RefloWaffle: A dirt cheap reflow oven - the Belgian way

"For her a Moulinex, for him delicious meals"

Though I don't do many PCBs, I guess every hacker must have a reflow oven. So this is a project I've been pursuing on and off for nearly 4 years:
A small, portable, and dirt cheap (less than $25) reflow oven.

After a few tests with a traditional electric oven recovered from the trash, I concluded its thermal inertia was so high it would require massive modifications to achieve anything close to a decent reflow profile, and as I didn't feel like spending much money on a large oven, I looked for a better way.

And I think I found it. Read on for more...

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Pfff... git...

OK, I may be old. I've used VSS, CVS, SVN and Mercurial and always felt comfortable with them.

But from the day I started to use git (because, you know, "git is the new black"), I can't for the life of me grasp what a correct git workflow is. Add github on top and welcome to the world of nonsense of git clone checkout pull fetch merge update origin master branch reset.

In the end, there is only one truth : Pfff...


Migrating this blog from Gandi to my NAS

In January 2020, I received a mail from Gandi, the registrar for my domain name, stating that they were ending the free "GandiBlog" feature after 13 years of service.

I admit I'm not using this blog much, but some posts have been somewhat popular, so I thought I had to migrate it and started considering my options:

Gandi themselves propose a migration path but it requires a paying hosting, and I didn't feel like paying for such a small use. So I started investigating the possibility of hosting the blog locally on my NAS, and here is the result...

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18650 Battery charger reverse polarity protection


Having many 18650 battery cells to charge, I bought a few dirt cheap TP4056 modules (0.22 EUR per piece) and discovered that they are "not designed for" reversed polarity cells. In other words, reversed battery = instant magic smoke.

As I know for sure I will insert more batteries in the wrong orientation again sooner or later, I wondered what the best reverse polarity protection would be. This thread addresses this very topic, but at the time of this writing, it ends with:

Q: "Has anyone actually tested this solution in real life?"

A: "Good question..."

So I thought I would test and share the results here.

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Turning a Quick Charge 3.0 charger into a variable voltage power supply

Disclaimer: the following refers to some cheap USB chargers which may not comply with local safety regulations and could pose a hazard. All you do is at your own risk and I cannot be held responsible for use or abuse of those chargers.

1. Introduction

A few months ago, I stumbled upon a Hackaday post presenting the QC2Control library by Timo Engelgeer (Septillion), which makes it very easy to turn a Qualcomm Quick Charge 2.0 compatible USB charger into a 9V or 12V power supply. I used that trick successfully to power a small project that required both 5V and 12V, and its simplicity made me want to dig a bit further into Qualcomm's Quick Charge technology.

As you may know, Quick Charge 3.0 adds the possibility to request any voltage between 3.6V and 12V (with 0.2V steps), and with some QC3 chargers available for less than 4 EUR, throwing in an Arduino clone and a few resistors make a very affordable way to power devices with custom voltages. Of course, for that price, don't expect top notch precision, protection, or power, but it is more than enough for most DIY projects, and the adjustable voltage can compensate voltage loss in long power lines (think wired sensors far from alarm system for example).

So I decided to try and see if QC3 could be controlled similarly to QC2. (Spoiler: it is the case, but required a few adjustments.)

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