DIY Farmers Walk/Carry Handles

After tweaking my back and starting a push-only program which has a lot of accessory movements, I’ve been all about unilateral movements. Constantly using the barbell for lifting can create a lot of imbalances. One of the movements we do a lot is a Farmers Carry with kettlebells or dumbbells. Options get limited if you want to go heavier though. Picking up a barbell in one hand, or even a barbell in each hand, never works well. It’s not easy to balance an empty 7 foot long bar, let alone when you have some weight on it.

img_8965Companies sell handles you can attach to a barbell, bars with integrated handles, and straps you can loop through weight plates. Most of the barbell solutions I’ve seen cost $150+ and a nice set of strap handles can be $70!

I wanted to come up with something on my own, so I made a trip to Home Depot. I found a 4-pack of 6 foot tie-down straps for $9.97. In the plumbing department they sell 2 foot long pieces of PVC pipe in various diameters. I bought a piece of 3/4 inch for $1.97 and had an employees cut it up.

That’s what I call a successful shopping trip.

Works pretty well. For less than $13 I was able to make a set of handles for myself and a set for a friend. In the video I had no problem using a couple of 55 pound competition bumper plates. I tried two 45s and a 55, but the width of the plates was too much for me to get the handle back through the loop. Two 35s and a 55 might work. If you use thin metal plates you’ll have plenty of strap length and with these rated for 466 pounds, the limitation will be how much you can lift.

Combining 74HC74 & 555 Integrated Circuits

After working with some basic 74HC74 and 555 circuits, it was time to get fancy. I replaced one of the button triggers from my 74HC74 circuit with a 555 timer delay.

74HC74-555-button-wiring.png

Then I replaced the other button with a 555 timer delay as well.

555-74HC74-555-wiring.png

What do you think happens if I swap out the 22 μF capacitors for 4.7 μF? Remember the capacitor charge time formula from the 555 post? Multiply the capacitance (farads) by the resistance (ohms) to get the time. I’m still using the same 100 K ohm resistors.

t = RC

100000 * 0.0000047 = 0.47

So the delay decreases from 2.2 seconds to 0.47.

There is really no point in the 74HC74 here. You can connect two 555s to each other for a similar result. The video shows a double 555 circuit with 3 different timings, where I swap the capacitors from 22 μF to 4.7 μF and then 1 μF (delay of 0.1 second).

double-555-wiring.png

Are there any other circuits I should try with the 74HC74 and/or 555?

Using a 555 Integrated Circuit

555-pins

555 Pins

I posted about the 74HC74 flip-flop on Saturday. For the same project I’m going to use that IC for, I’ll probably use a 555 timer. It’s often referred to as one of the most useful ICs you can get. I’ve never used the 555 either, so I wired up some simple demos using it. In order to show two common timing uses, I’ve created similar circuits each triggered by the same power source and button.

The circuit on the left shows a delay off timer and the one on the right shows a delay on timer. Notice when power is connected (or the button is used as a reset) that the red LED turns on right away and turns off after a few seconds. Just the opposite, the white LED is off when the timer is reset and turns on after a few seconds.

The length of the delays is determined by the capacitor and resistor used with the 555. I’m using an Adafruit Feather to provide 3.3 volts to the circuits with a 22 μF capacitor and 100 K ohm resistor. Using the capacitor charge time formula to multiply the capacitance (farads) by the resistance (ohms), it’s easy to get the time.

t = RC

t = 100000 * 0.000022

Comes out to 2.2 seconds. To change the time delay all you have to do is use a different capacitor and/or resistor.

Here is a simplified wiring setup because it’s hard to see how everything is connected in the video.

555-wiring.png

Also check out Combining 74HC74 & 555 Integrated Circuits.

Using a 74HC74 Integrated Circuit

74HC74-pins

74HC74 Pins

I received some advice to use a 74HC74 flip-flop for a project idea I’ve had. I’ve never used an integrated circuit so I thought a good first step was to put together a very simple demo I could hack around with it. This IC is big enough it actually provides two flip-flops, one on each side as you can see from the pin diagram on the right. Both sides work the same, but are completely independent other than sharing power and ground. I’m only using the first side for this example.

 

As I press the buttons connected to CLR and PRE, you can see the outputs (Q and not Q) alternate. I’ve set the data (D) and clock (CLK) pins to ground. The truth table for the 74HC74 comes in handy to understand what’s going on.

74HC74-truth-table.png

Here is a simplified wiring setup because it’s hard to see how everything is connected in the video.

74HC74-wiring.png

Also check out Combining 74HC74 & 555 Integrated Circuits.

Fidget Cube

Last summer I saw this “toy” on Kickstarter and thought it looked neat. When I’m out to dinner I tend to fidget with something. Usually it ends up being the paper wrap you take off the napkin and silverware. I also like to grab something lying around my desk to keep my hands busy when I’m on a work audio or video chat.

A month ago an ad on Facebook caught my eye, claiming something like 80% off. Sounded like a good deal, at just under $15 after shipping, so I placed an order without thinking twice. Turned out to be a bit of a mess and may actually be an imposter. The ad had said shipping within 24 hours, so after not receiving my item for a couple of weeks I went back to check things out.

The Facebook page associated with the company (I’m refuse to even link to it) selling this fidget cube was full of angry customers. Yikes! Not a day later, I finally got a shipping notification. It shipped directly from China, so I’m almost certain it’s a knockoff. It looks exactly like the one from the Kickstarter though and the construction feels pretty good. If you want to grab the original, head over to Antsy Labs.

fidget-cube-front

fidget-cube-back

So far so good. I pick it up all the time when I’m thinking about a problem, reading something on the interwebs, watching a video, or participating in a video chat.

AdaBox002: Make Robot Friend

Adafruit’s 2nd AdaBox is everything needed to build a full functioning robot, controlled over Bluetooth via their Bluefruit app.

When I got it a couple of months ago, I put it together and wrote a bunch of notes for improvements I wanted to make. I finally got around to spending some time on it. Adafruit’s learn guide and the associated code were a great start and I referenced some ideas from their Multi-tasking the Arduino series. Some of the things I customized with my robot:

  • No need to hold buttons in the Bluefruit app to keep the robot moving.
  • Increase/decrease speed by pressing buttons 1-4.
  • Allowed turning left/right to be combined with forward/reverse.
  • Added a backup beeper.
  • Added blinkers.
  • Added stop/go LEDs. The stop LED will blink when going in reverse.
  • Improved the increasing/decreasing speed so the robot doesn’t pop a wheelie or tip over.

I put all of the code and wiring info on GitHub. Here’s a very poor and unedited video of the robot in action. I did a terrible job of keeping the iPhone in frame.

At some point in the future I should update this to work with the iPhone’s gyroscope instead of having to press buttons. Getting my ideas for AdaBox002 wrapped up came just in time since I now have an AdaBox subscription and AdaBox003 ships out tomorrow. I’m excited to see what it is!