Here is my photography cheating scale for rating what's cheating and what's not:
Saturday, July 2, 2022
Photography cheating scale. How much of a cheater are you?
Thursday, April 14, 2022
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.The build is so simple:
Worth noting:Friday, April 8, 2022
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?
Wednesday, June 30, 2021
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.
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.
Sunday, June 14, 2020
Motorcycle cheap Aliexpress clock voltmeter thermometer
Wednesday, May 13, 2020
Edifier S350DB high pitch noise defect
- High pitch noise independent of speaker volume
- Only happens in Bluetooth, PC and AUX modes.
- Temperature dependent. As the unit warms up (after 10 min), the noise gets lower but never disappears. The colder the room, the worst.
I captured this picture with a spectrum analyser app:
I investigated the problem. The sound amplification electronics are in the subwoofer box. It seemed like there was a problem with a switching power supply that steps down 20V from the main PSU to 5V for other parts of the circuitry. This noisy supply is controlled by a AOZ1210 IC. If one blows or apply heat to this IC, the noise frequency changes very noticeably.
I observed with an oscilloscope the supply output but no noise was being injected. This made me think, the noise wasn't being produced at the output but could be inductively coupled to other part of the PCB.
After this I decided to return the speakers, since, this was a manufacturer problem, not mine.
The replacement
The replacement speakers luckily worked fine. There was no noise at all.
As for the serial numbers, this new unit was manufactured actually before the defective one.
Defective unit SN: 441405044429
New unit SN: 441405042325
I try to visually inspect the PCBs of both units but couldn't notice any differences. The PCB revision was the exact same one, so no layout changes. The codes written in the AOZ1210 package were also the same ones.
The defective:
The new:
(The IC and the supply circuitry are located in the bottom right corner, next to the antenna).
The remote
Just as a remark, in my first unit the remote needed to be pointed exactly to the receiver in the speaker. It was very tricky but now I feel it's better. (BTW, the battery was more than OK).
Bottom line
I couldn't really tell what was the reason of the problem. but if you are in the same situation as I was, return them.







