arduino - which way did you connect on test? Update - re the freezing problem, there does seem to be an environmental factor. In my living room, the scanner is showing a fair amount of 2.4 GHz activity (router and Bluetooth devices close by) and seems to run for extended periods but moving into my kitchen, where most of my testing has been done, signal levels drop dramatically and within a few seconds, the display freezes. However, the boot problem was occuring in the living room before I added the pull up resistors.

Got nowhere with the trial and error approach other than establishing that going much above or below 10k made it worse. A4 (SDA) seems to be the more critical pin to pull up in order to get it to complete the boot up. I'm wondering if a small 5v regulator to power it through the Arduino's USB connector would be the easiest solution.

Working from a couple of different devices for me. Maybe an ISP caching issue? Try a shift/refresh...

Hmmm....the saga continues now that I've put everything back together. While it now starts up and functions (almost) every time, the display locks up after a varying amount of time. It looks like I might have to continue experimenting with resistor values... One slight worry though - when my wife just turned on the (fairly new) microwave, it detected strong activity!

As soon as I hit enter on the post above, I had a thought based on some research I did a few days ago and Googled "Arduino pull up resistors" - which came back with a suggested value of 10k. With little to stop me and in the fine old spirit of "poke and hope", I did a temporary lash up based on Phil's earlier suggestion and lo and behold, it worked straight away! I'm not entirely sure about the function of these pull ups, which seem to be to better define 1 or 0 conditions and how this affects the working of the circuit but perhaps 1k resistors are now too low a value with the latest boards?

Well, I don't think it will come as a total surprise to Phil that connecting a new OLED made no difference! My replacement OLED didn't have anything connected to the C2 terminals either... The scanner works perfectly when connected to a 5v supply to the onboard USB port but despite measuring 5.08v at the 5v terminal when supplied by the PP3 it resolutely refuses to complete the boot sequence. Phil - can you recall whether you powered the board that you so kindly sent me from a PP3 while you were testing it? Scanner powered via on-board USB I'm wondering if anyone else has tried running this simple circuit while powered from other than the USB port? Perhaps something has been changed in the currently available Arduino boards? Anyone else here having a go at putting one together ? I see 8 people have downloaded my case design...

That's a fair point but on reflection it's probably more likely they put the tabs inboard on the trailing edge rather than on the ailerons to avoid all sorts of mass balance complications. Splitting the effect between the two wings would reduce the assault on the J60's aesthetics - perhaps a similar approach would make reduce Mike T's horror if you still have the model David?

I believe an upgoing trim tab like that will reduce tip stalling propensity but its interesting that the full size solution to correcting the effect of one twisted wing was to provide two inboard tabs.

I used to own a share in a pre-WW2 Rhonbussard glider which had been rebuilt with a twist in one wing after modifications and glue replacement by a German university group. The German authorities refused to give it a Certificate of Airworthiness without the wing being completely rebuilt and it was sold to a new British owner after consultation with a member of the BGA Technical Committee. After initial test flying revealed a pronounced roll to the left, it was fitted with aluminium trim tabs just inboard of the ailerons. These were unnoticeable over the normal speed range and only started causing any stick pressure over 75 knots. Stall behaviour was benign and typical of the type. I built a model of it when I returned to model flying - and quite spookily found it needed a lot of trim to fly level - so I happily fitted some scale tabs!

Many of our members (including me) have been impressed with GNB batteries. We’ve used them extensively in EDFs (as well as for less demanding applications) where they’ve lasted very well.

I asked you nicely not to pursue your line about another member Rich so I’m afraid it’s time to lock this thread. You should have sufficient information by now.

I think it’s time to stop blaming anyone other than supplier if you consider that they have published misleading information. Rich, this thread is turning into an unwarranted and unjustified witch hunt and if this continues it will be closed.

As far as I can tell, your transmitter should work to control the model in conjunction with an S-Bus receiver. Hopefully, someone here may have had direct experience with these models and will step in to assist you but your problem should be referred to your supplier, not the wholesaler. If the wholesaler chooses to assist you, that’s a bonus but it is not their responsibility in law. Have you contacted whoever you bought your models from? If they claimed that you could simply bind your transmitter to the model as supplied, then that’s who you made the contract with, and who you need to resolve it with.

Do you fly at a BMFA affiliated club? The A isn’t a licence, it’s meant to be a measure of achievement. Many clubs do require members to have passed the A before flying unsupervised but this would just be a local rule. They would normally help you get to the required standard and most have examiners or will have a way to arrange testing. If you don’t need one but want the freedom of flying at club sites as a visitor - or even just see it as something to aim for as a personal measure of progress, there’s no reason why you can’t ask the local area scheme coordinator to arrange a test.

Depending on the lengths involved, usual recommended practice is to use standard length battery side cables and extend wiring on the motor side. This is due to issues affecting the input circuitry of the ESC - some ESC manufacturers recommend low ESR capacitors at intervals across the extended battery side wiring should you choose that option.

I don’t claim any in depth knowledge of Radiolink but it might be that you have to use an S-bus receiver via the included connection lead. https://wheelspinmodels.co.uk/i/radiolink-r8sm-24ghz-8-channel-sbus-ppm-334150/ This video might help but I have a feeling that your radio might be too basic to upgrade to run TopRC protocol

Common term for rendering a device useless by incorrectly upgrading firmware, either by error or flawed firmware. i.e. turning it into something resembling a brick.

Thanks for the advice Phil. Luckily - and more in deference to the fine thread in the PLA case - I used minimal force on the screws! I’ve added an appropriate note as requested.

Off topic posts specific to scanner construction from the "swamping" thread moved here to unclutter the topic. As a moderator, I feel a little guilty for starting the sub-discussion so I'll offer a little present for anyone contemplating building one of these simple devices (thanks for the info and help from Phil Green) so if it's of any use to anyone, I've attached an STL file for printing the case I designed for mine. Spectrum Analyser Case.stl I tapped the holes for the display mounting screws but this version has the threads printed which should allow short M3 screws to run in. The case bottom should attach with servo screws and the Arduino slips in at an angle - I retained mine with a couple of dabs of UHU POR on the top edge which allows easy removal.

I seem to have rather taken this discussion rather off topic so I've split the scanner specific posts off into a new topic.