Category Archives: 往期活动

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(中文) 创客音乐频谱彩灯

Making Refinements to the Old Project

I put together the Color Organ Triple Deluxe over a year ago. It was a bare minimum version of color organ circuit using LEDs instead of incandescent lamps that traditional color organs use.

The circuit worked pretty well, considering the simplicity of the circuit. However I just kept feeling like this project deserves further refinements. So I went back to the drawing board (or breadboard) and took a hard look at the circuit…

The result? Please take a look at the video.

Step 1: The Problems & the Solutions

Picture of The Problems & the Solutions

The Problems

There were a few problems. The transistors in the circuit was biased in the way that it was supply voltage dependent, as well as device dependent – in other words, if the voltage was too high or too low, or the transistors had a bit of different characteristics, the circuit did not perform well.
The filter performance was also a bit poor – the separation between the frequency bands were not so great.

The Solutions

First, I changed the initial gain stage from single transistor design to two transistor design. It’s a basic class-A common emitter amplifier followed by an emitter follower. They are direct coupled for optimum performance, as well as reduced part count (always important for me to design circuits with the least number of parts). Adding the emitter follower stage allowed the low output impedance needed for the filters to perform well. The biasing circuit was also revised to be less device and voltage dependent.

Second, the filters were refined to have better separations. Input and output impedance to the filters are better matched to achieve better efficiency as well.

Third, the LED driver circuits were given another transistor. Actually, in the original design, the output buffer and the LED driver was done by the same transistors. Now the filter outputs are buffered by emitter followers, then the filtered audio waves are rectified before going into the LED drivers.

Those changes made a huge difference. And I tweaked the component values obsessively to get the best performance. Sensitivity adjustment control is also added.

There are many additional parts compared to the earlier version, but the result is totally worth it. The LEDs now respond to music very, very nicely.

Step 2: Circuit

Picture of Circuit
Picture of Circuit
Picture of Circuit

Here are the circuit schematics, BOM, as well as the PCB layout. The filter response graph is also shown. Keep in mind that the graph is more of a perceptual one than actual.

The circuit is loosely based on the many vintage circuits before it, with a few improvements.

The input buffer/gain stage is designed to have low output impedance. This is important for the filter stages that follow. This stage is also designed to give high gain and maximum output signal level, since the filters are of passive type so will lose some signal.
(This amplifier stage took me the most time to design. I tried out many topologies and parameters. I think I found the best balance between simplicity, stability and performance. Unlike using op-amp, designing amplifier with transistors is an art of compromise.)

The use of emitter follower as rectifier is my original idea. (Q3, 5 and 7) Combined with the bias point set (by R8 and 9 and so on) right below the point the LED driver turns on makes this color organ very sensitive to the lower volume of audio input, while eliminating the diodes typically used here.

BOM

  • 3x 47 ohm – R4,17,20
  • 6x 150 ohm – R10,15,16,16b,21,21b
  • 2x 270 ohm – R11,11b
  • 1x 470 ohm – R6
  • 2x 1k ohm – R1,2
  • 2x 4.7k ohm – R7,12
  • 4x 10k ohm – R3,9,14,19
  • 3x 270k ohm – R8,13,18
  • 1x 1.2M ohm – R5
  • 1x 10k ohm potentiometer – VR1
  • 1x 4.7nF (0.0047uF) – C9
  • 2x 22nF (0.022uF) – C6,7
  • 1x 0.22uF EC – C3
  • 1x 1uF EC – C4
  • 3x 4.7uF EC – C5,8,10
  • 1x 10 uF EC 16V or higher – C2
  • 1x 47uF EC 16V or higher – C1
  • 8x MPS2222A or Equivalent – Q1-8
  • 6x Red LED (super bright type recommended) – D1-6
  • 6x Green LED (super bright type recommended) – D7-12
  • 6x Blue LED (super bright type recommended) – D13-18
  • 1x 3.5mm Stereo Jack – CN1
  • 1x DC Power Jack

All resistors are 1/8W (or higher) carbon film type, 5% precision. Small capacitors are film type, and 0.22uF and above are electrolytic type having voltage rating of 16V or higher.

Parts Substitutions

This type of analog circuits tend to be picky about the part values, so it’s best not to change out resistor values, etc. unless you know what you are doing.

Resister and capacitor types are not very critical, so just use any type you might have. Using ceramic capacitors instead of film for example, is fine.

I used MPS2222A transistor, which can be substituted by number of general purpose transistors of similar specs. The ones I tested are 2N4400, 2N4401, and 2N3904.

Q1 is more critical than other transistors in this circuit. The biasing is adjusted for transistors having the hfe around 200. If you use different transistor, you might want to check the voltage at Q1 collector – the voltage here should be between 4.5 to 6V when 12V supply is applied. Adjust R5 or try different transistors for Q1 if it’s too high or low.

PCB Layout
PCB layout is provided as PDF for home brew PCB makers. It’s a single layer design, so it should be easy to make your own.

Kits and PCBs
Kits and PCBs of this project are available at my website.

Step 3: Assembly

Picture of Assembly
Picture of Assembly

There are 8 transistors, and many resistors, capacitors and LEDs, but the assembly is very straightforward as they are all familier through hole parts (and no ICs). In a way, Color Organ Triple Deluxe II is built like the circuits from the 70’s. If you are like me, you will appreciate the modern-vintage feel of all discrete component design.

I recommend soldering the lower profile parts, first, then move on to taller and taller parts. I arranged the BOM in the order of soldering below:

Soldering Order

  • Resistors (bend the leads) (reference on color code)
    • 3x 47 ohm (yellow, violet, black, gold) – R4,17,20
    • 6x 150 ohm (brown, green, brown, gold) – R10,15,16,16b,21,21b
    • 2x 270 ohm (red, violet, brown, gold) – R11,11b
    • 1x 470 ohm (yellow, violet, brown, gold) – R6
    • 2x 1k ohm (brown, black, red, gold) – R1,2
    • 2x 4.7k ohm (yellow, violet, red, gold) – R7,12
    • 4x 10k ohm (brown, black, orange, gold) – R3,9,14,19
    • 3x 270k ohm (red, violet, yellow, gold) – R8,13,18
    • 1x 1.2M ohm (brown, red, green, gold) – R5
  • 1x 3.5mm Stereo Jack – CN1
  • Capacitors (watch the polarity of electrolytic capacitors – long leads go into the holes with “+” sign on the PCB)
    • 1x 4.7nF (0.0047uF) Film Capacitor – C9
    • 2x 22nF (0.022uF) Film Capacitor – C6,7
    • 1x 0.22uF Electrolytic Capacitor* – C3
    • 1x 1uF Electrolytic Capacitor* – C4
    • 3x 4.7uF Electrolytic Capacitor* – C5,8,10
    • 1x 10 uF Electrolytic Capacitor* – C2
    • 1x 47uF Electrolytic Capacitor* – C1
  • Transistors (polarity – make sure to orient them to the shape printed on the PCB)
    • 8x MPS2222A or Equivalent – Q1-8
  • LEDs (polarity – make sure to orient them to the shape printed on the PCB)
    • 6x Red LED – D1-6
    • 6x Green LED – D7-12
    • 6x Blue LED – D13-18
  • 1x DC Power Jack
  • 1x 10k (50k) ohm potentiometer – VR1

Notes on Solder Resin/Flux
Some solder resin/flux is electrically conductive. (resin or flux is inside solder wire to help solder to adhere to the joints) Some parts of Color Organ Triple Deluxe II are very sensitive to even a tiny amount of electrical leakage caused by soldering resin/flux. If the LEDs on Color Organ Triple Deluxe II stays lit without any sound signal coming in, you need to clean the PCB to remove the resin/flux.
“No Clean” type flux cause no problems (as the name implies), but more typical resin type flux can cause good amount of leakage, and cleaning might be required.
You can use an acid brush or an old toothbrush immersed in rubbing alcohol to scrub the back of the PCB. Rinse out the brush, wet with alcohol again and scrub another round or two until all the resin residue is gone. Make sure to dry the PCB completely before connecting to the power supply.

Step 4: Use

Picture of Use
Picture of Use
Picture of Use

Color Organ Triple Deluxe II is designed to run by 12V DC power supply. The circuit works pretty ok with 9V power, though. However 9V battery is not recommended as a power source because of the relatively high current draw (about 25mA at idle).

It’s best to connect to a regulated 12V DC power supply. Be careful if you want to use a typical wall wart – they can output much higher voltage than they are rated – sometimes as high as 18V from a 12V one. Color Organ Triple Deluxe II can operate safely from up to about 15V power. (If you want to use non-regulated AC adaptor, try a 9V rated one – they typically produce around 13V).

Audio source can be any “line level” output from audio equipment, or headphone output from computer sound cards and iPod/MP3 players. If you want to listen to the music while using Color Organ Triple Deluxe II, you might need a splitter cable.

Connect Color Organ Triple Deluxe II to your audio source of choice, and give it a play. I found music with good amount of beats to give best results. Adjust the potentiometer (sensitivity level) according to the sound level.

The LEDs react to the sound volume in a pretty linear manner that it feels like the Color Organ is translating sound into light.

The light out of the LEDs are blinding bright. You can use Color Organ Triple Deluxe II as a wall wash – project the light towards walls or ceiling and dim the lights in the room.

You will discover a new joy of listing to music.

Arduino创客手表套件

Description:

The Solder : Time™ watch kit.

The Solder : Time is an original design watch kit that you solder and assemble yourself.  Delivered as a through-hole kit, you solder the components to the PCB, and enclose it all in four layers of laser cut acrylic.

Introduced at Maker Faire Bay Area in Mid 2011, an instant hit.  The supplied battery lasts a really long time, and the onboard Dallas RTC keeps impeccable time.  This is the first SpikenzieLabs Kit that is a ‘wearable’.

Solder : Time is not only a wristwatch. Set it up as a desk clock, badge clip-it to your clothes, thread a chain, and you’ve got a pocket watch.

More advanced tinkerers will see the bottom side I2C lines broken out, for hacking, and integrating RTC into other projects. There are also pads on the backside of the PCB for DC supply, as well as an ‘always-on’ function.

Resistors:

Start by bending the leads to all three resistors to look like these in the photo.

Solder them in place and trim the leads. They go in either direction.

Clock crystal:

The crystal for the real time clock is the very small silver part with two leads.

Solder this as in the photo.

IC and Capacitors:

Note:

  1. 1.The notches on the two IC chips (RTC and PIC) must match-up with the notches printed on the white silk screen.

  2. 2.These two ICs are soldered directly onto the PCB. For best results, only apply heat from your soldering iron for 1 to 3 seconds per leg.

Solder the two orange-yellow capacitors in place.

Trim all leads.

LED:

Place the 4 digit 7 segment LED onto the PCB. Push flat, making sure all the legs go through the holes.

NOTE: Make sure that the LED is installed up-side right. Check that the decimal points are on the bottom as in this photo.

Solder and trim the leads.

You may want to peel the thin clear protective layer from the LED. Use your finger nail to lift an edge and then gently peel it off.

Button:

Push the button into the PCB. It should almost click into place.

Solder and trim the leads.

Assemble the watch body:

Battery holder:

The battery holder is very light and likes to move around as you solder it. Solder it in place with the open edge facing down.

Taping the battery holder in place, with masking tape, while soldering it works best.

Another way to solder the battery holder without tape is to heat the pad and battery holder by placing the tip of your soldering iron on the PCB’s battery pad and just barely touching the battery holder. After a second or two add some solder. Once one pad is soldered, do the other one, and come back to add more solder to the first one if required.

I’ve tried soldering a blob of solder onto one of the pads, and then heating the battery holder … this didn’t work.

Building the circuit board: This is an easy to solder kit.

Peel the protective layer on the plastic parts:

In order to protect the plastic parts during manufacturing they come covered by a thin plastic / tape layer. These should be removed before you assemble the watch.

NOTE:

  1. 1.Only use something soft like your finger nail to scrape the edge of the protective layer and then peel it off.

  2. 2.VERY IMPORTANT: Some of the layers have very thin parts that can crack easily. The best way we have found to peel the protective layer off of these parts is to hold the part down evenly on a flat surface with one hand and peel with the other hand. Holding the part in the air while you peel may snap the part you are peeling. (Don’t worry after the watch is assembled and screwed together it is very strong.)

Stacking the watch:

With the battery in the battery holder start making a stack of parts.

Close up of button details:

Battery:

Slide the battery into the battery holder on the Solder : Time PCB with the CR2032 “+” label text facing up. When the battery goes into the holder the watch should turn on and display 12:00. If not, remove the battery and check your work. After about five seconds the display will go out, this is normal.

NOTE: As tempting as it may be, don’t touch the battery holder while soldering – you will burn your finger!

  1. 5.Place the front face of the Solder : Time on the top of the stack.

  2. 6.Using your fingers, screw the layers together with the included screws. Don’t tighten them fully until all four screws are installed (this will help you align the layers).

  3. 7.Almost done, slide the wrist band in from the bottom edge, under the bottom and up through the other hole in the bottom and out the top edge.

  1. 1.Start with the plastic watch back oriented with the two larger holes at the top and bottom and place the PCB over it.

  2. 2.Next, place the plastic PCB layer part around the PCB, with the open end facing down.

  3. 3.Place the plastic switch layer on top of the PCB layer plastic. The opening for the switch is on the right side.

  4. 4.Place the switch lever into the space on the right side of the Switch Layer. Make sure that the switch touches the Solder : Time button and does not bind. Test it, the Solder : Time should turn on when pressed and off after a few seconds when released.

How does it work ?:

Parts Selection:

When we came up with the idea for the Solder : Time, one of our big concerns was battery life. We knew that we would need a RTC and some type of micro-controller. After experimenting with a bunch of different RTCs we decided to go with the Dallas Semiconductors DS1337+. This RTC clock runs at over a range of voltages which included our required voltage of 3v. It has extremely low current when in standby mode and uses I2C to communicate with the master micro-controller.

For the micro-controller we chose the PIC16F631. This IC has only a few peripheral functions built in (with keeps the cost down), and since we didn’t need many this also saves some power. The PIC16F631 has a very low power sleep mode, has enough pins for our project (and only one spare one), and also runs at 3volts. The PIC16F631 does not have built in I2C, so we used a bit banged version to control the RTC.

Battery Life:

In order to maximize battery life, we also used a couple of tricks. For the I2C bus we used higher value pull-up resistors (10k vs 4.7k) to reduce current and for the one unused pin on the PIC we set it to be a low logic value output (Microchip’s spec sheets, recommend this as a power saving set up). In testing the watch’s current draw, we estimated that given the average power of a CR2032 battery, the watch should keep the time for five years, before needing a battery swap in stand-by mode. Overall battery life will depend on how often the display is turned on.

Seven Segment Display:

The LEDs: One of the objectives when designing the Solder : Time was to make sure that all of the segments of the digits had equal brightness. In some cases only two segments are lit, as is the case for the number “1”, When the “8” is on, all seven segments are lit. Battery power was also a concern, the battery we chose for this project is the CR2032 which is a 3v low current battery. Our solution was to light only one single segment at a time, this way if the digit being displayed was a “1” or an “8” all the segments would be equally bright and we wouldn’t over tax the battery by drawing too much current. (If you wave the watch in the dark, you may be able to see the flashing pattern.)

Use a timer:

To light only one segment at a time we used one of the internal timer peripherals in the PIC. A timer may also be used as a counter, but in this case we used it as a timer to time the on time of each segment. When the timer runs out, the PIC programming jumps into a interrupt routine. To display a number, the PIC looks up the segments in a table that stores the on and off values for the segments. It starts with the first segment of whichever number it is displaying and then turns the segment on (or not, if that segment isn’t on). After this, the program returns to the normal main loop of the program and waits for the timer to run out again. When it does, the PIC turns on the next segment of the current digit. Even if the segment of the current digit is not turned on, the timer still waits.

After all of the segments of a digit are displayed, the next digit is displayed, and after the last digit is displayed the colon is displayed and then it starts over at the first digit.

Flashing Colon:

There is a special case when displaying the colon. It flashes when in time setting mode. It took a few tries to get the flashing to look good and steady in the three states of the time setting mode; slow forward, fast forward and idle. To achieve a steady flash rate we used another timer. This timer simply toggles the colon on or off ever time that it times out, then when it is time to display the colon it is simply lit or not.

Sleep Mode:

For the Solder : Time’s sleep mode we use a manual counter variable. This variable is incremented every time the program goes through a loop, and when it over flows (gets too big for the size of the variables holder) a sleep flag is set and the watch goes to sleep. If the button is pressed before the watch goes into sleep mode, the sleep counter is reset to zero and counting starts again. This way, the watch will go to sleep consistently after about 5 seconds from the last time you pressed the button.

Before the watch goes to sleep it turns off the LEDs. The watch button is set to wake the watch up if it is pressed. Nothing is done to the RTC since it goes into stand-by mode when no data is being transfered and it simply keeps the time.

http://www.spikenzielabs.com/SpikenzieLabs/SolderTime.html

 

激光雕刻版画DIY工作坊

当前沿科技遇上复古工艺,当激光雕刻遇到木刻版画,当木头烧灼碰上油墨清香,这一切的邂逅将会迸发出怎样的火花?

先为各位工友介绍电子画稿的制作方法,完成画稿后使用激光雕刻机制作印刷模板(椴木板),印刷模板制作完成后就可以开始版画的印刷。

关于版画

版画是视觉艺术的一个重要门类。广义的版画可以包括在印刷工业化以前所印制的图形普遍具有版画性质。当代版画的概念主要指由艺术家构思创作并且通过 制版和印刷程序而产生的艺术作品,具体说是以刀或化学药品等在木、石、麻胶、铜、锌等版面上雕刻或蚀刻后印刷出来的图画。版画艺术在技术上是一直伴随着印 刷术的发明与发展的。古代版画主要是指木刻,也有少数铜版刻和套色漏印。独特的刀味与木味使它在中国文化艺术史上具有独立的艺术价值与地位。

下面就来一睹为快吧!

原图处理

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图像去色并调整图像阈值

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处理后的图片

242975908388347531

 

雕刻前的预处理

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完成雕刻的印刷板

485887956874553250
919724770999133287

 

在印刷板上涂油墨

37996039300510735

 

把白纸覆盖在印刷版上,使用油墨滚筒躺平

871147939140583242

 

完成后的作品!

165758980536135489