Andy's Postbag and random ebay links

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RogerClark
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Re: Andy's Postbag and random ebay links

Post by RogerClark » Fri Jun 09, 2017 9:35 pm

@zoomx

I have an old DJI phantom. But its always been a problem. The remote control Tx had ( still has) an intermittent fault, which caused the Phantom to go into emergency mode, and attempt to fly back to its last known home location.

Luckily, I was being very cautious and had it tethered to a weight by 100m of lightweight cord, so it did not escape.

After that, I lost faith in it, and replaced the FMU with the old version of Ardupilot, and had to buy a new remote control system. But the old Ardupilot did not support the Futaba data protocol, so I had to use an Arduino pro mini as a converter.

But by this time, the spontaneity had left the project, so I put the Phantom in a cupboard and bought the Hubsan which I can fly indoors, albeit but not in hallways etc as the backwash from the rotors blows it all over the place.

I guess, with the Phantom, I should probably get rid of my old Ardupilot and buy a F7 based FCU instead.

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Re: Andy's Postbag and random ebay links

Post by RogerClark » Tue Jun 13, 2017 12:11 am

Slightly off topic, but someone posted a question to one of my old YouTube videos about flashing to a mini quadcopter that he though had a STM32 in it

Anyway, it looks like its this quad

https://www.banggood.com/Eachine-H8-Min ... mds=search
(also available on eBay etc)

And has already has open source firmware https://dronegarageblog.wordpress.com/2 ... acro-mode/

But it looks like the its actually a GD32F130 not a STM32F1xx

https://blog.banggood.com/eachine-teard ... 29789.html

But different generations of the same quad seem to have some variation in which processor is fitted, so they could possibly come with a GD32F103 or even a STM32F103 etc


Still... As a hackable STM32 of GD32 quad, its pretty cheap !

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Re: Andy's Postbag and random ebay links

Post by RogerClark » Tue Jun 13, 2017 5:18 am

BTW

My $1 motion detector boards turned up at lunchtime, but I've not had time (yet) to wire them to something.

I don't know if the output has enough current just to drive a LED, but thats probably the simplest way to initially test them

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zoomx
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Re: Andy's Postbag and random ebay links

Post by zoomx » Tue Jun 13, 2017 6:20 am

Eachine H8 seems interesting and cheap!

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RogerClark
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Re: Andy's Postbag and random ebay links

Post by RogerClark » Tue Jun 13, 2017 7:23 am

zoomx wrote:Eachine H8 seems interesting and cheap!
Yes... My thoughts, exactly

But I already have a small Hubsan quad, which I don't use much, so I cant really justify buying another one I won't use much :-(

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Re: Andy's Postbag and random ebay links

Post by RogerClark » Tue Jun 13, 2017 11:23 am

I wired up one of those "motion sensors" to a BluePill and it does indeed work, in terms of sensing either motion / no motion.

One interesting effect I observed is that it seems to be triggered more by the size of the object that is moving than the speed of the object.

If I stand about 3 m from the board and wave my arms wildly, it does not trigger, but if I walk very slowly forward or backward (or sideways etc), it triggers almost immediately.

This falls into line with my theory that its using the whole environment as part of some sort of tuned circuit.

However what is odd, is if I whirl a piece of wire around, being careful to only move my hand, it still doesn't trigger.

I would have thought that if it was a tuned circuit that, moving a long piece of copper wire around, would be more likely to trigger it than moving the "mass" of my body.
But this is not the case.

If I get time tomorrow, I'll try looking at the signals on the pins of the RCWL9196 chip and see if any of them looks like its a voltage related to the amount of movement.

BTW. I though I read somewhere about someone looking at the pins using a scope but I can't find the information at the moment

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Re: Andy's Postbag and random ebay links

Post by RogerClark » Wed Jun 14, 2017 1:55 am

Just a bit of a tease....

But one of the pins on the RCWL 9196 seems to have analog data on it, which is related to the movement

I've only just hooked it up, so I'll post more later, to another thread ;-)

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Re: Andy's Postbag and random ebay links

Post by zoomx » Wed Jun 14, 2017 7:03 am

I found that tha small JJRC H20 has the same H8 pads so it would be possible to identify the chip!
Image
Sorry, I didn't find a smaller one!

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Re: Andy's Postbag and random ebay links

Post by RogerClark » Wed Jun 14, 2017 7:16 am

zoomx wrote:I found that tha small JJRC H20 has the same H8 pads so it would be possible to identify the chip!
Image
Sorry, I didn't find a smaller one!
Hook up a STLink and see what it finds !

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Re: Andy's Postbag and random ebay links

Post by RogerClark » Wed Jun 14, 2017 7:17 am

Re: Motion / speed sensors

I've just posted my findings on those cheap $1 motion sensors, to another thread

viewtopic.php?f=19&t=2193

I suspect they would not be much use for detecting the speed of passing cars, as the range is probably too low, but they do have some interesting properties

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