PC/laptop auto power ON schematic when AC is connected

With this simple schematic you can make your PC turn ON when AC is connected, if this behaviour is not possible to achieve by tweaking your BIOS/UEFI. This is a custom circuit I designed for my particular laptop but it should work in most computers.

The blue area represents the circuit to build while the outside indicates the parts that are present in the mother board. 

When power is applied to the circuit through R4, Q1 simulates the user pushing the power ON button. This pushing is stopped when the power ON LED is activated due to the computer being turned ON.

Note that the supply 3.3V or 5V must be present in standby before the computer is started. I tapped 5V from the battery charging LED.

Hope it helps someone.

Photography cheating scale. How much of a cheater are you?

 Here is my photography cheating scale for rating what's cheating and what's not:

Level 0. No cheating.

Applying modifications that affect the entire photo. 

Basically, most of the things that can be done on Lightroom. This is not considered cheating. Eg. Modifying white balance, color tone, exposure. shadows, highlights...

Level 1. Basic cheating.

Editing elements of the photo.

E.g. The photo has the moon in the background and you make it bigger.

Level 2. Medium cheating.

Editing the elements of the photo by obtaining material from another photo that you took at the same time.

E.g. In the background there is a bird flying and you add another one from another picture that you took at the same moment.

Level 3. Extreme cheating.

Editing the elements of the photo by obtaining material from a photo of another person (the internet).

E.g. You change the sky in your photo for other one from the internet.

How much of a cheater are you?

DIY simple PC fan/cooler speed regulator with LM317T

After wasting some time online, I was surprised I couldn't find any simple LM317T schematic for PC fan speed regulation with a potentiometer. WTF?

So I share my version. The values are intended to be easy to find lying around.

Worth noting:

- As with any LM317 based schematic, the maximum output won't reach 12V but a bit less.

Le me know if you found this useful.

DIY 3.5" hard drive power supply for USB cable

 I got this USB interface from Aliexpress that allows you to connect any HDD/SSD to your USB ports.

Unfortunately 3.5" hard drives need external power in order to work. You can get this power from a ATX power supply or from a dedicated hard drive power supply that can be found online.

To keep my shit low cost I built my own power adapter with things I had around. I used:

- 12V 2A power supply. Got it from an old router.

- Mini 360 DCDC converter. Dead cheap from Aliexpress, so useful. Must have several at home.

- SATA or IDE power connector. Chopped from an old ATX power supply.

The build is so simple:

Worth noting:

- The Mini360 output voltage is adjustable with the potentiometer on top. You need to set it to around 5V with a multimeter.

- Wall adapters with lower output current than 2A will almost surely not work due to the required start up current of the HDD. (Tried with 1.5 A, didn't work).

- I used a piece of heat-shrink tubing to cover the mini360 and make it neat in the middle of the cable.

Let me know if you found it useful.

Olympus M.Zuiko Digital 14-42 mm II R vs EZ (pancake)

 If you doubt about what lens is better among the 14-42 II R and EZ, let me tell you what I found. This is a compilation of all the info that I found online. I'm no expert. This may save you some time.

The only advantage of the EZ is the small size, period. It seems it depends on your specific unit how well it performs. At best you can get the same results as with the IIR. At worst people seem to experience vignette and/or a little bit of lack of sharpness on the edges. It seems a mixed opinion. In any case, no one claimed to obtain better picture quality with the EZ. 

The electronic zoom on the EZ seems to be slow and significantly less easy to operate due to the electronic control. A noticeable amount of users reported issues with the electronics that required servicing the lens giving the impression that it's less robust than the manual IIR.

On the other hand, the IIR seems to be better at everything other than the size. Regarding this, the difference is only 25 mm in length more than the EZ which isn't a big deal. 

I think the IIR is the one to go. I reckon the only case in which the size can make a difference is if you wear a big jacket because you can fit the camera with the EZ and not with the IIR. However wearing any other clothes you're going to need a bag or something else anyway. Even if it fits your clothes, will you carry it like that?

Soehnle scale software tricks users

I own a Soehnle Style Sense Safe 100 scale and it feels like it's a quality product. Also, the German brand Soehnle is reputable to my knowledge.

Picture stolen from Amazon

The thing is, I recently discovered how the brand tricks the users into thinking the scale has perfect measurement exactitude. This is not difficult to notice because when using it to weight the same thing several times during a short period of time, it is strangely always spot on. So, based on my observations, I presume this is what the software does to trick the user:

1. When using it the first time, it stores the measurement of let's say 70 kg.
2. If it's used to weight the same thing several times in a short period of time, the measurement is performed as usual but just before displaying the final result, the previous stored value of 70 kg is recalled and showed, tricking the user into thinking, the scale measured the same.
3. If the scale detects that it is being used to weigh something that differs a certain amount (maybe 500 g more or less) than the last stored measurement, then it forgets that stored value and show the real measured one.
4. After some timeout that I didn't test (maybe 5 min, 1 hour, who knows...) the scale, as in point 3, forgets the value stored and performs a 'real' measurement again when it is used.

One can test the above by using it with a object A, then with an object B of different enough weight, and then back with A. In the last try, Object A will almost for sure show a drifted result, maybe by 100 g, 300 g or even 400 g. Now we are seeing here the truth.

That's all, I though it was interesting to share this. To a common user, this not only would be unnoticeable but also, will leave an impression of a wonderful product that always measures the same. However, not everyone can be tricked so easy. 

Motorcycle cheap Aliexpress clock voltmeter thermometer

Hello, this time I want to rant about this cheap thing I bought for my motorcycle:

Picture stolen from an Aliexpress user

This is actually the second one I buy. The one I bought first cost me double and was a double piece of shit because it was so dim, I couldn't see shit while riding during the day.

The one I bough this time has the looks like the one in the picture, a fake Rizoma. It's funny because looking at the pictures of the users, it seems like each one gets one slightly different. The white letters, the size and the package differs from one user to another.

Anyway, I wanted to share some measurements I made to check how shitty these things are and this is what I found:

-  Voltage measurement: Resolution is 0.1 V. The measurement seems to be off by -0.1 V consistently across the hole range. 

Opinion: This maybe caused by some diode in series to protect against backwards connections. Considered how easy it is to achieve a proper 0.1 V resolution voltage measurement, this shit is totally unacceptable.  

- Temperature measurement: Resolution is 1 ºC. The measurement error differs but generally it's 1 to 2 degrees off the right value.

Opinion: The temperature is sensed with an NTC. Considered how easy it is to achieve a proper 1 degree resolution voltage measurement, again this is totally unacceptable.  

- Current consumption during operation: approx 30 mA.

Opinion: This really doesn't matter much, 30 mA is the typical power used by a multiplexed LED segment display plus some bits of circuitry more. Nothing new here.

- Current consumption during standby: approx 3.9 mA.

Opinion: This is absolutely huge power for standby. This can empty a full 6 Ah battery in a couple of months. This is not a surprise though... A regulator that can achieve standby consumption in the uA range is expensive, no way this was going to fit it.

Conclusion:

The specs of this cheap shit are completely out of the acceptable and the performance is pretty poor. This piece of crap belongs in the bin. 

However did I installed in the bike? Yes. 2 simple reasons:

- This cost under $4 while the original Koso Mini 3 is near $100 or in some places even more! Unfuckingbelievable! 

- There seems to be no better alternative that has the 3 features of this one for a reasonable price of let's say, maybe $15 or $20. So, I think I'll live with one this for now.