And now for something completely different:

I’ve used my trusty ERSA TIP 260 soldering iron for the last 15 years or so, and I’ve never had to replace the tip. It’s still as shiny as on the first day. Yes, I do treat it well.

Now I’ve made the step and have finally bought a more advanced piece of equipment, namely the WELLER WMS 1 soldering station. I didn’t go for the one with the additional battery pack, as I don’t plan to do any ‘wireless’ soldering in the field. Some 60 bucks well ‘not-spent’. I had looked at the WD1 as well, but I didn’t feel like spending close to 500 monetary units. It was bad enough that I had to wait almost two full weeks until it got delivered. I gave the shop a call and was told that ‘somebody’ (I curse you, do you hear me!?! One day of vastly accelerated bowel movements to you!) was on a shopping spree and emptied their stock completely.

The main impetus to get it was, and still is, the horrible trouble I have with soldering SMD RGB LEDs coming in a PLCC-6 5050 package. The plastic just melts way too easily. My TIP 260 is set to a fixed temperature of 350°C and melts the package like a hot knife cuts through butter.

The WMS 1 can be adjusted from 100°C to 400°C and packs a whoppin’ 40Watt heating element into the RT 3 tip. That way I can be sure I’ll be able to find the correct temperature for the job. As the heating element is in the tip itself, there’s not much thermal inertia and everything should work perfectly. The WMS 1 can quickly adjust for the energy/temperature loss in the tip due to melting of solder. My old TIP 260 works with a PTC heating element and sometimes it takes a while until it reacts to a drop in tip temperature when melting a big blob of solder. This is now a thing of the past. Nevertheless I will not abandon it and keep it for odd jobs that don’t require advanced soldering tools. One advantage of it is that it fits into the storage containers I use.

It comes with these parts: 12V, 50W switching power supply (no power switch), main unit (no power switch, GND plug), soldering pencil, soldering tip, soldering stand with brass cleaner. As the WSM 1 doesn’t come with a power switch (the WSM 1C has it, it also comes with a battery for portable soldering but it also costs 60 bucks more), you’ll want to watch standby power consumption. I’ve measured it with one of these ‘kill-a-watt’ like devices and it’s about 0.5W, which is tolerable. Nevertheless I switch off all of my gear with a master switch anyway. A switch in the main units wouldn’t do much good anyway, as the 0.5W standby loss is caused by the switching power supply itself. Fortunately the main unit starts up in OFF mode by default. No chance of accidental fires after a power loss.

The soldering pencil is very light and its cord is very flexible, what a joy. One of the most outstanding features of this soldering station is the extremely short heat-up and cool-down time, as well as temperature stability. It takes about 4 seconds to go from ambient temperature to 400°C!

www.youtube.com/watch?v=pmlcpCgVhz8

www.youtube.com/watch?v=tK4Qi99Kvjs

The user interface consists of a big LC display and 2 touch sensor buttons labeled “-” and “+”. By pressing “+” or “-” shortly, you can quickly switch between two adjustable temperature setpoints. I use Sn60Pb40 solder and 240° for sensitive parts and 280°C for bigger ones with more copper. Pressing the buttons longer increases or decreases the temperature. With no buttons pressed the display switches back and displays actual temperature. Pressing both buttons for some time switches through the settings menu. You can adjust a standby temperature (called setback) and the associated timeout, the power off timeout, a global temperature offset and a lock code. It’s very easy to use and the manual only consists of a few pages. Standby mode and auto power off are only triggered if the soldering pencil rests in its stand. If in standby mode the iron is instantly reheated as soon as you pick it up again.

Although it cost me A LOT, I give it a big thumbs up. Even if you don’t want to pay as much for a soldering station and are serious about electronics as a hobby, try getting a decent soldering station yourself. Not having to use 350°C for everything is sooo nice. Less burning of flux on the tip, less thermal stress for sensitive SMD parts, less oxidation of the tip and therefore less cleaning is needed :-)

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For those of you who might now have heard about this hyped new stuff, it’s silicone putty that comes in different colors, can easily be formed using bare fingers and after curing into elastic rubber it permanently sticks to all sorts of materials. Wood, glass, metal… you name it. Quite useful.

I used it to fix my bike’s U-lock problem. It was constantly hitting the frame, abrading the paint and damaging the aluminium underneath. Nothing special really, but this stuff just works ;-)

Just like with ordinary silicone goop surfaces that must not be adhered to, should be treated with a water/dishwasher fluid mixture.

There are may of possible uses for it. I’m planning to use some of it in electronics as well ;-)

One thing I’m missing is more colors though. Currently you can get these: orange, blue, green, black.

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Today I’ve killed 3 – THREE – of these friggin’ things, and I only have about 10 spares left. That’s a loss of more than 1€ of semiconductor. Time to get more spares it seems.

In this shot I managed to show what’s going belly up here. It’s always the green ones that die. As shown here, the bonding wire has been ripped off the left pad due to stress.

Looking at this image again a few hours later, it seems the whole pad has moved to the left opening a gap of maybe 0.1mm. What a heap of shit. Could the surface tension of the solder create such a big force and pull the pad out of the somewhat softened plastic body?

I’m trying to keep the heat down and be quick, but today was a very bad soldering day. I have a feeling they wanted to save time and material in the bonding process and the wires are a bit overstressed anyway. Maybe they also ‘tweaked’ the gold content a bit and it got too brittle.

If these LEDs are soldered in a reflow oven this problem might not occur at all, as the epoxy around the wires will soften a bit. Given the correct temperature-vs-time profile is used. Time to get an SMD toaster? Maybe. Any recommendations? Hotplate? And I don’t want to spend a fortune on it as well. Oh BTW, I hate things that suddenly just sublimate without any signs of warning! I’m looking for reasonably priced quality products here. Nothing fancy, but fully functional with a minimal amount of cursing.

Something completely different:

Today was also the very first time that I just couldn’t reliably upload code using a bootloader with the chip running on the internal 8MHz RC oscillator. Maybe this is due to the somewhat elevated temperatures we’re having here right now. It’s in the middle of the night right now and I’m still getting 26°C in my room. Or maybe this AVR’s factory calibration is just terribly wrong. Luckily I had previously assembled another one of the boards, so I just swapped them. The good one is sent away and I keep the rebellious one for further testing. I’ll put it into the freezer tomorrow and see what happens to it.

→ Update 1: 08.07.2010:

Well, deep freezing the chip didn’t change anything. I’m using the Moderndevice BUB FTDI adapter to upload code. It’s got the option to switch between 3.3V and 5V for the signal lines, the supply voltage stays at 5V at all times. Using 5V for the signal lines throws upload errors most of the time in the verification stage of the bootloader. Switching to 3.3V works most of the time. I’m puzzled. There should be enough decoupling capacitors on the board. This is the very first time I’ve encountered this problem, and I’ve built and spread more than 40 boards around the world by now. When I get access to a suitable storage oscilloscope I’ll have the board send a test message a look at the signals and measure the actual baud rate and see if it’s withing the error margin.

→ Update 2: 29.07.2010:

Well, today I plugged many of these ring boards (mostly old prototypes) onto the perfboard I made for my bike and both atmega chips got warmer than expected. I was using the “baby milk bottle” method (a.k.a. my lips) to sense the temperature. It was near to unpleasant, so I guess it must’ve been above 45°C. Then I did the same thing to the up-to-date board that showed uploading problems. Same old. Then I removed the jumper used to bypass the onboard voltage regulator and the thing was still running, which it shouldn’t have – or so I thought. Fast forward a few minutes. Hint: 2 input pins were now exposed to VCC and GND. And they have clamping diodes ;-)

Anyhow. The uploading problems started to get worse and worse. End of story: I’ve replaced the darn chip with a new one and everything works as expected.

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Content: 100% pure stream of consciousness, Q&A from the chat, shredded laptops, exploding multimeters, broken chairs and of course the famous rants.

My favourite phrases so far: Unbox my Arse, Heap of Shit, WHY???

Oh BTW: BZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ.

No related posts.

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Among the prizes are 2 AVR microcontroller starter kits, 3 retro short wave radio kits, 2 books about finding errors in electronic circuits and last but not least 3 PONG games.

Want to win something? Go check it out!

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In my previous post I described how and why I’ve temporarily wrecked my beloved power supply. Thankfully these 390mΩ 5W resistors are available. Right now I could only find 5% types, but ” bettar tan nottin’ ” as The Voodoo Lady might say. I’ve been playing ‘Tales of Monkey Island lately’. A great game. So I’ll be able to fix the shunt resistor and my power supply should be good again. And I will never use it on a lead acid battery. It should have worked just fine, as it’s got voltage and current regulation, but only IF the control logic is powered = fuses not blown. Now why did the fuses blow… I shall never now. Nor will I try it again.

Back to the beginning: my car’s dead battery. The charging procedure did not pump enough energy into the battery to make the starter work, it just did “whoop…” once. But there was enough juice left to power the ignition system and fortuitously my car was parked on a slope. It was finally started by gravitational pull, after I pushed and shoved it quite a bit. The brakes were jammed by rust a bit. Three weeks in the rain and not being moved a single mm is not good.

I checked the idle current that my car was drawing from the battery: 0.33A !! To make sure nothing funny goes on, I pulled every single relay one after another and rechecked, but still 0.33A was drawn. Then I started pulling fuses. Pretty much everything was controlled by switches anyway, and I made sure these circuits were shut off. The remaining suspects were: motor control, internal lighting (trunk, reading lights and so on) and my radio. I had pulled out the radio the day before.

End of story: THE FRIGGIN’ reading lights were on AGAIN.

I don’t know when or how I could have touched the switch, but the sucker was on. Although my car is quite old now, there’s a buzzer for almost everything. Leave the headlights on: BEEP. Leave the blinker on: BEEP. The radio powers off automatically. Pretty much the only two things that are beyond ANY control are the reading lights and the cigarette lighter. The latter is used for heating the driver’s seat, which has killed a few batteries as well. But the reading lights… they have tortured me many times, but not anymore!

Behold: Mr. Blinky LED

This one had a wrong capacitor, 220pF instead of 220nF, and was therefore blinking at about 3kHz. I’m not that fast. Having a frequency counter in my digital multimeter is quite nice. The displayed RMS value was 5V, a bit low I think. For a square wave the average and RMS should be the same, no? The circuit was powered with 12V, so I expected 6V. The green LED was way too weak as well.

Version 2 comes with a more suitable capacitor of 1µF. Together with 1MΩ it blinks at about 1Hz, clearly visible to humans. The circuit can be found in the datasheet. Component count is minimal ;-)

www.youtube.com/watch?v=_vOP2-EP9Tg

The camera doesn’t properly show the contrast between the LED and the light bulb. In reality it’s much more visible. Placement of the LED isn’t ideal as well, but I don’t have access to drills and other tools right now.

And now with sound, if you can call it that way. Better turn down the volume!

www.youtube.com/watch?v=I3RWxo9MaEA

I wish the engineers at VW had included something like this when they were designing this car. Even better, they should have added a buzzer, or as in more modern cars: auto power off. Oh well. I was also thinking about adding a shunt resistor to my car’s battery, but I’m not sure how much I would have to shell out for one capable of say 500A or something. Its resistance would have to be of extremely low value and I’d definitely need a decent opamp for it. For e.g. a burden voltage of 250mV @ 500A that would be 0.5mΩ To get a resolution of say 50mA I’d have to reliably measure voltage steps of 25µV… in a noisy car. Nope. Somebody else can have a go at that.

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Yesterday I discovered that my car’s battery was 100% empty. Not only didn’t the starter move at all, but also the LCD clock was dead. Total lack of power. This has happened to me numerous times before and most of the time it was my fault (forgot to turn off the lights, heating for driver’s seat and so on), but this time all of it was off – I swear to “insert favourite deity”. The car was standing for 3 weeks though. Well… so I decided to recharge it with my trusty power supply. It’s a good thing I’ve parked the car on a sloping road, so I may be able to get it started by gravitational pull, if I can get the battery charged up enough to power the ignition system. I set it to current mode and 500mA and let it do its job over night. When I got up this morning, the voltage on the battery read something like 11.8V, the power supply displayed 0.0V and 2.8A… ARGH. Its heatsink was terribly hot. After removing the battery and letting it cool down it still was not behaving correctly. As soon as I turned it on, it internally shorted the output ;-(

The two MJ2501 PNP transistors couldn’t be the source of the problem. They can dissipate more than 100W each and there’s a temperature sensor on the heatsink as well. As it is a linear power supply the PNP transistors act as adjustable high-side resistors in series with the load, so there’s really nowhere they could short to. I knew from daily use that there are some relays (at least two) in there as well. One clicks as soon as you tell it to provide voltage to the screw terminals, the other one is used when switching into offline current adjust mode. It internally shorts + to – in this mode. At first I thought one of them had gone bad, so I removed it. But that wasn’t the problem at all.

Thankfully I found a Digi-35-CPU schematic on the web. One word of caution! There are several different versions of this device out there. While the schematic is quite similar to mine, it’s not quite the same. Some of the current setting potentiometers are called Rxx in the PDF and Pxx on the PCB. And as usual, pull the plug before you stick your fingers in there!

All in all it is a good device, but one aspect of it sucks though:

NC: normally closed, NO: normally open, NE: not energized, E: energized

As you can see case 1 and 4 are identical as far as the relays are concerned, BUT in case 4 we have power applied to the transistors! In current mode the relays have the same switch-state as in case all AC power is gone. The same thing happens when two fuses are blown (the left ones in the picture below) which supply the logic with power, which is exactly what happened here. If the microcontroller and the relays don’t get any power, relay 1 shorts the output terminals (as if in current mode – 4) and all the power gets pumped into the transistors. Also the current shunt (R22, 0.39Ω, 5W) gets way too hot and burns its insulation.

I will have to replace this current shunt resistor. Some of the windings may touch anytime and confuse the current regulation completely.

The only advantage of having + shorted to – when the AC power is gone is that the smoothing capacitor is rapidly discharged and the output voltage drops fast. This may be desired as well, but it is definitely NOT desirable that a power supply shorts itself when the fuses for the microcontroller blow. They should have added another 5V relay to disconnect the main transformer winding from the power transistors, if the control logic is offline.

I assume that when a fuse inside a device blows, it should be in a much safer state afterwards. Here it was quite the opposite I think. The control logic board might have started to burn without the fuse, but 75W being pumped into the power transistors for several hours and a blazing hot heatsink is not exactly safe as well. WTF!?!

Oh, and while I’m at it, have a look at some of the solder joints…

I could have tolerated it for ordinary low current connections, but these wires are connected to the power transistors…

The rightmost pad is just sad. It should have been the same size as the other ones. You just don’t want to see what it looks on the other side. “Now how do we make this thick wire stick to such a tiny pad…”

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Well as of next Monday 18:00 CET to be honest (May 17th 2010). I’ve already added it to zen-cart, but it’s still marked as sold out. This morning FedEx didn’t manage to deliver the shipment from Mouser containing the vital ATmega168 chips — and they didn’t even leave a note :-(

I haven’t done all of the math yet, but basically I’ll be giving these away at cost. The fun is in the making and releasing. I couldn’t live on selling these things anyway. …1 or 2 days later… I’ve done the math and ‘at cost’ is 9.35€ + shipping.

It has been upgraded to version 1.21 and now comes with proper LED ordering, fully functional auto-reset and last but not least an onboard ultra low drop voltage regulator. You can supply it with 4 to 14V DC and it will work just fine. No costly boost converter for 5V is required anymore. The voltage regulator is very powerful and can drive more than just this little board. If other parts of your project should need 5V as well, you can use it to feed power to them. It should be good enough to drive an Arduino board and a few standard LEDs.

You should feel at home with soldering SMD parts of sizes 0805 and larger. If you haven’t completed any SMD projects before, better watch a few tutorials first. It is not difficult as such, but you’re likely to kill the SMD LEDs without “enough” practice -- and they don’t come cheap. Nowadays taking apart broken devices is a good and cheap source for SMD practice material!

To get started you’ll need an AVR programmer (usbtiny, AVR ISP MKII …). Once you’ve flashed the Arduino bootloader, I recommend using an FTDI adapter such as the Moderndevice BUB or the FTDI Basic Breakout -- 5V for convenience.

I can recommend the USBtinyISP or the Pocket AVR Programmer. Both cost about 15$-25$ and are compatible with AVRDUDE and work on Linux and MAC OS (and windoze if you have that). You can also easily use the Arduino IDE with both of them.

As seen on hackedgadgets and in previous posts [1],[2] on my blog.

Assembly instructions:

0. List of parts

1x PCB (big round orange object)
1x 10k Ohm 0805 (R4)
1x 91 Ohm 0805 (RED, R2)
1x 390 Ohm 0805 (GREEN, R3)
1x 110 Ohm 0805 (BLUE, R1)
2x 10µF, 16V, tantalum, polarized, A3216
1x 10µF, 25V, ceramic, X5R, 1206
2x 100nF, 50V, ceramic, X7R, 0805
1x TS 2940 CW-5.0, voltage regulator, SOT-223
1x anti static bag
2x 10x1 female header (need cutting to size)
2x 3x2 male header
1x 6x1 male header
1x 3x1 male header
1x Atmega168-AU, TQFP-32 7x7
4x low profile jumper h=4mm
8x RGB LEDs PLCC6 5050 (ebay: JELEDHK, green very! efficient, R: 1.76V, G: 2.34V, B: 2.52V)

1. Identify all parts

The single biggest and most obvious component is the printed circuit board. Its orange color will make it stick out quite nicely.

The 8 RGB LEDs are easily recognized, as they’re white. The ATmega168 microcontroller sits like a fat black spider in its web. Both components require proper orientation and have orientation marks (dots, notches…).

The remaining components are all on the back side of the board.

The brownish parts are unpolarized ceramic capacitors (C1, C2, C3). As long as they’re put to the right spot, orientation doesn’t matter. The black components are resistors, right spot required, orientation doesn’t matter (R1-R4). The somewhat larger and 4 legged IC is a low drop 5V voltage regulator and only fits in one orientation. The orange parts with the bar are polarized tantalum capacitors. They will blow up if orientation is wrong. The bar points to the anode (+). All the rest is just headers and jumpers. The 10pin female headers need to be cut to size before they fit. It is quite easy with a good and sturdy wire cutter. Take a look at the images in the soldering section.

If there are any missing parts, please let me know.

2. Solder it

Be sure to use plenty of flux. It is imperative that you keep soldering time and temperature at an absolute minimum. The resistors, ceramic capacitors and, to some degree, the ATmega168 are quite forgiving, but the tantalum capacitors and especially the RGB LEDs are easily damaged terminally!

There is no strict order for soldering, but I suggest putting on the ATmega168 as the first part and then continue with the 8 RGB LEDs. Then take care of the voltage regulator. The remaining resistors and capacitors go on as you please. The headers should be put on as the very last parts to avoid interference and burnt plastic.

Correct orientation of critical parts:

• The bar on the tantalum capacitors (C4, C5) must point to the (+) mark on the PCB
• The orientation notch on the RGB LEDs (D1-D8) must point to the center of the PCB
• The orientation dot on the ATmega chip must match with the dot on the PCB

How to safely solder and test the RGB LEDs:

www.youtube.com/watch?v=_X86rdlwcvA

Due to a last minute change of the RGB LEDs, the silkscreen on the PCB is incorrect! Please assemble the LEDs as shown in the video.

2.1 Paying special attention to the RGB LEDs

As mentioned before these RGB LEDs don’t particularly like heat. Especially one pad of the green LED, the smallest one, overheats easily. In the picture below it is the middle pad at the bottom.

For this pad I advise extreme caution. If you have an adjustable soldering station (which I highly recommend), set the temperature to 240°C and you’ll be fine with Sn60Pb40 solder. Anything above that is likely to kill the LEDs. If you have a multimeter check if the LED works after having soldered the middle pads (top and bottom). Don’t use this pad for initial tacking! Use any other one, but not this one.

A damaged LED looks like this:

Replacing the LED is the only way to ‘fix’ it.

2.2 Soldering tips:

As you should know by now, always keep the tip clean and shiny. Use flux. If you have an adjustable soldering station, don’t turn it too high. This will make the tip last longer, less black stuff will accumulate and the flux won’t boil off as quickly. Always make sure you touch the parts and pads long enough to make the solder flow properly to all spots. For this kit I’ve used these temperatures and Sn60Pb40 solder: 240°C for the RGB LEDs and the small parts including the ATmega chip. You’ll have to touch the LEDs’ pads a bit longer to make the solder flow everywhere, but at least the darn things won’t melt. 280°C for all the headers and the voltage regulator, as there’s much more copper to heat up.

3. Flash it

Your first step will be to make sure the 4 jumpers are placed correctly. For now it is recommended to keep the VSEL jumper in its default position, which is next to the mark on the PCB. Due to it being a low drop regulator, this will work in most cases. If you know exactly what you’re doing, do as you please.

The ISP_E jumpers must be removed for ISP programming, as the pins are shared with the LEDs. Once the bootloader has been flashed you can put them back and won’t have to touch them anymore. Pin1 of your programmer’s cable will be marked by a red wire and must line up with the arrow mark on the PCB.

1
2
3
4
5
6
7

* ! DO NOT USE THE ARDUINO IDE FOR BURNING THE BOOTLOADER
* ! IT WILL USE THE WRONG FUSE SETTINGS AND BRICK THE BOARD
*
* If you use an Arduino bootloader, I recommend the "ATmegaBOOT_168_pro_8MHz.hex".
*
avrdude -c usbtiny -p atmega168 -P usb -b 115200 -e -u -U lock:w:0x3f:m -U efuse:w:0x00:m -U hfuse:w:0xDD:m -U lfuse:w:0xE2:m
avrdude -c usbtiny -p atmega168 -B 10 -P usb -b 115200 -U flash:w:ATmegaBOOT_168_pro_8MHz.hex -U lock:w:0x0f:m

Make sure to follow these instructions. It is extremely critical that the FUSE settings are correct, as a bricked chip requires quite some effort to be revived. The bootloader hexfile comes with the Arduino software and can be found in this folder: “/arduino-0018/hardware/arduino/bootloaders/atmega”.

4. Be creative

For starters I recommend using the Arduino IDE! You should choose the ‘Arduino Pro or Pro Mini (3.3V, 8MHz) w/ ATmega168′ in the boards menu. This makes sure your code is compiled with the correct CPU frequency settings. Demo code for grabs. You’ll find all design files in KICAD format (including schematic as PDF and Gerger files for easy reproduction) there as well.

4.1 I²C / 2-Wire

As I²C devices only pull the SDA/SCL lines low, you need pull-up resistors to the supply voltage! It may be the case that the libraries supplied with the Arduino IDE enable internal pull-up resistors, but they are only weak pull-ups. It may be necessary to add dedicated 4.7kΩ resistors to make it work reliably.

5. Hacks, Mods

5.1 More light hack

If all you care for is getting the most BANG out of the little bugger and don’t mind color balance much, you can use 91Ω resistors for all colors. The green LEDs gain the most out of this hack, so everything gets a little greener. Yellow becomes a greenish yellow, but white is still white though. The blue LED get a little brighter, but not much. I’d post pictures or a video showing the effect, but my camera is saturated already. The current going through the LEDs (and the micro) is still safe and nothing should fry.

5.2 Extremely more light hack

This one doesn’t affect white balance, everything just gets brighter ;-)

It needs some changes in the code as well. Essentially each color is now driven by 2 GPIO pins in parallel resulting in more current going through the LEDs. You’ll need 3 fine wires and another set of 3 resistors (390Ω, 91Ω, 110Ω). Just decreasing the resistors that are already in there would over-stress the output drivers. The bottom left (GREEN -- 390Ω) goes to the AVR pin #32 (PD2), the middle (RED -- 91Ω) to #1 (PD3) and the right (BLUE -- 110Ω) to #2 (PD4).

The code necessary to drive this can be found in the ‘WIP’ branch of the GIT repository. It should be considered as ‘experimental’. If you should choose to apply this hack to your board, make sure to only switch the anodes (e.g. RED_A, RED_A2) at the same time. If e.g. RED_A2 is not used, it must first be declared as an input ( DDRD &= ~(1 << RED_A2) ) and 2nd the internal pull-up resistor should be off ( PORTD &= ~(1 << RED_A2) ). Otherwise it will quasi short RED_A to GND. It doesn't instantly kill the board as there are resistors in there, but nevertheless it's not good practice.

www.youtube.com/watch?v=Py5sKQjTLxA

This hack pushes the AVR chip to its limits - and maybe even above. For example one possible and unfavourable LED state is just having _one_ LED statically on. As long as you keep two or more LEDS lit it should be OK. Using the full RGB PWM mode or the 7 color mode is somewhat safer, as the LEDs are multiplexed. Nevertheless if the chip dies I blatantly refuse to be responsible. You've been warned.

6. Upload code

Connect your favourite USB/TTL adapter to the board and upload using the bootloader. Make sure the pinout matches the silkscreen on the board.

7. Share your projects

Please post a comment with a link to your creations!

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Here the German sentence “Ich kriege einen Anfall” is equivalent to “I’m getting a fit of rage”. At least some time ago IKEA was, from my experience, prone to missing parts. There are not many things more annoying than having almost completed a new shelf and finding out that one single bolt is missing, which of course is necessary to hold all of it together. Driving to the next IKEA is out of the question, because it’s Saturday evening. It would be a 2 hours drive anyway.

Today, a Sunday, my “local” IKEA was open for business and as I’ve just moved to a new temporary home, I was still needing a few things to make the place worth living in. This included three cacti and a pretty nifty solar lamp called SUNNAN. This time my problem is not at all related to missing parts. After having read this post, people may argue that it was caused by missing brains though – please refrain from telling me that I’m right.

Anyway. Usually IKEA markets are clearly visible from highways, impossible to miss. I knew exactly where I had to go, meaning I had the street address. But it seems my mind was wandering a bit. Suddenly I saw the yellow IKEA sign a few km away, so I took the exit right before and even managed to get there. Street signs said “Möbelzentrum” (“furniture center”), which seemed pretty close. When I got there it looked a lot bigger than your standard IKEA buildings, lots of loading docks, didn’t seem quite right. Bummer!

Anyway, after adding some more miles to my car and running quite low on gas, I finally arrived at my intended target and bought some “stuff”. IKEA shopping spree you might say. Thankfully I didn’t take a cart and the yellow IKEA bags are not bigger inside than what they appear to be on the outside.

End of story: don’t let your mind wander while driving, or buy a navigation system ASAP.

Pictures of the SUNNAN solar lamp:

Solar cell data using a 20W halogen light bulb:

• 5.78V at no load
• 50mA short circuit current

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I must have read “Feet of Clay” by Terry Pratchett numerous times, but it seems I hadn’t payed this quote the necessary appreciation:

“Can’t see it myself, sir,” he said.

“Of course you can’t,” said V. “Because there’s nothing to see. You can’t see it. That’s how you can tell it’s there. If it wasn’t there you’d soon see it!” He gave a huge manic grin. “Only you wouldn’t! See?”

“You all right, sir?” said C.

Guess what they’re talking about.

And another one… I’ve finished “Feet of Clay” and turned my attention to another Discworld novell called “The Truth”. It covers the development of a free press in the fictitious city of Ankh Morpork, a mediaeval-ish Moloch ruled by a calculating tyrant named Vetinari. His name is a jocular reference to the old Medici family dynasty, which ruled the city of Florence, Italy several hundred years ago. Vetinari is a trained assassin and cunning politician. Opposed to the politicians inhabiting our little world, Vetinari is not corrupt and almost obsessively interested in his city functioning properly.

The dwarfs can turn lead into gold…

It reached the pointy ears of the dwarfs.

“Can we?”
“Damned if I know. I can’t.”
“Yeah, but if you could, you wouldn’t say. I wouldn’t say, if I could.”
“Can you?”
“No!”
“Ah-ha!”

And that was just on page 2 of the book. I shall have a good time reading it.

If you liked these quotes, you can find more on The L-Space Web or Terry Pratchett Quotes.

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