DIY – Page 6 – VoltLog

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.

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.

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.

Smart Christmas Tree With RGB LEDs & ESP32 | Voltlog #344

For this year I wanted to add a personal touch to our Christmas tree and so I have started thinking about what features it should have. Lately I’ve been playing a lot with HomeAssistant and so the obvious path was to put an esp32 in there so that I could control it from the app. Next I thought about making it battery powered but considering I wanted to use at least 10 RGB LEDs and I also had the ESP32 in there which is kinda power hungry, the kind of battery needed to run the whole system for a decent amount of hours before needing a recharge would make the whole thing too heavy so I instead went with usb power because I always have a socket available at the bottom of the tree to power the tree lights so I could easily add a small 5V adapter and run a micro usb cable through the tree. So these were the main decisions I had to make regarding this project and the rest is just support circuitry.

Would I still recommend these products after using them? | Voltlog #343

In this video I’ll be going over some of the most important gear I have in my lab, this is stuff I have reviewed in previous videos but I want to share my thoughts after using the gear for extended periods of time. Sometimes you might discover stuff that you miss in the original review video.

VW Can Bus Hacking With SavvyCan & Cantact – Voltlog #342

In this video I’m gonna walk you through the process that I use for hacking a VW cluster CAN bus(PQ35 platform). The tools that I’m going to be using today are very accessible price wise and open source on top of that. As hardware I’m going to be using the Cantact usb to can bus adapter, this is going to allow a computer and operating system to access and communicate on the CAN BUS. As software I’m going to be using Savvycan which is once again an open source GUI tool for hacking and reverse engineering CAN BUS data.

T-962 Reflow Oven Custom Profile Calculator | Voltlog #339

In the last video I showed you how I upgraded the T-962 oven to fix some of the issues that were present on this oven. I also mentioned that there is an option to configure a custom reflow profile with this oven and that’s probably something you’re gonna have to use sooner or later because there are so many options of solder paste on the market and not only that but also there is variation between different ovens so it’s likely you’re gonna have to tweak that.

So in this video I’m gonna show you how to define a custom reflow profile in the open source unified engineering firmware. Before doing any actual configuration on the oven you need to start with the specs of your solder paste. For this example let’s assume we are working with the NP545 series from Kester, we need the datasheet of this product to check out the recommended reflow profile. Inside the datasheet we can find the recommended graph, it’s an unusually small one for this paste but luckily we can zoom in and increase the size of the graph.

At this point I recommend you grab a screenshot of this profile and import it into your favorite img editing tool because we need to draw some lines on this graph to extract some values. First I added a scale on the Y axis with a line at each 5 points. Then I added these lines to plot the absolute values on the Y axis. So we now have a set of temperature values for every 30 seconds of the profile but the firmware on the oven, the procedure for inputting a custom reflow profile expects data points every 10 seconds so we need to somehow extrapolate our values to generate more points in between.

T-962 Reflow Oven Upgrades & Fixes | Voltlog #338

This is the famous T962 reflow oven coming from China, you might find it under a bunch of different brands, it’s available to order directly from China but also from a bunch of local distributors who are importing these ovens but in general they all have this list of problems which can be easily addressed for improving the performance as well as the safety aspects of operating one of these.

I got mine for about $180 shipped from Germany so there was no tax involved and it got here pretty quickly but you can probably find it for less if you are willing to wait a bit longer and get it from China. I used to run my own reflow oven based on a toaster oven but trust me, unless you invest in a really expensive toaster oven you’re not going to get the same performance as with one of these dedicated ovens. They’re not perfect as I’m gonna show next, they still have a bunch of problems but once we address those problems it becomes a decent oven with superior performance when compared to a toaster oven.

So let’s start with the paper tape insulation problem. This oven uses glass wool for insulation of the hot chamber and to seal that they used a combination of aluminium tape and paper tape, it really looks like the cheap painters tape. Now obviously the insides of this oven are gonna get hot and that paper tape is gonna start to burn and it will release fumes and a nasty smell. If you buy this oven and start using it right away without implementing this fix, you will need to vent that room most certainly.

Luckily this is an easy fix, the only thing you need is kapton tape. The idea here is to equip yourself with a pair of gloves and place the oven on a table that you can wipe clean when you’re finished to avoid contamination with the fine particles released by the glass wool. It’s best if you have some genuine kapton tape because it will stick better and you will have to remove all of the paper tape and replace it with kapton tape. You might also find some pieces of rigid cardboard/paper like material in there, I wrapped those in some kapton tape as well for protection against the heat and inserted them back where they were. Your oven should look something like this when you’re done.