Back in Action

Testing new stuff and rebuilding old stuff. Rebuilding my Old Sparky Tesla Coil. I'm currently rewinding the secondary and assembling a better primary capacitor bank, using Cornel Dublilier pulse capacitors (942C20P15K-F) 0.15mF, 2000VDC. My design is multiple strings connected in parallel. Also, experimenting with wireless security using some red team security testing software and hardware builds (Bruce, Halehound, Marauder), all based off the ESP32 and adding additional radio capabilities.

Project: Bat Detector

 

Summer is almost upon us and with it comes the biting insects that we all love. While we may not like all the gnat’s, mosquitoes, fly’s, etc., biting us but there are plenty of other animals that look forward to this time since for them it is a feast, this includes

• Birds - from swallows to hummingbirds

• Amphibians and reptiles - like frogs and toads

• Arachnids - including garden spiders and my favorite - jumping spiders

• And, most importantly for this post, Bat’s

Bat’s, like most animals, communicate through vocalizations. The difference with bats is that many of the vocalizations they make are beyond the range that we can hear (many of their calls are in the ultrasonic range).

In this project I’ll be using different techniques to convert ultrasonic bat calls from ultrasonic frequencies down to frequencies that we can hear. Human hearing range extends from 20Hz up to 20kHz (if you are young), but bat vocalizations extend from 12kHz up to 160kHz.

The main goals of this project are to:

• listen to bats

• locate bats\

• identify bat species

There are 2 main methods used to convert ultrasonic bat calls to frequencies within our range of hearing.

• The First approach uses the heterodyne method. This involves combining an internal reference frequency with a detected sound. The output that you her is the difference between the two frequencies. A simple example concerns a 42kHz bat call. The heterodyne technique would compare the call to a 40kHz reference frequency and the audible output would be a 2 kHz tone

• The Second approach divides the detected frequency. Using this technique the frequency is usually divided by 16 – so a 42kHz bat call would come out as a 2.6kHz tone.

Each method has it’s pro’s and con’s. Before we can look at them I’ll first have to get the circuits working. Which I hope to show in the next post.

Fungus is Amongus

Over this this past year I’ve developed a renewed interest in mycology. This current experiment developed out of my renewed interest and my continuing fascination with mycology.

My current experiment involves growing Blue Oyster Mushrooms indoors using the Monotub technique adapted for use with sawdust as a substrate (growth medium).

This video summarizes the procedure and technique for setting up a Monotub (The Complete Monotub Tek Cultivation Walk-through 

I have seen oyster mushrooms grown on manure compost in Monotubes or in bags of sawdust or straw as well as outdoors on hardwood logs.  Since I have no access to a yard and since I have used the Monotub technique in the past I'm hoping that it will work with using sawdust as a substrate (growth medium).  I haven't seen anyone else growing them on sawdust in a Monutub and there may be good reasons for this though I haven't come across any yet.  Keeping my fingers crossed.

I am using standard storage containers, like in the video linked above.  For the growing medium I am using 10 cups of hardwood sawdust pellets, 2 1/2 cups wheat bran, 9-10 cups of spring water along with 1/2 of a 6lb bag of grain spawn. All of this was mixed up by hand in a 5 gallon bucket and transferred to one storage tub.  I repeated the process for the second tub.  

tubs with sawdust and spawn

Pictures at 5 days after inoculation.

tub fully colonized with mycelium

After 5 days I added a layer of casing, about 1 ½ inches of coconut husk fiber hydrated to “field capacity”.  "Field capacity" means that when you squeeze a handful of the material you should get a drip or 2 of water out.  Oyster mushrooms will fruit without a casing layer being added, unlike many other mushrooms.  I added the casing layer specifically to help maintain moisture and humidity levels within the tub.

Prep for adding casing layer

 

After adding casing layer

Now that the mycelium has fully colonized the sawdust substrate and I've added a casing layer of hydrated coconut fiber it is time to ensure correct conditions for fruiting (the fruit being a mushroom).

The most important environmental considerations in growing mushrooms are: light exposure, ventilation/air changes, humidity and temperature.  Each type of mushroom requires different conditions.  I've listed the specifications for "fruiting" for Blue Oyster Mushrooms in the chart below (this is a compilation of information from different sources and is not meant to be exact).

The simplest way to maintain these conditions is to open the tubs and use the lid to fan them several times a day along with using a mist sprayer to add water after each ventilation while keeping them in an area that is the correct temperature.

My next Fungal post will address controlling these conditions using sensors and micro-controllers.

The main supplies that I've used in this experimental test are listed below:

North Spore

• 10lbs Hardwood sawdust pellets

• “Harbor Blue” Pleurotus ostreatus (discount grain spawn)

Local hardware store and grocery store

• 2 gallons spring water (Ice Mountain)

• wheat bran (Bobs Red Mill)

Further information on growing Oyster Mushrooms can be found all over the internet.  A few reputable sources are listed below:

https://extension.psu.edu/cultivation-of-oyster-mushrooms

https://smallfarms.cornell.edu/projects/mushrooms/indoor-production/

Project Shocker/Zapper Training Knife

(This is a potentially dangerous device so home experiments are not recommended - it is far safer to use commercial products that have been tested and certified as safe).

I wrote this up a few years ago and it is still on my back burner as something that could be a useful training tool.

Having an extensive background in fitness training and martial arts (especially Filipino and Thai martial arts) I was exited to see a very useful training on Hack Your Brain - the ShocKnife.  In the past I've used wooden blades, foam blades, aluminum training blades, rubber blades and even ratan blades (while wearing padded armor) and even real (live) blades when doing drills.  I've always been concerned since it wasn't always obvious if I'd been hit and so was the training/sparring I was doing effective?

The ShocKnife seems to solve this, or at least makes it more difficult to ignore that you've been tagged in some way.  Seeing it, I really want one (or better yet 2 for sparring) but at a price tag of $200 each it is unlikely.

After some searching I found that a few other people made attempts at DIY versions:
https://fightsciencesresearchinstitute.wordpress.com/2011/08/29/diy-electric-training-knife/
http://www.martialmakers.com/?p=89

Seeing these attempts, and looking at the actual specifications of the ShocKnife I can see a few issues:

• total power delivered
• current delivered
• voltage delivered

For safety we need minimal current levels (even 30mA can kill at the right voltage level).
Voltage needs to be high enough for the shock to get through clothin.

Looking at the commercial product ShocKnife the StressBlade is their entry level trainer and the specifications they list are 

• 7500Volts, less than 1mA (7.5kV at 0.75mA which comes to 5.625Watts of Power.

Reviewing the Specifications of the Fly Swatter Racquet and a standard commercial Stun gun.  Before I reveal the actual specs I will say that both of these devices, without alterations, can produce burns and other injuries - the ShocKnife seems to not do this.
Specs

• BugZapper Raquet - 2AA bateries (3V) seem to be a few hundred volts (maybe in the thousands) - with a high milliamp output
• Stun Guns seem to use 100,000's to 1,000,000's Volts at a few milliamp's and the ones used by law enforcement can cause significant burns
  

For a DIY solution we definitely need to ensure a very low current output but at an output frequency that is irritating while being harmless to human tissue.

I am still quite tempted to just purchase one of the commercially available StressBlade.  It isn't something I actually need for training but just something I feel would add to knife defense training.

Resources:
Shocknife
Voltage Multiplier Design Guide

Multiple Project Updates Coming Soon

I've been working to update a number of projects that have been sitting on my to do shelf for way to long.  In the next few weeks I'll be doing write ups on the following:

• Rebuild of my 12kV (~900Watt) Spark Gap Tesla Coil (Old Sparky). Mainly a build of a new DIY low inductance High Voltage capacitor that should allow for better resonance and energy transfer (and bigger arc's).
  
  
  
• My DRSSTC build using OneTesla parts - I couldn't afford the complete OneTeslaTS kit so many of the parts I've fabricated on my own.
  
  
  
  
  
  
• Further work on my Voight Kampff machine - its been a long break but I'm back at it
  
  
  
  
  
  
  

COVID Isolation Project #14 PPE Tuesday AGAIN

COVID Isolation Project #14 PPE Tuesday AGAIN
I'm gearing up to produce a lot of face masks this week for the Illinois PPE Network. They gave me a lot of fabric to work with. To make some parts of the process easier I 3D-printed some pieces including a rotary cutter in Onshape (since all local sources were sold out even though they had blades). I worked up a simple design that I could 3D-print and assemble with parts I had on hand. (Rotary Blade Cutter).

I'm working on this project concurrently with my Tesla Coil upgrade.

COVID Isolation Project # 13 - Tesla Coil Upgrade

My Original big coil, "Old Sparky", needs a new high voltage capacitor. Since I do not have the cash to buy one I'm making another one. At a minimum it needs to handle 12kV. I definitely won't finish it today but when it is done it will likely result in 4' arc's off of this old spark gap coil. First pic is the old capacitor, next is the supplies for the new on, spark gap for coil, power supply (outputs 6kV peak to peak), voltage doubler (increases it to 12kV), variac to control input voltage and finally Old Sparky. I'll post video when it's working at full capacity again (hopefully by this weekend).

COVID Isolation Project #3- A Better Portable Harmonograph

What is a Harmonograph? It is much simpler to show what it does than explain the math and theory behind what it does so here is my current design in action:

Some drawing examples:

I've used a Harmonograph for outreaches and community activities in the past but the one we use is awkward to transport and had a rather large footprint (the width is greater than many standard tables – still works great though). For a long time I’ve wanted to design sleeker version that is easier to transport but performs just as well, if not better than our larger, heavier version (it’s a work horse and has worked for many years and stood up to a great deal of punishment).
My goals for this more portable Harmonograph are as follows:

• Made from easily sourced parts (making potential repairs much easier – nothing exotic in its design)
  
• Easily portable – fold up into a flat form (ideally into a flat box)
  
• Magnetic Drawing Platform to easily secure paper (no tape needed)
  
• Sturdy – difficult to damage (stands up to eager children)
  
• Safety features
  
• Carrying case should be a "Grab and Go" (no need to take additional supplies)
  
• Carrying Case will hold:
  
  • paper
    
  • colored pencils (lighter weight, less expensive and do not dry out)
    
  • pencil sharpener 
  • I found that colored pencils needed to much pressure (meaning increased friction and drag and shorter toal swing time).  Returning to pens
    
  • extra parts and tools (if needed)
    
  • Simple diagrams for setup (affixed to the inside of the case)
    

My current design utilizes a single piece of 3/4” conduit bent into the shape of a “U”. The base is made up of 4” x 1” lumber. This prototype does not fold up but the dimensions are set up to allow it once all other design features have been met.
The current drawing platform is made up of plywood and sheet metal (magnetic) and is sized to fit standard 8.5” x 11” paper including the magnets holding the paper down.
My initial pen/pencil holder was a spring loaded one that held the drawing instrument vertically above the board.  It ended up not working well.  The spring load mechanism would get stuck at random times.  It's possible that if it was machined on a lathe it may have worked out (though that might make it to delicate). 
My next pen/pencil holder design was a simple swing arm holder. In testing it proved too wobbly and resulted in poor drawing and increased friction (it only drew a few lines). In a much earlier trial (2 years ago) I used a more precise swing arm design that worked great but it was much to delicate (good lab design but not a good practical design).
I’m now attempting a more engineered design, stabilizing the swing arm with the addition of bearings, etc. My current prototype is not very elegant but I’m keeping my fingers crossed that this design will function better than the last one.
Making something new is always an iterative process. As long as you can learn something new from a design that fails to perform then you are making progress.
This design is definitely a work in progress but it’s getting closer every day to meeting my design goals. Once I get it to how I want it functioning then I’ll have to actually make the box for transporting it (another adventure in design… that I look forward to).
What I've discovered so far:

• need a heavier drawing platform to increase momentum (resulting in longer swing time)
• enlarge the drawing platform, possibly making it square to allow different orientation of the paper.
• I would like to add a method to adjust the length of the x or y axis pendulum motion to allow other figures to be drawn

COVID Isolation Project #2 - Short Shop Stools

Another simple woodworking project using basic tools.  I needed a few short stools so that I wouldn't have to kneel on the floor of my garage.

The stool dimensions are:
Top 12" x 5"
Sides 15" x 5"
I did place a central support in each stool that's 11" x 5"
Everything was glued prior to nailing (I don't have compressed air).

After gluing, nailing (I did use a punch to drive them below the surface) and sanding I applied 3 coats of Polyurethane (brushed on).

Supplies:

• 1/2" Baltic Birch Plywood
• Wood Glue
• Poylurethane
• 1 1/4" 3D finish nails

Tools:

• Saw (I used a circular saw with a homemade guide track) but a hand saw would do
• Hammer
• Clamps (I mainly used corner clamps)
• Drill to make guide holes for the nails

So far they are very stable and handle a lot of weight.

COVID Isolation Project #1 - Plane and Chisel Sharpening Jig

Due to COVID-19 and Social Isolation, to stay busy I’ve been trying to finish up a slew of projects that have been on my mind and some that I started but haven't finished yet due to other more urgent issues.  Some of these are very practical, some are experimental, others are likely a little silly or just for building a certain skill (Learning by making).

My first project, which I completed over the weekend is a jig for sharpening hy hand planes and chisels.  It's one piece that holds my wet stone and stops for setting blades in the xxx for standard sharpening angles.  The base is Baltic Birch 1/2" plywood.  My goal was to keep the setup as compact as possible. I used 1/2" square dowels to surround and hold the wet stone in place, these were clamped and glued in place. After the glue was dry I applied multiple coats of Polyurethane just to minimize water damage to the wood from the wet stone (water resistant but not water proof).

After the multiple coats of Polyurethane were finished drying I screwed down the right angle aluminum extrusion pieces as end stops for the 25 and 30 degree angles for chisel and plane blades.

Supplies

• 1/2” square dowel
• Baltic birch 1/2” plywood
• 1/2” right angle aluminum extrusion
• 8 x #6 1/2” screws
• Wood Glue
• Polyurethane

 Tools

• Saw
• Screwdriver
• Clamps 
• Ruler
• Right angle, 1-2-3 blocks or something else to align the blade stops

Heating element testing

I decided that I would finally test a 10cm length of 36 AWG nichrome wire with a current limited supply of varying voltages.  Since my windmill generates under 1 Amp of electricity I decided to use an LM317 integrated circuit to fix the current at a max of 220mA.  I put an LM317 in a bread board and attached its output to a 10cm length of 36 AWG nichrome wire (from the hair curler heating element).  Below is the circuit diagram for my LM317 set to limit current to 220mA:

Using the LM317 as a current limiter

Need to connect the 3 terminal chip as below:

     pic

To calculate the resistance that you need to limit the current to what you want:

     formula

In an effort to maximize the effectiveness of the heating element I decided to test different thicknesses (or gauges - higher the gauge thinner the wire) of Nichrome wire to see which would work best (produce the most heat with the power produced by the windmill - just under 2 watts). With this in mind I ordered 40 and 38 AWG Nichrome wire from Jacobs Online . They mainly sell Nichrome wire for making foam cutters and igniters for model rockets (the larger scale rockets). They are fairly inexpensive since you can order lengths as short as 10 feet – for $6 I got 10 feet of each of the 2 sizes I mentioned before (if I had wanted 100 feet of each I think it would have only cost me around $12 – better deal but I just don't want all the excess around).

Some basic notes on Nichrome wire:

• higher gauge (thinner) = higher resistance per unit length and heats up at lower power (less current)
• coiled wire produces higher temps than straight wire (with the same voltage and current)

More in depth info on nichrome wire take a look at the Wikipedia Page for Nichrome Wire

Resistivity of 1 foot straight Nichrome wire at room temperature:

AWG Ohms

40       70.2

38       42.2

36       27.0

Need some type of temperature resistant insulation between the wire  and the aluminum casing to prevent shorting out the current to the wire (do not want the wire in direct contact with the aluminum since it also conducts electricity). Insulation: Mica sheet, fiber glass fabric (welding supply, car body work with Bondo)

Ni-chrome Wire Calculator

Nichrome Wire Calculator

Gives you some ideas of what you need even though the lowest temperature on the calculator is 400 degrees Fahrenheit.

If average wind speed is 15mph – which produces 220mA at about 9volts. That gives us our average power available. Ohms law states V=IR rearranging we get R=V/I:

R = 9v/0.220Amps

R = 40.9 Ohms

So, with the windmill running with a 15mph wind producing 9 volts with 220mA (which is just under 2 wattS – P=9v*0.22A) if we use a length of wire with 40.9 ohms resistance it should use up all the power. Yes, I know its not perfect reasoning since resistance increases with increasing temperature in the wire but I'm just trying to get an idea of what I need before I begin trying things.

Project Neurofeedback: Going a bit further with EEG hacking (Part 3 - smaller unit)

Remove the TGAM1 Board

(This step is optional – I just wanted to remove parts that are not actually used and free up space. If you do this then you also need too add a 3.3v regulator circuit to the power supply, same as I did)
Separate the TGAM1 Board from the main board in the Mindflex Headset. This reduces the size significantly – Bluetooth board will fit with room to spare.

• Cut headers attaching boards
  
• Desolder and remove cut header pins
  
• Keep connections to (Header P1 connections on data-sheet)
  
  • Ground (electrode)
    
  • Reference (electrode)
    
  • EEG (electrode)
    

Adding a 3.3v regulator, with filter caps, to the power supply (3 x 1.5v AAA batteries in series).
3.3v regulator board (strip board)

• linear voltage regulator
  
• filter caps

SHOW-AND-TELL LIVE VIDEO! 9/6/17 #showandtell @adafruit #adafruit

Project viEwMotion

The goal of viEwMotion is to facilitate communication for individuals who have difficulty expressing emotions due to inherent neurologic issues like Autism, Parkinsons, etc (conditions that make it hard express emotion outwardly and as a result for others to read emotion expressed by the effected individual).  viEwMotion will do this by interpreting real time physiological data acquired from a wristband which is then processed by a single board computer and displayed to allow others to see the persons emotional state.  This will have a profound effect on the ability of people to communicate effectively - changing how they experience and interact with the world around them (in effect changing the world for them and those they interact with).
viEwMotion is a wearable device (worn on the wrist like a watch), that monitors and transmits data to a mini computer which interprets the data and outputs it to a display worn by the individual.

Voight-Kampff LED Bar-graphs

Working out the LED bar graphs on the Voight-Kampff machine:

Project Voight-Kampff

My objective is to build a functional Voight-Kampff machine from the classic Sci-Fi Movie Blade Runner. 

Leon's test :

Rachel's test:

Currently, I'm working on developing the software, integration of sensors and the actual body of the machine.

I currently have this project entered in the Hackaday Sci-Fi Contest  (Voight-Kampff Project Page) and I plan to exhibit it at the Chicago 2017 Maker Faire.

I have much of the mechanics (arm raise, extension, and rotation of the eye sensor) worked out using servos and micro-controllers.

My current design calls for using a Raspberry Pi as the central processor for the VK. The sensors that I'm currently working on integrating are:

• Melexis MLX90614 Non-contact Temperature sensor (for Blush response)
• Raspberry Pi NoIR Camera Board v2
  • using software adapted from PyGaze to measure pupil dilation/constriction
• Separate hand held module for test subject containing:
  • MAX30100 pulse ox sensor
  • Galvanic Skin Response Sensor

I aim to have it all contained in the classic VK machine with read outs from the sensors going to the 3 separate monitors (and the 2 LED Bar Graphs).

Project: A Maker Loupe

This project is also published on Hackaday.io as Maker Loupe
Commercial Products that work - but don't meet goals and restrictions:

• Dental Loupes (Links Comming)

What I've tried so far:

• Simple Magnifying Glasses – hand held and fixed
  • need to be very close to object being viewed

• Reading glasses (various magnifications)
  • higher the magnification → closer you need to be to what you are viewing
• Binocular Microscope
  • works quite well but still need to be bent over the scope
  • a movable stage would improve its ease of use
• USB Microsope
  • not much experience but they can have a bit of a delay (what you see can be a fraction of a second behind what is happening at the moment).
• Video Scope – NTSC camera, lenses and composite display
  • works reasonably well
    • may be able to improve by moving view screen lower and angling it

 Project Goals/Objectives:

• Comfortably working with small parts, components, etc. without having to be bend over or bring the parts close to my face.

• More comfortable – better ergonomics
• same as above
• able to sit upright while working (not bending over)
• inexpensive (under $100 or better yet, under $50)
• hands free / wearable / light weight
• Magnification (at least 2x)
• Field of view (at least 3cm)
• Depth (about 3cm, enough that working on projects does not lead to neck strain from holding position).

Project Restrictions:

•  Price - affordable for most people
• ideal is re-purposed parts 

Updates coming soon.

Update for the Start of 2017

Sorry for the long hiatus ...

Getting to the Finals of the Hackaday Prize and trying to get my project to a functional prototype really burned me out for a little while - I needed a little rest but I'm back now.

Have a look at the winning entries for the Hackaday Prize 2016 (they are really amazing).

• Hackaday Prize
• Hackaday Prize 2016 - Submissions
• Final 10 Entries of the 2016 Hackaday Prize 
• First Place for the 2016 Hackaday Prize
• Top 5 for the 2016 Hackaday Prize

I was hoping that I might be able to make it out to the Hackaday Conference (I even submitted a proposal for a talk). Well, I didn't make the cut.  But here are links to the amazing talks at the conference:

Not that I've ever stopped making stuff, just that I took a break from working on my Universal Glucose Meter, etc... and worked on some other areas for a bit.

Here's some stuff I've been busy with since November 2016:

• Cheapo SphereBot (from salvaged parts)
  
  
  
• Portable Oscilloscope Build (from kit, mostly) 
  
• Reflow Oven (ControLeo 2, some very minor additions from me)
  
• 2 Watt LED (445nm) Laser for 3D Printer, CNC (kit build, and review)
  
• Sous Vide Build 

I'll link each of these to individual project pages with build information ASAP.

Chicago Southland Mini Maker Faire 2016

A basic word of warning to others: Static Electricity Generators are not a great idea in high humidity conditions (relative humidity inside was over 50%).  My Van De Graaff generator experienced a mess of problems - from belt problems (thankfully I brought a backup with me), alignment of brushes and (of course) output.  The size of my Van De Graaff should make discharges at least a foot long - due to humidity I could only achieve about 1/2 inch.

This years Faire was great, even with the hot and humid weather (we were all, thankfully, inside).
See Pictures below: