# brmarcum

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I've always loved to figure out how things work, so hacking and making just fits for me. I'm a husband, a father, an EOD technician with the U.S. Army National Guard, an intern at Digilent Inc., and a student at WSU.

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• brmarcum commented on brmarcum's instructable AC to DC Conversion1 week ago

Good question. Thank you for providing sample data. It makes it easier to pinpoint the solution.Cheers

You're stepping down your AC too far.You need to supply voltage regulators with at least 2 volts more input than you expect on the output. So with the 7812, if you want 12V out, you have to supply it with at least 14V bare minimum, preferably over 15V. That 15V is the output from the diode bridge, which will also drop the voltage about 0.7V per diode. The current travels through two of the four diodes at any point in time (all four are still used though) so the input to the diode bridge needs to be at least 17VAC.The datasheet four the 7812 will list the max input V at around 30V (double check that), so if you use a 10X step down transformer that outputs ~22VAC you should have no problems, though you may need a heat sink on the 7812.Your setup as is will only provide enough voltage to d...see more »You're stepping down your AC too far.You need to supply voltage regulators with at least 2 volts more input than you expect on the output. So with the 7812, if you want 12V out, you have to supply it with at least 14V bare minimum, preferably over 15V. That 15V is the output from the diode bridge, which will also drop the voltage about 0.7V per diode. The current travels through two of the four diodes at any point in time (all four are still used though) so the input to the diode bridge needs to be at least 17VAC.The datasheet four the 7812 will list the max input V at around 30V (double check that), so if you use a 10X step down transformer that outputs ~22VAC you should have no problems, though you may need a heat sink on the 7812.Your setup as is will only provide enough voltage to drive a 7805 5VDC voltage regulator or lower.

• brmarcum commented on bekathwia's instructable Bullet Journalling2 weeks ago

I really like this idea. And your art is beautiful.I would recommend people follow the link you provided to the Bullet Journalling website. It gives a fantastic overview of the core principles but without the artsy embellishment.Your I'ble is also well done. Clear and concise with tons of illustrative (and did I mention beautiful?) photos. Nice job.

• brmarcum commented on Max Maker's instructable Make a 40\$ Cold Juice Press!2 weeks ago

This is really cool. Nice design and build. Good I'ble as well. Clear and concise.I even have a spare 5-ton bottle jack laying around...

• brmarcum commented on brmarcum's instructable 555 Timer Basics3 weeks ago

C1 is a filtering cap on the power supply. It's a universal component in most electronic circuits to filter out small but rapid fluctuations in the voltage source. Depending on the stability of your source, you can remove it, but it's good practice to always use one. The value is dependent on the power requirement of your circuit.The idea is that if the input voltage from the source drops, the capacitor acts like a short term backup battery and tries to maintain the input voltage until either the source recovers or the cap runs out. Larger caps will take longer to drain, but also take longer to fill. If your circuit requires a fair bit of power, a small cap may not be able to supply enough electrons to properly filter the source fluctuations since it would drain too quickly.

• brmarcum commented on androkavo's instructable Wooden Digital Clock1 month ago

Bro.What the...I can't...How did you...Could this be any cooler!?

• brmarcum commented on Gronings Wild's instructable Exploding Sun Lamp Design1 month ago

That's really cool. Nice design.

• brmarcum completed the lessons Model Rockets, Pump Rocket, Stomp Rockets, Tools + Supplies and 1 other 1 month ago
• brmarcum enrolled in Rockets Class1 month ago
• brmarcum's instructable Programming Digilent FPGAs Using NI Multisim's weekly stats: 1 month ago
• 121 views
5 favorites
• brmarcum commented on mikeandlauren's instructable DIY Powder Coated Yeti Cups1 month ago

That Gerber tho!! HAHAHAI've always heard powder coating was simple and easy. Nice work.

• Thanks gzumwalt! As is usually the case the solution here was both simple and elegant. Nice work.

• brmarcum commented on brmarcum's instructable 555 Timer Basics2 months ago

I apologize for the confusion. The text should have referred to C2 and not C3. I have now fixed that. The values for C1, C3, and C4 as shown in the schematic are default values that I almost always use when I connect a 555, but none of them have any effect on the 555's performance as an oscillator.C2, R1, and R2 are the components that directly effect the oscillation frequency and duty cycle. Those values are chosen based on your requirements for your circuit. The nominal values as shown were chosen at random for this particular project, but will produce a 3.1 kHz signal at 66.67% duty cycle. You can do the math the long way or use a calculator like this one.I hope that explains it better.

• I'm completely blown away by this project. Especially since it was for your school. This looks like a professionally manufactured unit. Very well done.Your I'ble is well done as well. Good flow, tons of clear pictures, and everything clearly explained.Nice job.

• brmarcum commented on JohanL39's instructable 3D Printed Ratchet Screwdriver2 months ago

Impressive. Nice work.

• brmarcum commented on gzumwalt's instructable Four Whistles Version 22 months ago

I am so thoroughly impressed by your designs. Simple and plain, yet at the same time elegant and well designed.If at all possible, I would love to see a separate Instructable on how you designed the cylinder. How did you determine the size, shape, length of the note, etc. in order to accurately play the song? How many cylinders ended up in the bin before this one was the one that worked?

• This is cool, but where's your I'ble on video editing?

• 173 views
3 favorites
• brmarcum commented on makjosher's instructable A Simpler Tripod3 months ago

Impressive. Nice work.

• brmarcum commented on Craftcorner's instructable A Meter Big Quilled Mandala!3 months ago

That's really pretty. Nice project.Well planned Instructable as well. Clear and concise with the right pictures showing the right concept at the right time. Nice work.Except for one thing. The YouTube video showing basic quilling shapes is blocked by Sony Music Entertainment (SME). I assume they didn't like the music you used and since they own the copyright they are flexing their giant iron fist. Overlay some different music and load it again, you should be good. I'd like to see it.

• 3 months ago
• brmarcum completed the lessons Simple One Part Mold, Flexible Block Molds, Tools & Supplies, Two Part Molds and 2 others 3 months ago
• brmarcum's instructable Using the Voltmeter With the Analog Discovery 2's weekly stats: 3 months ago
• 120 views
5 favorites
• brmarcum commented on CraftAndu's instructable WorldÂ´s Smallest Portable Table Saw?3 months ago

I'm thoroughly impressed. Well done. I wouldn't use it for fine furniture, but you make the point that it's not for that use anyway.Two thoughts I had. The first is how well do the clips hold the saw to the underside of the table? Does the vibration of the motor loosen them over time? The last thing you need is for a clip to give out in the middle of use. So many bad days.The second is how to maintain the 'squareness' of the rip fence. In the video you can see the end of the fence opposite the user (nearest to the camera) flex as you push material through. Any thoughts on how to secure both ends so the cut stays square?

I think metal might work better as it is less prone to wear compared to wood.Maybe some kind of a cam style clip that has a small indentation on the saw side of the clip that would catch on the lip of the saw's base plate. There would be a noticable 'click' feel as the indentation fell into place over the base plate. This would make it harder for the vibration to overcome the tension holding the saw up.

• This is really cool. Simple yet functional, like every tool should be.

• brmarcum completed the lessons Leavening Agents, How Baking Works, Fats, Eggs and 7 others 3 months ago
• brmarcum completed the lessons Tools + Materials, Ripping Wood, Meet Your Saw and Mitres in the class Table Saw Class3 months ago
• brmarcum commented on pseaton's forum topic Profile Page Updates4 months ago

Where did the image library access go? Yes it's still technically there, but stupid restricted now.I frequently embed images directly into the text using HTML and direct links to the image file on the server, but now I can't access images like I could before. I want to be able to choose which version of the image I want to use. I've found a work around for now, but it's way more difficult and non-intuitive than it was, and the process was already cumbersome before.Is better image library access something that is coming, or are we doomed to suffer with it as it is now?

• brmarcum commented on brmarcum's instructable AC to DC Conversion4 months ago

I added a fuse to this project //www.instructables.com/id/Motion-Activated-AC-Switch/ but not on the ac/dc rectifier portion. I split the ac mains input to use as a switched ac source controlled by the dc portion.

I would add a fuse between AC mains and the transformer. The correct fuse rating needs to be determined by the max input current capacity of your transformer, or the max input capacity of your circuit, whichever is lower.

• brmarcum commented on makjosher's instructable The Anywhere Outlet5 months ago

Excellent I'ble! Clear, concise, and extremely well documented. The pictures are clear and focused and leave nothing to question.I've been thinking of doing something similar for a small behind-the-couch table I want to build. I was just going to flush mount the panel, but then the outlets would be face up and dirt and drinks (let's face it, I'm going to spill my beer at least once!) would get in there. This solves that 100%.While others have correctly brought up the concern of pulling too much current through the circuit breaker, I wouldn't worry about maxing the circuit if you use this plug only for charging small devices. My concern would come from how many devices you have on and/or charging, connected to all outlets on the circuit, all at the same time. You've stated that it is the...see more »Excellent I'ble! Clear, concise, and extremely well documented. The pictures are clear and focused and leave nothing to question.I've been thinking of doing something similar for a small behind-the-couch table I want to build. I was just going to flush mount the panel, but then the outlets would be face up and dirt and drinks (let's face it, I'm going to spill my beer at least once!) would get in there. This solves that 100%.While others have correctly brought up the concern of pulling too much current through the circuit breaker, I wouldn't worry about maxing the circuit if you use this plug only for charging small devices. My concern would come from how many devices you have on and/or charging, connected to all outlets on the circuit, all at the same time. You've stated that it is the main hub, and while electronics engineers are pretty good at minimizing power consumption, having them all on at once could definitely pose a problem. But that's considering all wall outlets connected to the main circuit breaker, not just this outlet box.It really comes down to common sense, and when in your life have you ever had the curling iron, toaster, space heaters, clothes iron, vacuum cleaner, blender, and pocket arc reactor all plugged in to the same circuit and running at the same time? Yeah, never.

• brmarcum commented on 2Witches's instructable HotGlue/Aluminum Art 7 months ago

What is the symbolism in the picture?

• brmarcum commented on MagicManu's instructable Make a Children's Log Cabin With Pallets7 months ago

I love this. Great work.FYI - bastaing translates to plank. For the floor bastaings you would say joist, the wall bastaings would be studs, and each roof support on either end would be a truss. All of these come together to form the framing.

• brmarcum commented on brmarcum's instructable AC to DC Conversion7 months ago

I would have to see your circuit. The capacitors between the diode bridge and the regulator should take care of a lot of the AC ripple in, and the capacitors after the regulator should filter anything else that gets through.Is the "jumping" you are seeing happening at regular frequency? Does it appear at several places in the circuit or just on the output of the 317? Are you using long wires that could be acting as antennas and picking up signals from other devices nearby?What voltages are you working with at each stage? AC input, after the diode bridge, into the regulator, and after the regulator? If you are trying to get your 317 output to be close to what you put into it, but flat, you will likely have problems. You need some buffer voltage in that you can afford to lose to...see more »I would have to see your circuit. The capacitors between the diode bridge and the regulator should take care of a lot of the AC ripple in, and the capacitors after the regulator should filter anything else that gets through.Is the "jumping" you are seeing happening at regular frequency? Does it appear at several places in the circuit or just on the output of the 317? Are you using long wires that could be acting as antennas and picking up signals from other devices nearby?What voltages are you working with at each stage? AC input, after the diode bridge, into the regulator, and after the regulator? If you are trying to get your 317 output to be close to what you put into it, but flat, you will likely have problems. You need some buffer voltage in that you can afford to lose to the regulator to let it do its job properly.

• brmarcum commented on mdheath's instructable Concrete and Wood Slab Table7 months ago