A Raspberry Pi post for Pi day

I’ve recently fallen in love with Raspberry Pi computers again. The discovery of MQTT and io.adafruit.com for data logging lead me to Node Red.

Node Red is awesome! It’s like scratch programming for things!

Monitoring a fridge is as simple as drawing a few lines between some boxes.

For example. My fridge is starting to have some issues. It wants to keep freezing everything in the fridge. It dials the temperature setting all the way up and we don’t know why. I’ve taken the fridge apart as best as I can the last time we defrosted it just to wiggle all the wiring connections.

A quick gauge showing me the current fridge and freezer temp.

I wanted to really see what was going on with the fridge. I grabbed a Raspberry Pi Zero W and a couple of 1 wire digital thermometers and put together a Fridge monitoring system in a couple of hours. I can now see what happens with my fridge. It does a defrost sequence and comes out of it cold, freezing up the fridge.

I made my own ‘flat’ wires from some old phone wire and electrical tape. This allows the doors to still close and seal around the wires.
With the Raspberry Pi hiding underneath this ‘hat’ or ‘bonnet’ circuit board, the electronics doesn’t look like much. A pair of one wire (really 3) temperature probes and a pull-up resistor. Crazy simple.

A quick dashboard configuration, and I now have a view of the current temperature and a graph of the temperature history.

Hey, something changed! I removed a beverage allowing the cold air from the freezer to hit the temperature probe directly and show a wider temperature swing.

Add a couple of more nodes and I now get email notifications when the fridge is too cold. Another node, and the Google Home announces the too-cold temperature.

My fridge now complains that it is cold.

How epic is that? Under $20 worth of parts to give my fridge a voice.

I recently picked up a Seek Thermal camera which plugs into my cell phone and allows…

I recently picked up a Seek Thermal camera which plugs into my cell phone and allows me to see temperatures of stuff. It's a cheap unit, so it doesn't have the built in calibration tables that the expensive 'real' test equipment has. But it's good enough for most people's needs in a non-technical use.

I am reading all up on emissivity, and the science of how it works. Because this influences my usage of my laser cutter, and blacksmithing and even cooking and anything that relies on heat.

So I decided I am going to make a Mobile Science set. Mobile is dual usage, one, it's portable, two it's centered around my mobile phone.

My phone has a lot of sensors and capabilities already.

The Seek Thermal camera gives the phone another super power.

I also want to add a Consumer Physics SCiO https://www.consumerphysics.com/myscio/ which is a molecular identifier. I've wanted this thing since they ran it on kickstarter several years ago. I have actually seen it work in person and absolutely love what it can do. I think it will turn out to be a disruptive technology. This item will be the primary tool in my Mobile Science lab once I get one.

To compliment these two IR different sensors, I want an assortment of basic hand tools that will facilitate in preparing materials for the phone accessories.

I will be working with botany and geology. Also a bit of chemistry.

Optics is a pretty natural option too, given the camera on the phone. I will be making some bead lens microscope adapters for the cell phone camera. A spectrograph as well.

I also found a phone accessory weather sensor that I will be picking up.

I made up a cardboard tray on my laser cutter to organize the few bits I have gathered already. These are fitting in a waterproof cell phone case. I am looking for a waterproof tablet case.

My goal is to have a solid Science Lab the size of a Science textbook. I will likely carry this set about anywhere I go.

I am crazy excited about this idea.

In album 2/22/17

Internet of Things Phone Smart Charger

I pre-ordered one of the Samsung Galaxy Note7 phones. The ones in the news recently for being an explosion hazard.

I love the new phone – pocket computer really, the way I use it. I wasn’t about to give it up over some silly thing like spontaneous combustion.

I had read that Tesla runs their car batteries between 40%-80% for normal use to maximize the lifetime of their very expensive car batteries. I figured that cell phone batteries would benefit from similar treatment. A bit of research generally confirmed this, with http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries being the most concise write-up. The first half basically demonstrates that you can get the same amount of total power to flow through the battery regardless of how much you charge it – summed over the total life of the power draw in the data tables. The 2nd half is more interesting. It says that high voltage charges and heat shorten the overall lifespan of the battery.

The Note7 is a sealed phone wihtout a replaceable battery. I can’t pull my usual trick of replacing the battery after a year of abusing it.

Heat seams to be the trigger for the phone explosions. So I can make my phone more safe, and make it last longer by managing the top voltage and heat in the battery.

I can do this.

I bought a wireless Qi charger to charge the phone because it charges slower. The fast charger can charge the phone crazy fast, but it gets HOT when it does this. Hot is bad. Thus, slow is good. The wireless charger will also reduce wear on the USB C port. A nice side benefit. No phone explosions while I sleep and burn the house down – this is a good thing.

I bought a Belkin WEMO wifi controlled outlet. It is If-This-Than-That (IFTTT.com) capable so I can control it from my phone. There are other smart plugs available that will work, this is simply the one I could find in a store that I could verify would work with IFTTT.

I configured IFTTT to have 2 different actions. One for turning the WeMo on, the other off. I set these up as Maker Channel triggered recipes. There are other triggers that you can use such as email or SMS, but I am a web developer, so web-based triggers are a natural fit for me.

Image of The Rules set up in IFTTT
The Rules set up in IFTTT
Photo of the IFTTT Off rule
The OFF rule in IFTTT. It uses the Maker Chanel for the trigger, which means a web request will trigger this. It turns off the WeMo controlling the wireless phone charger.

I installed Tasker on the phone and configured it to monitor charge state and battery temperature.

I created 3 tasks, one to turn the charger on, and two to turn it off.

photo of Tasker rules
The rules in Tasker to control the phone charging.

The ON trigger looks for the battery to be below 80% charged, and below 35 degrees Celsius. This will make a request to the IFTTT.com Maker Chanel URL for ON.

One OFF trigger looks at the battery temperature. 35.1 degrees or higher. The other OFF trigger looks for the battery charge to be 90% or higher. These two both make a web request to the IFTTT.com Maker Chanel OFF URL I set up.

So now as the phone battery heats up or gets close to full, the phone tells the charger to turn off. I let the phone have a 10% charge window so I am not toggling the switch and charger on and off all night long.

Tasker with both OFF rules turned on. The phone is both charged to 90% or more as well as running hotter than I would like.
Tasker with both OFF rules turned on. The phone is both charged to 90% or more as well as running hotter than I would like.

I also programed the WeMo to turn itself on a little while before my alarm is set to go off. This is to let the battery be closer to 90% charged rather than 80% charged when I wake up. I haven’t found the right time for this yet. I still need to play with it a bit.

I know there are other ways to make a smart phone charger. This is what I came up with. I will be getting an additional smart plug and building one for at the office so I don’t over-charge my phone when at work. I will try a different brand likely to see if I can come up with a cheaper way.

Thoughts on headphones

I don’t like loud noises. I use an electric lawn mower because it’s quieter than a gas mower. I prefer to use my old-fashioned reel mower because it’s quieter than my electric mower. I have carried a set of earplugs in my pocket everywhere I go for a couple of years now.

I am not much of a music person. Don’t like concerts, too loud. I had a roommate in college who is a true audiophile, so I learned a little bit about the technology from him. He built me a custom speaker set that I turn down real low, for rich sound. I will probably keep these speakers for the rest of my life. I like them that much.

I’d not put much thought into headphones until a couple of years ago, when I had to move from a private office to a community office. I decided to get a set of headphones so I can drown out my office mates.

I thought I wanted a set of bluetooth noise cancelling headphones. I can’t afford such a beast. I found a bluetooth Sony sports headphones at BigLots for $30. These were good. I needed to turn them up a good amount to overcome the room noise.

Then I found a bone conduction bluetooth phone headset. The aftershokz bluez 2. I love these! I bought a set of in-ear shooting ear plugs to use in conjunction with the headset. Bone Conduction audio doesn’t push noise into your ear, it vibrates your jaw-bone instead. The headset doesn’t cover or block the ears, it sits in front of your ears. Wonderful device. You can have a conversation just fine with them on. In the office, I would stick in the shooting earplugs and be in my own little world. One of my favorite uses is while driving. I can have a conversation in the car and have the phone navigation system on the headset. I just love these. Wore them every day, every day for over a year.

Really, these things are just awesome. I love them.

Like anything made from plastic that gets used all day, every day, they broke. Buttons fell out which I used thread to tie back on. One of the temple pieces broke which I taped back up. Really, I need to get the newer model as they fix the few issues I had with the current set, but I can’t really justify $100 on something that I already have, even if broken but functional.

I just discovered a noise cancelling headphones set at Aldi. $30. I bought them for my wife, she goes through cheap headphones frequently. A pair a year or so. I thought I would get her a good set of headphones for a change. Right after I bought them, I borrowed them for a work trip to Rhode Island. I fell in love with them on the plane. Noise cancelling headphones are designed for airplanes I think. They have microphones in them that listen to the noise around them, and then play back a sound that will cancel out the sounds they hear. They emit a very faint his that you can hear if you listen closely. They knock most of that engine and air noise down to nearly nothing. I think half of my discomfort on planes is the noise – the other half is that my 6’4″ self doesn’t fit in them. They don’t do much reduction on people talking to you, maybe 25%? They do seem to help with that background drone of many people’s voices.

I liked them so much I bought a pair for myself, and another pair for a friend.

I was fiddling with them at work today. I plugged them into my computer, and turned the sound all the way down with the volume buttons, then up 1 press. I started playing some music at 50% volume on the music app. The sound is basically turned down all the way. You can’t hear the sound on the computer speakers. Using the headphones, you can barely hear the sound until the noise cancellation is turned on. All the noise from the air handlers and machines in the building just goes away, and music plays. This is how quiet I like noises. Basically no sound. It’s amazing how loud my building is.

So, it seems I like 2 extremes. Headphones that either completely cut out the noise from the outside world, and those that don’t cover the ears and block sound at all.

I made a leather business card holder for my new business cards

I 3D printed the frame and embossing element. I also incorporated a NFC tag so I can use the case to transfer info digitally from the case as well.

A bit of high-tech, and a bit of old-school leather work. My favorite way of doing things. My leather working skills aren't good yet, but they are getting close to fair. I love being able to do stuff.

It's even on GitHub if you want one of your own. https://github.com/creuzerm/openscad-projects/tree/master/Leather%20Business%20Card%20Holder

Lots of photos with descriptions to look at in the album.

In album 3D printed & Leather business card holder

My new business card! I added a NFC tag inside the case so I can also just tap a smart phone to the business card holder and transfer the data that way. A very high-tech business card holder.

The logo doesn’t show well under flash yet. I suspect a few months in a pocket will change that. You can see how I started at the computer & 3d printer to make the business card holder.

Printing a plastic frame and an embossing logo at the same time.

The printed frame. Note the rivet holes, sewing holes, and the steampunk themed monogram.

My printer is pretty loose and sloppy, so I clean up all the holes with a drill press. A few minutes here saves lots of frustration when sewing.

I am loving the rotary cutter for cutting this thin leather. No pulling and stretching and causing ill-fitting leather sides.

The leather is VERY thin, so I bond it to plastic to make it more resilient. This happens to be a Mt Dew 2 Liter Soda Bottle. Lots of poking holes so I can sew it later.