Search found 1657 matches

by ahull
Sat Dec 16, 2017 10:12 am
Forum: New users MUST post here first, and let us know a bit about you and your projects
Topic: Hello from UK
Replies: 6
Views: 64

Re: Hello from UK

The darkness of the sky is slightly better in Scotland, away from the central belt. Generally the further north and west you go in Scotland, the better. We do see the aurora round where I live, from time to time too. These links may be of interest. http://www.darkskydiscovery.org.uk/ http://scotland...
by ahull
Thu Dec 14, 2017 11:32 am
Forum: Off topic
Topic: DS212 Open Source Oscilloscope.
Replies: 10
Views: 109

Re: DS212 Open Source Oscilloscope.

Btw. In tha video the analog input seems to be done with a 4053 http://www.ti.com/product/CD4053B They are quite cheap Yes, they seem to be quite a popular choice for this kind of application. Something related/similar using a 4052 http://www.seekic.com/uploadfile/ic-circuit/20097523048609.gif http...
by ahull
Thu Dec 14, 2017 11:30 am
Forum: Off topic
Topic: DS212 Open Source Oscilloscope.
Replies: 10
Views: 109

Re: DS212 Open Source Oscilloscope.

RogerClark wrote:
Thu Dec 14, 2017 11:07 am
Andy,

the eBay link asks me to sign in...
Ooops. :oops: Fixed.
by ahull
Thu Dec 14, 2017 10:07 am
Forum: Off topic
Topic: DS212 Open Source Oscilloscope.
Replies: 10
Views: 109

Re: DS212 Open Source Oscilloscope.

If someone came up with a decent analog front end for the pig-o-scope at pocket money prices it would be great. It is getting to the stage that a mass produced pig-o-scope level scope could easily be churned out by the usual suspects in China for not much more than the ubiquitous DM830B multimeter. ...
by ahull
Thu Dec 14, 2017 9:28 am
Forum: Off topic
Topic: DS212 Open Source Oscilloscope.
Replies: 10
Views: 109

Re: DS212 Open Source Oscilloscope.

I agree there are other options, and better bandwidth at that price point. The look and feel of the thing, its portability, robustness, open source nature and features make me feel there will be a market for it. Personally for that money I would probably look at picking up a "real" second hand scope...
by ahull
Thu Dec 14, 2017 7:18 am
Forum: General discussion
Topic: GOing mad trying to sort out sleep mode on STM32F103 Bluepill board
Replies: 12
Views: 218

Re: GOing mad trying to sort out sleep mode on STM32F103 Bluepill board

This seems to happen because of a race condition where if you plug/unplug too quickly (and it dosn't have to be very quick), the old /dev/ name hasn't cleared in time to allow the port to re-enumerate with the old name. I've seen it happen quite a lot (I'm using Ubuntu, so it probably affects most D...
by ahull
Thu Dec 14, 2017 7:05 am
Forum: Off topic
Topic: DS212 Open Source Oscilloscope.
Replies: 10
Views: 109

DS212 Open Source Oscilloscope.

Yet another STM32 based oscilloscope. lxxS6rvrk3o It uses the STM32F303VCT6 - skip to around https://youtu.be/lxxS6rvrk3o?t=280 for more details. Comes in at around $90 - > https://www.ebay.com/sch/i.html?_odkw=ds212&_sop=15&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xds212+oscillos...
by ahull
Mon Dec 11, 2017 12:17 pm
Forum: General discussion
Topic: AC Dimmer
Replies: 40
Views: 360

Re: AC Dimmer

It is no more dangerous than that high power resistor. Neither has galvanic isolation.
by ahull
Mon Dec 11, 2017 11:41 am
Forum: General discussion
Topic: AC Dimmer
Replies: 40
Views: 360

Re: AC Dimmer

... Also... The circuit is really wasteful, as it uses high wattage resistors to drop the mains voltage to the 2 or 3 v needed to light the LED in the opto coupler. Half watt resistors will get hot as they will need to dissipate around 0.96W i.e 96% of their maximum rated value ... It occurs to me,...
by ahull
Mon Dec 11, 2017 10:35 am
Forum: General discussion
Topic: AC Dimmer
Replies: 40
Views: 360

Re: AC Dimmer

The issue is that you need to actually synchronise the dimming with the zero crossing point of the mains, and this needs to be detected. You cannot estimate it, as the mains frequency is not 100% accurate (and neither is the timer on the STM32F103), so there will always be some discrepancy between t...