voltlog – Page 8

Testing The Xiaomi 100W Type-C Car Charger – Voltlog #355

In a previous mailbag video I showed this Xiaomi dual USB port car charger which is capable of power delivery over USB Type-C. Xiaomi claims this is capable of up to 20V 5A output on the USB Type-C port. In the mailbag video I wasn’t able to test these claimed specs but today I have prepared a test setup so we can take a closer look at these specs.

In terms of specs I had a better look at the small user manual that comes with the product, it’s all in chinese so I had to use google translate on these but the unit takes 12 to 24V DC input. It’s unclear to me if you can use this in a 24V car system because you would be operating right at the upper limit of the input and the manual isn’t clear on that aspect.

You got two outputs, USB-A port capable of quick charge protocol 5V at 3A or 9V at 2A And a second USB type-C output which supports power delivery protocol up to 20V and 5A max. If you’re using both ports at the same time the maximum combined total power output is 68W.

InTheMail | Voltlog #354

Welcome to a new InTheMail, the series that will touch both your passion for electronics and your bank account at the same time. We’re gonna start this video with an item I do not recommend buying, this is a power meter that has been sitting in my mailbag basket for over a year now if not more and these past few days I powered it on for the first time, I realized it’s not very useful, because the accuracy is pretty bad. It does claim to measure up to 140A which would probably make it okay for some high current measurements and that was the original reason I got this to measure to brushless motor power consumption at various loads but if we’re talking about currents below 5A the accuracy is pretty crappy so I wouldn’t recommend you get something like this.

Reverse Battery Protection With Mosfet (no voltage drop) – Voltlog #353

Welcome to a new Voltlog, today we’re going to be talking about reverse battery protection, I’m gonna be showing you a few methods for achieving this protection but I’m going to be focusing specifically on low power designs, where you might be using let’s say a single coin cell battery.

When we’re talking about higher input voltages, battery protection is pretty simple, you can simply add an inline Schottky diode, if the input voltage is reversed, the diode will be reversed biased and it will block the current flow. There is about 0.5V voltage drop on your diode but if you have a 9V input into a 5V regulator, there’s plenty of margin to afford losing half a volt. There is also the power dissipation to consider in that case, so you multiply the current with the voltage drop and you get your power dissipation into the diode, you pick an appropriate diode capable of dissipating that and the problem is solved.

Now when you start talking about low power devices, specifically those powered by coin cells, it gets a little tricky to get some reverse polarity protection into your circuit. Because our battery voltage is now just 3V we can’t afford losing 0.5V on our input diode, that will ruin our battery life, it will waste the little precious energy we have stored in the coin cell and might prevent our circuit from powering up.

Best Technique For Soldering & Inspecting BGA Chips – Voltlog #352

Welcome to a new Voltlog, in this video I’m gonna show you my method of soldering BGA chips because in the previous video where I showed the eMMC to microSD card adapter PCB I mentioned I don’t use any stencil for soldering the WFBGA153 package. I’m also gonna be showing you a method for easily checking if the BGA chip is soldered correctly or not.

So let’s start by talking about the BGA package that I used in this project, it’s the WFBGA153, this package has 153 lead-free balls, each is 0.3mm diameter and the pitch between balls is 0.5mm. Now the footprint that I used has 0.35mm pads for each of these balls, which means that when you consider the 0.5mm pitch, in between pads you are left with just 0.15mm which is roughly 6 mil, you basically can’t route any tracks in there using any of the standard PCB services.

eMMC Flash Memory To microSD Card Adapter – Voltlog #351

Welcome to a new Voltlog, today we’ll be talking about eMMC memory chips and how you can use them in your next project and whether or not they provide any advantage over a more traditional sd card.

So historically MMC memory was first and then SD memory cards were developed based on MMC specification but added new features. Both technologies are based on some form of flash memory and they both contain a controller in the same package with the memory. Electrically it’s the same interface for both in most cases however software-wise SD card ads some new features which are not supported in the MMC standard. While standard MMC comes in a card form similar to how SD memory cards are, eMMC stands for embedded MMC and it comes in a BGA package.

The purpose of eMMC is to be used as non-volatile storage in embedded devices and almost all mobile phones and tablets used this form of flash for main storage up to 2016, when UFS started to become more popular.

InTheMail | Voltlog #350

I discovered this guy a while ago when i saw some images on twitter of this particular tracker being implemented inside an iPhone X, it was mostly a hobby type job because of how it looked and also because if any serious agency would want to spy on you they wouldn’t need to implant something like this into your phone, they will just do it through other methods like a man in the middle attack or tap your calls straight from the operator network but nonetheless this looked interesting and as far as I have seen so far this seems to be the smallest tracker that you can easily buy online.

Same as other trackers shown on this channel this is designed to connect to a Chinese cloud service for tracking, it uses the same website as the other ones which is 365gps.net and it probably comes with the same set of problems or limitations as I have shown in previous videos. So this module can do GPS based tracking and report back via 2G network connectivity, the short wire is a GPS antenna while the long wire is the GSM antenna.

How To Interface A GC9A01 Round Display With Arduino & ESP32 – Voltlog #349

I’m gonna start this video with a question, do you agree that technological advancements as well as market demand for technology is making our hobby nicer and more accessible by providing us with parts and tools that are cheaper and easier to get now than ever before.

That’s how I feel when as a hobbyist I can get my hands on parts and tools that just a few years ago were out of reach due to them being top hard to source, too expensive and too technically challenging as well. Here is one example, this is a 1.3 inch, 240x240pixels round display and it even comes installed on this nice little breakout board with 0.1 inch header connections. You can get such a module for cheap on aliexpress and I’ll place some links to this in the description below so you can check it out.

And no, the interface to this display is not some complex and hard to implement LVDS interface, it’s a very simple SPI interface that you are probably already familiar with. So join me in this video to learn how to connect these types of display modules to your favorite development board and you can drive them to display pictures and animations.

InTheMail | Voltlog #348

Welcome to a new InTheMail, the series that will touch both your passion for electronics and your bank account at the same time. This will be a great year hopefully, I’ll make sure to do my part and provide you with the best mailbag videos on youtube. We’re going to start with this utility knife, it’s the xiaomi type knife that I showed in a previous mailbag but I liked it so much that I got another one, I’ll keep one in my laptop backpack for general stuff like opening packages and one at the workbench for general purpose stuff. The body is aluminum, the build quality is great, they feel perfect in the hand, you can get them with a set of super sharp replacement blades and they’re pretty cheap with everything considered so if you haven’t already got one, I highly recommend these, you can find the links in the description below the video.

JTAG Adapter PCB 20pin 2.54mm to 10pin 1.27mm – Voltlog #347

Welcome to a new Voltlog, this will be a rather short project video, I thought I’d start the year with something simple. If you’ve ever used JTAG before, either to program or debug an ARM processor, or something like an ESP32 or maybe to load a bitstream into an FPGA, you’ve likely encountered the ubiquitous 20 pin JTAG connector which is this 2×10 0.1inch spaced connector. It’s a rather large connector, it takes up a lot of space on a PCB, you don’t really need that many pins but you can’t go without it because it’s usually present on the fully featured programmer/debugging tools. Here is an example: this is an ST-Link V2, or to be precise a cheap clone from aliexpress but for the purpose of this discussion it doesn’t matter, it looks the same as the original and it has this 20 pin JTAG connector.

And to some extent this isn’t really a problem if you are using big development boards like this STM32F4 dev board that I got from Aliexpress. This features the same 20 pin connector for programming so it’s a matter of connecting a simple ribbon cable and you’re up and running. However, most modern boards that you are going to be designing might not have enough space to install such a big connector, you might for example use the simpler 10 pin JTAG connection, cause you don’t even need that many signals, most of the pins are GND anyway on the 20 pin connection. And instead of using 2.54mm pin header you can use something smaller like half the size, 1.27mm, and this can save a lot of space on a board.

InTheMail Stats For 2020 – Voltlog #346

Welcome to a new voltlog, this is the annual review to present some stats on the number of orders and spending with regards to my activity. The InTheMail videos are my most popular videos so as you can imagine there is quite a bit of spending and orders placed behind the scenes. Same as last year, please let me know in the comments if you have any stats on your own purchases, I would love to get a feel for how everyone else is doing.

This year I’m not going to show any stats for ebay, I’ve stopped using ebay, I do most of my orders on aliexpress.com starting with 2020 and I also place a few orders on banggood.com. In fact I’ve also stopped placing links to ebay items in my mailbag videos because I don’t really use the platform anymore.