Category Archives: Engineering

Evil Mad Engineers

Every month or two since 2009, someone has sent me a copy of a particular comic from the webcomic Cowbirds in Love.  Here is today’s example, from @benk_at_work on twitter:

@benk_at_work tweets...

evil mad engineers @ cowbirds in love

 

Sigh.

There is, of course, only one appropriate way to respond in a situation like this: with another comic.

Back in 2011, I wrote an era-appropriate semi-autobiographical rage comic, that I could use as a standard response when people sent me that comic.

f7u12

Joking aside, we really do spend a lot of our time engineering— and many of our friends and colleagues are bona fide engineers. On the other hand, I love to cook, but that doesn’t make me a chef either.

XL741: Principles of Operation

XL741

Our two “dis-integrated circuit” kits are the Three Fives Discrete 555 Timer, and the XL741 Discrete Op-Amp. These two kits are functional, transistor-level replicas of the original NE555 and μA741 (respectively), which are two of the most popular integrated circuits of all time.

Last year, we wrote up a detailed educational supplement for the Three Fives kit, that works through its circuit diagram and discusses its principles of operation down to the transistor level. Today, we are doing the same for the XL741 kit, and releasing an educational supplement that explains how a ‘741 op-amp IC works internally, down to its bare transistors and resistors:

XL741 Documentation (PDF)

This ability to peek inside the circuit makes the XL741 a unique educational tool. In what follows, we’ll work through the circuit diagram, discuss the theory of operation of the ‘741 op-amp, and present some opportunities for experiments and further exploration.

You can download the supplement here: XL741 Principles of Operation (1.1 MB PDF)

Additional Resources:

 

 

 

Another take on Twisted Wire Bundles

Steve W. wrote in to share his improvement on the method for making wire bundles we wrote about:

 I’ve used the bend-it-over-and-stuff-it-in-the-chuck approach, but was not fully happy with it.

Binder clip on wood piece for drilling

So I drilled a 1/8″ hole in the back of a binder clip.  The drilling is easy if you clip a ~3/8 scrap of wood.

Wire twisting jig in drill chuck.

A 4-40 SHCS screw long enough to allow me to actuate the clip was not threaded all the way to the head, so I used a 1/4″ spacer between the binder clip and the 4-40 nut.  (Pan head screws are usually 100% threaded, but I would have had to look in the dreaded ‘other’ box to find one of those). Having the nut up against the chuck acted as a lock-nut.  I had been surprised when I first tried this that I did not have to work harder to keep it from loosening.  I had expected I might need a lock washer, and/or a second nut to lock the first.

Just grabbing the wires with the binder clip (my original plan) was not secure.  So I wrap the wires 180 degrees around a screwdriver bit and put that in the clip.

Works great, and it is quick to pop in and out when twisting many groups of wires.

Thanks for sharing your hack and sending the photos!

Hackaday Prize Deadline

The deadline for the Hackaday Prize is just a month away now!
BUILD SOMETHING THAT MATTERS
The creative energy and years of experience found in our huge community of Hackers, Designers, and Engineers is waiting to be unleashed. Let’s use that potential and move humanity forward.
We’re helping to judge the Best Product category, which has fewer than 50 entrants so far. The prize for Best Product is $100k and 6 months free rent in the Hackaday Design Lab with mentoring.
One example project is Eye of Horus, Open Source Eye Tracking Assistance, to increase accessibility for people who are disabled or physically separated from a work area.
Another entrant is DIPSY, an FPGA module in a DIP-8 package, shown here with an LED daughterboard in 6-pin DIL format.
Submissions are due August 17, so get your entries in right away! If you have questions or want feedback on your project, there’s a meetup on the hackaday prize channel on July 21 at 6 pm PDT.
We’re looking forward to seeing your entries!

A visit from the LEGOJeep

Lego Jeep at Evil Mad Scientist
Photo by Kevin Mathieu

We had a visit from one of our favorite art cars, the LEGOJeep. Our friend Kevin stopped by to work on some parts to infuse even more LEGO spirit into the Jeep.

Lasering Parts for the Jeep
Photo by Kevin Mathieu

We also had a couple of young visitors stop by to see what we were up to. Above, learning to use the laser cutter and calipers.

Lego Jeep

Very proud of her contribution to the LEGOJeep!

 

 

Super Awesome Reporting on RoboGames

Super Awesome Sylvia has posted a video report from this year’s RoboGames. Highlights include a couple of combat matches, one of Sylvia’s LEGO competitions, WaterColorBot receiving a medal, and Sylvia completely geeking out after Grant Imahara interviewed her in the audience. (For extra fun, watch the raw footage of the interview from RoboGames.) Our STEAM shirt makes a cameo, too.

A Lego Mosaic Printer

JK Brickworks made this amazing “pick and place” style Lego Mosaic Printer:

It is built entirely using LEGO parts. It first uses the EV3 colour sensor to scan the source image and save the data on the Mindstorms unit. It can then print multiple copies from the saved image data. The 1×1 plates used for ‘printing’ the mosaic are supplied using a gravity feed system and the printing head is simply a 1×1 round plate that can pick up and place the 1×1 plates.

More information about this project can be found at JK Brickworks.

WaterColorBot and BeetleBlocks

The Tinkering Studio posted on twitter:

BeetleBlocks is a system for enabling people to explore algorithmic 3D geometry by snapping together Scratch-like programming blocks.

BeetleBlocks block programming example

They posted a picture of the finished painting, which looks awesome.

Painted output in the WaterColorBot