Otona no Kagaku Ranking Chart

大人の科学.net
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The following comments and ratings are purely subjective, and solely the opinions of me, the author of this page. If you disagree with any of them, please give your own opinions in the comments section for others to see. All pictures belong to Gakken and are used here just to let you see what the kits look like. I put this knol together as a recommendation for kits that I believe are worth buying, and worth avoiding. This is especially an issue for those of you living in North America and are thinking of buying a kit as an import that is marked up 2-3 times over the cover price. I didn't comment on kits 3, 4, 5, 7 or 12 only because they're out of print and I'm not willing to pay the collector's prices to pick them up from auction sites.

The full list of kits, plus links to Gakken's online magazines, and the reviews on ThreeStepsOverJapan, can be found in the Gakken Kits List.

Explanation of grading items:

" Grade " is the overall worth of the kit, where "A" = "this is a great kit!" and "D" = "save your money for something else".

" Play Factor " represents the amount of fun you get in building the kit and in playing with it right away, where "A" = "put away the TV remote Martha, this kit's fun!" and "D" = "I thought this kit was supposed to do more than just sit there".

" Replay Factor " is the amount of time you spend modding the kit and continuing to play with it 2 or 3 weeks after initially building it, where "A" = "Ok, what else can I get it to do" and "D" = "Do I put it in a box in the attic, or toss it out now?"

" Quality " is the quality of the kit's components, where "A" = "this thing's built like a tank; hey, I know! Let's use it to build a tank!" and "D" = "I can't even breathe without something shattering into dust".


History:
10/06/14: Added entries for the Auto Writer, Steel Drum and Pocket Miku.


Other comments:

Click on the image to jump to Gakken's online magazine for that kit. Where available, clicking on the title will take you to the PDF version of the kit's assembly instructions. Keep in mind that the ratings below only refer to the kit. I love the mooks, and I buy the kits just to get my hands on the mooks.

Numbered Mook Kits

--- --- --- ---

No.

Title

Cover Price
(Yen)

Grade and Comments

1

Self-Propelling
Boat

1680

Grade: B
Play Factor: B
Replay Factor: D
Quality: A

A simple boat that swamps if there is a light wind. Best used in a bathtub or indoor pool. A nice idea and a good design, but not something you're going to play with often.

2

Finger Printing
Kit

1680

Grade: C
Play Factor: C
Replay Factor: D
Quality: C

An LED, finger printing powder and blood tracer. You do NOT want these chemicals used in your home. And, when the chemicals are used up, the kit's pretty much useless.

3

Pinhole
Camera

1680

No comment.

4

Crystal Radio

1680

No comment.

5

Illuminated
Microscope

1680

No comment.

6

Phonograph

1800

Grade: B+
Play Factor: A
Replay Factor: B
Quality: A

This is one of the coolest looking kits in the series, and basically, you're building a working record player that can be adapted to play any size record. The only problem is that it goes through batteries fast and it's hard to find a 1.5V DC adapter for it.

7

Steam Engine
Car

1800

No comment.

8

Slow Clock

1800

Grade: B
Play Factor: B
Replay Factor: C
Quality: A

Here, you're building a working weight-driven clock, which can easily be adapted into a chime player. Ignoring the obvious fact that there's only the hour hand, and that the weight will reach the ground in less than 24 hours, the real drawback is that it's noisy and not easily soundproofed. It's plastic, so it won't rust if left outdoors, but it may be distracting fast if you have to listen to it in a small room. Otherwise, it's fun to see something like this that you've actually built running.

9

Planetarium

2200

Grade: B
Play Factor: A
Replay Factor: B
Quality: C+

Having a star field projected in your room late at night is way cool. And if you're an astronomy buff, this is fun to look at when it's rainy or cloudy outside, since the star field is accurate. Unfortunately, the plastic panels get brittle over time and might shatter during assembly. Plus, if the light is off in your room when the planetarium is on, you're not going to be able to read books or do homework.

10

Sterling Engine

2100

Grade: A
Play Factor: A
Replay Factor: A
Quality: A

This is a great kit to show off to your friends, and if you have any places in the house with a temperature differential (like in front of window on a sunny day) or on a radiator, this kit will run quietly on its own forever (or, at least until the thin, soft plastic bellows piece wears out) Plus, you can decorate the spinning disk to change its appearance when you feel like it.

11

Newtonian
Telescope

2100

Grade: A
Play Factor: B
Replay Factor: D
Quality: A

Despite the lack of a replay factor, having a reproduction of Newton's telescope on your desk is a great conversation piece. It's a simple design, easy to build and it really works (if you put the mirror and lens in right.). It's just that the light-gathering ability of something this small is negligible, making it useful mainly for inspecting the moon on a clear night.

12

DaVinci
Helicopter

2100

No comment.

13

Kaleidoscope Projector

2100

Grade: B
Play Factor: B
Replay Factor: C
Quality: C

This is a projector-type kaleidoscope, and by putting opaque items in the plastic tube, you're cutting down on the light of the projected image. This means that you're limited to what can go in the tube, and the tube is brittle so if you remove and push in the stoppers more than once to change up the sparklies, the tube's going to shatter eventually. Plus, it's a static image, so if you want the projection to change dynamically, you're doing have to be moving the tube around yourself all the time. You may want to get the aurorarium (below) instead.

14

Stereo Pinhole
Camera

2300

Grade: B
Play Factor: B
Replay Factor: C
Quality: A

Stereo pictures are cool, especially if you take them yourself. And, if you really like taking pinhole-style pictures, this is an easy camera to do it with. However, it takes a lot of practice to get the exposure times right, which means going through a lot of film. Film and developing can get expensive fast, so you'll probably stop using this camera after a couple rolls. But, the quality of the parts are good and it's fun to build. It's better to get this kit than #3 since they're both pinhole cameras, but if money is a concern and you want to see what you're aiming at, you may want to get the reflex camera kit instead (#25).

15

Reflective
Movie
Projector

2300

Grade: A
Play Factor: A
Replay Factor: B
Quality: A

Like the phonograph, the stirling engine and the Newtonian telescope, the projector just looks cool, and it is fun to build. But, there's no shutter to block the light when the film is being advanced, so you don't really get the illusion of motion that you'd get with a regular projector (like Gakken's more expensive 8mm kit that doesn't have a mook). It takes forever to punch out the paper film strips, but you can make up your own movies to add to the replay factor. But, with a movie run time of about one minute (limited by the size of the spool housing), you're probably not going to watch a lot of movies with this. The quality of the parts are very high, though.

16

Mini
Tea-Carrying
Windup Doll

2300

Grade: B
Play Factor: B
Replay Factor: C
Quality: B

The doll looks good, especially since you can dress it up as you like. Just remember that the outfit you choose may freeze up the arms, preventing the doll from running. Or, you can decide to leave it naked, in which case it may run properly, assuming you can come up with a way to prevent the wind-up spring from getting sprung when the gears accidentally disengage. Since all the doll does is move back and forth in a short line, there's not a lot of versatility here. You're better off getting the more expensive version of this kit that comes without the mook.

17

Mini Theremin

2300

Grade: B
Play Factor: B
Replay Factor: B
Quality: A

The theremin is very easy to build, but hard to tune and even harder to master. In the hands of an average person, you're either going to get a high-pitched whine, or a farting noise. You can add a grounding post to improve the sound control, or gang two kits together so that one controls pitch and the other volume. This kit is probably best suited for musicians that want to add something unusual to their repertoire. It can be used to drive the SX-150 synthesizer, but the results don't sound much different than if you use the theremin by itself.

18

Wind-Powered Generator

2300

Grade: B-
Play Factor: B
Replay Factor: C
Quality: A

The little motor in this kit, when used as a generator, can output between 1.5 and 2V - just enough to power the internal LED and little else. But, the LED's going to flicker, even assuming that you have a 5-10 MPH wind. You can mount it in front of an air conditioner or electric fan, but it only works if it's no more than 12 inches away, or so. It's a great science kit for school kids, and may be most appropriate for people that can mount it on a balcony railing or a backyard fence.

19

Galileo-Style
Telescope (Galileo)

2300

Grade: B
Play Factor: B
Replay Factor: C
Quality: C - B

This is a very difficult kit to get right. The body is made up of two sheets of stiff paper, rolled up and glued together. Force the paper to roll and it may fold and crease on you; use too much glue and the paper will get soggy, lumpy and curved. Once, the body is glued together, it's about 2' long and hard to store. The authors suggest putting up the included astronomy poster on your wall and gluing the scope holders to the poster. Which is fine if you have a free wall for this, and don't mind the poster warping over time. Additionally, the eyepiece aperture is only 1/8", so that even looking at the moon doesn't give that good an image. If you like astronomy and want a conversation piece, get this scope, the Newtonian and the planetarium as a set. Otherwise, just get the Newtonian scope if all you want to do is some casual moon chasing.

20

Bird Organ

2500

Grade: D
Play Factor: D
Replay Factor: D
Quality: A

Of all the kits, including the spy kit, the bird organ is the most disappointing. Assuming that you can keep the air from leaking around the sides of the paper sheet, the output of the pipes isn't that loud. The real problem is that if the paper blocks the flow of air (when there's a pause between notes) the back pressure build up against the bellows prevents the crank from turning smoothly. I was never able to get the music to sound like anything recognizable. Only recommended for pipe organ players that want a conversation piece sitting next to their real pipe organ.

21

Magnet Motor
Car

2500

Grade: B
Play Factor: B
Replay Factor: C
Quality: A

The magnet motor car is a great way to teach children the basics of electric coils. You have to wind the coil yourself, but the rest of the kit is pretty easy to build and there's no soldering for the wire connections. But, all the car does is run forward (until it hits a wall or falls off the table), or goes in a circle. The motor is low torque, so if you attach something heavy to the pulley belt or the drive wheel, the motor will stop turning. It's fun to know that you built something like this yourself, but it's mostly going to just sit on a shelf (if it does, pull the battery out or it's going to drain in a few hours).

22

Edo-Era
Static Generator

2500

Grade: B-
Play Factor: C
Replay Factor: C
Quality: A

This kit is based on a spark generator created in the 1700's by Gennai Hiraga. It's a plastic roller that rubs against a sheet of cotton to make a small (1/8"-3/8") spark. It's very touchy and there are many factors that cause the static to bleed off before a spark forms. I've only gotten a good-sized spark once, otherwise I've just gotten sparks around 1mm long. Adding a Leyden jar (2 plastic cups wrapped with foil to make a capacitor) does store up enough of a charge to give you a serious bite. The book is an excellent source of experiments for teaching children about static electricity. A great book, a mildly interesting kit. May be more fun if you replace the hand crank with a small DC motor, or a Dremel tool.

23

Wire recorder

2500

Grade: B-
Play Factor: B
Replay Factor: C
Quality: A

This is a great idea, but the execution could have been better. A cassette recorder head is connected to an amp circuit, with a microphone and a speaker. Moving the head over any steel or iron surface lets you record your voice on it. It's just that the amp's not that great, and it's hard to hear the playback. You really need to use a better mike, amp and external speaker. It's fun trying to see what works as a recording medium, but this is really just another party trick. If you're going to record yourself seriously, you'll eventually want to just fall back on your little portable MP3 player (or, get a used cassette deck, pull the tape head free from the transport assembly and use that instead). The parts used for making the kit are very durable, at least.

24

4-Bit Microcomputer

(No assembly PDF file online)

2500

Grade: A
Play Factor: A
Replay Factor: A
Quality: A

If you like programming, or if you want to add a simple controller to a motor circuit (like making the high-end tea doll into a tread-driven machine of destruction), this is a fun little kit for learning machine language programming. It's easy to mod, and the mook shows a circuit for driving up to 3 SX-150 synthesizers. The memory's not permanent, so you have to reload the code each time you turn it on. And, since the keypad is just a sheet of conductive plastic, if you do want to use this kit very much, it may be best to wire in an external 20-key push switch pad. Also, if you want to use this kit at the office to play games, add a variable resistor in series with the speaker to act as a volume control.

25

35 mm Twin Reflex Camera

2500

Grade: A
Play Factor: A
Replay Factor: C
Quality: A

This is a fun kit to build, and took me about 1.5 hours to complete. The most interesting part is the shutter mechanism, which is a pair of spring-loaded levers. Essentially, this is a box with two lenses, one to focus an image on a roll of 35 mm film, the other aimed at a mirror that bounces the image to a view screen. Counter-rotating threads on the lens holders let you focus both lenses at the same time. There's no shutter speed control, flash or zoom lens. It's fun to play with right out of the box, and you can choose not to advance the film to create multi-exposure trick shots. But, the cost of developing film now may affect how much you want to keep using this kit in the long run. Very high-quality construction.

26

Mini Electric Guitar

3675

Grade: A -
Play Factor: B
Replay Factor: C
Quality: A

This is a fun kit to build and to try to play, but the strings stretch too much and it won't stay in tune. Essentially, this is a child's toy, with regular steel strings wrapped halfway along the neck. But, it's fun wrapping the pick up coil and assembling the guitar itself. Great for building, but best used as a conversation piece afterward.

27

8-bit Microcontroller

3360

Grade: A
Play Factor: A
Replay Factor: A
Quality: A

This micro-controller, AKA: Japanino is actually a version of the Arduino kit, meaning that all of the second-source circuit boards available for the Arduino will work with the Japanino. This gives you near-infinite replay value. The kit comes with the P.O.V., an animated LED stick. The stick is noisy, and clumsy to hand-crank, but you can edit your own graphics to be displayed on it, and it is a good introduction for programming Japanino hardware.

28


Edo-period Clock

2950

Grade: B
Play Factor: B
Replay Factor: C
Quality: A

This clock is based on a design common in 1600's Edo, Japan. It's a dual-pendulum style that allows for tracking daytime, and nighttime "hours". A leaf switch lets you connect the Japanino to sound an alarm hourly. The ticking is noisy so you may not want this running all day, but the construction is good and it's a bit of a challenge to build. Once built, there's not much to do with it.

29


Akari Paper Lamp

3000

Grade: B
Play Factor: B
Replay Factor: A
Quality: A

This is a 3-LED lamp with three pre-programmed settings (1 manual setting and two pseudo-random patterns). The kit comes with pre-creased paper for making 2 different origami lamp shades. Additional ideas include making shades of your own design, with or without scissors and tape. The Akari can be connected to the Japanino to drive the LEDs directly, and one sketch is provided to take weather data from a Mac to determine the colors to be displayed. The kit by itself is almost identical to the Aurorarium (below), but with the Japanino and your choice of lamp shades, it's almost infinitely customizable.

30

Animaris Ordis Parvus

3500

Grade: B
Play Factor: B
Replay Factor: B
Quality: A

The Animaris is a mini version of the "beests" series by Dutch artist Theo Jansen. Initially, it's intended to just be a wind-driven walking machine. Suggested mods are to add a solar-powered motor, hook up two motors and run them with the Japanino, and to run it with a rubber band. The torque on my kit seems to be unusually high and it won't run with the weaker motors suggested by Gakken. Even if it does run in the wind, it'll get boring fast. Best bet is to hook up the two motors and turn it into a programmable robot, which will increase its replay value. Very well-made, though.

31

Ornithopter and Entomopter

2400

Grade: B
Play Factor: B
Replay Factor: C
Quality: B

This is actually two kits in one, both are windup fliers. The ornithopter has wings that flap like a bird's, while the entomopter has a "wagging" wing that is supposed to emulate an insect's. They're simple to build but you have to follow the instructions carefully or you'll waste time trying to use the entomopter's parts for the ornithopter. Once the wing material is taped to the wing frames, if you've done it wrong, it's too late when you find out. Some of the thinner pieces can snap easily. Fully wound, the ornithoper will flap for 5 seconds and glide for another 3-5. The entomopter will flap for about 3 seconds and has a shorter glide time. There's a little "launcher" that's supposed to fire the kit into the air for you, but it's not worth assembling; you can hand-throw them better. Looks good when sitting on a shelf.

-- Mini-Rhinoceros 3500 Grade: B
Play Factor: B
Replay Factor: C
Quality: A

This is an unnumbered kit for some reason, possibly because it's the second of Theo Jansen's beests series. It's kind of small, at 7" long and 6" tall, but has 80 pieces and a 90 minute assembly time. The squirrel cage fan on the top makes it wind-powered, and you can use a small battery-powered fan to drive it, rather than blowing on it yourself. It's fun to build but not very interesting to play with unless you start modding it. It's great as a science kit for kids, but otherwise has little replay value.
32 Mini Electronic Block 3990 Grade: A-
Play Factor: A
Replay Factor: C
Quality: A

"Denshi" means "electric". The Denshi Mini is a scaled down version of the Gakken EX-150. It has 25 plug-in blocks with 50 suggested circuits you can build. If you're a beginner to electronics, this is a nice, safe way to get started. But, the overall kit is limited to what you can do (a few megaphones, some AM radios, and some LED flashers) and ultimately you're going to hit its limitations. When that happens, the replay value goes down, unless you start making your own blocks.
33 Desktop Vacuum Robot
2940 Grade: A-
Play Factor: A
Replay Factor: B
Quality: A

The initial intent of this kit was to create a smaller version of the commercial Roomba vacuum cleaning robot, but as an all-mechanical design. From a technical viewpoint, Gakken succeeded admirably. Kit #33 is a challenge to build, and fun to watch running as it avoids collisions and falling off the desk. But, the vacuum suction is weak, so it doesn't clean all that well. Then again, the greatest appeal of the Roomba is that you can mod it to repurpose it. And that's also the case with this kit. The mook suggests adding LEDs, servos, smartphones and the Japanino. One mod is to make it look like Pacman. Plus, it's in the $36 USD range if you can get it at Japan prices.
34 Twister
2940 Grade: A-
Play Factor: A
Replay Factor: B
Quality: A

The Twister is a continuation of Kit #31, and is a variation on the entomopter design. Motive power is from either a rubber band, or a light-weight DC motor. The mylar sheets and carbon fiber rods make it only a few grams in weight, and even with the DC motor and capacitor it's only about 8 grams. Flight time is 10-30 seconds, and it can cover up to 30 meters (100 feet) in distance. The hand-crank and gear shafts snap-fit onto the carbon rod, and switching between them for going from rubber band-driven to motor-driven power is a major pain. You'll probably want to pick one method and stick with it. It is fun to watch it fly, and it would make an interesting variation on frisbee golf. The pieces are all good quality, and if you treat the mylar gently it should last a long time.
35 2-Cylinder Steam Engine
3150 Grade: B-
Play Factor: B-
Replay Factor: C
Quality: A

Kit #7 was a 1-cylinder steam car; kit #35 is a V-2 steam engine without the car. It's a very simple kit to assemble, and the included pulley lets you drive a Lego car, a small DC generator or you can connect a photo cell and measure the RPMs with the Japanino. The issue is that you need some kind of fuel that burns hot and clean. Lighter fluid burns too hot and is really sooty. Rubbing alcohol is clean but not hot enough. Gakken recommends only using the cooking alcohol that goes into camping stoves. DO NOT try gasoline. A second issue is that the steam vents from the front of the kit and spits water out of the tray. If you mod the kit to overcome these issues, and you don't have kids or pets, then this is a fun kit to play with.
36 Edison Wax Cylinder Recorder
3650 Grade: A-
Play Factor: A
Replay Factor: B
Quality: A

One of the first premium kits Gakken released under the Otona no Kagaku brand was the plastic cup-style Edison Cylinder Recorder, in 2000. Mook #36 is being treated as the 10th Anniversary of the numbered mook kits and because of this, kit #36 is a revisit to the cylinder recorder, this time with a wax cylinder. The kit is very solidly built, with sturdy plastic and steel components. There are two soundbox head assemblies, one for recording and the other for playback. You use two adjustment bolts to set the head height and needle angle, which are fairly critical for proper playback. There should be a lot of wax shavings if you do it right. If not, playback will be very weak. But, just use the included smoothing tool to scrape off the old recording and try again. The kit comes with 5 cylinders, and you're encouraged to try other materials, such as crayons or color pencils. Records about 15-30 seconds of sound when you shout into the speaker cone. Uses 2 AA batteries for the drive motor. Very limited replay value, but it looks very nice as a display model on your shelf, and can be a good conversation piece at parties.
37 Animaris Imperio, mini-Beest
2950 Grade: B-
Play Factor: B
Replay Factor: C
Quality: A

According to one of the Gakken email newsletters prior to the release of this kit, the Imperio was inspired by the desire to make a bipedal robot. It's the third in the Theo Jansen mini-beest series, and visually is one of the least interesting. It is very challenging to build if you don't read Japanese, though. It's not designed to carry much of a load, so if you want to mount a battery pack and motor or circuit card, you'll have to find a way to attach mountings, and to keep it light. But it is fun to watch as it waddles forward, initially with wind power.
38 Radio-Synchronized Flip Clock
3500 Grade: B+
Play Factor: B
Replay Factor: B
Quality: A

This kit is based on the flip clocks that were popular in the late 70's and 80's. There's a small radio receiver that picks up a time signal from the nearest radio station to calibrate the clock and reset the time. It takes a while to build, because of all of the flip sheets, and there are a few mods that you could make to turn it into something more visibly interesting. The flipping action is loud though, so you may not want it in your room at night. Uses 2 AA batteries. The receiver is tuned to Japanese frequencies and may not work elsewhere.
39 Updated Pinhole Planetarium
3500 Grade: A
Play Factor: B
Replay Factor: B
Quality: A

Kit #9 is the original planetarium. #39 is very similar, but boasts a more detailed map of the Milky Way, a motor for rotating the globe every 15 minutes, options for selecting either the northern or southern hemispheres, and an auto-off circuit. The push switch has 3 settings: Lamp only; Lamp plus motor; and, Off. The lamp is custom-made to have a smaller than normal filament, which will make it hard to get a replacement if the bulb burns out. But, the star patterns are nice to look at, and the motor is very quiet. Uses 2 C-cell batteries.
40 Miniature FX Camera
3675 Grade: A
Play Factor: A
Replay Factor: A
Quality: A

Basically, this is just a web camera with an adjustable close-up lens and a short handle. As such, you could probably make one of your own for $10, if you could find the lens and built up your own case. Or, to save yourself the work, you could buy this kit. Takes about 15 minutes to assemble and then plug into your PC. It's compatible with both Windows and the Mac, and Windows downloads the drivers automatically. The target use for the camera is miniature effects movies ala Godzilla and Ultraman. To make the movies, you can use Windows Movie Maker, or any other number of related programs. The Gakken site has Tokusatsu AR available for download for adding explosions and such to your movies, but if you're on a laptop, AR may insist on using your built-in webcam rather than the kit camera. I think the only fix for this is to go into windows and disable the built-in camera, but I haven't tried this yet. The replay value for this kit revolves around the software you use and how much you want to make miniatures movies.
-- Electromagnetic Speaker
2960 Grade: A-
Play Factor: A
Replay Factor: A
Quality: B

Gakken is promoting this as "Otona no Kagaku Plus", where the "Plus" indicates that the kit is designed for conducting experiments, for kids as well as adults. The kit is an external speaker for your MP3 player, and uses a coil to wirelessly power 4 LED units. Essentially, it's a transformer with an air core. Volume control is from your player, while the kit has controls for syncing the LEDs with your music. If you want to wrap your own mini coils, you can add more LEDs to be lit by the main unit. Fun if you like playing with electronics. Gakken loses one point for having a solder splash on the main circuit board.
41 Auto Writer
3500 Grade: B+
Play Factor: B
Replay Factor: C
Quality: A

The basic concept of the Auto Writer is very simple and comes directly from automata (mechanical dolls) that could write an entire page of text. In essence, the writing mechanism is an x-y plotter with the ability to raise the pen from the paper, using a matching set of three cogs that push against return springs in the x-, y- and z-directions. In combination, the cogs can produce a single letter or simple drawing. As-is, the kit is a bit too simple. But, if you have access to thin sheets of acrylic and a coping saw, you can make your own cogs. Fun to watch, but not immediately practical unless you replace the cogs with servo motors driven by an Arduino.
42 Electronic Steel Drum
3300 Grade: A
Play Factor: A
Replay Factor: A
Quality: A

If you want to learn how to play a steel drum, or if you want a novelty item to go with your other drums, this kit is worth getting. The pan is only 6" in diameter, so to make up for the weaker sound, a guitar-style pick-up is placed at the back side, and you can plug it into a guitar amp. The kit has the option of broadcasting to an FM radio at the 88 MHz band, but none of my radios are picking up a signal from the transmitter, so I don't know if this is a common problem or just something wrong with my unit. If you hit the pan right, it does sound pretty sweet, and you can play it as much as you like, if you like playing drums.
43 No picture Hurricane Humidifier
TBD No tentative release date. Not reviewed yet.

Unnumbered Mook Kits

For some reason, Gakken decided not to number certain kits that are accompanied by a mook. These mooks only talk about the science or technology behind the respective kit, and may or may not include suggestions for modifications.

SX-150 Analog
Synthesizer

3000

Grade: B
Play Factor: B
Replay Factor: A
Quality: B

By itself, and straight out of the box, the SX-150 is kind of cheap and flimsy. The bottom plate is just a cutout from the box the kit comes in and the mounting screw is too short to reach through the cardboard. The resistive strip feels cheap, and there's little control with the stylus on the strip. The internal speaker sounds thin with little output range. However. There are so many mods that can be made to this kit that the final result is whatever you're willing to stop at. Plus, you can run several kits through one mixer, control them with the GMC-4 microcomputer, and even make your own sequencer. The replay value for the SX-150 for a musician is very high and the sound quality is better if you use the Ext. Out jack..

Aurorarium

(No assembly instructions PDF file online)

2500

Grade: B
Play Factor: B
Replay Factor: B
Quality: A

The Aurora-rium is an attempt to emulate an aurora (northern lights). The kit's aimed at children and only takes a few minutes to build. Essentially, it's three LEDs facing a slowly spinning disk with a diffuser screen to spread the light around. If you want a more modern version of a lava lamp, this is the kit for you. Only really good if you want a weird nightlight sitting in another room, since the motor is fairly noisy. Still, it does look cool, and you can change the designs you make on the reflective mylar disks.

Hand-made Speaker

2500

Grade: ---
Play Factor: ---
Replay Factor: ---
Quality: ---

I'm debating whether to get this kit, just for the challenge of building a real speaker. Most of the issue is in gluing the pieces together, since there's not a lot of parts or otherwise any real assembly work. But, after that, I'd have just another speaker lying around, and I already have stereo speaker sets that work fine. Plus, those are already in housings and I don't have the tools to build a good-quality wooden speaker box for this kit Unless you want to get into making custom speakers for your friends, give this kit a pass and spend the money on a pre-built speaker.

Variometer Radio

(No assembly instructions PDF file online)

3150

Grade: A
Play Factor: B
Replay Factor: B
Quality: A

I'm not sure what the fascination is that the Gakken people have with radios (actually, not true - simple AM radios are cool and there are many different approaches to the concept) but there have to be 5 different radio kits on the market now, from the crystal radio, #4, to the higher end vacuum tube kits. This particular kit uses a rotating antenna coil to do the fine-tuning (course tuning is handled by a variable cap). The audio signal can be weak, depending on how far you are from the transmitter, so you'll want to add an audio jack to plug in a powered speaker. Parts are good quality. Replay will depend on how many AM stations are in your area and how resistant you are to listening to internet radio stations.