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.

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.

Designing A C5W Cree LED Bulb With Constant Current Driver | Voltlog #333

In a previous video I showed how I designed and assembled my own T10 style LED bulbs for the purpose of installing them in my car for the interior lighting. I was sick of these cheap bulbs I was getting from Aliexpress which didn’t last very long due to poor thermal performance and also they had this nasty blue tint color for the LEDs. The video I’m talking about is Voltlog #319, those bulbs have been installed in my car for the past couple of months, they are great. I love them and I’m pretty sure I will never have to replace those again.

Unfortunately T10 is not the only style of bulb that my VW uses on the interior lights, it also uses this style of bulb which is called C5W festoon for the lights on the sunvisor area. This comes in a few different lengths, I need mine to be 37.5 mm. So you can probably guess what I did next, I took the circuit I used previously and adapted the layout to fit the C5W outline.

Testing Kafuter Adhesives For Electronics | Voltlog #331

Welcome to a new Voltlog, in this video we’ll take a closer look at the various adhesive products that I could find and order on Aliexpress from this brand which has a hard to pronounce name, I would call this Kafuter but I don’t know, doesn’t sound right.

Since we deal with electronics on this channel, I’m particularly interested in how these adhesives would cope with use on electronics. As you may know in a typical product you may find different types of adhesives used: you might have some for securing wires/connectors, you might have a different type of glue used for securing big capacitors to stop them from flapping in the breeze, a different type of product for creating a seal against moisture, a different glue for securing trim pots in their final position.

And all of these products need to do their specific job while at the same time ensuring that they do not break down or become corrosive or conductive over time. I’m not gonna be able to give you any guarantees to that as my testing methods are not exactly industry standard so I’ll mostly be giving you like an overview of these cheap products that we can find on aliexpress and I will mainly recommend them for hobby use but if you have any experience with this company or it’s products, please do share in the comments below.

PCB Solder Trainer | Voltlog #328

Welcome to a new Voltlog, the title probably gave it away already, this video is about a pcb solder trainer that I designed to measure ones soldering skills. This is not a new idea they have been around for a long time and there have been different designs around but you can join me in this video to see how I designed mine. 

I remember how soldering felt back when I was just starting tinkering with electronics, I think I was about 7-8 years old and I had this big communist soldering iron that I got from my father, this was about 100W rated, it had a small flashlight incandescent bulb and it used this thick copper wire as the soldering tip. It was great for soldering big stuff due to the power rating and the ability to transfer that heat efficiently. I remember I was using too much solder, I was making these huge solder blobs.

So back to the board design, let’s take a closer look at what I have in here. On the left we start with 01005 passives, these are 5 resistors in series and at the end of the string there is an LED. The LED has to be bigger because you can’t get them that small so the LED starts at 0402, imperial size. If you get all 5 resistors and the LED soldered right and you apply 5V to this header, the LED should light up and that’s your indication that you’ve at least electrically got everything connected right.

And the size of the components then goes up to 0204, 0402, 0603, 0805, 1203 then we have some resistor networks which I believe are 4×0603. Then we have some SOT23 devices these can be dual diodes also connected in series that will light up an LED.

Depending on the type of LED you choose and it’s forward voltage you can calculate what resistor values you need so the LED will light-up. In general a green LED with 47ohms resistor should work for this and the pads for each of these passive components are the hand solder type which makes them wider so that’s something to help you out.

Making Kelvin Test Leads For My LCR Meter | Voltlog #326

A common mistake when building kelvin 4 wire test leads is to use standard alligator clips because in a standard clip the top and bottom jaw are electrically connected at the hinge point. This kinda defeats the purpose of having separate sense lines if they are getting shorted at some point with the current carrying trace. For a true kelvin connection you would need a special type of alligator clip, like the ones shown in this video, these have a plastic hinge and the top and bottom jaws are not electrically connected. These can be quite expensive if they are made by a good manufacturer but I got mine from aliexpress for cheap, they do not excel in quality but good enough for the type of instruments I am going to be using them with and with the amount of work volume they are going to see on my bench they will last a while.

Gopher NPS1601 Open Source Control Panel | Voltlog #322

A while ago I decided to start this project of re-designing the front panel for this power supply to give it more functionality, make it an awesome power supply cause as it is, it’s a good power supply but I think we can make it an awesome power supply. I made an announcement on the channel a while ago so several people joined the project, this is a team effort and right now it’s time to show you the first hardware prototypes and to discuss the choices we’ve made in terms of hardware. 

3D Printer Monitoring With An ESP32 Smartwatch And Octoprint API | Voltlog #320

Welcome to a new Voltlog, in this video I’m gonna show you how I built this project where an ESP32 based smart wristband allows me to track the progress of my 3D printer in real time. So I thought about how I could solve this problem and I came up with a project where I’m using a LILYGO T-Wristband which is basically an ESP32 development platform built into this smart bracelet form factor. The bracelet connects via Wifi to the local network where Octoprint runs and manages the 3d printer.