Posts Tagged ‘workshop’

Prusa MK3S ~ Stop Button

Monday, April 6th, 2020

This was a one day build. I leave my printer running unattended and I know that others in my home would have trouble finding the reset button or off switch if/when something went wrong. Solution, add a big friendly stop button.

Remixed control panel

I have built several arcade machines over the years, so I had plenty of control panel buttons. This is a 46mm 12V red button. I pulled apart the switch and swapped the built in resistor to be 100 ohms, so I could run from 5V.

Prusa’s 3D printers are open source. Even better, they design their 3D printed parts using openscad. My favorite 3D CAD program.

I grabbed the LCD-cover-ORIGINAL-MK3.scad file and modified so the length of the face was a parameter. Then added the button hole and swapped the text. You can download my file here: LCD-cover-MK3_ArcadeReset.scad

The button’s LED is wired into the LCD pins labeled VDD (5V) and VSS (GND). The button’s switch is wired to replace the existing X Reset button.

The reset wiring goes from the LCD PCB to the EINSY controller to the Reset pin of the Atmega2560 chip. This pin could be reprogrammed to do something other than hard reset the chip. However, that would make future firmware updates tricky. So I left the firmware alone.

Portable Solder Iron

Saturday, February 1st, 2020

On a whim, I purchased a $20 USB Solder Iron from Aliexpress to play with. After playing with it using an old phone charger, I saw a video on Adam Savage’s Tested channel and got inspired. Drill Batteries as the power source. What a great idea! I have lots of those and always keep a few charged up and ready for projects.

However, finding a drill battery adapter for my Black and Decker 20V set was a challenge. It’s all discontinued. Black and Decker only sell new bluetooth batteries with USB ports built in. No adapters to be found. Searching for a solution, I found forum posts saying that black and decker 20V batteries and craftsman 20V batteries are made by the same company and are compatible. So I purchased a craftsman 20V USB adapter only to find that it did not fit my black and decker batteries. Bummer!

I junked the craftsman 20V USB adapter for parts. Salvaging the circuit and battery blades. Now I just needed a new plastic case to 3d print. There are a few on thingiverse that said craftsman/black and decker compatible… I printed them and surprise! they did not fit my black and decker batteries either. So I ended up making my own in openscad. You can download it here:

After some sanding, painting, and adding decals. I ended up with an awesome finished product.  I even added a spare volt meter display for some extra coolness.




I showed my creation to a few colleagues.  Everyone was impressed.  One of them shared their own solution using the TS100.  I played with it and instantly fell in love.  Wow. The TS100 is hands down the best portable solder iron I have ever seen.  The open source firmware makes it extra awesome.

So when my dad saw my portable solder iron and asked me to make him one too, I jumped at the opportunity to get him the TS100 and an adapter for his drill battery set.  Luckily, he had Milwaukee brand and I could just purchase the right adapter.  No extra leg work.  It all just plugs into each other.

For anyone else who wants a portable solder iron using 20V drill batteries, here is the part list.

TS100 Solder Iron

The TS100 solder iron is popular and easy to find.   It is about $40-50 for the iron.  They sell sets with the iron and accessories for $60-100.  Watch out for which tip is included in the description.  The B2 tip is a pencil tip, the BC2 tip is wedge shaped, and the TS-I is like a needle.

Battery Adapters

Search for your drill brand + usb adapter.  Look for one that has a barrel jack in the photos.  That will give you access to the full voltage from the battery.  Here are some I found that have the barrel jack.

If you can’t find a battery adapter with a barrel jack, you can buy one with just usb.  Open it up and install your own barrel jack.  The 5V from USB is painfully slow to use for soldering.  You want 12-20volts.


To connect the battery to the iron, you need a male to male barrel jack cable.  The iron is 5.5mm OD x 2.5mm ID.  The barrel jack on the battery adapter will either be 5.5×2.5 or 5.5×2.1.  The 5.5×2.5 plug cable will fit in a 5.5×2.1 jack.  So a 5.5×2.5mm to 5.5×2.5mm cable is your best bet.  A 5.5×2.1 to 5.5×2.1 cable will not work.  A 5.5×2.5 to 5.5×2.1 cable might be ok, but depends on your battery adapter socket.  If you are worried, check the product description for barrel jack dimensions. Then get the matching cable.

I like digikey, because I can search for exact matching cables.

Barrel Jacks

This is optional.  If your battery adapter doesn’t have a barrel jack, is easy to add one.  Just pop open the casing and wire it up to the 20V.  The positive wire attaches to the center post of the barrel jack.