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And we’re back with our fifth installment of Your Comments. Here are our favorites from the past week, from Make: Online, our Facebook page, and Twitter.

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vt-pete sends his regards to the creator of the 30MPH electric mountain bike:

“Unfortunately, Jennifer has already wrecked the bike and broken her elbow,” — ha! Get well soon, and keep up the great work. I’m guessing a little lack of mobility will give her some brain-time to work out the kinks in her system.

A comment by MadRat left us scratching our heads at what we could have done to prompt it. Oh yeah, it was that post about using squirrels as a power source:

I imagine you could create a squirrel catapult that would throw a squirrel safely into a net where it could climb up the net and get a free meal. It would be interesting to see how many squirrels would be willing to put themselves into a squirrel launching device and be thrown across the yard to a free meal. The scientific and entertainment possibilities are endless. Imagine a warm, Summer day, relaxing on a chase lounger, sipping an ice cold drink and watching squirrels flying over head and recording the result for science! The question is how would you calibrate, power and reset the squirrel launcher?

Indeed! Where can we sign up?

Our DIY Digital TV Coat Hanger Antenna project remains a top favorite. VanHalensing recently built it, and offers these tips:

My wife and I built this antenna, and it works better than the amplified one we had before. It picks up all of the local stations through all the apartment buildings in our complex with no troubles. The only suggestions I have are these: 1. Use both the video and the PDF, some of the dimensions are hard to use unless you use them both. When it says a 3″ board, they mean 3″, not a 3″ wide board from the store (2.5″), they’re using exact dimensions. So, measurement wise, the screws are 2.5″ apart, which is important. 2. I would use a 4″ board from the store (which is actually 3.5″ wide when you measure it, see number 1) for stability. 3. The middle screws are centered, ignore the 10″ dimension on the right in the PDF, this causes them to be non-centered. Alternatively, you could change the 2″ on the top to 1 3/8″, which would also fix this. 4. Measure your hangers, not all hangers are wide enough to provide 2 8″ V’s, so you may require more hangers, and you shouldn’t skimp on the length of those V’s, it will mess with your reception. 5. If this is going anywhere people may touch it, I suggest using a metal file on the tips of your wires, those wires can be wicked sharp. Other than those minor things, this is an awesome antenna! We painted our boards black first, and sanded the coatings off of all of the hangers, and the whole thing is black and silver now, very cool. I suggest this antenna to anyone who is having antenna troubles.

Over on Twitter, MAKE writer Sean Ragan made a profound observation:

“I stand behind this product, because it’s not safe to stand in front of it.”

Commenter bbum shared some wisdom about The curious case of the 7% resistors:

Lots of electronics are made with a similar attitude. First you manufacture something in bulk, then you test the product and price it according to how fast/error-free/close-to-tolerance it is.

Two examples:

Any given model of CPU comes in multiple speeds. They are all really from the same manufacturing line. In the test harness, the manufacturer runs the CPUs up to the various standard speeds. If it succeeds at a lower speed and fails at a higher speed, the part is marked for distribution as the lower speed, cheaper, SKU.

For memory, a manufacturer will generally try to run a production line targeting the higher margin, higher capacity, parts. If a part fails, it is determined if a particular bank of bits are bad. If they are and if the addressing lines can be rewired to effectively turn off that bank, the part will be sold as a lower capacity, cheaper, component. If a part is failed because the error rate is too high for, say, operation in a computing device, it may be packaged and sold into applications that can handle the high error rate. For example, the memory used in voice recorders doesn’t really have to be that terribly bulletproof as it is generally recording a pretty darned low quality signal in the first place. A few extra bits of error here and there just doesn’t make a difference.

It really is a very fascinating sector of industry. I’m sure there are many more examples (and I’m sure my examples have been further optimized in the years since I first learned of them).

And on Facebook, Eric Singer had his own method for how to Spruce up an old BBQ:

Here’s how I “spruced up” my Weber kettle BBQ:

Get a 10′ roll of 1/2″ soft copper coil. Loosen the coil so it looks like it will fit in the bottom of your grill, under the charcoal grate. Straighten out the outside end so you have an extra 2′ straight (uncoiled). Cut the excess off (invest in a tube cutter).

Take the inside end, flatten with a hammer, fold and flatten again so it’s sealed. Drill 1/16″ holes at ~1″ intervals on the top side of the coil.

Drill a > 1/2″ hole through the grill near the bottom, and install the coil such that it sits in the bottom and the straight part sticks out the hole.

Cut the straight part again to the desired length. You can snake it down to the ground, around a leg or whatever (this will make more sense below).

Get a brass gate valve (the kind that you attach a garden hose to). The smallest you’ll probably be able to get retail is 1/2″ (or order 1/4″ from mcmaster.com, though $). Attach the protruding end of the copper tube to the gate valve. Depending on the type of valve and what adapters you attach to it, you can solder (hard), flange-fit (easier but requires a tool) or compression fit the copper.

Get a propane hose with a POL (standard propane) fitting on one end, and either a threaded other end, or with the other end cut off. If cut off, use a barb fitting on that end and secure with a hose clamp. Screw this to the other end of the gate valve.

Now you have propane->gate valve->copper coil sealed at one end and drilled with little holes aka a combo gas/charcoal kettle grill. If you’re feeling lazy, just use it as a propane grill. If you want to use charcoal, fill the bottom with charcoal, ignite the propane and regulate it (using the gate valve) so that it dances above the charcoal. In a few minutes, you’ll have white-hot coals.

Other important things:

Everywhere you screw fittings together, use yellow gas-rated teflon tape or gas-rated teflon pipe dope. If tape, hold the outside-threaded fitting in your left and and overhand-wrap 6-7 turns of tape on the threads.

You can use soapy water to check seals for leaks.

Don’t substitute air hose for the propane hose. It’s not rated for gas.

To light, make sure both valves are off, put a flaming paper towel in the grill bottom, then open the propane, then the gate valve.

Make sure the vents at the bottom are open, so the flame can get air. BTW, it gets a lot of its air from the top, so it doesn’t work well with a lid on. At least, leave the lid ajar.

Like these comments? Be sure to sound off in the comments! You could be in next week’s column.


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