Tag Archives: larson scanner

Larson Scanner modding


Anton wrote in to ask:

I want to purchase your Larson Scanner kit but need to be able to run it from household current … is there a converter that you would recommend?

Since the Larson Scanner normally runs from 3 V DC, a regulated 3 V power supply can be hooked up in place of the 2xAA battery box. However, 5 V power supplies (like this one) are much more common, and the circuit can be run from 5 V with only minor changes. if you replace the nine 16 ohm resistors in the Larson Scanner kit with 120 – 150 ohm resistors, you can power it from 5 V directly.

Another related question we occasionally get is how to run the Larson Scanner with green LEDs. (Note: by green, we mean “pure” green LEDs which have a forward voltage of about 3 V. Older style yellow-green LEDs with a forward voltage of ~2 V can be used as drop-in replacements for the red ones.) 

If running off of battery will work for you, this is an even simpler change: merely replace the 3 V battery holder with a 4.5 V one, such as a 3xAA. It is a happy coincidence that the circuit can run with red LEDs at 3 V or green LEDs at 4.5 V using the same 16 ohm resistor value. So how about running a green Larson Scanner from a 5 V power supply? Replace the nine 16 ohm resistors with 39 ohm resistors and you should be good to go.

You can find the documentation for the Larson Scanner and more stories about modding it on our wiki. We’d love to hear about any mods you do to the Larson Scanner in the comments or see pictures in the flickr pool.


Red Eye

Andrew Probert, the designer of the Cylons for the original Battlestar Galactica TV series, wrote to say:

Years later, now, I just was made aware of this great pumpkin idea of yours and wanted to thank you personally for keeping my toaster ‘alive’ in a fun new way… this is SO cool.

Our Cylon Jack-O-Lantern project and Larson Scanner kits are carrying on the tradition!

Field Trips: Atmel Headquarters


Super Awesome Sylvia and I were invited to attend Bring Your Kids to Work Day at Atmel recently. (Atmel, of course, is the company that makes the microcontrollers found inside Arduino products and in many of our own projects and kits.) We were there to help provide tangible, interesting, and playful examples of how Atmel chips can be used. And of course, we weren’t going to miss an opportunity to visit Atmel headquarters!

Photo courtesy of Atmel

The biggest hit with the kids were the Octolively interactive LED modules (sporting the Atmel ATmega164P). When the kids waved their hands over them, the LEDs would light up and ripple. Some of the kids would start out by poking and grabbing at the LEDs until they lit up, but as soon as I told them it would work “even without touching it” their eyes would get big, and they’d wave their hands over the top, enthralled.

Some of the other things we brought were our handheld game, the Meggy Jr RGB (with the ATmega328P); a Bulbdial Clock (Atmega328P again), which points rings of LEDs at different heights down at a central point to create shadow hands of different lengths; our giant Alpha Clock Five (ATMega644A); and the Larson Scanner (ATtiny2313A), which lights up nine red LEDs to make a scanning robot eye.

Photo courtesy of Atmel

Another project that captured the kids’ attention was a Keepon by BeatBots. Other demonstrations included a quadcopter and a hacked hexabot.

Photo courtesy of Atmel

We got to have lunch in the bright sun in the courtyard with Avary Kent, who was demonstrating the PuzzleBox, a brain-controlled helicopter.

Photo courtesy of Atmel

Sylvia got to give the PuzzleBox a try, triggering it to fly as soon as she concentrated hard enough.


After lunch, we got to tour of a couple of labs. This workbench was well stocked with a Metcal soldering iron (our favorite) and lots of tools and supplies.


Apparently the poor Pleo on this bench needed some repair.

Chip testing machine

This machine is for inspecting and testing chips after they have been removed from their housing.

We got to go into the RF anechoic chamber, and watch as our cell phones stopped receiving any signals.

Horsing around

We also had some time to hang out and horse around with friends new and old. Our friend Paul Rako seemed to be having as much fun as the kids.

Photo courtesy of Atmel

Thanks to Paul and Atmel for inviting us to visit!

Halloween Projects from Evil Mad Scientist Laboratories

The Great Evil Mad Scientist Laboratories Halloween Project Archive!

Halloween is one of our favorite holidays, and our collection of Halloween projects continues to grow. Every fall we update it to include our latest projects for the season. In the list that follows, we’ve organized dozens of our Halloween projects into categories: costumes, pumpkins, decor and food.

Continue reading Halloween Projects from Evil Mad Scientist Laboratories

A new Kraftwerk-inspired LED tie kit?

LED Tie - 28.jpg

Well, almost— With a breath of new firmware, our Larson Scanner kit takes us on a trip to the late 1970’s.

In the old videos of electronic music pioneers Kraftwerk performing their classic The Robots, a prominent prop is the animated LED necktie worn by each member of the band. If you haven’t seen this, or it’s been a while, you can see it right here at YouTube. (Additional viewing, if you’re so inclined: Die Roboter, the German version.)

The Kraftwerk tie has nine red LEDs in a vertical row, and one lights up after the one above it in a simple descending pattern. And what does it say to the world? One thing only, loud and clear: “We are the robots.” Now, if you’re anything like us, the most important question going through your head at this point is something along the lines of “why am I not wearing a tie like that right now?


The good news is that it’s actually easy to make one. And the starting point? A circuit with nine red LEDs and just the right spacing: our open-source Larson Scanner kit. With minor modifications– a software change and dumping the heavy 2xAA battery pack–it makes a pretty awesome tie. In what follows, we’ll show you how to build your own, complete with video.

Continue reading A new Kraftwerk-inspired LED tie kit?

Cylon Snow Plow

johngineer posted this Cylon Snow Plow video and writes:

    “Took the EMSL Larson Scanner I got at the Open Hardware Summit, and stuck it on my dad’s snowplow-equipped John Deere. It fits perfectly! Good times. I need to get a few more of these kits for the snowblower and the Kubota — they are incredibly well made.

    Get the Larson Scanner kit at evilmadscience.com/tinykitlist/152-scanner

    Sorry for the shaky video — I shot it with my phone, and I was shivering.”

The Expandable Larson Scanner!

Three Units

“The Larson Scanner rocks, but it’s too short!”

“How can we expand the Larson Scanner?”

“Can you link multiple Larson Scanners together?”

These are just some of the questions that I have asked about the Larson Scanner.
And now, there’s an answer, in my first guest blog post here on Evil Mad Scientist Laboratories!

Continue reading The Expandable Larson Scanner!

Larson Scanner Review

Justin over at WyoInnovations writes:

“My 14 year old daughter put together the Larson Scanner Kit offered by the Evil Mad Science Laboratories (EMSL). We have put together quite a few soldering kits around here and this one is, simply put, the best “learn-to-solder” kit I’ve ever come across.”

Thanks, Justin!

Kits are in stock over at the Evil Mad Science store, just in time for Halloween!

Evil Mad Scientist Laboratories: Year 4

The Larson Scanner Kit

Today we’re releasing a new open-source project and kit, which is an updated approach to the “Larson Scanner.” The Larson scanner is named in honor of Glen A. Larson, the man responsible for producing both the original Battlestar Galactica and Knight Rider television shows, and consists of a set of red LEDs that scan back and forth.

Three years ago, we showed how to make a Cylon Jack-O-Lantern, in what has become one of our all-time most popular tutorials. The circuit for that project was based on a 555 timer, driving a 4017 decade counter, and has 6 pixels of resolution. To create the incandescent fading effect, we added low-pass transistor drivers. We also wrote up a version of that article for the 2007 Make Magazine Halloween special, which included a slightly nicer version of that same circuit.

And while it’s been popular, we’ve always had some nagging reservations about it, and in particular its battery life. This year, we decided to do something about it and made a much betterversion of the Larson Scanner, and so here it is:

Continue reading The Larson Scanner Kit