Our Thanksgiving Weekend Sale


It’s our Thanksgiving Weekend Sale! use checkout coupon code TURKEY to save 10% storewide at Evil Mad Scientist.

Save on popular items like the brand new AxiDraw MiniKit, surface-mount 555SE and 741SE soldering kits, and everything else too.

Our biggest sale of the year, it’s a great time to get that AxiDraw SE/A3, EggBot, or through hole 555 kit too.

Sale runs through Monday, December 2.

The 555SE and 741SE surface-mount soldering kits

555SE and 741SE kits

Today we are pleased to announce the release of two new soldering kits: the 555SE discrete 555 timer and the 741SE discrete op-amp.

Both of these new kits are surface mount soldering kits — our first surface mount soldering kits — and we think that you’re going to love them.

555 kits, big and small

You might be familiar with our Three Fives discrete 555 timer and XL741 discrete op-amp kits. Both are easy soldering kits that let you build working transistor-scale replicas of the classic 555 timer chip and the famous µA741 op-amp. Those two are constructed with traditional through-hole soldering techniques and are styled to like “DIP” packaged (through-hole) integrated circuits.

Our new 555SE and 741SE kits implement the same circuits, now with surface mount components, and are styled to look like smaller “SOIC” packaged (surface mount) integrated circuits, complete with a heavy-gauge aluminum leadframe stand. Side by side with their through-hole siblings, the new kits are exactly to scale, with half the lead pitch and a lower profile.

555SE kit for scale

The 555SE and 741SE kits each come with eight (tiny) color-coded thumbscrew binding posts that you can use to hook up wires and other connections.

You can also probe anywhere that you like in these circuits — something that you generally can’t do with the integrated circuit versions.

741SE kit close up

The new 555SE and 741SE circuit boards are black in color, with a gold finish and clear solder mask so that you can see the wiring traces between individual components. There are a few other neat details here and there, such as countersunk holes for mounting the board to the leadframe.

The surface mount components are relatively large, with 1206-sized resistors and SOT-23 sized transistors, and assembly is straightforward with our clear and comprehensive instructions. These kits are designed to be a joy to build, whether you’re an old hand at surface mount soldering, want some practice before tackling a project, or are introducing someone to it for the first time.

Family portrait

And here is the new family: XL741, the Three Fives, along with the new 741SE and 555SE.

You can find the datasheets and assembly instructions for these kits, as well as links to additional documentation, on their respective product pages.

Both new kits are part of our ongoing collaboration with Eric Schlaepfer, who we have worked with on a number of dis-integrated circuit projects including the four kits here and the MOnSter 6502.

Watch the transit of Mercury with us!

Solar telescope and binoculars set up in front of Evil Mad Scientist sign.

Tomorrow morning is the transit of Mercury, which is where the planet Mercury is visible directly in front of the sun. This won’t happen again until 2032. If you happen to be in Silicon Valley and would like to see the transit with your own eyes, please join us tomorrow morning (weather permitting—assuming that the sun is out).

What: Viewing the transit of Mercury
When: 8:30 – 10 am Monday, November 11, 2019
Where: Evil Mad Scientist, 1285 Forgewood Avenue, Sunnyvale, CA 94089

We’ll be setting up solar binoculars and a telescope with a solar filter so that we can safely watch Monday morning. It will take Mercury about 5 and a half hours to cross in front of the sun, and we’ll be watching the last hour and half. We’ll start viewing at 8:30 am until the end of the transit at about 10 am.

Linkdump: October 2019

Halloween Project Archive

Array of Halloween Projects

Looking for inspiration for your Halloween projects? Need ideas for snacks, costumes or decor? Not sure what to do with your pumpkins this year? Head over to the Halloween Project Archives for a list of our projects over the years.

Halloween is one of our favorite holidays, and … we’ve organized dozens of our Halloween projects into categories: costumespumpkinsdecor and food.

Linkdump: September 2019

Sea urchin teeth

From the mailbag: Geometry with AxiDraw

Mark from MN wrote in to say:

I persuaded my school district’s community foundation to buy an AxiDraw for me to use with my high school geometry students. It’s SO GREAT! These kiddos are seeing their 2D creations come to life because of AxiDraw, which is a great motivator for their future studies (either computers or mathematics or art or all/some of the above).

We’ve written about how AxiDraw gets used in the classroom before, and we love hearing from teachers who are using it. Thanks for the note, Mark!

Spicy Plum Chutney

Jars of chutney

I’ve been using my Plum Chutney recipe for years and enjoying every batch. Our own plum tree is now mature and producing lots of wonderful fruit each year, so I have had many opportunities to reproduce and refine my recipe. Here’s my new spicier recipe, with notes below on ingredient changes and other tips I’ve learned over the years.

Ingredients:

  • 8 cups cut up pieces of plums, pits removed, skins left on, fresh or frozen
  • 3 lemons, (optionally peeled) cut into small pieces, seeds removed
  • juice from 3 more lemons
  • 1/4 cup fresh ginger, peeled and grated (a microplane works great) or cut into matchsticks
  • 2 Tbsp cumin seeds
  • 2 sticks of cinnamon
  • 1 tsp cayenne pepper
  • 1 tsp garam masala
  • 1/4 tsp salt
  • 4 cups sugar (granulated or brown)

Throw everything except the sugar in a sauce pot and cook, stirring occasionally, until the fruit starts to soften. Add sugar and cook, stirring regularly, until it thickens to a consistency you like. You can test the consistency by putting a spoonful in a cold dish in the fridge for a few minutes. Remove cinnamon sticks after cooking. You can also follow your favorite canning procedure for longer term storage. Makes about 3-4 pints.

Fruit and spices in pot

We’ve tended toward more flavor intensity in our cooking over time, and I’ve settled on a version with twice as much spice as before. Sometimes I’ll cut the some or all of the ginger into matchsticks instead of grating it, which results in little bursts of ginger flavor when you’re eating the chutney. If you like that, by all means, use matchsticks! For a more even flavor or consistency, stick to using the microplane. I added a small amount of salt, which makes all of the flavors shine just a little bit more.

I’ve stopped adding water to my preserves. It cooks a little faster without as much liquid, and there’s enough liquid in the lemon juice to get it started cooking even if the fruit isn’t covered. I’ve also started removing the lemon peel for most of the preserves I make other than marmalade. The peel gives it a stronger lemon flavor, and keeps the pectin in the pith from gelling from as well. If you want a thicker consistency, you can leave the peel out. If you want zingier lemon flavor, leave it on.

Using potato masher to crush fruit pieces

One other consistency related tip: if I want a less chunky consistency, I use a potato masher to crush the fruit pieces early in the cooking. During fruit season, I try to preserve as much as I can by making jams and chutneys, but I usually run out of time and end up cutting up the last of the crop and freezing it. Using frozen fruit for jams seems to work just as well as fresh. The other thing I usually run out of is sugar, because I often forget how much it takes to make preserves, so I started using brown and granulated interchangeably in the chutney. I even used palm sugar once! Which sugar you use doesn’t seem to affect the flavor significantly, so use whichever you have on hand.

From plottertwitter: a first painting

Corey Haber just posted a clip of his AxiDraw finishing its first painting: