Sunday, November 18, 2012

My Top 3 Favorite Cameras

Rolleiflex 3.5F
Rolleiflex 3.5F

Leica M2
Leica M2

Homemade super wide pinhole camera 18mm F120 with Mamiya RZ67 Professional II film back
Homemade super wide pinhole camera 18mm F120 with Mamiya RZ67 Professional II film back 

Wednesday, September 30, 2009

YAHA Headphone Amplifier

I created hybrid headphone amp using op-amp & electron tube. (quite unique!)
see for details.
Most of parts are bought from and
Capacitor: Nichicon Muse KZ
Op-amp: TI OPA2134P
Resistors: Dale
Case: Hammond Steel Instrument (1454 Series)

The schematic. I changed some parameters from the original.

The board.

I bought 2 electron tubes from, electro-harmonix 6922 and Sylvania Jan 6922 (deadstock made in 1972). electro-harmnix tube is less noisy. People say this amp produces a lot of distortion but I think this amp creates better sound than the original iPod touch. Especially the low sound is much better than iPod touch.

Im sartisfied with this headphone amp. It sounds nicely! Also the orange light from the tube makes me relaxed!

Tuesday, June 02, 2009

iPod Line Out Dock Adapter

Got iPod Connector ("iPod Connector Male Style 1" sku: DEV-00633) from

Cut Universal board, make it U-shaped, and put it in the iPod connector.

This is Kobiconn 3.5MM Stereo Jack 161-7300-EX ordered from File it and make the diameter a little shorter to put it in the iPod Connector.

Attach the stereo jack to the U-shaped board with bus wire or magnet wire.

Put it in the iPod connector.

Wire and solder the pins between iPod connector and the stereo jack. pin2 is connected to GND (white line), pin3 is connected to Right (Green line), pin4 is connected to Left (Orange line). See for details. Took those lead lines from 10Base-T cable. Also, if you are using iPod touch (2nd) or iPhone (2nd), connect pin11 and pin15.


Sunday, July 01, 2007

Home Coffee Roasting with Stovetop Poppers

Stirring coffee beans in a pan over head was the earliest method of coffee roasting.
so why don't we try the method ? Here is the instructions of roasting coffee with stovetop popper on

So, got a stainless steel stovetop popcorn popper sold by Back to Basics.
The crank turns the wire vanes inside that rotate right above the bottom of the pan and agitates the corns and prevent the corns from scorching.

Drilled a hole through the lid and inserted thermometer.

Ok. Let's get started.
Put beans and crank crank crank...


Saturday, June 02, 2007

Modifying Poppery II for coffee roasting

Got West Bend Poppery II Air popcorn popper on eBay.
This is known as air coffee roaster.

Poppery II can roast coffee without modifying it. But if you modify it, it allows you to control the tempreture and roast speed.
Jeff Mielke's web site has the great instructions of how to modifiy Poppery II. has another nice article How-To: Make a popcorn popper coffee roaster which has lots of pics.

The chanber is like this.

Bought all these tools at Ace Hardware and at Radio Shack.

Detach black lid by removing 3 screws, also squeeze restainer and pry it out.

The bottom of the chanber. There is a motor attached on it.

The motor. The label says "MODEL HR 355OU 20.5 VOC 1.78 A MAX"

Remove the 3 screws.

Open the lid with the motor.

Remove 2 rings.

the heater section.

now deassembled like this.

See the heat coil in the head section.

The bottom of the aluminum chamber.

The top of the aluminum chamber.

Remove the tiny metal from the thermostat to disable the thermostat.

Remove the wire connector.

now the black wire is detached like this.

Remove the solder and detach the red wire.

Solder the black wire on the motor.

Well, that is all I have done till now so far. The project is still in progress...

Tuesday, May 15, 2007

Home Coffee Roasting with Presto PopLite Hot Air Corn Popper

Presto PopLite Hot Air Corn Popper
2 Colanders
Coffee Green Beans (half cup)

The chamber of poplite is not a recommended design on Sweet Maria's though.

Add green coffee beans on the chanber.

Turn on the popper. Sounds like a hair drier.

in about 6mins, turn off the popper, and pour the beans on the collander. The bean got a nice color!

toss between 2 collanders quickly until they are warm to your touch. don't touch the beans directly yet. It is really hot!

done! Ready to brew coffee next day.