Snoopy & Early October 2024 News. Help with that Servo Current Limiter & bigger topics.

[Robin Lovelock on robin@gpss.co.uk]

Hi Guys. I've updated Snoopy's "Blog11" on http://www.gpss.co.uk/rbblog11.htm and this is not just those into Microtransat and Trans-Atlantic Robot Boats - which can benefit from wisdom of pensioners into radio controlled boats - perhaps after radio controlled aircraft and drones ;-) Pensioners often have wisdom on a wide range of subjects, including physical & mental health, A.I., electronics, warfare, welfare, and much more ;-)

Technical Guys: can anyone help on that "servo current limiter" in Blog11 ? :-)

https://www.youtube.com/embed/hU7S3ikj8Pc?si=vlCp3hDa0gxAeLzY is a 1.75 hour video with the trails of photos shot between Friday 4th until Thursday 10th October 2024. The video starts with Robin's usual amusing introduction, shot on Thursday 10th and recent days, walking down their front drive at 22 Armitage Court in Sunninghill. Robin shows you Snoopy's Robot Boat in the front garden, on 24/7 Static Test, researching improving solar power. Not yet done. The boat should soon be ready for a Bray Lake Test, before a 2024 Atlantic Attempt. Photo trails show how, with the right help, they might get the house, back to what is was several decades ago.  This, and earlier videos, have important detail for potential helpers in "property maintenance" ;-) They need plenty of experience and "common sense" ;-) After the photo trails, Robin wraps up with video shot in July 2023: prophetic words of James Lovelock about Global Warming, and Robin's suggestions about the DVLA. He still has not received his driving licence. Most guys would be annoyed, but Robin is often amused by incompetence - so long as it does not result in suffering, pain, or death. It has been very "inconvenient", with more load put on June, coping brilliantly with her health problems. With the right "nudge", June spoke to the same paramedic at Magnolia House and got an X-Ray on 9th October. Results may be available on 11th October. The DVLA letter on Friday 4th appears, but is dealt with more clearly on Robin's PRESS and DVLA pages ;-) Yes, as can be expected, from Robin's career, then hobby interests, there are plenty of examples of people, GPS Tracking, and technology being exploited. e.g. wildlife and people caught on CCTV; Sunninghill Comrades Club; Pub Lunches ;-) The automatic subtitles/captions were soon available, with translation into any language. Well Done Youtube Guys, whoever and wherever you are ! ;-) Footnote: Youtube used to give a choice of three images, for the "title picture" - and now just one. Often a good choice. You can do it yourself - and not an image bigger than 2 MB ! Not difficult with old Paint. Google and Youtube things change - fewer people to employ and pay ? Bring back people, simply aided by A.I.  ! :-)

That's the Youtube description above. Topics overlap, and I've known for years that my best advice on anything, including technical things and health, is often from my overlapping networks of friends, both local and far away overseas. My thoughts are with you, in these difficult times. 

Closer to home, thanks to my small circle of Grumpy Old Men, providing good health advice to wife June - key member Snoopy's Team-Joker, from when the late John Sylvester got me started. This morning, I had to ring old friend Gary Carter, of http://www.carmech.co.uk because we needed help to know how to get to the car battery of June's Merc K555GPS seen in the video. June hadn't told me she had an MOT at 1400 today - or we might have been better prepared: all three of the "fast starters" were flat, as was the K555GPS battery, because the car had not been used for days. "Be Prepared" is an old saying taught to school boys ;-) Gary is also the guy who gave me the first of Snoopy's Robot Boats - all on the "Snoopy" page http://www.gpss.co.uk/autop.htm and many linked pages :-)

Take Care

Robin Lovelock in Sunninghill

http://www.gpss.co.uk and www.gpshobby.info and http://www.nhscare.info

"Contact" page http://www.gpss.co.uk/contact.htm

[Robin Lovelock on robin@gpss.co.uk]

H Guys. I've just updated Snoopy's "Blog11" on http://www.gpss.co.uk/rbblog11.htm and sent the following message to the Picaxe Forum where I got that brilliant advice from Buzby, mentioned above  I hope the copy and paste works, but it should be clear enough in the Blog11 above >>>

Hi Guys - particularly Buzby. I've been updating that "blog11" on www.gpss.co.uk/rbblog11.htm with progress, particularly on that LM317 based current limiter. You need to scroll down to the latest stuff near the end, with relevant pictures. LOTS of photos taken, of step-by-step work, but that will be a few days before I publish the "Mid October 2024" Photo trail video. However, in short, I now have LOTS of LM317, from the two batches that arrived yesterday: 48 + 10 = 58 and I've only used 2, so far. The first was a "lashup" that worked OK, with 5 ohm, into my "Servo Test Rig" autopilot, based on my old Picaxe 08M solution. 10 ohms and it tended to "twich". But it was only when I tried the more neatly built LM317, on a bit of veroboard, that I started tests on the boat system - based on the Picaxe 28X2. This just twitched, even when I lowered the resistance by using THREE 10 ohm resistors. This is all shown more clearly in that "Blog11" above. You will see that I was wondering if the problems were related to the servo drive

system, coming out of my Picaxe 28X2 based autopilot. I certainly do not want to change this - I'd rather do it "cleanly" with a module between the

28X2 and the servo. You will see that this raises that earlier problem: I have no spares for that Picaxe 28X2 Autopilot. I repeat: I'm happy to pay anyone to build and supply something that has been tested. But let's not get distracted: maybe someone can suggest a simple test with what I have here. Thanks Buzby - it was certainly easy to get those LM317 and an easy job to put together ;-)

Take Care

Robin

www.gpss.co.uk and Snoopy on www.gpss.co.uk/autop.htm

[Robin Lovelock on robin@gpss.co.uk]

Hi Guys, particularly those on the Microtransat Google Group, that I'm hoping several of my local "Grumpy Old Men" friends will join, if they have not already. Many recent updates made to near end of Snoopy's "Blog11" on http://www.gpss.co.uk/rbblog11.htm including from neighbour Richard, who was into radio controlled model boats WAY BACK in early 1960s, or was in 1950s ?. You may also like that old photo from 1964 of Dick Bailey - who you can't miss on my "Snoopy" pages. Lots of bright ideas being given, by guys like Richard, and that's why I suggested he join the Microtransat Group. Some might think a good idea, and others can tell him it was tried and tested decades ago ;-) On a related topic, particularly when a page like that above is being updated frequently, is the "Who has Visited" section, that anyone can see. It is not difficult to guess who it is - very important if sending them an email reply, after a change has been made. For the first time in years, I saw Richard's visits from "Ascot" removed from the Revolvermaps statistics, rather than simply hidden or "disguised" - that very few people do. e.g. as it says, I tend to come up as "Redhill", rather than "Sunninghill" or "Ascot". I was curious about that visit from "Switzerland", which could be from this group, ROBINLOVELOCKSFRIENDS, or anyone visiting the page. No need to be shy, or tell you exactly where you live, but it reminds me of that lovely Microtransat meeting in Austria, back in 2008 :-)

Take Care

Robin

http://www.gpss.co.uk and http://www.nhscare.info and http://www.gpshobby.info and http://www.carmech.co.uk

Gary Carter gave me at least two of Snoopy's first robot boats :-) 

"Contact" page also useful: http://www.gpss.co.uk/contact.htm No need to be shy ;-)

On Friday, October 11, 2024 at 03:32:22 PM GMT+1, Robin Lovelock on ro...@gpss.co.uk <gp...@compuserve.com> wrote:

[Philip Smith]

Robin,

regarding current limiter, I think your concept will have problems like the twitching you have seen. To limit the current to the servo any system (like your LM317 circuit, or just a plain resistor) will have to reduce the voltage supplied to the servo. This will protect the battery side of the system, but will give odd effects from the servo. I did very similar things to you and got similar results (with a completely different servo: a KST MS825), ie continuous rotation at low supply voltage, twitching if current limited. I think the twitching is because when the current goes high the voltage is cut, which turns off the servo control electronics, which reduces the current so the voltage rises back again, then the servo turns on, takes too much current so the voltage is cut, and so on. To stop this behaviour, and keep current low, you need to turn off the servo completely. I don't know what control you have over your servo power supply, but on my circuit I only turn on the servo power whilst it is moving, then turn off the supply current. (I actually also turn off the PWM control before cutting the power as my servo stays put if no PWM: yours may behave differently.) So to do a move, turn on the servo, start the PWM (having remembered what it was when you turned off the servo), do the move, stop the PWM, and turn off the servo. You should set the software servo angle limits to be within the hard stops so it shouldn't ever bang into the stops, which is when it will take a lot of current. You can keep a current limiter to act like a fuse and protect the battery, but anticipate erratic behaviour if the current is being limited. I do have a current limiter, but only as a last ditch safety in case something goes badly wrong, as I don't want the servo to flatten the battery too quickly.

Hope this is helpful, and good luck.

Phil Smith

[Robin Lovelock on robin@gpss.co.uk]

Great Stuff Phil ! Thanks. I was about to update "Blog11" on http://www.gpss.co.uk/rbblog11.htm

with latest voltages, etc, but now I've put a brief few words thanking "Phil" on the Microtransat forum.

In Brief: it looks like I'm wasting my time with that "Current Limiter" idea - BUT, I've added a few words,

without any diagram, of Richard's bright idea of two timers, to cut power for a few minutes at a time.

Best I direct you to the link, because it means I can update stuff as I get more info.

Also, very few of my relevant friends are on Microtransat Group - despite my suggesting it.

This is where those Revolvermaps "Who has visited" stats might be useful.

Could that be you, visiting last Sunday, from "Cambridge" Englan, UK ?

I have mates near there, but you seem more likely - if my flakey memory serves me right ;-)

Your boat has always impressed me the most, even if I'd tweak the sails and keel a bit if it were me,

so it was easier to sail in any wind direction. Not difficult to make it semi-autonomous :-)

Lots of other things going on here. Track me on my "Contact" page to see what I'm up to.

e.g. maybe Sunninghill Comrades Club again late tonight :-)

Mid October photo trail video probably only a few days away now :-)

But if someone gives me the right lead, I can order some more components to try.

Better still if I find some mug to do a prototype for me :-)

Thanks again

Robin

http://www.gpss.co.uk and Snoopy on http://www.gpss.co.uk/autop.htm

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