Andy's Postbag and random ebay links

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ag123
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Re: Andy's Postbag and random ebay links

Post by ag123 » Wed Jun 07, 2017 2:27 pm

those 'transistor tester' seem like quite a fun project to do in stm32 too, i.e. measure transistors hfe, diodes, continuity tester (yup need beeps), volmeter, current, capacitance, resistance, inductance, signal generator (and multiple patterns, square, triangle, sine, pwm), rotary encoder, fft signal analyzer, frequency meter, how many things can 1 pack on a proto board? or perhaps one can 'pre wire' a breadboard :lol:

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ahull
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Re: Andy's Postbag and random ebay links

Post by ahull » Thu Jun 08, 2017 8:55 am

The original transistor tester project is open source, and uses an AVR. This is what all of these Chinese clones are based on. Porting to STM32 would certainly be "do-able", but may require a lot of work. Perhaps best to start here -> https://www.mikrocontroller.net/article ... stortester
- Andy Hull -

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ahull
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Re: Andy's Postbag and random ebay links

Post by ahull » Thu Jun 08, 2017 9:04 am

One other thing.. One of the IR helicopters appears to work, although it needed a bit of tweaking to straighten out the tail rotor and convince it to fly roughly straight and level. I haven't managed to charge the 2nd "Stealth" heli. yet (work in progress, watch this space)... and the quad is missing a battery, so some minor surgery to those two may be required in order to make them easier to use with the many small lipo cells I have lying around. I've ordered some suitable (tiny) connectors.

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The small red IR heli. is currently getting abused by a complete novice pilot. So far I have managed to collide with pretty much every vertical surface in the room, and of course both the ceiling and floor (mainly the floor) without causing any serious damage. Great fun for under £2. The battery doesn't hold much charge, so I suspect the novelty of 5 minutes flying for every 20 minutes charging may wear off pretty quickly. Perhaps a larger capacity lipo cell might be the answer, but I suspect there is pretty limited lift available, so finding one that hits the sweet spot for max capacity and min weight may be a problem. I also suspect It is too anaemic to carry a camera unfortunately.
- Andy Hull -

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ahull
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Re: Andy's Postbag and random ebay links

Post by ahull » Thu Jun 08, 2017 10:47 am

Office defence system upgrade.

I indulged in a bit of empty headed rocket surgery on the "Stealth" copter (well I couldn't fly it so the next best thing is to take it apart).

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It appeared to be suffering from a couple of issue, that would have made it a pretty effective ground hugging machine. First off, the LiPo seems to have an over inflated ego, and secondly the previous owner seems to have ground looped it once too often as one of the main rotor motor gears had all but slipped off the end of its shaft.

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Since there doesn't seem much point in pinching the battery out of it for the other one, I instead fixed the gears and put it back together. Looks like I need three small LiPos.. and then I will probably have three fully functional machines for irritating my colleagues in the office :D

More teardown pics here -> https://goo.gl/photos/Tfi4wXQnr5ZaNGHVA

BTW the pictures don't give a real impression of how many very small things have been crammed in to a very small thing. These machine are a minor miracle of modern manufacturing. Having said that.. does it really make any manufacturing sense to use 16 tiny self tapping screws in two different sizes just to attach the skids and the covers to the thing.. surely a couple of screws and some well engineered plastic clips would have done the trick.

EDIT: I forgot to mention the entertaining Chinglish on the rotor blade of the red beast. Take care and don't hurt your fuselage now children. ;)

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I'm sure those little nicks in the blade weren't there when I got it.. :lol:
- Andy Hull -

zmemw16
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Re: Andy's Postbag and random ebay links

Post by zmemw16 » Thu Jun 08, 2017 11:08 am

( panel with tabs and one screw v panel with 3 screws ) + ground bounce = broken tab :)

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ahull
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Re: Andy's Postbag and random ebay links

Post by ahull » Thu Jun 08, 2017 11:47 am

zmemw16 wrote:( panel with tabs and one screw v panel with 3 screws ) + ground bounce = broken tab :)
You could well be right.. It has taken four full charges and a fair amount of tweaking, but I can now actually fly the thing without (always) hitting anything, so the screws are probably there to ensure that the thing mostly stays intact when flown by an inept buffoon like me.

The best crash so far. I managed to loose control when the thing was next to the ceiling, hit the roof, hit the wall, hit the window and landed in the dogs water bowl... which naturally was full of water. Despite almost literally rolling on the floor laughing, I did have the presence of mind to switch of the thrashing complaining improvised fountain of a machine and take it through to the hand dryer in the gents... five minutes of forced air drying and yet another re-charge of the battery later and it appears to be none the worse for its experience.


I am actually doing some work at the same time I might add.. honest I am... but there is a touch of the "my code is compiling" about the whole thing.

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https://xkcd.com/303/

BTW It flies a lot better if you don't fly it too hard.. let it do its own thing, and adapt to the lag in the controls and its actually very easy to fly. The moment you panic.. chaos.

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With a little care, I can set it in a hover, put down the remote, pick up my camera and take pictures of it slowly drifting round the room.

... now I wonder if my bash script has finished doing my morning's work for me. :P
- Andy Hull -

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RogerClark
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Re: Andy's Postbag and random ebay links

Post by RogerClark » Thu Jun 08, 2017 9:54 pm

I was given larger version of that heli about 5 years ago, but the motors would randomly cut out when it was about 20ft in the air and the motors would not resume in time to prevent it impacting the ground rather hard.

In the end I pulled it apart for spares, and the best bit was the lipo cell pack, approx 250mAH which had a dedicated, cell balancing charger.

The battery is now powering the display unit on an excercise bike that someone threw away for the council to collect as part of our local "hard waste" collection service.


I also have a very small Hubsan quad copter, whuch runs on very small lipo cells, but only flies for around 5 mins before the battery goes flat, so I bought a pack of 4 batteries fairly cheaply on eBay, and also a multi battery charger.

Having said that, my brain needs a rest after about 5 mins of trying to fly the thing, so I hardly ever bother to swap the batteries and try to keep it from crashing into the ceiling, or walls or furniture or the floor ;-)

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zoomx
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Re: Andy's Postbag and random ebay links

Post by zoomx » Fri Jun 09, 2017 7:30 am

I bought a small JJRC H20 then dismantled a little camera that weight about 7g (without case!) and attached to it with a rubber band. Some days ago I won an auction on ebay and got a Cheerson CX10W for 11 euro, it has a little cam and is capable of trasmitting it on a smartphone. I am waiting for it.

Then my wife and my son bought me a Parrot Bebop 2 that is much much simpler to drive because it is able to stay stationary, even in wind, using ultrasonic and optical flow sensor (a little 640x480 cam) when close to the ground, GPS when it is more high.
Unfortunately the motors hasn't power enough to fly at high altitude, I tested it on Mt.Etna at about 3000m and it wasn't able to take off.
The DJI Phantom, used by my colleagues, instead works well at that altitude.

I have also two smalls helicopters bought for my son some years ago.

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ahull
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Re: Andy's Postbag and random ebay links

Post by ahull » Fri Jun 09, 2017 9:53 am

I spotted one of those cheap quads in my local Lidls yesterday, as I did my monthly trawl through to see if they had any interesting tools or other random stuff. Didn't buy it obviously, but it was interesting to see that they are now so mainstream, even the discount supermarkets are pushing them.

It was a no-name 2.4GHz machine, for £19.00 - its pretty tiny, and not powerful enough to lift a camera (well maybe one of those little 808 keychain cameras if you stripped away all of the casing etc, but it would be a stretch for the thing). Last month they had some small "indoor/outdoor" helicopters but they were a bit pricey for what they were, and again they were probably pretty anaemic in terms of range and lifting ability.

These tiny heli and quad-copters are good fun little toys, but have absolutely no practical value. One thing I did think of though is that the receiver and motor controller board could theoretically be re-purposed by getting it to drive some much beefier transistors and real motors... but then again you can pick up quadcopter controllers online from the usual suspects for <£20, so if you wanted to build your own that would probably be a smarter bet.
- Andy Hull -

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zoomx
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Re: Andy's Postbag and random ebay links

Post by zoomx » Fri Jun 09, 2017 6:36 pm

I dismantled this one
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the 808 keychan one is heavier by some grams.

Yes, they are all toys but they can fly indoor. Bebop is able to fly indoor but there is a strong air movement because of the more powerful engines so I was not able to fly it in the hallway.
Now I am waiting for this little one
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It has a cam that is streamed over wifi :shock:

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