Home Made Soda Pop

It’s the half way point in my year of one-per-week projects so I thought it would be a nice change to do something a bit different and refreshing!
Home made soda pop!

Making your own soda pop is a pretty straight forward process. You’ll need some brewers yeast, a sweetener like sugar or honey, a two liter plastic soda bottle and the flavoring of your choice. The part you have to pay close attention to is the temperature of the water you dissolve the yeast into. It should be between 98 and 110 degrees F. Anything hotter will kill the yeast and anything lower won’t activate it. Once the yeast is added to the sugar and water mixture, it reacts with the sugar and the byproduct is carbon dioxide which is what makes all those wonderful bubbles.

Another important factor is cleanliness. Everything that comes in contact with the yeast and water during the mix process should be clean and sterilized. You can buy food grade sanitizer at the same place you buy the brewers yeast. It’s basically an iodine mixture that you dilute in water and use to rinse the items you want sanitized.

Watch the video for step by step intsructions and … keep on hackin!

Three Transistor Voltage Detector…

Ahh yet another transistor project!! Well, this will be the last one for a while I promise. 🙂

This is an amplifier of sorts. In fact a viewer of the video posted below with the screen name MonkeyFCoconut summed it up very nicely with the following comment:
“Pretty cool? man. I whipped up your circuit in LTSpiceIV and it seems to have a gain of 95 Million with still enough current to light the LED. This is basically a SUPER-Darlington Transistor 😉 The front end copper strip forms one side of a capacitor, and then when you bring it near a voltage potential a super tiny current flows between air dielectric of the “cap”. This is mega amplified with the high gain BC547’s and viola, the LED lights up. Might be able to detect pre-lightning strikes??”

This is a fun project to build and test out on different objects. It’s surprising what the thing will, “detect”

Keep on hackin!

Parts List:

1 – 1 Megohm resistor
1 – 100K ohm resistor resistor
1 – 22 ohm resistor
3 – BC547 NPN transistors


JFET Audio Preamp with Piezo Guitar Pickup

I’ve been on a transistor theme here lately and there’s one more I’d like to cover, the JFET. JFET stands for Junction Field Effect Transistor. These transistors are well suited for high impedance inputs and since a Piezo electric device measures in the multi-megohm range it’s a perfect match.

I found the schematic for this circuit on this webpage: Design Guidelines for JFET Audio Preamplifier Circuits By Mike Martell Thanks Mike! Great write up.

After some bread boarding and testing I decided this would be a great preamp for a Piezo pickup mounted inside my acoustic guitar. I salvaged a Piezo element from a Roomba vacuum I had in the scrap pile. They use them as a dirt sensor mounted above the rotating brushes as you’ll see in the video.

I glued the Piezo element inside the guitar on the sound board near the sound hole and connected it to a 1/4″ audio jack that I mounted on the lower body side. It sounds great but there is a bit of 60 cycle hum getting in the signal. I’m assuming that this is coming from the circuit being on a bread board. I plan on mounting the components to a PCB and finding a suitable metal enclosure to put it all inside of. I think the metal will help shield outside noise.

This is a pretty easy project to put together. You can get JFETs from most electronics suppliers. I got mine from Tayda Electronics for $.25 each.

Keep on hackin!

Parts List:

1 – 10 ohm resistor
1 – 470 ohm resistor
1 – 1.2K ohm resistor
1 – 1 Meg ohm resistor
1 – .1 uF polarized capacitor
1 – 2 – 4.7 uF polarized capacitors
1 – 100 uF polarized capacitor
1 – J201 Transistor


Simple Transistor Tester

This is basically a high gain amplifier with feedback that causes the LED to light and flash at a rate determined by the 10u and 330k resistor.
Remove one of the transistors and insert the unknown transistor. When the transistors are inserted with the pins in the correct position as shown in the photo, the LED will flash. To turn the unit off, remove one of the transistors.

Parts list:

1 – 10 uF polarized capacitor
1 – 1K ohm resistor
1 – 330K ohm resistor
1 – 22 ohm resistor