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Archive for November, 2013

29
Nov

Chair Legs

My daughter bought a couple of comfy living room chairs last year and at the time, there was a problem with one of them. One of the seat frames was warped about 1/2″ on the front corner and it caused the front leg to hover off the floor. But she didn’t want to return the defective one. Because. Why? Because. Now quit asking.

I suggested something like this as the simple solution:

IMG 4288

She evidently didn’t go for that “look” and asked me today to “fix” it and also test move a sofa. Yea, how many people you know want to “test move” a sofa. All we wanted to do with the sofa was see if we could manage to get it down stairs in her townhouse. We didn’t carry it all the way, but I think it will go. So, sofa, so good.

IMG 4276

The chair is made from something that closely resembles wood. At one time. Perhaps many glued and stapled pieces thereof. Perhaps a wood recovery project someplace. The legs are probably the strongest part of the chair since they are solid.

IMG 4277

There are threaded inserts in the legs for the bolts to cinch into. And for the most part, they seem sturdy enough.

I used my Festool table (it’s flat) and set 4 pop cans on it to act as “legs”. I wanted to see what the gap was in the left front corner. You can see I easily stuck a pencil in the gap and there was still room. Thus, almost 1/2″ as I originally measured.

IMG 4283

As I was pondering how to level the legs without sawing them and then refinishing them, the wife noticed that the legs had plastic buttons underneath. Probably to stop marring on the floor. Although I doubt that would work considering the quality of the buttons. But they were fairly thick.

Grabbing them with some slip joint pliers and giving a quick tug dropped three legs by almost 1/4″. I then inserted all the legs in the chair bottom, put some weight on the chair and used a small impact drill to set the bolts for the chairs lowest and most level position.

No, it’s not a perfect fix, but it sure beats cutting and sawing, staining and finishing. Besides the chair wasn’t all that expensive to start with. On the bench, the end fix is easily seen. The buttons removed on three legs, felt pads installed on ALL legs and it sits level. Least it will be less stress on the, dare I call it that, frame? What ever.

IMG 4284

But once on the floor, it’s not all that bad:

IMG 4285

Mission accomplished…although I still think the original fix I suggested is more “artistic”.

27
Nov

iBarometer

The single most addicting thing I have on my work bench is…wait for it…an Arduino.

MEGA, UNO, and MINIPro just unleash the TinkerToy complex in me. I feel like Simon Bar Sinister. That’ll give you something to mull over.

Since I’m an avid golfer, I’m also a sucker for weather stations. I have two AcuRite’s, and recently just bought a third, er I mean turd. Say what?

That’s right. As far as I’m concerned, it’s a turd. But it’s a trending turd I’m seeing so…The one I purchased is this one, ACU-RITE® 0135CCDI:

ACU RITE® 0135CCDI

Comes with AC adapter, screen is always on so you can see it (you can turn it off), according to the package it connects to your “pc” and you can read the data on your computer or your iPad, iPhone. Since the fine print required my glasses that I did not bring, I couldn’t read the print that said, “Windows”. Don’t you hate fine print.

Thus, I don’t have “Windows”. I have five Macs. At any rate, I’ll explain how the “magic” works, because I downloaded and read the manual before becoming throughly disgusted and returning it.

AcuLink System Requirements: PC with always-on Internet. Mobile device with app access (optional).

You need Windows, the main weather station connects to Windows via USB. Your computer must be POWERED ON 24/7 to read the data and then sent to a web site (maybe AcuRite’s web site, I didn’t bother looking) where you sign up for an account. When you want to read the data with your iPad or iPhone, you log onto the “web” page and read the data.

So apart from the fact you need a Windows computer, on 24/7, you don’t actually connect to your own LAN to read the data with a mobile device. You wander out on the world wide wait to do it.

Ask yourself WHY would they do this?

The answer I think is, cost. They can hire any number of minions (apologies to Gru) who can write Win code to parse the data or just send it to the remote server. There after the data is stored in some SQL database. When you connect to said web server, the host then serves your data.

Because first off, your bandwidth doesn’t cost them any money and second everyone knows leaving a computer on 24/7 is energy responsible.

I can think of any number of ways that this would have been better implemented, apparently AcuRite doesn’t have that forward vision. Not exactly a progressive bunch of thinkers there.

If at some point in the future AcuRite decides they can charge you to use “their” service, hey, you supported them by purchasing their product, so like any good politician they’ll assume they have the mandate to do whatever they want.

An energy conscious person might decide that leaving a PC on 24/7 is not the best use of energy nor is it free. AcuRite has the solution for this in their AcuLink Internet Bridge. Which they sell you for about the same price as the weather station. Yep, requires an always on internet, still sends it to their site. Big whoop.

The paranoid may like the idea of Acurite handling the data since they can send you “weather alerts”. Because you know that the AcuRite weather alerts are going to be more accurate than anything you hear on the local TV or radio stations. Big whoop x 2.

As I said, this is a trend I see in a number of new devices that I don’t like. No, not the fact you need Windows, the fact that you need an always on internet connection and someone else manages your data. Maybe their idea is to use your data to create the most accurate and awesome weather station the world has ever seen. That’d be the control fetish of the century.

There’s been a number of people who have successfully decoded the Manchester encoding from various weather stations and as far as I know AcuRite doesn’t publish their protocol. You know, because of that control fetish they have. I briefly considered going that route and getting a station that had been decoded. But where’s the fun in that.

So out came the Arduino MEGA2560, DS3231 RTC, a BMP085 barometer and a ColdTears 5″ TFT display with matching shield. This is NOT an economical project. Matter of fact I wouldn’t really advise anyone other than a dyed in the wool tinkerer with doing it.

Having said that, I did it any way because I have that many spare pieces in my parts bins. The DS3231 and BMP085 are standard I2C devices and I have them wired together and they play nice together.

I added one of my Bluetooth HC-05’s so I can connect to the station and do minor programming changes on it (like setting the clock/date or something), or get a CVS listing of the previous 24 hour pressure readings.

IMG 4262

The Coldtears 5″ display is 800 x 400, and the two reasons I use it is that first it’s BIG, second is that it has a font IC in flash ram on board with eight or so different fonts. So I don’t need any software fonts, I just use the built in ones.

So this is what the display looks like:

IMG 4259

I hard coded the lat and long for the sunrise, sunset calculation. I record inHG/mBars from 900 to 1100. If it goes above or below those, well, that should prove to be interesting. I save the full results from the past 24hrs, and every three hours I check for rising, falling or steady. The icon at the top right will change based on the rate of change in that three hour span.

The graphics are stored on a 1GB MicroSD card on the display.

I’m still trying to figure out weather “prediction”. Acurite seems to have some small degree of success with that in spite of the fact that it is nothing more than a best guess.

And while I’m taking AcuRite to the task, I have two identical AcuRite units outside here. One is in the front yard, one is in the back. They are 4 feet of elevation different. Neither one agrees with the other on barometric pressure. The one in the front reads 29.91, the one in the back reads 29.97, my BMP085 is reading 29.86.

I suspect it has something to do with the altitude correction. There is no way to set the altitude on these barometers so I think it takes a flaming guess at it and “adjusts” itself based on the temp or carrot production. Some where. Is it right? No idea.

What I found was you really want to see the trend and having a weather prediction would be nice but not critical. And to put a nail in that, according to my back yard barometer it’s going to rain, the front yard one says mix of sun and cloud. Gee, does that sound like the weather report you get on TV? I think they have 60 different words or phrases to describe rain.

Ultimately, if you really want to predict weather with any degree of success, it’s going to take a lot more than a backyard weather station. Like maybe a satellite photo or two. Or wait a few years until enough people use AcuRite stations so they can do an “Our Man Flint” weather control scheme.

26
Nov

Get the LED out

Sitting around today with a wicked sinus cold, the postie delivered some LED lights, GU10 and MR16’s that I’d ordered from FleaBay. I’d ordered some before but the market has changed slightly on these so it was time to try something new.

What’s new? It’s the word to describe that fluffy white stuff on the ground at Christmas when you have a head cold. Alright, that was Canuck humour. Sorry if you didn’t get it. Or not. Blame it on my sinus…

Scanning through the LED home lighting bulbs on eBay is like wiping your butt with a hoop. There’s simply no end to it. Every seller has a listing that claims they sell the best product. There’s more total Lumens in those listings than the sun emits in a decade or so.

In my opinion, almost every one of these sellers also has an over productive fantasy life. Roughly on par with the honesty you’d expect at a used car lot. Psst, hey sonny, have I got a deal for you…

If you’ve been following my past observations, er rants, you’ll know that I was trying to find an LED light that actually worked to replace those light emitting energy furnaces called Halogens.

Some of you correctly ascertained that I’m an idiot for doing so. And you’d be 100% correct. But since when did being stupid ever stop anyone from trying to reach a goal? Be a lot less YouTube video’s labeled “fail” if that were the case wouldn’t it? Where’s the fun in that?

So I’ll press on here for your enlightenment.

Last year I saw the emergence of 3 WATT CREE (okay, the sellers said they were CREE but you and I know better don’t we). Various sellers jumped on the LED bandwagon and suddenly we had 3, 6, 9, 12 watt “CREE” LED replacement bulbs to fit GU10, MR16 and E27.

The part they kind of glossed over was the fact that these LED’s were all using 3 WATT LED’s and multiple units to give the wattage. In front of the LED’s was a prefocused piece of plastic, to spread out the beam, which they don’t do very well (25 degrees maybe). They were claiming 600-800 lumens. Sure.

The second part they glossed over was that as the wattage of the LED’s went up, so did the length of the bulb. A lot.

A standard halogen is roughly 2″ x 2″. That’s round and length. The LED’s I got all all 2″ round but 5W LED’s are 2.5″ long. If you have a nice holder that has no wiggle room for the extra length (makes you ask yourself why it doesn’t because all the heat should go someplace; halogens are 300C on the bulb surface), these long LED’s are not really an option. What I found is that most ceiling pot lamps have ample room for putting in the 2.5″ LED 5 WATT bulbs. Not a chance with the 12W LED’s.

So what happens when you leave them in for a while? Well, since they do run hot and you might get less than stellar construction:

IMG 4255

What happened to this one? Well, I guess it liked the socket so much that it kind of fused itself in there and then when I tried to pull it out, the three plastic “rivets” simply broke off from being exposed to the heat over time (I’ve had them for almost a year).

So my first advice, apart from the fact this one of the 3 x 3W CREE jobs that runs HOT (54C), don’t EVER try to take one of these out when it’s powered on. That’s a big aluminum heat sink, conductive and you will do the AC short circuit dance if touches the hot terminal. Trust me, your life is worth more than a $9 LED bulb.

Runs hot you say? It’s LED it shouldn’t run hot…well, it does. I grabbed my IR probe and measured a bunch of different LED’s (the multi-CREE ones). 50C to 59C was the range. So yea, hot. No touchy.

The new generation of LED is the COB, or chip on board LED’s. Supposed to be brighter, better beam spread, and run cooler.

Being the LED daredevil that I am, I ordered from two unrelated eBay sellers (actually I have no clue if they’re related or not), first a 5W LED:

LED5W

And then a 12W uber bright LED:

LED12W

You’ll notice that the 12W version has a hole through the center. No, I don’t know why. Maybe that’s were the LED baker crawled out. Beam angle spread on these is supposed to be 100+ degrees. Closer to about 70 would be my measurement. Lumens on the 12W are supposed to be 700+. The 5W is 450 lumens. I’m going with the 5W seller because it’s closer based on my light meter and a pair of 50W halogens I replaced with them.

Now, about lumens, or the endless search of. If you have one of those “light meters” from FleaBay and it reads lux and FC, keep in mind that 320-500 LUX is about the same level as average office lighting. So lay your meter down where you want the light and measure it. Don’t stick it up next to the bulb and say, “Wow that’s super bright!”

The further the light has to travel, the more it spreads out and gets darker.

Notice that both bulbs have reflectors inside to spread the light. LED lighting is naturally very focused. Think of a flashlight. How much light actually reflects behind it? Now look at your typical tungsten bulb. The light comes from all over and it’s a source of heat. The light will reflect off the walls, ceiling, floor, grandpas bald head and so on.

Heat? Ah yea. Remember when those CFL environmentally unfriendly things were pimped like the neighbourhood kids ride? Sure you got “light”, and there’s some question about the amount of light, but what you lost was heat. On your typical tungsten bulb, 90% of the energy consumed is converted to heat. Ever stand under a halogen ceiling light? Toasty. And of course, nice in the winter, not so wanted in the summer. So it’s a good thing we don’t need lights as much in the summer. Isn’t it?

And lastly, lets go to “temperature”. Yes there is a lighting temperature. Cool white is 5500-6000K, warm white is 2700-3000K (note that both of these will vary so it’s just for a comparison here). There is a new light that’s about 4000K that they call “natural” light. 4800K is direct sunlight.

All of these LED bulbs tend to vary. The warm will look like a tungsten, the cool will look blueish to you.

I grabbed my IR meter and tested the 5W vs the 12W temps. 5W came in a 43C, the 12W came in at 54C. The 5W reflectors seem MUCH better built than the 12W versions. No, I didn’t rip one apart to verify that. But when I was changing lights I was muscling the 5W versions pretty good and they stood up. The 12W felt less “solid” to me.

We decided to replace the three halogens above the fireplace with three cool white LED’s. The halogens were connected to a Leviton Mural dimmer:

Mural Dimmer

With this dimmer you can set the amount of brightness that the lights will go up to when you switch them on and they will gently fade out when you turn them off. Which brings up some interesting things we found out today…

I’d replaced TWO of the three halogen bulbs with LED’s and then I disconnected the third halogen bulb the two LED’s started to flash about once a second. Looked like an Arduino “blink” sketch. if I reconnected the halogen, the LED’s stopped flashing. Tells me that the dimmer circuit needs to detect some feedback current to keep itself off, or it “fires”. The LED’s won’t do that. So even when the dimmer is “off” there’s some residual juice being used.

The LED’s I’d installed were NOT the ones than can be dimmed. So perhaps this would have made a difference.

At any rate the halogens were didn’t really do much for the painting on the wall, nor did they spread out far enough to even cover it. The cool white 5W LED’s were far better.

IMG 4253

Evidently the wife has always hated these “dimmer” switches we put in when we rebuilt the kitchen a few years back, so I replaced the other dimmer that ran the kitchen 5″ halogen pot lights. Whoa. First thing, with a standard ON/OFF switch the halogen are significantly brighter.

Which lead me to assume that regardless of the setting on the Leviton dimmers, there is no way to set them for maximum during a fade up. When I checked the Leviton manual, you have to double tap the top to get full brightness, or double tap the bottom to get a fast off. Sheesh.

None the less, no more tappy, and really some of the halogens you want full on any way. Not sure why we even put in dimmers.

I then took two LED’s and put them over the sink (wife said standing under the halogens was toasty on the noggin’). Here’s what they look like:

IMG 4258

The LED’s 5W again, disperse the light (warm white) and are not as focused as the halogens. She’s a happy camper now. Depending, I might change the 5W cool whites over the fireplace to warm white.

The work bench area has nine 12W LED lights now on a track light system, four are pointed down directly over the bench, the others spread around the room. So in the photo, that’s warm white on the right, cool white on the left.

IMG 4251

So what used to use 450 watts of power to light the room, now uses 108 watts. That’s a significant reduction in power. And heat.

Note that all of the photos were taken with no flash. Just the available light from the LED’s. When I checked the bench with my LUX meter, I read from 360 to 490 on the top of the bench. And it seems like ample light, for a change. With the halogens, I didn’t measure the light at the bench, but I can say that I NEVER needed any heat on in the room, even in the winter. With the LED’s I do. So maybe…hum, there’s a trade off.

So here’s my observation, for what it’s worth. If you plan on replacing halogens with LED’s, you need COB LED’s, minimum would be 5 WATT units and plan on installing 3 to 5 of them to give yourself the same working light. Keep in mind that there is a large difference in the comfort factor between cool and warm white. The cool white is more clinical.

I measured some of the other house lighting. A standard 4 foot, 2 tube florescent is 400 lux, three CFL’s are barely 200. All measured at bench height from the light source.

The one thing I haven’t mentioned is warranty. This is a $9 LED bulb from Asia via eBay. Really, you can’t use the word warranty and eBay in the same sentence. Lifespan of the bulb is reported to be 50,000 hours. Which you may treat the same as the report of pigs flying.

12
Nov

Rigol DS1052E Upgrade

It was about three years back when I watched Dave Jones from EEVBlog do a rant on an oscilloscope. I’d been thinking of one of those DSO Nano scopes. Dave was driving in his car and doing the scope rant (episode #86) and I guess it struck home because I didn’t buy one. Why? Cause Dave said they were junk.

Dave’s a sharp cookie, much brighter than I’d ever hope to be with electronics, so I was smart enough to avoid those DSO scopes. But I still wanted a scope. I then started looking through some of Daves older posts and found #37 where he talked about a Rigol 1052E.

So I bought one. It’s a great scope, decent software, LOUD fan. And. It. Drives. Me. Nuts.

Then early last year (2012) I found EEVBlog #70. Turn your DS1052E (50Mhz) into a DS1102E (100Mhz). It was all done in software. Turns out the folks at Rigol use pretty much the same motherboard and just apply a software patch to change the model that the scope thinks it is. At that time it needed a Windows computer (it’s all Macs here), some patch files and you could brick the scope if you’re not careful.

I passed on this at the time.

About a month ago, I needed a 100Mhz scope. Wouldn’t you know it.

So back I went and found a huge forum with a LOT of messages about everything from guys who bricked their scopes to guys who it worked perfectly for. Someone even write a special patch that worked via USB so you didn’t have to use a RS232 terminal to do it. I’d installed Windows XP in VMWare’s Fusion on my workbench Mac so…in for a penny…

I read everything I could find first. And there’s some good information on the steps to do it right. I only wanted to do it once. Right. I read, re-read and downloaded all the patches, made sure I understood the order and away I went. Took me about half an hour. And it worked perfectly. No issues at all.

My DS1052E is now a DS1102E. I did the tasks I had to get done with the scope and then…I noticed that I still HATED the fan noise. There’s some amazing products coming out of Asia, simple quiet fans are not one of them. So back to the forums I headed and low and behold, I found a LOT of guys hated that fan. So they swapped them out. Plus did a little work inside the DS1052E to ensure longer life…(heatsink on the 7905 reg).

I found the service manual for the DS1052E and read about how to take it apart. Four screws and some tugging and it comes apart. The screws are on the bottom and under the handle at the top. Typical torx.

IMG 4196

The hardest part is getting the side off that the AC plug is on. The service manual suggests applying FORCE to get it off. I couldn’t find any photos of what it looks like, so here it is.

IMG 4199

You can see the piece laying on the top. That piece is the root of all evil. The case is fit into it rather snugly. The guys I read about were taking the mounting screws out of the AC socket, which then falls inside the power supply. Not a good thing to do in my opinion.

So I did some prying and yanking, as the manual suggests and it actually does come off. When I reassembled mine I left off that little piece. As I see it, it’s purely aesthetic any way.

The fan, well, there’s the hard part. The factory mounted fan is a “GLOFN GFA06015H12H”. That is a 60x60mm running at 5500rpm @12V DC. According to the manufacturers website it has an air flow of 34.2m3/h at 36.5dBA of annoying noise. To save you the effort of conversion, that’s 20.12 CFM. But it sounds like it’s 2000CFM.

IMG 4206

I seen others trying to shoe horn in 80mm fans, fans with reducers, grills cut out and re-drilled, grills enlarged and so on. Some of it not too pretty either.

I wanted to stay with a 60mm fan, but quiet was the order. I checked every company I could find and apparently small quiet fans are hard to find or make, or something. I stumbled across a post who said they used a 60mm Xilence fan that they got from Germany on eBay. So that’s where I started looking and I found one:

Xilence 60mm case fan:

Specifications:

  • Size: 60 x 60 x 12mm
  • Hole-Distance(Diagonal): approx. 66mm
  • Voltage: 12V(7V-13.2V)
  • Fan-Performance: 2100 RPM / 29,7 CFM
  • Bearing Type: Xilence Hydro/Fluid Bearing
  • Noise Level: 22dB
  • Plug: 3-Pin Molex Connector(Mainboard)

So not only more quiet, but better flow rate too. Bonus. Best $13 CDN I spent in a while.

Before I carry on with the fan and other fix, these are the shots of the insides of the DS1052E power supply.

IMG 4200

Then the left side where the fan is:

IMG 4201

More than just a few guys who’ve done the fan mod have commented on the fact that the 7905 gets hot so the fan helps keep it cool. On the left bottom corner of the photo here you can see the 7905 just standing in a field of capacitors.

The original fan and 7905:

IMG 4202

I had some heat sinks that I use for MOSFETs so I cut one of those down to fit, then I changed the fan. Note it’s a three wire fan I put in, but you only connect the Vcc to it, the blue wire is for the RPM sensor. I just taped it up and left it off. I didn’t leave the heat sink sloped over, I moved to a more upright position so the sink wouldn’t touch the capacitors or the ribbon cable.

New fan heat sink:

IMG 4205

I have to say the scope works amazingly well, rise times are far faster for traces, and the fan is now, finally, at, last, quiet. Ah.. tis heaven.