An EggBot is a compact, easy to use art robot that can draw on small spherical and egg-shaped objects. The EggBot was originally invented by motion control artist Bruce Shapiro in 1990. Since then, EggBots have been used as educational and artistic pieces in museums and workshops. We have been working with Bruce since 2010 to design and manufacture EggBot kits, and our well-known Deluxe EggBot kit is a popular favorite at makerspaces and hackerspaces around the world.
The EggBot Pro is as sturdy as can be: Its major components are all solid aluminum, CNC machined in the USA, and powder coated or anodized. (And isn’t it a beauty?)
The most common mechanical adjustments are faster with twin bicycle-style quick releases, and repositioned thumbscrews for easier access.
The frame also has an open front design that gives much better visibility while running, and greatly improved manual access when setting up.
And, it comes built, tested, and ready to use — no assembly required. Assuming that you’ve installed the software first, you can be up and printing within minutes of opening the box.
- How It’s Made: Glass Marbles
- The Pangraph, a Spirograph-inspired pancake making machine
- Some thoughts on Open Source Hardware and Kickstarter
- Handmade Asteroid Belt
- We now live in a world where clever hackers repurpose abandoned spacecraft for the public good: http://spacecraftforall.com/ (Incredible project; watch the video!)
- The Hyperlapse stabilized time lapse video technique.
- How big is Rosetta‘s comet, 67P/Churyumov–Gerasimenko? See these comparisons versus earthly monuments, and science-fiction spacecraft.
- The Feynman lectures on physics: Now free to read online.
We’ve just given the WaterColorBot a little bump up to kit version 1.5. The new version now comes with a pair of beautifully machined aluminum winches.
The winches are precision cut on CNC machines and anodized clear. We add a few extra little parts (flat-head rivets to wind the winch around, screws, and a stamped and polished stainless steel “clamp” to hold the string end), and wind them with the same “100 pound” Spectra cord as we did before.
We described the process of making and winding our older laser-cut wooden winches in our blog post about the making of the WaterColorBot, and again in our post about the winch cutting jig. For better or worse, transitioning to the new aluminum means that we’re no longer using our older wooden winches that we described in those blog posts. But in the end, these new winches are a better, more elegant solution.
WaterColorBot kit version 1.5 is now shipping from the Evil Mad Scientist Shop.
For the robotics team that we mentor (FRC team 3501), we created an “Advanced Bristlebot Competition” to serve as an off-season team building exercise. We are publishing our competition template (PDF download) here so that anyone can use it as a starting point for their own events. The goals of the competition are to provide a self-contained, resource-constrained and time-limited introduction to a robot competition environment, and to get new and continuing students working together on solving simple engineering challenges.
The competition consists of three challenges: sprint (distance time trial), mountain climbing (same, on an inclined plane), and sumo (a two-robot competition that rewards going in circles).
The group of students is split into teams of two, trying to pair new students with team veterans.
Each team is given a set of rules and a small pile of toothbrushes, motors, and batteries.
Beyond this, one table is designated for tools and supplies, and has an assortment of craft supplies including things like coffee stir sticks, wires, twist-ties, googly eyes, pipe cleaners, pom-poms, and tape. Building tools include hot glue guns, scissors, bolt cutters (for cutting the heads off of toothbrushes), and wire strippers.
After a building period, the robots are “bagged and tagged” prior to competition. For the BristleBots, this means they are placed on paper plates marked with their team number for inspection to ensure that they meet the competition requirements.
The competition takes place in two rounds, separated by an interval of building time between them. The extra time allows the students to redesign and implement changes based on what they learned during the first round of matches.
We witnessed a couple of great moments during our event. We overheard some students watching our original BristleBot video on a phone, and when they noticed us watching them, they defended themselves, saying, “The rules don’t say we can’t!”
One of the most technically inclined students on the team, after building several prototypes and studying the performance of his BristleBots on the ramp for about 10 minutes asked, “This can’t actually be done, can it?” Minutes later, a veteran student from another team, proudly set his robot on the ramp and it whizzed up in one solid go in about 10 seconds. Later, during competition, another student watched her BristleBot zoom up the ramp in 3 seconds flat, using a variation on that successful design.
Materials & Resources
- BristleBot Competition Template (PDF download): includes arena specifications, rules, suggested schedule, scoring mechanisms, and handouts.
- Vibrating Motors (from Evil Mad Scientist)
- Cheap Toothbrushes (at the Evil Mad Scientist Garage Sale)
- CR2032 coin cell batteries are available from various suppliers including Digi-Key, IKEA, and Costco
- BristleBot: A tiny directional Vibrobot
Ever since we released our Three Fives discrete 555 timer kit last year, people have been asking us “When are you going to come out with a 741 op-amp?” It has taken us quite a while to get here, but the answer is… Today!
Our XL741 Discrete Operational Amplifier is a real, working op-amp that you can build yourself. It’s a transistor-scale version of the original μA741 integrated circuit, that incredibly versatile and popular analog workhorse. As with our 555 kit, you can probe inside to see the inner workings of the circuit as it works. And, like our 555, it comes with a beautiful anodized aluminum “IC legs” stand, so it even looks great when it isn’t plugged in.
The kit was designed and developed as a collaboration with Eric Schlaepfer, and is a direct adaptation of the equivalent schematic from the original Fairchild μA741 datasheet.
If you’ve ever used operational amplifiers, you’re probably familiar with the μA741 (or colloquially, just “the 741″). Designed by Dave Fullagar and released by Fairchild in 1968, it’s the quintessential and most popular op-amp of all time. While newer op-amp designs easily outperform the μA741 in just about every possible respect (speed, noise, voltage range, and so on), the 741 remains widely beloved and in active production by multiple manufacturers even today — over 45 years later.
And, if you haven’t used an op-amp, this a great way to learn. Op-amps are simple, wonderful building blocks for making analog computers. With op-amps, you can build circuits that can (for example) add, subtract, amplify, take logarithms, perform integration, or perform other operations on your signals. Or buffer and copy them, or cleanly convert current to or from voltage, and on and on and on.
A regular op-amp is an integrated circuit; a little black box. The XL741, on the other hand, is a big black box, with a heck of a lot of points where you can can probe inside, to see what’s going on, in real time. And that’s a unique opportunity.
The XL741 is a quick, easy to build soldering kit, with through-hole components, and not too many of them. (And, have you see our awesome resistor wallets?)
And, best of all, the XL741 is in stock, and begins shipping today.
Visit our store page for links to the XL741 datasheet, assembly instructions, and additional documentation resources.
Umbrella Upcycle is a project site filled with things you can do with cast-off and broken umbrellas, including our Better Bat Costume. The project is aimed at reducing the numbers of umbrellas that end up in landfills, and they link to project tutorials, methods of recycling, and recommend places to donate both umbrellas and finished umbrella projects.
There are culturally common activities like wine and cheese tastings that explore variations of a particular theme. There are also flavor tripping parties specifically for trying out the taste bud altering miracle fruit. And there are molecular gastronomy and modernist cuisine that are intended challenge your expectations of texture and flavor. In the spirit of these kinds of experiences, we came up with a wide-ranging set of interesting (and sometimes challenging) items that can be shipped through the mail and shared between internet friends.
The goals of the project include isolating a few interesting flavors that are not normally tasted on their own, understanding a bit about the ways that shape and texture affect flavor, and play a bit with some of the available “mouth altering” spices and flavors.
Most of the items we included in our tasting kit are from Indian or asian grocery stores. For herbs and spices, getting them from a shop with high turnover will help in obtaining fresher spices that are more full of flavor. They’re also likely to be less expensive at places that expect larger quantities of spices to be used in foods (we’ve written about this before). Ethnic groceries are better at this than mainstream ones, and places with bulk bins can be just about the worst. A few items we shopped for online, and a couple came from our garden.
For tasting order, we opted to start with more subtle flavors and end with mouth-altering ones. Our general itinerary was divided into four parts: flavors & scents, shapes, adventures, and light.
Of special note: many people are sensitive to particular (and sometimes esoteric) food items. Be sure you have discussed food allergies with all participants before plying them with unknown ingredients. Decide if you want to try things before announcing what they are. Have water and neutral flavored crackers or bread for cleansing the palette between flavors as needed or desired.
One of the joys of life is introducing people to new flavors and textures that you love, whether they are from your own kitchen or your favorite restaurant. Every so often, that will backfire, when someone ends up not liking your beloved dish. But sometimes you’ll see that “eureka” moment when someone lights up from the new experience. Eating involves many kinds of sense perception, including smell, taste, texture, temperature, and sight.
Part one: Flavors & Scents
- Fenugreek Leaf (Methi): fenugreek has an aroma reminiscent of maple syrup and is one of the magic ingredients in tandoori marinades. Crumbling dry herbs in your fingers will help release aromas.
- Makrut (Kaffir) Lime Leaf: a crucial ingredient in many Thai curry pastes and soups. This double-lobed citrus leaf is available fresh at many asian groceries, and we’ve written about it before.
- Curry Leaf: used in south Indian cuisine, such as the soups you find at dosa shops. We have a little curry tree, but leaves can be obtained fresh at Indian groceries.
- Ajwain: spicy, somewhat reminiscent of thyme or oregano. Also from Indian cuisines and spice blends.
- Saffron: always used in very small amounts due to its potency and expense. Almost never tasted alone.
- Chat (Chaat) Masala: used primarily on Indian snack foods. Key spices include black salt, mango powder, cumin and asafoetida. Try it on some fresh fruit.
- Black Salt: very sulfurous pink colored salt mined from the Himalayas.
- Truffle Salt: an excellent way to experience the heady aroma of truffles. Try sprinkling it on vanilla ice cream.
Part two: Shapes
- Sugar Crystals: these large (~1/4 inch) sugar crystals are available at Indian and middle-eastern markets, sometimes labeled as “sugar cubes” despite their elegant shapes. They don’t seem as sweet as granulated sugar because of the low surface area to volume ratio.
- Salt Flakes (hopper crystals): because of the huge surface area, these taste even saltier than granulated salt. Great for when you want to have lots of salt flavor and are sprinkling on a surface that will not dissolve the salt. Trader Joe’s is selling small containers with huge crystals. Alternately, Maldon Sea Salt Flakes are large enough to see the crystal structure.
- Shredded Red Pepper: we came across these dried pepper threads at a Korean grocery store and have been garnishing our soups with them ever since. They’re preserved with salt and rehydrate to show the cross section from the center of the fruit to the skin.They’re beautiful and spicy, but not as spicy as red pepper powder because of the difference in surface area.
Part three: Adventures
- Citric Acid: we found large granules of this at an Indian market. One big granule is enough to make just about anyone pucker. This is the full-strength version of the powder that is used to make sour candies sour.
- Sichuan Pepper (Prickly Ash, Wild Peppercorn): one of the components (hydroxy-alpha-sanshool) triggers an anesthetic reaction. After chewing on a couple of these husks, your tongue will go numb and tingly. It increases your ability to eat super spicy foods, and has been described to us as “a party in your mouth.” We’ve also seen very panicked faces of people who just wanted the sensation to stop. Some people don’t seem to be as sensitive to it, or perhaps didn’t get very active pieces, and they usually find the lemony flavor to be pleasant.
- Super Soda Gum: we discovered this great bubble gum through the Candy Japan subscription service and we now purchase it at our local Japanese grocery store. It has a powerful punch of fizzy powder inside, which makes your mouth foam up like crazy. It is awesome good fun, and it seemed to help the sichuan pepper effect to subside. Even after the excitement from the foam settles down, it is really good quality gum.
- Miracle Fruit Tablets: we got these tablets from Amazon. They’re a little bit expensive, but the miraculin binds to sweet receptors on the tongue, making sour foods seem sweet. The berries are also available, but are more expensive, and harder to get shipped.
- Citric Acid (again): after dosing with the miracle fruit, citric acid tastes like candy. Be careful, or you’ll inadvertently eat a lot of highly acidic food because it is so fun. Try other sour foods like lemon, lime, grapefruit, vinegar, and tamarind.
Part four: Light
- Wint-O-Green Lifesavers: sugar crystals are a triboluminescent material, meaning that when you crush them, they emit light. However, they emit ultraviolet light, and so we don’t normally get to see the effect. Wintergreen oil fluoresces blue, so eating wintergreen flavored candies in the dark in front of a mirror or with friends will let you see it. Go into a very dark room. Wait until your eyes are accustomed to the dark. Bite the mints with your teeth to crack them to see the glow.
- Asafoetida (Hing): a very powerful garlic and onion substitute from Indian cuisine.
- Seaweed: for someone who hasn’t been exposed to the flavor of dried seaweed, it can be a shock.
- Dried Sumac: a sour fruit used in the spice blend za’atar along with sesame seeds and dried herbs.
- Tamarind: a sour fruit that is less well known in mainstream American cuisine, but can be found in many familiar sauces (even some Worcestershire sauces). Commonly available as a paste or as pulp.
- Other less common fruits, such as dragon fruit, soursop, jackfruit, and durian.
- Fresh vs. freeze dried vs. canned textures and flavors.
- From our group came the suggestion to create a flavor symphony, walking through various movements of flavor rather than isolating each one. It could be interesting to add more familiar herbs like mint, thyme, and rosemary to the mix.
An exploration like this is fairly simple to lead when everyone is in the same place, but can also be done remotely. We packaged up our ingredients into little bags and tucked them into plastic organizer boxes (commonly available from the dollar store) to conceal the contents until the right moment.
The list above is strongly influenced by our personal experiences and cooking preferences. Depending on your background, things we find exotic may seem perfectly normal. It is interesting to see which ingredients stir up memories from the participants, and which are new to them as well. If you come up with other ideas, we’d love to hear about them!