For the most part, Korean colors make sense. For example, the color sky blue is 하늘색 in Korean. 하늘색 literally translates as "sky color". However, when it comes to some common pants colors, Koreans named things a bit differently.
My wife bought a couple pairs of pants for me the last time we were in Korea. One was khaki, and the other was green. She asked me how they fit, and I told her, "The khaki ones fit fine, but we should return the other pair." After I said that, she picked up the khakis and put them in bag to return them to the store.
"What are you doing?" I asked, confused. "Those pants fit fine."
"But you said the khaki pants," responded my wife, as she put the khaki pants back into the bag to go back to the store, "fit okay."
"Yeah, I did. So why are you returning them?"
"I'm going to return the beige ones," said my wife, gesturing to the khaki pants.
After a bit of back and forth, we discovered that the color Americans know as "khaki" is called "beige" in Korea and the color Americans know as "green" is called "khaki" in Korea.
Confused? Yeah, I was too. Here's a picture labeled with the Korean color names to make it all a bit easier to understand:
Korean color names for what I would call khaki (left) and green (right).
So, here's a table just to make everything crystal clear:
Did you find this interesting or have a similar story to share? Let me know in the comments!
Photo by Jerrit Peinelt
My key fobs have been acting a little funny recently. Only some of the buttons on one of them would work reliably. The other one was getting shorter and shorter range until it stopped altogether. I replaced the batteries in both of them, but that didn't fix the problem in either one.
I could just buy a new one and get it reprogrammed, but I'd rather not. My car requires that it be taken to a locksmith or dealership to reprogram the key fobs. If I can just fix it myself, then I can save a couple bucks and a trip to a dealership. In the event I can't fix it myself, at least the key fob itself is pretty cheap.
My key fobs are registered with the FCC (as most electronic equipment is), so I was able to look them up by their FCC ID to get a lot of information on them. The FCC ID of my key fobs is written on the back of the case: "KOBLEAR1XT". The FCC entry for KOBLEAR1XT has a schematic, a block diagram, and even internal photos of this device. By looking at these I was able to figure out, generally speaking, how my key fob works.
Here's the schematic from the FCC website:
KOBLEAR1XT schematic from the FCC.
And here's what the key fob circuit actually looks like:
KOBLEAR1XT circuit top and bottom.
In the picture below, I labeled the interesting bits of the circuit: the "rolling code generator IC" (a Microchip HCS361), the 315 MHz SAW resonator, 94430-T44 RF transistor, a trace used as an inductor, and the trace used as an antenna.
KOBLEAR1XT labeled circuit.
I did some digging and found out that the "rolling code generator IC" is a Microchip HCS361 (even though it's labeled as HC361 in the schematic.). I probed the PWM output of it and found that it outputs a PWM signal (duh). There are short and long pulses and short and long pauses. If you look at where the signal goes high, you can see it ripple at (I assume) 315 MHz as the transmitter draws power from the battery and causes the system voltage to droop. The short pulses and pauses are about 210 us long, and the long pulses and pauses are about 420 us long.
HC361 PWM output probed with an oscilloscope
The signal appears to consist of a synchronization frame followed by a payload. The synchronization frame is six short pulses and six long pauses followed one extra-long pulse and one extra-long pause. The extra-long pulse and pause are 2.1 ms long.
Following the synchronization sequence, the transmitter sends the data payload. The pulses in the data payload are either a short pulse followed by a long pause or a long pause followed by a short pulse. This means the period of a single bit is about 630 us. That gives a data rate of about 1.6 kbps.
The payload is 67 bits long. According to the HCS361 datasheet, it consists of 3 parts: a 32-bit hopping code, a 32-bit serial number, and 3 status bits. The status bits are used indicate to the car if it should lock, unlock, open the truck, or sound the alarm.
One of my key fobs was easy to fix. First I cleaned the gold-plated contacts on the PCB. Then I resoldered the battery clip as it had broken loose from the PCB:
Broken solder joints on battery clip
The other key fob also had broken solder joints going to the battery, but resoldering them wasn't enough to get it working. It seemed that the resonator in my second key fob has been damaged: the top of the SAW resonator's package fell off.
The lid fell off the top of the SAW resonator in my second key fob.
Unfortunately, 315 MHz SAW resonators in this package are no longer being produced. Instead, I bought a 312 MHz resonator and a 318 MHz resonator hoping that they would be close enough to get my key fob working again.
First, I desoldered the old broken resonator and replaced it with the new 312 MHz resonator:
Soldering the 312 MHz resonator into place.
I fired up my oscilloscope, probed the output of the RF transistor, and pressed a button on the key FOB. I saw high-frequency noise in the pulses and no high-frequency noise in the pauses between them. I took that as a sign that the resonator was working and assumed that the high-frequency noise was probably 312 MHz.
Scope shot showing the PWM output of the code generator with a high-frequency component when the code generator is outputting a logic high.
After reassembling the key fob, it was time to test it out. I walked out to the parking lot and hit the lock button on the key fob with the new 312 MHz resonator. Nothing. I tried locking my car with the other key fob that I knew worked, and the car locked. I was in range for the working key fob, but the modified key fob wasn't working. Dang.
I walked closer to the car and continued to press the lock button on the modified key fob. Nothing happened until I was within about 15 of my car's trunk (where the keyless entry reciever is located. Once I was really close to the car, I was able to lock and unlock the car again with the modified key fob. Success!
So the key fob works with the new 312 MHz resonator, but it has a diminished range. Why? Well, the receiver probably has a band pass filter centered at 315 MHz. That band pass filter attenuates the 312 MHz signal from the fixed key fob, and an attenuated signal means shorter range.
Now I'm left with two options: 1) live with the shorter range of the modified key fob, or 2) try to find a 315 MHz resonator that kind of fits where the old one was. I can't get a 315 MHz resonator in the exact right package, but it's possible that one exists where the two active terminals are approximately the same distance apart as they were on the original resonator.
For the moment, I'm happy with the reduced range. I'll revisit this topic later when I feel the need to fix my modified key fob's range. In the mean time, I'm just happy to have two working key fobs again!
Have you done something similar with your car/car accessories? Let me know in the comments!
Photo by Jessica Paterson
Korea has a lot of different cafes. In America, if you want coffee, you can pretty much choose between either Starbucks or Starbucks. In Korea, that's not the case. Starbucks is there if that's your cup of joe, but the other options are often far more interesting.
The first time I walked into a cafe in Korea that wasn't Starbucks, I was really surprised by their menu.They had a list of drinks in Korean (with English underneath) and two columns of numbers next to them. The first column was labeled HOT, and the second was labeled ICED. And for pretty much every drink on the menu, the iced version was ₩1000 (about $1 USD) more expensive!
My brother-in-law took this picture of the menu in a cafe in Seoul for me for this blog post. You can see the higher prices they charge for cold drinks. 형님 고마워요~~!
Since I was visiting Korea in August and planned to take my coffee with me as I walked around Seoul, I bit the bullet and forked over the extra ₩1000 every single time. I'd never seen this pricing practice before in America, so I was really annoyed by it. I thought that the only difference between an iced drink and a hot drink was a couple of ice cubes that cost almost nothing, so I couldn't understand why cafes would almost universally charge about $1 USD more for cold drinks.
I recently asked my (Korean) wife about this, and she did a little bit of research. Apparently there are two popular theories as to why this is done. The first theory is that electricity is expensive in Korea, so it costs a lot of money to make ice cubes. (This is somewhat believeable since the last time I checked, electricity prices in Korea were about eight times higher than those in Texas.)
The second popular theory is that some cafes will add an extra shot of espresso to cold drinks to counteract the diluting effect of melting ice cubes. Therefore these cafes charge extra for the extra shot. This theory in turn gave rise to a subtheory that some cafes that originally did add an extra shot to their iced beverages have recently begun skipping the extra shot as a cost-cutting measure without reducing their prices to reflect that.
Whatever the real reason cafes in Korea charge more for iced drinks, it's a fascinating example of how things we take for granted as "normal" in America can be completely different from the things Koreans take for granted as "normal" in Korea.
Have you noticed any other interesting pricing strategies in Korea or elsewhere? Let me know in the comments!
Photo by fireskystudios.com
When I first got my 3D printer, I didn't know anything about how it worked. I read a few articles and getting started guides, but I felt pretty lost. There was a lot of 3D printing jargon that made it hard to make my way all the way through any article about 3D printing. I felt like I was reading a foreign language. I trudged along and researched what each new word meant in the context of 3D printing, and I've collected much of what I've learned here.
3D prints sometimes have trouble adhering to the print bed. On the Monoprice MP Select Mini, or any printer where the print bed moves, this is a problem because the material that had already been printed will move with the print head instead of the print bed if the print loses adhesion to the print bed. On other printers, the edges of the print can curl up. In either case, the print will be ruined and valuable printing material wasted.
This cute dragon was printed with a raft and manually created supports.
Rafts are a couple of additional layers that are printed before the actual print that give the print a flat base to print onto. The idea is that on complicated prints, a raft will help to prevent the base of the print from curling or coming off the print bed and ruining the print.
Rafts easily snap off the base when it's done printing.
Here's what that cute dragon looks like after removing the supports (front left) and raft (front right). Much better!
Supports are additional vertical sections that are printed undeneath any parts of the print that are not directly supported by the rest of the print. These areas that do not have any support in the print itself are called "overhangs". Overhangs are a problem because if the filament doesn't cool immediately, then it can sag without any support. When you print with added supports, the extra sections of material will hold up the print and they can be easily snapped off after the printer is completed.
The hot end, or hotend, is the part of the 3D printer that gets hot and melts the filament. It includes the nozzle, I think. Anyway, hot ends eventually clog because the filament going through the hot end is sometimes dusty. That dust can get lodged in the hot end and clog it. When that happens, sometimes it's possible to clear the clog, but other times you'll just have to replace the hot end.
On My Monoprice MP Select Mini, the first thing I printed was a hot end adapter so I could replace the hot end with an
E3D HotEnd when it finally gets clogged.
The surface that the 3D print is printed onto is the "print bed". As the plastic cools, it shrinks and becomes less adhesive. This can cause problems when your 3D print detaches from the print bed and causes your 3D print to fail. To prevent this from happening, a heated print bed warms up to about 50°C. That way the printed plastic remains fairly close in temperature to the freshly printed plastic on the top layer and the whole print cools at the same time.
By making sure each layer is close in temperature to the layers above and below it, we can ensure that each layer shrinks at the same rate and doesn't pull away from any other layer.
Are there any other common 3D printing terms that I missed? Let me know in the comments!
I just got a new car with Android Auto, and I'm doing a little bit of work to make it work the way I like. The first problem with Android Auto is that it (mostly) requires a data connection for navigation. In this post, I add a hotspot with free data to my car that turns on and off automatically with my car.
I don't want to use my phone's data because I don't want to pay for more data. To get free data, I just signed up for FreedomPop and got one of their cheapest hotspots, a Franklin R850. This gets me a measly 500 MB of data each month, but that should be enough for just navigation.
The first problem with leaving a hotspot in my car is the summer heat in Texas. The battery in the hotspot says "Do not expose battery to temperatures above 113°F (45°C)."
Considering temperatures in August in Dallas, where I currently live, often reach over 105°F in the shade, it's likely that any battery left in a car for a single summer would be toast. Autotrader measured the interior temperature of a car to be 113°F on a day when the outside temperature was only 95°F!
Obviously, the battery had to go. Removing the battery solves two problems: 1) the hotspot will now shut down when the car is turned off, and 2) the battery will not degrade over time due to heat.
Removing the battery was super simple, I just had to pry off the back cover and then pull it out:
Removing the battery cover.
Inside the battery compartment.
Next, I needed a way to power on the hotspot with the car. The hotspot powers on when it has power and the power button is pressed for 2 seconds.
Originally I had considered just taping the power button down, but once the hotspot is on, the power button is used to cycle through some menus. Obviously, whatever I use to press the power button has to press it only temporarily.
GIF SHOWING BUTTON PRESSES
Next, I decided to open up the hotspot and do a little investigation to find out how it worked. 99% of the time, buttons are simple switches that are connected to a pull-up or pull-down resistor and an input pin on a microcontroller (MCU).
Buttons and pull-up resistors from a SparkFun Tutorial.
When I opened up the R850, I was pleased to see the board had many well-labeled test points.
Circuit board inside the Franklin R850 hotspot.
Using my trusty multimeter, I figured out that one side of the power switch was connected to ground via a 10k resistor. (The resistor is a pull-down! It's not a pull-up!) I also found that when the power button was pressed, it connected to +5 V from the USB connector.
Luckily the three nodes I needed access to all had test points located near each other: GND, USB_VBUS, and POWER_ON. GND provides a 0 V reference. USB_VBUS provides 5 V when the R850 is plugged in to a USB power supply. POWER_ON is connected to the switch and is normally pulled low through a 10 kΩ resistor. The pushbutton on the front of the R850 connects POWER_ON to 5 V.
Useful test points on the Franklin R850 hotspot circuit board.
I now knew enough to get to work designing a solution. I needed a circuit that would provide +5V for two to ten seconds and then turn off. Well, that makes the output portion of the circuit obvious: It should be an open-drain p-channel MOSFET. P-channel MOSFETs provide a high voltage to their output (drain) when their input (gate) is low, and their outputs look like large resistances when their inputs are low.
So if I want my p-channel MOSFET to be on for a couple seconds and then turn off, I need to provide a low voltage to the MOSFET's gate for a couple seconds and then a high voltage forever after that. That's easy! I can just use a resistor and a capacitor for that.
If I charge a large capacitor through a large resistor, then the capacitor will slowly charge up to the supply voltage. The voltage of the capacitor is the perfect input to my p-channel MOSFET.
My proposed circuit for pressing the power button when power is supplied to the hotspot. Note: R3 is part of the hotspot and is only included in the schematic for simulation purposes.
With my circuit designed, I simulated it to make sure it would work the way I hoped it would.
The green trace is the power from the USB connector. The blue-gray trace is the voltage on the capacitor as it charges up over time. The red trace is the voltage at the output of the MOSFET.
It works! Well, it works in theory. The MOSFET drives its output high for about 7 seconds and then lets the 10 kΩ resistor pull it low. After the first seven seconds, it's like the MOSFET isn't even there anymore and the physical pushbutton can be used to send signals to the MCU as normal.
Finally, I had to actually build the circuit. I picked a couple parts off Digi-Key, ordered them, and set to work.
First, I took some strip board and cut it in half with a hacksaw so it would fit in the battery compartment. I used a small clamp to hold the strip board still while I was cutting it.
The strip board when cut in half is about the same size as the battery. Perfect!
I then soldered wires to the GND, USB_VBUS, and POWER_ON test points on the R850's circuit board and pushed them through a small hole into the battery compartment.
Wires soldered to test points.
And then I built the reset circuit on the strip board.
I cut one of the strips on the strip board to break them into two separate conductors because the MOSFET was not large enough to be able to solder it to three separate strips on the strip board.
While soldering, I heated the board to 200 °C with a Hakko FR830 to make the solder reflow more quickly.
I soldered down just the MOSFET first.
Then I soldered the 100 kΩ resistor between the gate and source of the MOSFET.
Next came the 47 μF capacitor.
Then I tinned the three strips to which I would need to solder the wires from the R850.
And I made a solder bridge between two strips to connect the drain of the MOSFET to the wire going to the POWER_ON test point connection.
Reassemble the R850 and poke the wires through a hole into the battery compartment.
Solder the three wires to the strip board.
Put the strip board in the battery compartment and close it up.
After closing up the case, it was ready to test. I plugged it into the nearest power source, waited a couple seconds, and the world "Welcome" popped up on its display. It worked!
Testing the Franklin R850 automatic power on circuit.
Was this information useful or interesting to you? Do you have any automobile/hotspot related hacks? Let me know in the comments!