5V Relay Module

You can buy all sorts of 5V relay modules on Amazon for as little as $3-4 (probably even less if you get really cheap). They even sell boards with multiple relays if you need to switch more than one thing. Since I had all of the necessary parts I built my own. Yesterday I finished the board, because I had to do something before National Week of Making ended.

It worked great switching power from a 9V battery, but the real test was hooking it up to mains power. Electricity gets a lot more dangerous at 120V! It was a little scary plugging everything in and flipping the input, especially after reading so many warnings online, but there were no sparks.

Tester shows the wiring is correct.
I need to pick up a plastic outlet box to house everything so it’s safer with the exposed soldered circuit board in there; I don’t know what I was thinking when I bought a metal one. I’ll publish a more detailed post this weekend when it’s complete.

Update: I realized the relay I used in this module can’t handle the amount of current I need, so I ordered a different type of relay and will be making a new module. I’ll take the opportunity to make a more compact design as well. I did shrink this one a bit and cut off some of the board. I’ll save this module in case I ever need it for a project.

A Raspberry Pi HAT

I successfully built the second piece to a large project I’m working on. I’ve essentially built my own XL Raspberry Pi HAT (Hardware Attached on Top). Since I’m not following the specs, I shouldn’t really call it a HAT.

I’m not sure how, but once again I correctly connected everything on the first try. Either I’m extremely lucky, my attention to detail is paying off, or a combination of the two. I’m just waiting for some catastrophic failure to happen soon when I solder things the wrong way one of these days. Every one of my solder bridges worked. I did run continuity tests on all of the early bridges, which I’m sure was a big factor to my success.

Any guesses on what this board does? Leave your best guess in the comments. It’ll be at least a month before I share more details because I need to finish the entire project first.

Fidget Spinners

I made a couple of fidget spinners out of wood, screws, and a couple of 2 cent coins from Spain. The bearings came out of old Rollerblade wheels. Even after cleaning up the bearings, neither one spins very well, so I think I need to get some ones before making more spinners.


This was a good excuse to buy a Dremel, which I’ve been wanting for a long time. Awesome tool to have. I didn’t buy it until I’d already cut out the basic shapes and done some basic sanding though. The next batch of spinners will be much easier with the Dremel available for the entire process.

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.

Repurpose

component-video-switchAfter watching recent Adafruit videos (12, & 3) about IR and getting a neat new microcontroller which has a built-in IR transmitter, it looked fun to hack around with. I don’t have an IR receiver though. Then I remembered this old component video switch was in a storage closet. I tore it apart and easily got out the IR receiver. While I was destroying the device I figured I might as well take a bunch of parts that may be useful. If nothing else it was good practice desoldering.

The big PCB with a lot going on is already gone with the trash. The two small PCBs with buttons and LEDs (a triple set and a single) are cool and will be fun to work with since they’re already wired up. Would be neat to use these in an actual project some day.

img_8931The other components I kept are:

  • IR 4 button remote
  • L7805 voltage regulator
  • PIC16C505 CMOS microcontroller
  • HD74HC126P quad buss buffer

  • 2x CD4052BE analog multiplexer/demultiplexer
  • HA17358A dual operational amplifier
  • 78L09L voltage regulator
  • A1515S PNP transistor
  • 71M4 IR receiver sensor

Of course, I can’t find a datasheet for the one part I want to use. IR is pretty standard, so I’m hoping they didn’t go rogue when developing this device. I’ll post more once I get a chance to experiment.

Several months ago I would have had no idea what any of this stuff was, let alone how it worked. I still don’t know what several of those ICs do, but at least I’m able to look at the traces on the PCBs and follow connections to get a general idea of how everything works.

Never stop learning!

WingTite Shower Drain

The stall shower in my master bathroom was leaking. I tried getting the drain out, but quickly realized it wasn’t possible without access underneath the shower. I didn’t want to cut a hole in the ceiling of the floor below and wasn’t going to tear out the shower. I found this WingTite drain (less than $35 on Amazon). The instructions looked easy enough for me to tackle.

Once I was able to cut out the old drain, the install was a breeze. It helps to get the right mini hacksaw, which was only a $3 add-on when I bought it. It’s been installed for a few months and there hasn’t been any leaking since.

DIY Camera Mount 

I’m usually very good at keeping parts, but for some reason, a couple of months ago, I threw away all of the mounting brackets for an old Dropcam. Sure enough, I moved the camera to the garage and had no way to mount it. It had been sitting on my vise shelf ever since.

While cleaning out the closet in my office this weekend I came across an old cell phone car mount. Took apart one of the elbow joints, removed the big suction cup from the bottom, and screwed the whole thing directly into the wall using a longer screw and an anchor. It squeeze around the camera for a solid hold, but I looped the cable around the bracket just in case the arm springs fail at some point, so it won’t go crashing to the floor.

Getting it up high provides a better view as well.