Idea Log

a record of ideas I've come up with

List of my favorite …

This is my favorite every thing list


Color…Snow fox white


Book…Slaughter House five
Movie…Twelve Monkeys
TV show…Firefly


Actor…Charlie Chaplin
Artist…Andy Goldsworthy


Subatomic particle…
Bird family…Bower Birds
Animal…Pink fairy armadillo
Crystal structure…
Carbon structure…


US State…Washington
US National Park…Yosemite


Capacitor type…ceramic
Microcontroller…Atmel AVR
OS…Debian Linux
Window manager…XFCE4
Terminal emulator…terminology
Web browser…Firefox
Ascii char…
Programming language…perl
Keyboard key…Esc


My cheese list. Reviews, opinions, ratings

This is mostly a list to so i can remember what i like.

General Cheese Types


Name Type Rating notes
Swiss Swiss 8
Baby Swiss Swiss 7
Stilton Bleu 4
Bleu Bleu 4
low moister skim milk mozzarella mozzarella 8
paneer paneer 4 mostly flavorless
Gouda Gouda 8
Feta Feta 7
Cheese curds 7
Cotija 6
Queso Fresco
Oaxaca 9
Rancharo Queso Fresco 7
Muenster 6
String Mozzarella 8
Pepper Jack 4
Colby 6
Colby Jack 6
Cream cheese 6
Provolone 7
Havarti 6
Parmigiano-Reggiano 9
Romano 8
Asiago 7

Specific Cheeses

Manufacturer Name Type Rating notes
Babybel Mini Semi-soft 5
Beecher’s Handmade Cheese New Woman 9 spiced
Cacique Oaxaca mozzarella-ish 8 Kinda like string cheese
Cacique Ranchero Queso Fresco 7
Cacique Queso Fresco 7
Lucerne Low-moisture Part-Skim Mozzarella Mozzarella 6 low quality mozzarella
Murry’s Pawlet Swiss-ish 4
Murry’s Smoked Gouda Gouda 7
Murry’s Parrano with Truffle 4 not to my taste, not vegetarian
Murry’s Muenster Enchilado Muenster 7
Murry’s French Double Crème Brie Bree 4
Murry’s Raclette 2
Sartori Kentucky Bourbon BellaVitano 8
Trader Joe’s Toscano Cheese with Black Pepper 9 creamy, nutty, nice pepper added, good on bread or crackers
Trader Joe’s California Mild 7
Tillamook Vintage Extra Sharp White Cheddar Cheddar 9 Good, not vegetarian
Tillamook Medium Cheddar Cheddar 9 all around good
Jarlsberg Emmentaler cheese Swiss 10
Castello Edam mozzarella-ish 5 taste like cheap mozzarella, better when melted

Murry’s cheeses
wikipedia cheeses

Script to test internet connectivity and log results

I was having intermittent problems not being able to connect to the internet and needed to find out when and how often it happened.

I also wanted to see if it was WIFI, or entire network that was the problem so i had multiple computers using different connections to the network. So i could run the script and compare logs


So here is the bash script:


DELAY=60 # every 60 sec

while true; do
$WGET -q --tries=20 --timeout=10 -O /tmp/google.idx &> /dev/null
if [ ! -s /tmp/google.idx ]
echo `date` "--- Not Connected..!" 2>&1 | tee -a connectivity.log
echo `date` "--- Connected..!" 2>&1 | tee -a connectivity.log

sleep $DELAY

The script check the internet every 60 seconds and displays date and time with the internet status and logs in to the file connectivity.log

Example output

Mon Sep 10 13:52:31 MDT 2018 --- Connected..!
Mon Sep 10 13:52:37 MDT 2018 --- Connected..!
Mon Sep 10 13:52:42 MDT 2018 --- Connected..!
Mon Sep 10 13:52:48 MDT 2018 --- Connected..!
Mon Sep 10 13:52:53 MDT 2018 --- Connected..!
Mon Sep 10 13:52:59 MDT 2018 --- Connected..!
Mon Sep 10 13:53:04 MDT 2018 --- Connected..!
Mon Sep 10 13:53:10 MDT 2018 --- Connected..!
Mon Sep 10 13:53:15 MDT 2018 --- Connected..!
Mon Sep 10 13:53:21 MDT 2018 --- Connected..!
Mon Sep 10 13:53:26 MDT 2018 --- Connected..!
Mon Sep 10 13:53:32 MDT 2018 --- Connected..!

Idea: Incorporate speaker profiles in computer audio output.

I just read that this article about Apples HomePod speaker performance, and read how the DSP corrects for the actual speakers natural imperfect frequency response.

Ideally you want you audio to have a flat frequency response.  Audio in = audio out at every frequence. Speakers aren’t perfect so this doesn’t happen.  Some are louder at lower frequencies others are louder at mid frequencies, and so on.

What the HomePod does is increases the volume on frequencies the speaker is poor at, so the speakers output has a near perfect frequency response.  This isn’t difficult for a DSP to do if you know the speakers frequency response curve, and this is common thing measured for every speaker.

So my idea is, What if you could enter you speakers “Brand” and “Models number” into your computer and have its DSP auto-correct for your speakers imperfect frequency response.  This should be fairly easy to do.  A database of speaker profiles would have to be created, but after that computer DSPs already accept custom frequency response profiles (bass-boost, vocal, etc)

I have a similar thing with my digital camera and graphics editor.  I can enter my cameras lens in the graphics program and it will correct for my lenses slight distortions in color, geometery, etc.  And this is much more complex than speaker profiles.  Its hard to believe no ones done this.

Some possible challenges.  Speakers distort if volumes are too high volumes.  Having DSPs correcting for speakers poor outputs at certain frequencies  may require the volume to increase at that frequency to make the distortion noticeable.  So these factors would have to be added to the speakers profile.  Such as max volume profile curve to each frequency.  Another factor is the amplifier, or any other stages between computer and speaker.  Audio amplifiers ideally have flat frequency responses, but this is not always true.  So these profiles may want to be added as well.  But these are minor difficulties and easy to correct.

So if anybody want to take up this idea and make it reality, go for it.

Sort of common sources for chemical elements

Here is a list of Elements that you can find at home in their relatively pure form. Or as pure as possible.  Some of the sources are less common.  Some are very rare.


Common metals

Hydrogen [1]

Helium [2]

  • Helium tank for balloons [purity > 90%]

Lithium [3]

  • lithium grease [purity <10%] (low purity source)
  • lithium medicine [purity = 13.6%] (low purity source)
  • lithium batteries [purity <5-10%] (low purity source)

Berylium [4]

  • White ceramic electrical insulators (Beryllium oxide) [purity = 35%] (low purity source)

Boron [5]

  • Boric acid [purity <50%] (low purity source)

Carbon [6]

  • pencil graphite [purity > 95%]
  • graphite lubricant [purity > 90%]
  • dimonds [purity > 98%]
  • charcoal

Nitrogen [7]

  • The air around you is 78% nitrogen

Oxygen [8]

  • oxygen tanks at hardware stores or medical supplies [purity > 95%]

Fluorine [9]

  • Teflon thread seal tape [purity = 75%], best you will probably get

Neon [10]

  • neon lamps
  • small neon bulbs  (in old power indicators) [Purity >95%]

Sodium [11]

  • lye [purity  = 57%] (low purity source)

Magnesium [12]

  • Camp fire starter [purity = 97.2%]

Aluminum [13]

  • soda can
  • aluminum wire [Purity > 95%]
  • aluminum foil
  • aluminum heatsink [Purity > 99%]

Silicon [14]

  • microprocessor die

Phosphorus [15]

  • red striking surface of match box  (red-phosphorus) (low purity source)
  • strike-anywhere matches (low purity source)

Sulfur [16]

  • Pharmacies sell sulfur powder at [purity > 95%]

Chlorine [17]

  • table salt (NaCl) [purity = 50%] (low purity source)
  • Calcium chloride ice melter (low purity source)

Argon [18]

  • the gas inside a basic incandescent bulb [purity > 90%]

Potassium [19]

  • Salt substitute (NoSalt, Diet Salt) [purity = 52%] (low purity source)
  • Potassium Permanganate –  Aquarium disinfectant [purity = 25.7%] (low purity source)
  • Potassium Hydroxide – caustic potash –  [purity = 69.7%] (low purity source)
  • Potassium Carbonate – white powder solution leaking from an alkaline battery –  [purity = 56.6%] (low purity source)

Calcium [20]

  • Chalk (Calcium carbonate) [purity = 40%] (low purity source)

Scandium [21]

  • metal-halide bulb, Microsun bulb or dual-arc bulb [purity <1-2%] (low purity source)

Titanium [22]

  • titanium nuts and bolts [purity > 90%]
  • titanium golf clubs, tools, or jewelry [probable purity > 90%]

Vanadium [23]

  • chrome-vanadium steel [purity <1%] (low purity source)

Chromium [24]

  • stainless steel [purity <13-26%] (low purity source)
  • chrome-vanadium steel [purity <1%] (low purity source)

Manganese [25]

  • Lithium-manganese battery [purity < 50%] (low purity source)

Iron [26]

  • Nails [purity > 98%]

Cobalt [27]

  • Cobalt blue paint [purity <30%] (low purity source)

Nickel [28]

  • Canadian quarters pre 1990
  • The flat tab/wire attached to lithium ion battery cells in lithium-ion batteries

Copper [29]

  • copper wire [Purity >99%]
  • copper pipe
  • US penny, 1909-1982 [Purity =95%]
  • copper heat sink [Purity >99%]

Zinc [30]

  • US penny 1983-current, just remove the copper plating [Purity = 97.5%]
  • Zinc plated nails (low purity source)

Gallium [31]

  • Galistan thermometer [Purity < 65%]

Germanium [32]

  • Old germanium diode [purity = 99.99%]
  • germanium lenses used to focus infrared lens [Purity = 99.9%]

Arsenic [33]

  • CCA treated wood [purity < 5%] (low purity source)

Selenium [34]

  • photocopier drums [purity < 10%]

Bromine [35]

  • Hot tub salt/cleaner (NaBr) [purity = 77%]

Krypton [36]

  • Krypton Flashlight bulbs [purity > 90%]

Zirconium [40]

  • Old camera flash bulb, filament [purity > 50%] (low purity source)
  • Cubic zirconium [purity = 74%]

Niobium [41]

  • Belly rings and other niobium piercings [Purity > 80%]

Molybdenum [42]

  • Moly grease [purity <10%] (low purity source)
  • Moly powder (Molybdenum Disulfide) [purity = 60%] (low purity source)

Ruthenium [44]

  • pewter-colored beads (ruthenium plated)[plating purity = 99%]

Rhodium [45]

  • Rhodium plated jewelry [plating purity > 90%]
  • Reed switches [plating purity = 98%]

Palladium [46]

  • gold-palladium spark plug [purity <50%] (low purity source)
  • Catalytic converter [purity = 1%] (low purity source)

Silver [47]

  • silver jewelry (marked 925, is 92.5%, 999 is 99.9%)
  • true silverware
  • Pre 1964 USA dime/quarter/half dollar coins (purity = 90%)
  • pre 1967 Canadian coins

Cadmium [48]

  • Ni-Cad batteries [purity  = 3-17%] (low purity source) [2]
  • Cadmium yellow paint [purity <30%] (low purity source)
  • Photoresistor (Cadmium sulfide) [purity <30%] (low purity source)

Indium [49]

  • LCD screen (indium tin oxide make clear wires on thin film of LCD) (very low purity source)

Tin [50]

  • lead-free fly fishing, Split-Shot and Weight
  • Lead Free plumbing solder Alloy of 95% Tin and 5% Antimony. [purity = 95%]
  • Old tin toys

Antimony [51]

  • Lead-free plumbing wire solder [purity = 5%] (low purity source)
  • Antimony toys (like tin toys, but with antimony)
  • Antimony jewelry box

Tellurium [52]

  • CD-RW, DVD-RW Tellurium suboxide [Purity < 1%] (low purity source)
  • thermoelectric heat pump, Bismuth telluride heat pump. [Purity < 20%] (low purity source)

Iodine [53]

  • Tincture of Iodine [purity < 5%] (low purity source)

Xenon [54]

  • strobe light flash [purity > 95%]
  • Xenon short-arc lamp [purity > 99%]
  • small flashlight xenon bulb [purity > 5%] (low purity source)

Cesium [55]

  • Cesium Chloride [purity = 79%]

Barium [56]

  • Barium enema [purity < 50%] (low purity source)

Lanthanum [57]

  • Gas lantern mantels [purity < 40%] (low purity source)
  • Lighter flints (mischmetal) [purity < 20-30%] (low purity source)

Cerium [58]

  • Lighter flints (mischmetal)[purity < 20-30%] (low purity source)
  • campfire starter flint(mischmetal) [purity < 20%] (low purity source)
  • Cerium oxide – glass polisher conpount

Praseodymium [59]

  • fake peridot (cubic zirconium, tinted with Praseodymium) [purity < 1%] (low purity source)

Neodymium [60]

  • Neodymium (NbFeB) magnets [purity = 29-32%] (low purity source) [ref]
    • remove the nickel shell to get to the magnet partsome

Promethium [61]

  • No known common sources

Samarium [62]

  • samarium cobalt magnets [purity < 30%] (low purity source)
  • Guitar pickup(with samarium cobalt magnets) [purity < 30%] (low purity source)

Europium [63]

  • Glow in the dark power [purity < 2%] (low purity source)
  • Glow in the dark paint [purity < 50%] (low purity source)

Gadolinium [64]

  • No known common sources

Terbium [65]

  • No known common sources

Dysprosium [66]

  • Neodymium (NbFeB) magnets from electric cars may contain 0.8-1.2% dysprosium, but hard drive magnets do not. [ref][ref]

Holmium [67]

  • No known common sources

Erbium [68]

  • Erbium-Doped Fiber optic wire

  • Pink Torchworking/Lampworking glass rods [purity < 10%] (low purity source)

Thulium [69]

  • No known common sources

Ytterbium [70]

  • No known common sources

Lutetium [71]

  • rare, uncommonly used and expensive
  • No known common sources

Hafnium [72]

  • Hafnium Plasma cutter electrode [Purity > 70%]

Tantalum [73]

  • Tantalum capacitors [Purity: 40-50%](low purity source)
    • have a tiny pure tantalum rod(anode), surrounded by tantalum-pentoxide(dialectic), the case and leads, easy to crack open the removed[ref][ref][ref]

Tungsten [74]

  • incandescent light bulb filament [purity > 90%]
  • Tungsten carbide tools and stuff [purity < 50%] (low purity source) varies, can be higher

Rhenium [75]

  • Rhenium camera flash bulb [purity > 50%] (low purity source)
    • The igniter is rhenium, not the filament

Osmium [76]

  • Some Osmium phonograph needles [purity < 50%] (low purity source)
    • some Osmium phonograph needles have none

Iridium [77]

  • iridium spark plugs [purity > 90%]

Platnium [78]

  • platinum spark plugs [purity > 90%]
  • platinum jewelry

Gold [79]

  • 24K gold is 99-100% or close to it

Mercury [80]

  • old thermostats
  • old thermometers

Thallium [81]

  • No known common sources

Lead [82]

  • automobile tire balance  (with steel attachment removed)
  • lead fishing weight
  • lead bullet

Bismuth [83]

  • “Safe” shotgun shot pelets [purity = 97%]
  • pepto-bismol [purity <57%] (low purity source)

Polonium [84]

  • polonium is radioactive and has a half life of 138 days, so what ever your source it won’t last more than a year
  • Phonograph antistatic brush [purity <20%] (low purity source)

Radium [88]

  • Radioactive!
  • spinthariscope [purity <0.1%] (low purity source)
  • radium watch hands, probable the best source you will find [purity <1%] (low purity source)

Thorium [90]

  • Some old coleman-type camping lanterns, probably the best source you will find. [purity < 30%] (low purity source)
  • thoriated tungsten welding rods [purity = 1.75%] (low purity source)

Uranium [92]

  • Fiestaware ceramic tableware [purity < 5%] (low purity source)
  • Vaseline glassware [purity < 5%] (low purity source)
  • Vaseline glass marbles [purity < 5%] (low purity source)

Neptunium [93]

  • Smoke detectors
    • Smoke detectors actually contains Americium, which has a half life of 471 years. and decays into neptunium.  So the Americium turns to neptunium about 1% each decade.
    • radioactive, it is safe if kept in glass bottle, since alpha particles don’t penetrate glass, or the cork.

Americium [95]

  • Smoke detectors
    • radioactive, it is safe if kept in glass bottle, since alpha particles don’t penetrate glass, or the cork.

Noncollectable elements:

In pure form:

  • Fluorine[9]:Pure form can’t be stored for any reasonable time, combustive on contact to pretty much everything

In general:

  • Technetium[43] – radioactive and pretty impossible to get
  • astatine[85] – extremely short half-life
  • radon[86] – Radioactive gas, has a half-life is only 3.8 days, so it can’t be collected by its self. Thorium breaks down to Radon, so if you have some Thorium in a sealed container, then you have a microscopic amount Radon.
  • francium[87] – extremely short half-life
  • actinium[89] – extremely short half-life
  • protactinium[91] – extremely short half-life
  • Plutonium[94] – Pretty much illegal to own
  • Rutherfordium[104] – does not occur in nature, extremely short half-life
  • Dubnium[105] – does not occur in nature, extremely short half-life
  • Seaborgium[106]
  • Bohrium[107]
  • Hassium[108]
  • Meitnerium[109]
  • Darmstadtium[110] –
  • Curium does not occur in nature, but it can be created in nuclear reactors and it has a few industrial applications. It is extremely radioactive, extremely toxic, and extremely hard to get.
  • Berkelium does not occur in nature, but it can be created in nuclear reactors and it has a few industrial applications. It is extremely radioactive, extremely toxic, and extremely hard to get.
  • Californium – does not occur in nature, but it can be created in nuclear reactors and it has a few industrial applications. It is extremely radioactive, extremely toxic, and extremely hard to get. [1]
  • Einsteinium
  • Fermium[104] – does not occur in nature, extremely short half-life
  • Mendelevium[104] – does not occur in nature, extremely short half-life
  • Nobelium[104] – does not occur in nature, extremely short half-life
  • Lawrencium[104] – does not occur in nature, extremely short half-life



Here are some items that have high purity while still remaining fairly cheap.  It is sometimes cheaper to get it in wire form, while others are cheaper in lump for.  I try to list the cheapest form.

  • 10mm X0.15mm 99.7% Pure Nickel strip for 26650 18650 21700 battery spot weld ($2-4)
  • Niobium Nb1 wire 99.99 pure ($2-5)
  • Pure Titanium wire 0.5mm uncut 99.99 Ti wire grade A ($1-4)
  • 10 grams 1.76oz High Purity 99.7% Manganese Mn Metal Lumps Vacuum packing ($1-3)
  • 10 grams High Purity 99.999% Zinc Zn Metal Lumps Vacuum packing ($2-4)
  • 10 grams High Purity 99.99% Chromium Cr Metal Lumps Vacuum packing ($2-4)
  • 5 grams High Purity 99.995% Indium in Metal Lumps Vacuum packing ($5-8)
  • 5 grams High Purity 99.99% TELLURIUM Te Metal Lumps Vacuum packing ($3-7)
  • 10 grams High Purity 99.99% Cobalt Co Metal Lumps Vacuum packing ($2-7)
  • 2 grams High Purity 99.99% Vanadium V Metal Lumps Vacuum packing ($3-7)
  • 20 grams High Purity 99.9999% Monocrystalline Silicon Si Metal Lumps ($3-7)
  • 10 grams High Purity 99.99% Bismuth Bi Metal Lumps Vacuum packing ($1-4)
  • N1 Rolls 99.95% 25g 70ft Magnesium Ribbon Lab Chemicals ($2-4)
  • Lanthanum Metal 99.7% Pure 5g ($6)
  • Dysprosium Metal 99.5% Pure 5g ($5)
  • Cerium Metal 99.95% Pure 5g ($5)
  • Gadolinium Metal 99.9% Pure 5g ($5)
  • Erbium Metal 99.9% Pure 1g ($5)
  • Iodine “Metal” Crystals 99.8% Pure 10g ($6)
  • Terbium Metal 99.5% Pure 1g ($5)
  • 0.1 gram 99.99% Scandium Metal in glass vial – Pure Element 21 sample ($12-20)

  • Molybdenum Rod Mo Metal Rod Diameter 10mm Length 50mm Purity 99.95% ($6-10)

  • 10grams High Purity 99.999% Molybdenum MO Metal Lumps Vacuum packing ($4-6

 My collection:



DIY milk crate container on bike rear mount with lockable compartment

After the second time my homemade tire repair kit got stolen, I decided I needed a lockable place to keep it.  So I made a lockable container incorporated in my milk crate storage container.


  • Milk crate
  • Bolts (to attach milk crate to rear mount)
  • Polycarbonate sheet (stronger than plexiglass, and better in cold weather)
  • Wood blocks (to reduce stress on the hinges
  • 2 hinges (to hinge the compartment cover)
  • 1 hinge or latch (for the lock)
  • pop-rivets and washers ( to attach the hinges to the cover and crate)
  • steel L-bracket (to re-enforce the latch/lock)

You have probably seen milk crates attached to the rear mounts of bikes.  I added a small lockable compartment, using 3 hinges and a polycarbonate panel.  the third hinge is used as a lockable latch.  The wood blocks are added to reduce stress on the hinges.  I also added a polycarbonate panel on the top and bottom of the bottom of the milk create because the milk create wobbles sometimes and my last one broke.

Here are some out of focus photos of the lockable compartment.




Here I attached a bent L-bracket and the bent hinge/latch to create a stronger lockable latch.

Some final comments

This isn’t the strongest lockable compartment the hinges I used were lighter than heavy duty hinges.  The pop-rivets are better that using screws, as they can’t be unscrewed, but they are aluminum and can be drilled out.  So the hinges and pop-rivets can be pried up with a long screw driver or pry-bar.  Also the latch/lock thing can be broken.  But this will take allot of effort and can’t be done without causing a commotion.  So I figure it is safe enough, but wanted to warn you.

Uses for California’s excess power

Currently California is producing too much power, and its causing problems.  When power production is greater than power used, the power lines get overloaded, ironically creating outages.

31 days in 2017 California had so much power that it had to pay Arizona to take it’s excess power.

“In 2015, solar and wind production were curtailed about 15% of the time on average during a 24-hour period. That rose to 21% in 2016 and 31% in the first few months of this year.” [1]

Curtailing of power means that the solar panels are disconnected and/or the wind turbines are stopped.

The solution to this is to produce exactly the amount of power as needed.  Most power plants can’t do this, so this is unrealistic probably impossible.  The other solution is to dynamically add a load that uses the excess power.  This can be done by monitoring power produced and power used, then adding a constantly changing load so power produced is the same as power used.

Most residential, industrial, and commercial loads don’t/can’t do this.  The energy could be off loaded with giant resistors producing waste heat, but this is non-sensible.  So what to do with the excess power that is non-constant.  Here is my ideas.

  1. Desalinization plant: California needs water.  Desalinization plants could be made to turn on only when there is too much power
  2. Distributed computing:  Get a university to set up a ton of old/obsolete computers in a big warehouse, then use it to preform massive calculations, when there is too much power.
  3. Crypto-currency: Make a deal with a company to create crypto-currency only when there is too much power, give the power for free or cheap, then split the profit, or something
  4. Hydrogen production:



Replacing cordless power drills batteries with lithium batteries

  • Lithium batteries have great capacity, light weight, long lifetimes.
  • NiMH batteries are OK-ish, medium capacity, good voltage levels over discharge level, heavy weight, medium lifetimes
  • NiCd batteries suck. low capacity, normal weight, low lifetimes, bad for environment.

So I replaced my old battery packs with lithium-ion batteries from old laptop batteries.

Dead laptop batteries often have only one or two dead cells or have been left uncharged for too long.  So I measure each cell and if the battier is above 2V I keep it, lower I recycle it.  Mixing Li-Ion batteries is not the best solution but I had to use various old laptop batteries, and it works.  Possible problems with mixing batteries are if 2 different batteries with different capacities, the lower capacity could discharge below minimum level and cause damage, lowering the capacity even more.  Not the end of the world.

Drills I have modified

Skil 2585

  • Voltage Rating: 14.4V
  • Original batteries: DW9061
    • C-cell, NiCd
    • Capacity: 1.2Ah
    • Load: forgot to measure before I recycled them
    • Cost: $50
  • New homemade battery configuration
    • 8-cell Lithium-Ion 18650
    • Configuration: 4S-2P
      • 4 is series gets pretty close to the voltage rating
      • 2 in parallel  @ 2C, with new batteries, max recommended current would be 16A
    • Voltage: 14.8V (12-16.8V)
    • Capacity: 4Ah (2Ah with my used batteries)
    • Measured Load: forgot to measure
    • Protection circuit: 15A 4S Li-ion Charger Protection Board
      • Max average current: 15A(Natural cooling 10.A, add heat sink 15A, the maximum instantaneous current 30A)
    • Add-on: 4S Lithium Capacity meter indicator/display


Dewalt DW952

  • Voltage Rating: 9.6V
  • Original batteries: DW9061
    • 8-cel, C-cell, NiCd
    • Capacity: 1.7Ah(DW9061 XR)
    • Load: forgot to measure before I recycled them
    • Cost: $50
  •  New homemade battery configuration
    • 6-cell Lithium-Ion 18650
    • Configuration: 2S-3P
      • I was worried that 3 in series would make the voltage too high (9-12.6V)
      • I decided to put 3 in parallel to supply the high current @ 2C max recommended current would be 18A
    • Voltage: 7.4V (6-8.4V)
    • Capacity: 6Ah (3Ah with my used batteries)
    • Measured Load: 5A(no load), 20A(extreme load)
    • Protection circuit: 2 S 15A 7.4 V Li-ion  Battery Protection Board
      • Maximum continuous discharge current: 15A
      • Over current protection: 20.8A
    • Add-on: 4S Lithium Capacity meter indicator/display


Batteries used


  • Nominal Voltage: 3.7V
  • Size: 18650 (Cylindrical)
  • Capacity: 3000 mAh
  • Chemistry: Lithium Ion (Rechargeable Li-Ion)
  • Brand: LG



  • Nominal Voltage: 3.7V
  • Size: 18650 (Cylindrical)
  • Capacity: 2800 mAh
  • Chemistry: Lithium Ion (Rechargeable Li-Ion)
  • Brand: LG
  • Max Charging current: 2.7A
  • Max Discharging current: 5A

Sony US18650GR (G6 date code)



Power strip controlled by computers on/off status

So i wanted to have some of my peripherals turn off when my computer is off. Speakers and lamp and such.  I made a simple one using USB power to switch on/off a power strip but modern PCs have USB powered on always.  So without some intelligent circuitry, this will no longer work.

So what i use now is a power strip controlled by the PCs power supply.  Essentially I have a relay that switches when the computers power supply is on.  But with some added protection, so I wont damage anything inside the PC.


The PCs power supplies “12V” output is hooked into an isolation DC-DC converter, then a linear regulator.  This protects the PC if there is a short or if the external wires touch a high voltage by accident.  I put these all on a card to make it pretty, and more convenient.  After the protection circuit a cable connects to the power strip.  Inside the power strip a relay is controls the hot line of the power strip.  I used a small power strip to save space and to remind me not to plug too much into it.


Parts List:

  • Molex 8981 – Disk Drive Power Connector
  • VB1212LS-1W – Isolated 12V-12V DC-DC converter
    • VB1212LS datasheet
    • You can use any isolated DC-DC converter that allows Vin=12V and Vout>6.5V and max power > 0.1W
  • 5V linear regulator
    • You can use any 5V linear regulator or LDO that allows Vin=12V
  • 5V relay
    • You can used any 5V relay with switch voltage>=110Vac
    • Note that the max switch current of the relay is the max current you can use on the power strip
    • I used a 4.5V relay, because that is what I had.  If you use a 5V relay remove the diode, “diode1”
  • diode
    • Can use any switching or rectifier diode. I used 1N914
  • 1uF capacitors
    • I used 1uF electrolytic capacitors
  • Power strip









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