electronics – 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.

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.

Designing PCBs With Castellated Holes | Voltlog #335

Welcome to a new Voltlog, in today’s video we’re going to be talking about castellated holes and how you can create them in your CAD tool. If this term is new to you, it’s pretty simple, you’ve certainly come across them if you’ve ever played with a bluetooth or wifi module because those 99% of the time will use castellated holes, which are these semi-plated holes on the edges of a PCB. Having these connection points allows these modules to be soldered on top of a main PCB which contains our main circuit.

You might ask yourself why do we use castellated holes, why not use a simple through hole header as a board interconnect or just some simple SMD pads. Well in my opinion the most important reason is the relatively low difficulty for soldering castellated holes. If you think about it, having some SMD pads that go on the bottom of the PCB makes it pretty hard to solder, at least without proper equipment, you need to deposit solder paste on those pads, you need to get it in the right amount and then you need to have perfect alignment of the module on top of the pads which reside on the main PCB. Having these connection points underneath our module makes it very hard to align because you can’t see them. Also debugging such a module is going to be a pain because you won’t have access to all of those connection points.

So this where castellated holes improve, by having the plated half-holes at the side you can solder them even with a simple soldering iron, alignment is pretty easy because you can clearly see the connection points and debugging these is much easier because once again you can access them, you can do measurements with your scope probes or whatever instrument you are using.

Another advantage of having castellated holes on a design is to think of it like a building block, you might improve this building block externally or switch to a new building block that uses the same pinout and you just drop it into your system as a simple upgrade.

And believe it or not but having a module with castellated holes can lower your BOM cost in some cases because let’s say you need to use an RF module which might be 4 layers or a complicated system on module that may be 6 or 8 layer PCB with a powerful processor. Instead of building your entire system on an 8 layer PCB and assembling that complicated BGA chip yourself, you can buy the module ready made, it has castellated holes and you just drop that module into your system which may be a 2 layer mainboard or 4 layer mainboard that costs less.

Voltlog #297 – How To Parfocal A Trinocular Microscope

Welcome to a new Voltlog, in this video I’m gonna show you how to parfocal your trinocular microscope, this means getting both the eyepieces and the third camera port in focus at the same time and maintaining them in focus while adjusting through the zoom range of microscope from low to high.

This is extremely useful if for example you are using the microscope through the eyepieces, soldering on some board and at the same time you are using the camera port for recording or live streaming. Once you do this procedure, the camera and the eyepieces will be synced in focus even as you adjust a different zoom level but with some limitations, as I will show in a moment, these are the result of the camera optics which will limit the effective zoom range in focus.

Now if you are using a 0.5x barlow lens like I do and like most people doing electronics will be using, you need to consider the fact that the working distance is about 16.5cm between the barlow lens and the work surface. So keep that in mind, because the adjustment we will do later will be happening around that working distance.

Voltlog #296 – Microscope Camera Focus Issue Fixed!

Welcome to a new Voltlog, as you may remember in Voltlog #282 I got a new trinocular microscope and then in Voltlog #292 I got a new camera because the one shipped with the microscope had issues. Banggood till this day did not replace the camera which I believe is defective, they kept asking me to try these various settings in the camera menu to improve the brightness but none worked.

Now to get a good image and have both the camera in focus and the eyepieces you will need some kind of reduction, an optical adapter between the camera and the microscope port. So first I got this SZMCTV 0.3X adapter, after reading some reviews who were claiming this will give the best field of view.

After installing this adapter I noticed the field of view was almost the same as through the eyepiece which is great but I couldn’t get it in perfect focus with the limited adjustment available on the adapter and I was getting this tunnel vision which I couldn’t quite explain but it was obviously not what you want to see.

And so I got this newer wide body 0.5 adapter and installed it on my microscope and the problem was solved I could now get my camera into focus at the same time with the eye pieces but with a loss in the field of view due to the 0.5x adapter. Getting the SZMCTV 0.5X adapter would probably also work, that’s a bit cheaper, but I went with the recommendation of getting the newer type of adapter with better optics.

Voltlog #295 – Weekend Update

Welcome to a new Voltlog, this will be just a short weekend update video, to let you know what I’ve been doing in the past couple of weeks. So I’m staying at home and only going out for important stuff, which gave me more time to tinker and work on projects. I hope you are doing the same because social distancing is a good way to slow the spread of this disease.

One of the things I’ve been thinking of doing for a long time is a bench tool holder, the kind that will hold my tweezers, soldering iron tips, flux syringes, stuff like that. So far I’ve been keeping them in one of these pen holding cups but they fill up and it’s hard to grab the thing you need quickly. So I’ve started designing my own in Fusion 360, I included 6 deep pockets, 2 shallow ones in the front and 5 tubes for holding syringes.

The next thing I did with my 3d printer is related to the current pandemic, as you may know, medical staff in many countries which have been hit hard are lacking protective equipment, they just don’t have enough mask or suits or face shields, not to mention enough ventilators which are desperately needed for those in critical condition.

In parallel I’ve been designing the battery monitor circuit for the power drill I reviewed in Voltlog #285, this is the first revision of the PCB, the circuit works as expected but I’m still waiting on some parts to be delivered and I’ll do a separate video on this subject. It probably needs a second revision of the PCB because this one doesn’t quite fit in, the way I thought it will.

I also started designing a T10 automotive LED bulb. It’s using a linear constant current driver and some decent LEDs, because what I’m currently using in my car are the aliexpress bulbs which kinda start dying after a few months of usage. I’ll probably place an order for this panel today but who knows when I’ll receive it.

Voltlog #294 – InTheMail

Welcome to a new InTheMail, the series that will touch both your passion for electronics and your bank account at the same time. Before I get started I’m gonna take a second to remind you to subscribe to the channel and hit the bell notification icon because that’s the only way you will know for sure when I upload new videos.

Depending on which part of the world you live in, you might be dealing with the same isolation measures as I am, the government is recommending we stay inside as much as possible here in Romania, to avoid contact with other people. So that gives me more time to work on projects, learn new stuff and of course discover and order stuff from the internet.

I’m gonna start with this notebook which has a retro looking leather cover, I think it’s quite neat looking, I’m not sure if this is real leather or not, description just said leather. I always keep a notebook around the workbench, it can be useful for drafting a quick schematic, some dimensions or just for writing down some measurements. Another cool feature of this notebook is the binder style clips you have inside, which allow you to insert or remove paper and what’s even nicer is that you can find this type of paper with different grid styles and they’re very affordable.

Voltlog #293 – Buying From Banggood and Ebay Tips & Tricks

Welcome to a new Voltlog, this is a continuation of Voltlog #291 where I shared some tips and tricks about buying from Aliexpress, if you haven’t seen that video, I will link it on screen right now. Today I’m gonna share my experience with buying from Banggood or Ebay. These are my secondary buying channels, some of the stuff you see in my mailbag videos comes from Banggood or Ebay.

Voltlog #292 – Hayear Full HD 34MP Microscope Camera Review HY-1139

Welcome to a new Voltlog, you might recognize this, the trinocular microscope which I reviewed in Voltlog #282, it’s a great tool to have especially if you start to feel your eyesight is getting weaker but also if you have good eyesight you can’t possibly solder 0402 passives comfortably or you can’t spot very small problems on soldering joints without something like this.

However I had an issue with the camera, the image is too black and so far there has been no solution provided by Banggood but I am still in contact with them and they’ve told me they are working with the supplier to find a solution but due to the whole Coronavirus (COVID-19) issue, there’s been delays.

So I’ve asked them to send another camera for review, it’s a Hayear branded microscope camera, it’s capable of up to 2K at 30fps and 1080P at 60fps, it has HDMI and USB 2.0 output as well as SD card storage support. The USB output is capable of 1080P at 30fps but that’s okay, cause I will be using this on it’s HDMI output on the 1080p 60fps setting.

Voltlog #291 – Buying From Aliexpress Tips & Tricks

Welcome to a new Voltlog, today I’m gonna share with you some tips and tricks about buying from Aliexpress and I might follow up with another video about Ebay and Banggood. I received requests for doing such a video several times as the subject was brought up and I think I can share a few useful things with you because as you may know, some of my most popular videos are my InTheMail videos where I show you the stuff I purchase from China and I get a lot of stuff which allowed me to learn a few tricks over the years.