Hackaday Tours Northrop: Space Telescopes and Jet Planes

I was invited to tour the Northrop Grumman Aerospace Systems campus in Los Angeles this spring and it was fantastic! The Northrop Grumman lists themselves as “a leading global security company” but the project that stole my heart is their work on the James Webb Space Telescope (JWST) for NASA. On the one hand, I don’t see how it could possibly be pulled off as the telescope seems to cram every hard engineering challenge you can think of into one project. On the other hand, Northrop (plus NASA and all of their subcontractors) has been doing tough stuff for a very long time.

How Do You Tour Northrop Grumman?

This opportunity fell in my lap since [Tony Long] is a Hackaday reader and an engineer at Northrop. He’s the founder of their FabLab (which I’ll talk about a bit later) and was so bold as to send an email asking if one of the crew would like to stop by. Yes Please!

I was already headed out to the Supplyframe offices (Hackaday’s parent company) in Pasadena. [Tony] offered to pick me up at LAX and away we went to Redondo Beach, California for an afternoon adventure.

James Webb Space Telescope: Everything Hard About Engineering

James Webb Space Telescope (JWST)

I had heard of the James Webb Space Telescope (JWST) but had never looked closely at the particulars of the project. Above you can see a scale model which Northrop built. I didn’t actually see this on my tour. It travels to different places, taking two semi trucks, with a dozen people spending four days to set it up each time. And that’s a not-real, relegated to the surface of the planet, item. What is it going to take to put the real one into space?

It’s not just going into space. It’s going to the second Lagrangian point. This is past the moon, about 1.5 million kilometers from the earth. If this thing breaks we can’t go out there and fix it. There’s a lot of pressure for success.

The main problem facing this satellite is heat. It will use a mirror array to harvest infrared radiation from very distant astronomical bodies. For this to happen it needs to have a very good optical array to gather infrared light and focus it on a collector, and it must be isolated from the heat of the sun, earth, and moon.

There is an array of 18 hexagonal mirrors which reflect the infrared onto a collecting mirror and in turn to the sensors. These mirrors are not made by Northrop, but they did have a prototype on display and it was incredible! Each mirror is made by Ball Aerospace out of beryllium. The concave surface is coated in gold for reflectivity and an actuator mounted on the back of each mirror can flex the surface to adjust the concavity and thereby the focal length. This is in addition to the ability to adjust the roll and pitch of each segment.

In the Northrop high bay they were working on the mounting system for these mirrors. It showed much more progress than the two images seen above. This is the central mount structure for the optics. The width of this structure is dictated by the size of the rocket which will launch it into space. When I saw it, folding wings had been added to either side of this main structure to host a dual-row of mirrors which are folded back into the telescopes during its storage position. The black material itself is a composite manufactured by Northrop. The cross-section they showed as an example was not much thicker than your fingernail but obviously quite rigid in the cast pipe shape.

You can see an animation of the unfolding process which was playing in the high-bay viewing room during the tour. Note the five-layer heat shield that needs to automatically unfold without snagging. This reminds me of [Ed van Cise’s] recollection of solar panel unfolding issues on the ISS. It’s a tough problem and it looks like much time has been spend making sure this design learns from past issues. That animation doesn’t show too many details about the mirror mechanics. I found video demonstrating how the mechanical part of the mirrors work to be quite interesting.

Learning more about what goes into the James Webb Space Telescope project is worth a lot of your time. I’m not joking about this including everything hard about engineering. The challenges involved in meeting the specification of this telescope are jaw-dropping and I’m certain the people working on the project across many different companies will make this happen.

Hackerspace Driving Corporate Culture


It was nice that [Tony] and his colleague [Adam] came right out and told me they reached out to Hackaday because they want to get the message out that Northrop is rejuvenating their corporate culture. They’re in the process of hiring thousands of engineers and part of this process is making the job fit with the lifestyle that these engineers want.

One big move in this direction is the formation of their FabLab. [Tony] is an engineer but 50% of his workload is tending to the FabLab. This is basically a hackerspace open to any of the roughly 20k employees at this particular location. Northrop fabricates amazing things, and when equipment is no longer used, the FabLab gets dibs on it. Imagine the possibilities!

unexploded-armament-removalPart of this initiative is to get more engineers learning about the fabrication process. [Tony] used the example of researching by fabricating a simple proof-of-concept in the FabLab. This is an avenue to that buzzword: fail-fast. Before getting your department on board with what might be a costly and time-consuming project you can test out some of the parts which are a little hazy in your mind.

The device seen here is the product of a challenge that one of the groups participated in last year. They had about six months to develop a robot which can clear unexploded armaments. It was hanging out in one part of the hackerspace and is a great build. You can just make out a blue sphere hiding in the underbody. That’s a huge jamming gripper powered by the black and yellow shop-vac perched atop the chassis. The robot is remote controlled, with wireless GoPro cameras mounted all around and underneath. Of course the thing wouldn’t be complete without a giant silver air-horn. Safety first!

It will be interesting to see if the FabLab can build the kind of grass-roots community often associated with standalone hackerspaces. You can get a glimpse at the grand opening of the space in this video. We don’t quite remember seeing a hackerspace marketed in this manner. But if that’s what it takes to get the company on board it’s well worth it. A huge space, amazing tools, and no monthly membership fee make for a sweet deal. Oh, and the name FabLab apparently came from their mascot, the Fabulous Labrador, who can be seen in the clip wearing a string of pearls.

F/18 Assembly Plant


We wrapped up the day by touring the F/A 18 E/F Super Hornet assembly line. This is a huge plant. I don’t know how to better describe the sheer size of the assembly line than saying it took no less than twenty minutes to walk back to the parking lot at the end of this tour.

00036301Northrop Grumman serves as the principal subcontractor for Boeing on this project, so the end of the line isn’t quite a fully assembled airplane. But the fuselage — less cockpit, nose, wings, and engines — is still a formidable sight. I’ve never been this close to a fighter jet before and the size is impressive. Equally impressive is the building housing the line, which was build in 1942 and is still wood-framed to this day. They have huge engineered columns which have since been reinforced with steel. But that fact makes it no-less impressive.

The top concern during assembly is FOD, or Foreign Object Detection. These vehicles are exposed to huge forces and vibrations that will shake anything that’s not supposed to be there loose, and that can mean horrible damage to an expensive machine or much worse. Some of the things I found really interesting were the systems in place to make sure no part goes missing. All components come in cases that have an individual cutout area for each. Tools are scanned to each employee, if broken or worn out there are vending machines throughout the plant keeping track of them through a computerized system.

As part of the tour we walked through the composites plant next door. There are massive autoclaves for curing the resins. These are like a pipe sitting on its side with hemispherical doors on each end. I’m a poor judge of time and distance but I’d estimate these to be 18 feet in diameter and at least 35 feet long. Traditional composite fabrication — a worker laying down sheets of carbon-fiber on a mold — were under way. But the room next door housed a robot that looked like it was born in The Matrix. The spider-like head works next to a turning mandrel fitted with the form of the piece being fabricated. It lays out about seven strands of carbon fiber, building up a part that has no seams whatsoever. After curing the resin the mold is removed manually, piece by piece, from the inside of the part. To me the parts being built looked like air intake channels approximately 15 feet long and maybe 5 feet in diameter, although they were winding and not exactly cylindrical in shape. I wasn’t able to get very many details about them, but I was told these parts are for the F-35 Joint Strike Fighter. This is another subcontract Northrop Grumman has for Lockheed Martin.


Thank you to [Tony Long] and [Adam Gross] for spending to give Hackaday this tour. I had the impression that I was living an episode of one of my favorite programs How It’s Made, and that was awesome! Northrop Grumman has an educational outreach program so if you’re associated with a school in the area set up a tour of the JWST!

[Tony] ducked out with me for dinner; some excellent tacos — a quest I’ve been on during each visit to LA. He joined me afterward on a trip to Null Space Labs for their open night. They had moved since the last time I was there and if you’re in town you should check it out.


One thing I should mention is that I was not able to take any photographs on the premises. My story above is original but all the photos are stock or provided by Northrop at my request.

Main Post Image via JWST Flickr

Front Mirror via YouTube thumb.

Extended Reflection Mirror via YouTube video.

VCF East X: The Quarternet Steering Committee

Today was the first day of the Vintage Computer Festival East X. As is the tradition, the first day was packed with talks and classes about various retrocomputing ephemera, with this year featuring a great talk from [David Riley] about 8-bit computer music, a class on system architecture from our own [Bil Herd] (video coming soon), and a talk about vintage teletypes. One of these talks was about creating new hardware: [Jim Brain]’s steering committee on a networking solution for vintage microcontrollers. It’s called Quarternet: a two-bit solution for an eight bit world.

While minicomputers are easily networkable, designed around multi-user operating systems, and have the hardware for a lot of networking hardware, 8-bit micros are the exact opposite. That doesn’t mean 8-bitters don’t have networking; you can get an Ethernet cart for a C64, and just about everything can connect to a BBS. [Jim]’s talk was about whittling down the use cases for the Quarternet to something that could be implemented easily, but still give the most capability.

During the talk, the audience settled on using a serial connection from the micro to the outside world; this makes sense, as everything has a serial port. A ‘lightweight API’ was suggested to take up the software side of the problem, but there wasn’t much agreement over what that API would actually do.

[Jim]’s idea is for a box that plugs into the serial port of any old microcomputer and would connect to the Internet somehow. Ethernet, WiFi, or even a modem isn’t out of the question here. That takes care of connecting to the Internet, but there’s also the question of the cooler side of networking – network drives, file sharing, and the like.

For this, [Jim] is imagining a box with a serial port on one end, and a network port on the other. In the middle would be a cartridge slot for any hardware imaginable. If you want to plug in an Apple II disk drive, just insert the right cartridge and you’re good to go. If you need network access to a Commodore 1541 drive, just insert another cartridge, and it’ll just work.

It’s an interesting idea, but [Jim] is really interested in getting even more feedback for a networking system for old microcomputers. If you have any ideas, leave a note for him in the comments.

RadioShack Demise Could Signal the Rise of Mom-and-Pop

No matter how you feel about RadioShack, for many hackers it was the one place that components could be sourced locally. Upon hearing that the stores are being shuttered (at least for those seeking non-cellphone items) we wondered if someone would rise to meet the maker market. The answer may actually be mom-and-pops — independent stores owned by people passionate about hacking and making.

tinker-and-twist-boothAt SXSW Create in March the Hackaday booth was right next door one such establishment. [Martin Bogomolni] is hard at work launching his brick and mortar store called Tinker & Twist. In the video below he speaks briefly about the concept of the store, which focuses on curating the best products and tools available and stocking them locally.

The store will be located in a shopping mall in Austin, Texas. But it takes about 100 days launch a storefront considering the permits and build-out. [Martin] decided to take the store to the hackers by exhibiting (and selling products) at SXSW Create. How else would you do this than by building a store-front as your booth? The store’s sign was CNC routed from rigid foam, and combined with a set of columns and storefront window. We stopped by late on the last day of the event and they had been having a great weekend. What started as a very well stocked set of shelves looked nearly bare.

Tinker & Twist is just the most recent in a growing trend of standalone stores focusing on hackers and makers. Our friends at Deezmaker in Pasadena, CA gave us tour last year. They’ve married the concepts of hackerspace, small-run manufacturer (in the form of their 3D printers), and retail store all-in-one. These types of examples make us quite happy — it’s been years since RadioShack was tightly focused on those actually building things. We hope to see more stores like Tinker & Twist up and running to support and enhance hacker communities everywhere.

Where 3000MPG+ Cars Come To Compete: The Ecomarathon

Every year teams from around the world come together for the Ecomarathon, an event (ironically put on by Shell) that tasks teams from high schools and universities with creating energy-efficient electric, gas, and hybrid vehicles. This year’s competition was held in Detroit, so I headed over to check it out.

vehicle-blurThe event has two categories that vehicles compete in: prototype vehicles that compete for the highest fuel efficiency and “urban concept” vehicles that are more focused on normal driving environments and look slightly closer to street-legal vehicles. Cars in both categories can be fully electric or powered by gas, diesel, compressed natural gas, or other alternative fuels. Vehicles drive around a 0.9 mile track that weaves through downtown Detroit and the efficiency of each vehicle is measured as they complete a fixed number of laps around the track.

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Time for the Prize: Urban Gardening and Living off the Land

What kind of impact does growing your own food have on the world’s resources? Jump aboard for a little thought exercise on this week’s Time for the Prize challenge to brainstorm urban gardening and living off the land.

We figure for any kind of meaningful impact there would need to be wide-spread adoption of people growing at least some of their own food locally. This means making the process fun and easy, a challenge well suited for 2015 Hackaday Prize entries. Write down your ideas as a project on Hackaday.io, tag it 2015HackadayPrize and you could win this week’s prizes which are listed below.

Space, Information, and Automation

urban-gardening-thumbTo get rolling, we started thinking about three things that are needed to convince people to grow their own food or live off the land.

First up, you need space to grow. This has been the subject of a number of urban farming hacks like the one seen here which uses downspouts as a vertical garden apparatus. Openings are cut into the front of the tubes, which are each hanging from a PVC rack. Each opening hosts a plant, holding them where they have access to sunlight, while taking up very little space on a sunny balcony or sidewalk.

The concept also includes a bit of automation. It’s a hydroponic garden and simple sensors and controllers handle the water circulation while providing feedback for the gardener through a smartphone app. We think the technology of the system is one way to attract people who would otherwise not take up seed and trowel.

For those new to taking care of plants the other thing to consider is information. Not only does the sensor network need to monitor the system, but something valuable needs to be done with the data. Perhaps someone has an idea for city-wide aggregate data which will look at successes from one urban garden and make suggestions to another?

This is your time to shine. Get those ideas flowing and post them as your entry for the Hackaday Prize. Even if you don’t see the build through the idea can still help someone else make the leap to greatness in their own brainstorming.

This Week’s Prizes


We’ll be picking three of the best ideas based on their potential to help alleviate a wide-ranging problem, the innovation shown by the concept, and its feasibility. First place will receive an RGB Shades Kit. Second place will receive a GoodFET42 JTAG programmer and debugger. Third place will receive a Hackaday CRT Android tee.

The 2015 Hackaday Prize is sponsored by:

Peripherals Behind The Iron Curtain

The article Home Computers Behind the Iron Curtain sparked a lot of interest, which made me very happy. Therefore, I decided to introduce more computer curiosities from the Iron Curtain period, especially from the former Czechoslovakia (CSSR).

As I mentioned in the previous article, the lack of spare parts, literature and technology in Czechoslovakia forced geeks to solve it themselves: by improvisation and what we would today call “hacking.”  Hobbyist projects of one person or a small party was eventually taken over by a state-owned enterprise, which then began to manufacture and deliver to stores with some minor modifications. These projects most often involved a variety of peripherals that could only be found in the Czechoslovakia with great difficulty.

Much like the production of components, the production of peripherals was also distributed throughout the eastern block so that each country was specializing in certain types of peripherals. For example, East Germany produced matrix printers, and Bulgaria made floppy disks drives. This meant industrial enterprises had to wait for vital computer parts, because the production in another country was not sufficient to cover even the local requirements, let alone the home user.

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Logic Noise: More CMOS Cowbell!

Logic Noise is an exploration of building raw synthesizers with CMOS logic chips. This session, we’ll tackle things like bells, gongs, cymbals and yes, cowbells that have a high degree of non-harmonically related content in them.

Metallic Sounds: The XOR

I use the term “Non-harmonic” in the sense that the frequencies that compose the sound aren’t even integer multiples of some fundamental pitch as is the case with a guitar string or even our square waves. To make these metallic sounds, we’re going to need to mess things up a little bit, and the logic function we’re introducing today to do it is the exclusive-or (XOR).

An XOR logic gate has two inputs and it outputs a high voltage when one, and only one, of its inputs is at the high voltage level. When both inputs are low or both inputs are high, the output of the XOR is low. How does this help us in our quest for non-harmonic content? It turns out that the XOR logic function is the digital version of a frequency mixer. (Radio freaks, take note!)

Ideal frequency mixers take two input frequencies and output the sum and difference of the two input frequencies. If you pipe in 155 Hz and 200 Hz, for example, you’ll get out the difference at 45 Hz and the sum at 355 Hz.

Because we’re using square waves and an XOR instead of an ideal mixer, we’ll also get other bizarre values like 2*155 – 200 = 110 Hz and 2*200 – 155 = 245 Hz, etc. All said, the point is that we get out a bunch of frequencies that aren’t evenly divisible by one another, and this can make for good metallic sounds. (And Dalek voices, for what it’s worth.)

The 4070: Quad XOR


Which brings us to our logic chip du jour. The 4070 is another 14-pin wonder, just like the 40106 and the 4069UB and the power and ground pins are in the same places. Since an XOR gate is a three-pin deal, with two inputs and one output, only four XORs fit on the 14-pin chip instead of six inverters.

By now, you’re entirely used to the 4000-series logic chips, so there’s not much more to say. This is a great chip to add sonic mayhem very easily to your projects.

Frequency Modulation with XOR: More Cowbell!

Let’s make some metallic noise. The first step is to mix two oscillators together. Whip up two variable-frequency oscillators on the 40106 as we’ve done now each time, and have a listen to each individually. Now connect each output to the inputs of one gate of an XOR in the 4070. As promised, the resulting waveform is a lot more complex than either of the two inputs.

Now tune them around against each other and listen to all the strange frequency components created as the sums and differences slide in and out. Cool, no? Here’s a bonus video that you can skip, but that demonstrates what’s going on with the frequency mixing.

Two-diode VCA

After a couple of minutes playing around, you’ll start to realize that this sounds nothing like a cowbell. We’ll need to shape the volume of the sound in time to get anywhere, and this means another step in the direction of “traditional” synthesizers. We’ll build up a ghetto voltage-controlled amplifier (VCA) and drive it with the world’s simplest envelope generator.

An active VCA takes its input signal and either amplifies or attenuates it depending on the control voltage (CV) applied on another input. When the control voltage is high, more of the sound gets through, and when the CV is zero, the output is ideally silent. Building a general-purpose VCA is a bit out of scope for our needs, so let’s just cobble something together with a few diodes.

This circuit works by cheating, and works best with digital logic signals like what we’ve got. When the input from the XOR is low, diode D1 conducts in its forward direction and all of the control voltage signal is “eaten up”, sunk into the output of the XOR chip.

Conversely, when the XOR is high, diode D1 is reverse-biased and blocks the CV, leaving it nowhere to go except through diode D2 and out to our amplifier. The resistor needs to be large enough that the XOR can sink all of its current, but otherwise the size is non-critical.

cap_square_to_pulesNotice what’s happened here. The voltage at the output is no longer the GND to VCC of our logic circuit, but instead ranges only from GND to the control voltage (minus a diode drop). So if we want to make a quieter version of the XOR input, we just lower the control voltage. It’s a simple voltage controlled attenuator. Now we just need to create a voltage signal that’s got something like the amplitude contour of a cowbell.

Remember how we converted square waves into trigger pulses by adding a series capacitor? The resulting voltage had this steep rise and exponential trail-off.

If we add in another capacitor, we can lengthen out the decay. And then while we’re at it, we can add in a potentiometer to control the rate of that decay.


Capacitor C1 converts the square wave into a pulse and charges up C2 very quickly, applying the positive voltage to the input of our VCA. The charge on C2 drains out through the variable decay potentiometer.

This simple circuit actually works well, but has one shortcoming. For long decay times, as illustrated above, the decay gets cut off when the control square wave goes low. If you only want short percussive hits, the simple circuit is enough. If you’d also like longer decays, you’ll need to add a couple diodes to chop off the negative part of the control voltage spikes.


Now that only periodic positive spikes are getting though to our decay capacitor, we have a nice variable-rate exponential decay voltage envelope. Here’s how it looks on the scope (with some extra capacitance slowing down the attack — envelope_with_xor_drumit might have been connected to the laptop soundcard). You can clearly see the control-voltage envelope chopped up by the diode action and the XOR’s output.

Putting the XOR frequency-modulated sounds through the two-diode VCA that’s driven by our quick and dirty envelope generator gets us a percussive metal sound.  But it it cowbell?  We still have to tune the oscillators up.

The classic, love-it-or-hate-it, cowbell sound of the 1980’s has to be the Roland TR-808. And if you look through the 808 service manual (PDF download) you’ll see that it uses two square waves from a 40106 chip simply mixed together. We’re improving on that by XORing, but we can still learn a bit from Roland. In particular, they tune their oscillators to 540 Hz and 800 Hz.

Because we’re XORing two oscillators together, our peaks come in at the sum and difference frequencies. This means that we’ve got to solve X + Y = 800 and X – Y = 540. Grab pencil and paper, or just believe me that you’ll want to tune up the individual square wave oscillators to 130 and 670 Hz respectively. At least, to get something like that classic cheesy cowbell sound.

Amplification Aside

We’ve been trying to stick to the use of purely CMOS logic chips here, but this session we broke down and used a transistor. The reason is that the audio input on our laptop insists on a bipolar, centered audio signal. In contrast, the output of our “VCA” sits mainly at zero volts with very short peaks up around one volt. The input capacitor in the laptop is charging up and blocking the VCA’s diode output. Boo!

Indeed, we can’t use our old tricks with the 4069UB as an amplifier here either. The 4069UB works great for signals that are centered around the mid-rail voltage, but distorts near either GND or VCC. Unfortunately, we’d like our quiet drum sounds to taper off to zero volts rather than the mid-rail, so we’ll have to use something else to buffer our audio with.


The solution is to buffer the output with something suited to this unipolar signal, and the simplest solution is a plain-vanilla NPN transistor hooked up as a common-emitter amplifier common-collector amplifier. This configuration is a very useful analog buffer circuit; it puts out almost the same voltage as the input, but draws directly from the VCC rail and will certainly handle any sound card’s input capacitor. We used a 2N3904, but a 2N2222 or BC548 or whatever will work just fine.


Cymbals and similar metallic percussion instruments were pretty tricky to synthesize in the early days of drum machines. Until the LinnDrum introduced sampled cymbals, most just used a shaped burst of white noise. The aforementioned TR-808 used six 40106 oscillators linearly mixed together to approximate white noise. Again, we’ll improve on that by running it all through XORs with the result being somewhere between many oscillators and pure noise depending on how you set the oscillators up.

The inspiration for this circuit is the fantastic Synbal project (schematic in PDF) from “Electronics & Music Maker” magazine in 1983. It’s a much more complicated affair than what we’re doing here, but if you look at the left-hand side of the schematic, that’s the core. (If you’re copying the Synbal’s fixed frequencies for the oscillators, note that he uses 0.01 uF capacitors and we use 0.1 uF caps. Divide the feedback resistors by ten accordingly.)

cymbals.schThe trick to the cymbal circuit is making a lot of oscillators. We’ll hook up six of them, finally fully fill our 40106 chip. Then combine any pair in an XOR, take the output of that XOR and combine it with another oscillator. You’ve now got a complex oscillator that’s used up three 40106 oscillators and two XOR gates. Repeat this with the remaining oscillators and XOR gates and you’re nearly done. Connect the final two XOR outs through resistors to the output.

As with the cowbell circuit, this circuit can be made to sound “realistic” by picking the different component frequencies just right and tweaking the decay. We think that it makes a pretty decent hi-hat sound with a couple of the oscillators pitched high (1 kHz and up). On the other hand, if you’re into noise music you can skip the VCA altogether and tune the oscillators to similar, low frequencies. You get a vaguely metallic, almost rhythmic machine drone. Not to be missed.


We’ve snuck it in under the guise of making a cowbell sound, but the quick-and-dirty VCA here is also useful for modulating most of the synth voices we made in the first few sessions. We went for a percussive attack by using a capacitor to couple the driving square wave to the VCA, but there’s no reason not to use a variable resistor in its place to charge up the capacitor more slowly. If you do this, note that the attack and decay potentiometers will interact, so it’s a little quirky, but what do you want for two diodes anyway? Also note that any other way you can think of delivering an interesting voltage to the junction of the two diodes is fair game.

The XOR-as-frequency-mixer technique is pretty great, but you can also get a lot of mileage by using the XOR as a logic chip. Combining different divided-down clock outputs (from a 4040, say) with XORs makes interesting sub-patterns, for instance. And we’ll get more use out of the XORs in two sessions when they’re coupled with shift registers.

Next Session

We’ve got a whole lot of possibilities by now. We’ve got some good, and some freaky, percussion voices. We’ve got a bunch of synthesizer sounds, and if you recall back to the 4051, we’ve got a good way to modulate them by switching different resistors in and out. It’s time to start integrating some of this stuff.

If you’re following along, your homework is to build up permanent (or at least quasi-permanent) versions of a couple of these circuits, and to get your hands on at least two 4017 decade counter chips. Because next week we’ll be making drum patterns and introducing yet one more way to make music.