Re: Accelerometer to measure velocity
To know when an object is in free fall, the acceleration is 0. Thus it is easy to measure, so long as you know what is up. I have used a 3-axis accelerometer without any issues. Quite easy. Look at Kionix products. I have this in a project right now.
Derek Koonce
DDK Interactive Consulting Services
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On 1/22/2011 1:24 PM, Michael wrote:
Hello All,
I have been doing some reading, re using an accelerometer to measure velocity. I want to detect when an object is travelling too fast. It is an up/down or vertical movement, and maximum travel is only about 2m. Essentially I want to detect when object is falling, but it might not be in total freefall. The winch might fail, but there would still be some slowing friction.
Has anyone used an acceleromter for this type of application, can it work, what accuracies are needed, etc, etc?
Any advice would be much appreciated,
Mike.
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The 555 timer was originally designed in 1970, and since then a CMOS version has
come out, along with versions from other makers designed to run at higher
speeds, lower voltages, and lower power. People have?built all kinds of circuits
from this venerable, versatile, but?relatively simple timer. What can you build?
Jeri Ellsworth has started a 555 timer contest.
?Steve Greenfield AE7HD
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Re: Strange issue with LED Bulb
A good lesson here is that a reference schematic is not the same as a reference board layout. In many cases, part placement is as important as part value.
Thanks for the report on the solution, Sanmeet.
Donald.
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() no proprietary attachments; no html mail
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----- Original Message ----- From: "Sanmeet H" <sanmeeth@...>
To: "E_101 Group" <Electronics_101@...>
Sent: Tuesday, January 18, 2011 11:10:16 PM
Subject: [Electronics_101] Re: Strange issue with LED Bulb
I got the cause of the bug. The SMPS IC Vcc cap is located around 20cm
from the VCC pin. The Inductor and FET are closer to the SMPS IC and are
probably causing noise. Shifting the (ceramic)cap nearer (5mm) to the Vcc pin
lessened the problem. Increasing the Vcc ceramic and 'lytic cap took care of the
problem fully in all the power supplies.
Sanmeet
________________________________
From: Sanmeet H <sanmeeth@...>
To: E_101 Group <Electronics_101@...>
Sent: Mon, January 17, 2011 12:32:11 PM
Subject: Strange issue with LED Bulb
Hi,
I have made a 3 to 6 LED bulb driver using TI PFC controlller SMPS IC -
UCC28600. My schematic is exactly same as TI's reference schematic. I have
uploaded the schematic in files section---> LED BULB.pdf.
Everything is working fine but I have a strange problem. If I switch OFF a
working bulb and switch ON again within say 1 second, the LED start ON /OFF
cycling. ON for approx 0.5 sec and OFF for around 1 sec.
If the Power is switched OFF for more than 1 second and restored, the LED's
work just fine. I have made around 10 bulbs. All have the exact same issue.
Does anyone have a clue as to what is the reason... Any advice would be
appreciated.
Sanmeet H
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Re: Big box 'o free opto stuff
And I was at SEA-TAC just last Thursday :( Not that I know what I'd do with them.
Donald.
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----- Original Message ----- From: "Steve Greenfield" <alienrelics@...>
To: "W7DK Tacoma Amateur Radio Mailing List" <w7dk@...>, "Electronics_101 Mailing List"
<electronics_101@...>
Sent: Friday, January 21, 2011 10:25:01 PM
Subject: [Electronics_101] Big box 'o free opto stuff
I have a big box full of IR LEDs and photodiodes. All samples, just a few of
each.
Free if you pick up. I'm in Tacoma, WA, USA.
?Steve Greenfield AE7HD
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Re: Accelerometer to measure velocity
An accelerometer measures acceleration, which is the first derivative of velocity with respect to time. Theoretically, you can integrate acceleration over time to obtain velocity, but the problem is that small errors accumulate over time, and you never really know what the velocity is unless you measure it regularly. I would think it better to find a mechanism that measures velocity directly.
Donald.
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----- Original Message ----- From: "Michael" <mmk_tsm@...>
To: "Electronics 101" <Electronics_101@...>
Sent: Saturday, January 22, 2011 4:24:52 PM
Subject: [Electronics_101] Accelerometer to measure velocity
Hello All,
I have been doing some reading, re using an accelerometer to
measure velocity. I want to detect when an object is travelling too
fast. It is an up/down or vertical movement, and maximum travel is
only about 2m. Essentially I want to detect when object is falling,
but it might not be in total freefall. The winch might fail, but
there would still be some slowing friction.
Has anyone used an acceleromter for this type of application, can
it work, what accuracies are needed, etc, etc?
Any advice would be much appreciated,
Mike.
------------------------------------
Please trim excess when replyingYahoo! Groups Links
|
Accelerometer to measure velocity
Hello All,
I have been doing some reading, re using an accelerometer to measure velocity. I want to detect when an object is travelling too fast. It is an up/down or vertical movement, and maximum travel is only about 2m. Essentially I want to detect when object is falling, but it might not be in total freefall. The winch might fail, but there would still be some slowing friction.
Has anyone used an acceleromter for this type of application, can it work, what accuracies are needed, etc, etc?
Any advice would be much appreciated,
Mike.
|
Re: Big box 'o free opto stuff
I'll take the lot - as soon as you arrive here in New Zealand.
Daryl
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--- In Electronics_101@..., Ross McKenzie <valusoft@...> wrote:
Yeah but .... if you believe Oprah, Australia is the place to be; in
particular Melbourne where I am.
Cheers,
Ross
On 22/01/2011 2:37 PM, James M. (Jim) Geidl wrote:
Would it be a big problem for you to move to Northern CA...then I'll pick
them up. :-) How come the great deals are always someplace I'm not.
James "Jim" M. Geidl, K6JMG
-----Original Message-----
I have a big box full of IR LEDs and photodiodes. All
samples, just a few of each.
Free if you pick up. I'm in Tacoma, WA, USA.
Steve Greenfield AE7HD
|
Re: LCD Monitor power supply photos
"liquid residue under the 400 V capacitor"
I am not refering to the silicone goop used to hold some components.
Can you get a schematic for "the brick"?
Times are changing - we called WWII German piece of radar equipment from FuG 16 radio set a brick!
Vaclav
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Re: PCB house pricing comment
What part are you confused about on the GoldPhoenix website?
<>Their offer is much simpler
then the website may make it sound... You get 100 sq. in. of board for $100
or 155 sq. in. for $110. Within that size limit, they will give you as many
of your board as they can fit, so roughly 3 or 5 copies of your 5x6" board
respectively. They do have minimum size limits, so for your small board,
they are not a good candidate, even assuming you wanted a couple hundred
copies of it.
Certainly there are parts of their site that are a bit confusing, but it is
probably worth asking of you have questions. ;-)
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On Fri, Jan 21, 2011 at 9:39 PM, vaclav_sal <vaclav_sal@...> wrote: FYI
The confirmed my order today for
total price less than $5 for all six .8x.7 adapter boards.
I am satisfied with that.
I'll post some comments after I get them.
PS I cannot get anything inteligent from Gold Phoenix web site.
I have given up on them.
Vaclav
------------------------------------
Please trim excess when replyingYahoo! Groups Links
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Re: PCB house pricing comment
FYI
The confirmed my order today for total price less than $5 for all six .8x.7 adapter boards.
I am satisfied with that.
I'll post some comments after I get them.
PS I cannot get anything inteligent from Gold Phoenix web site.
I have given up on them.
Vaclav
|
Re: Big box 'o free opto stuff
Yeah but .... if you believe Oprah, Australia is the place to be; in particular Melbourne where I am.
Cheers,
Ross
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On 22/01/2011 2:37 PM, James M. (Jim) Geidl wrote: Would it be a big problem for you to move to Northern CA...then I'll pick
them up. :-) How come the great deals are always someplace I'm not.
James "Jim" M. Geidl, K6JMG
-----Original Message-----
I have a big box full of IR LEDs and photodiodes. All
samples, just a few of each.
Free if you pick up. I'm in Tacoma, WA, USA.
Steve Greenfield AE7HD
|
Re: Big box 'o free opto stuff
James M. \(Jim\) Geidl
Would it be a big problem for you to move to Northern CA...then I'll pick
them up. :-) How come the great deals are always someplace I'm not.
James "Jim" M. Geidl, K6JMG
No trees were harmed in the sending of this message; however, a large number
of electrons were terribly inconvenienced.
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-----Original Message-----
From: Electronics_101@...
[mailto:Electronics_101@...] On Behalf Of Steve Greenfield
Sent: Friday, January 21, 2011 7:25 PM
To: W7DK Tacoma Amateur Radio Mailing List; Electronics_101
Mailing List
Subject: [Electronics_101] Big box 'o free opto stuff
I have a big box full of IR LEDs and photodiodes. All
samples, just a few of each.
Free if you pick up. I'm in Tacoma, WA, USA.
?Steve Greenfield AE7HD
|
Re: Antique Instrument advice
Neat! I love it. I hope it is worth something just because it is so darn neat.
Steve Greenfield AE7HD
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--- In Electronics_101@..., "cboy2us" <cboy2us@...> wrote:
I purchased a piece of ELECTRONIC test equipment at a sale recently, and would like to know if it has any value.
"<>"
are pictures of it.
As far as I can tell, it is a "Sensimeter" manufactured by Hy-Cal engineering.
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Big box 'o free opto stuff
I have a big box full of IR LEDs and photodiodes. All samples, just a few of
each.
Free if you pick up. I'm in Tacoma, WA, USA.
?Steve Greenfield AE7HD
|
With the interest in ARM processors maybe I should just mention:
RISC OS is a full blown, mature, operating system running on ARM
processors. Indeed, it is /the original/ operating system for which the
first ARM processors were designed. It has available applications for all
normal computer uses including graphics, music, word processors etc. It is
still undergoing development and has recently been ported to the
BeagleBoard-xM.
--
Stuart Winsor
Midland RISC OS show - Sat July 9th 2011
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Antique Instrument advice
I purchased a piece of ELECTRONIC test equipment at a sale recently, and would like to know if it has any value.
"<>"
are pictures of it.
As far as I can tell, it is a "Sensimeter" manufactured by Hy-Cal engineering.
|
Re: LCD Monitor power supply photos
At 15:46 21 01 11, ae5ew wrote: I have wonderful news! You qualify as an 'Electronic Pack Rat'. Congratulations!!! Regretfully, there is no plaque, trophy, or
certificate awarded for this prestigious award. Thank you. I'll take my own pleasure, for the recognition by a kindred spirit in arms. Now why doesn't this !@#$%#$ work? Reese
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Re: LCD Monitor power supply photos
When I used to work with hundreds of Wyse 50 monitors, the most common failure(s) were multiple capacitor failures on the CRT driver. I had bought a capacitor tester (LRC) which proved very good at finding the faulty capacitors (in-circuit). It wasn't designed for in-circuit use but proved extremely useful for that purpose. I just worked up capacitor location test points on a board drawing, with values, and let the techs have at it. DMMs with capacitance measurement capability were rare at the time and/or extremely expensive.
Charles AE5EW
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--- In Electronics_101@..., "Joe in Texas" <joesmith@...> wrote:
Any other suggestions? Keep 'em coming. --
Stuart Winsor
=============================================>
This is not a suggestion,,,it is a FACT,, 1.Remove ALL white glue
2.Don't bother to check::::::REPLACE ALL capacitors
3.I have repaired over a dozen,,,ALL worked.
4.Heat is your enemy,,keep cover removed if possible/safe.
5.Do not be afraid to work on it. It is useless as is.
Joe Smith
West Point Monitor Repair
West Point
Texas
78963
Google me.
Joe.
|
Re: LCD Monitor power supply photos
I have wonderful news! You qualify as an 'Electronic Pack Rat'. Congratulations!!! Regretfully, there is no plaque, trophy, or certificate awarded for this prestigious award.
Charles AE5EW
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--- In Electronics_101@..., Reese <reeza@...> wrote:
At 08:43 21 01 11, vaclav_sal wrote:
There seems to be some liquid residue under the 400 V capacitor
( I cannot read the value). If you mean the large brown cap in the bottom right quadrant, it is
400 v 100 uF. The white goop is a fixant, to keep parts from moving
and causing stress fractures in leads and etc. Possibly a special
formula hot-melt glue. I've been reluctant to start removing that,
until I have a better idea of what is wrong and what needs fixing.
The cap seemed to test like a functional cap in circuit when connected
to an ohm meter, btw. More on that below.
The comment made about capacitor failures in this thread reminds
me about the subject of poor QA on some of the capacitors made I
have read somewhere recently.
Keep us posted about you progress. Stefan suggested I test the transistor at middle-bottom and the much
smaller cap at middle-top. Also the item that looks like a fuse
just off of the bottom left corner of the IEC connector.
Fuse-like item: has low resistance, tested in circuit.
both caps: have fairly low resistance, number decreases slowly.
When leads are reversed, number goes high, then slowly starts
decreasing again (as charge is taken from the ohm-meter battery).
Transistor at bottom-center: continuity between all pins, varying
values. Same with leads reversed. I didn't note the values but
can if that is wanted.
Transistor at top-left, just inboard of the green LED: same as the
transistor at bottom-center.
Any other suggestions? Keep 'em coming.
I should mention, I have a Huntron 100B on hand but I've never used
one before and might need a bit of coaching. Or didn't someone provide
a link to an owner's manual once? I'm sure I downloaded it but with
nearly 2 terabytes of downloaded/created things to search through, it
will take a while to verify whether I already have it or not. Starting
with the most likely places to save that sort of thing, then whole
drive searches if that becomes necessary.
Reese
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Re: LCD Monitor power supply photos
At 13:03 21 01 11, Joe in Texas wrote: This is not a suggestion,,,it is a FACT,, 1.Remove ALL white glue
2.Don't bother to check::::::REPLACE ALL capacitors
3.I have repaired over a dozen,,,ALL worked.
4.Heat is your enemy,,keep cover removed if possible/safe.
5.Do not be afraid to work on it. It is useless as is.
Joe Smith
West Point Monitor Repair
West Point
Texas
78963
Google me.
Joe.
I'll take that as a qualified and vetted answer. I guess my next step is disassembly, followed by identification, acquisition, and installation. I may be able to make the brick work again, for other things. Projects and the like. I wonder if you have any thoughts on the board from the monitor. It had one bad pixel, was fine otherwise (until this event). Reese
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Derek Koonce
Steven AE7HD