Showing posts with label DIY. Show all posts
Showing posts with label DIY. Show all posts

Thursday, December 29, 2016

Make an Old-school two-way pager with Arduino

I made a 2-way pager with an Arduino, GSM shield, and LCD shield. I’ve found this idea to be more useful than at first glance—I designed it so it could be used by children in lieu of a real cell phone, or it could be used as an “SOS” button for someone working alone outdoors or even exercising (if it was a bit smaller). And for the last few weeks, this device has been always on in my living room where my wife and I leave silly messages for each other.

Summary: This project sends and receives text (SMS) messages via an arduino with cellular modem built into a small enclosure with an LCD display and simple control buttons. Full details of the design and build are on

Could also be called "Most expensive pager made in 2016 ever."

Update: People seem to like this project! It has over 10,000 views, and was even featured on Hackster’s Handpicked Projects of the Week.

Friday, November 18, 2016

How to make a cellular-connected garden monitor

Check out this project I made to monitor the soil moisture level of my remote garden plot. Since the garden has no power or internet available, it uses a cellular data connection to send info back to a cloud service, and then that data gets passed to another cloud service for plotting. A great learning experience!

I posted all the details on, a community for hardware makers with lots of interesting projects:

Wednesday, March 2, 2016

How to make a vertical laptop stand from laser-cut acrylic

When my wife is working from home, she likes to sit at a proper desk with a monitor, keyboard, and mouse instead of hunching over her laptop. To make it easy, I set up an "umbilical cord" of power, USB, and display connection to plug in and off she goes. To free up room on her desk she lays her 13" Macbook Air on the floor which is always kind of awkward. To resolve this, I thought a space-saving vertical laptop stand could help, much like one of these made by Twelve South or Rain Design.

But it's no fun to buy one; let's design and build one from scratch out of laser-cut acrylic!

The two copies of the laptop stand I cut out of acrylic
The two copies of the laptop stand I cut out of acrylic

Sunday, February 21, 2016

Mini Book Review—Making Things Move by Dustyn Roberts

Making Things Move by Dustyn Roberts is well described by its subtitle "DIY Mechanisms for Inventors, Hobbyists, and Artists". I picked it up at the library to see if there were any fun new pieces or tricks I could learn from as an engineer. Highlights included the parts about the internal workings of stepper motors and a trick on how to drill a hole in the center of a shaft without a lathe. So while there were some cool new tidbits, it was mostly just fun to see all these topics in one place and easily approachable for new people.

Notable covered topics:
  • The six simple machines
  • Material types, properties, and tolerances
  • Fastening and joining
  • Forces, torque, power, work, energy sources
  • Intro to hobby motors and servos and their control
  • Bearings, gears, screws, springs, cams, linkages, and motion conversion
  • Lots of example projects bringing these concepts together
For a non-engineer getting into making projects with electronics or motors, this would be a great resource I would recommend. If you are already an engineer with some making experience, this book would be just for fun.

Thursday, July 9, 2015

How to set up an iPhone for international travel on AT&T

Traveling abroad with a smartphone plan is definitely confusing. You can have all the features you want pretty much as-is, but you have to be willing to pay for that convenience. In the worst-case scenario, it could literally bankrupt you if you're not careful. AT&T charges $0.0195/KB $0.002/KB for international roaming data, but don't be fooled by that small number. Your monthly phone plan at home might have 10GB included, but one tenth of that (1GB) in maps, music, youtube videos, and FaceTime calls (not unreasonable) while abroad will cost you $21,000 $1997. Whoops.

Update 2/23/2016:

  • It looks like AT&T made some changes on Nov 13, 2015 in our favor to keep up with the competition! After Verizon made roaming to Mexico and Canada for short trips incredibly easy (an automatic $2/day for the same service as your home plan), AT&T made roaming in Mexico completely free! Unfortunately, no change in pricing for Canada.
  • However, pay-per-use data cost seems to have come down, and this blog now reflects this. I could not find any evidence online of when this exactly happened (do any of you know?) so I assume it was at the same time as this other change. The new rate of $0.002/kB is $1997/GB which is 1/10 of the previous mind-boggling $21,000/GB. Still too high to use casually!
  • Passport packages remain the same price

How do we get around this? Here are a variety of options that start with the simplest and safest for not having any overages, and slowly increase in service, cost, and complexity. Given your individual needs and budget, take a look and choose what's right for you! Most of these tips will be applicable to Verizon or T-Mobile plans, too. I tried to be comprehensive since I've never seen another website that lays it all out with detail.

Option Voice Incoming / Outgoing Text Incoming / Outgoing Data Capability Difficulty Cost
0. Turn off your phone None / None None / None None Paperweight Low Free
1. Airplane mode + WiFi None / None None / None WiFi only All your apps/camera with data on WiFi only Low Free
2. Data roaming off to have most phone functionality Straight to voicemail / Outgoing works No extra charge / $0.50 extra charge WiFi only, but can turn on cellular data for extra charge (risky) Most functions work; very popular Med Low
2A. Set up a Google Voice account Like above with better voicemail Low
2B. Turn on data roaming when needed Get data on-the-go at risk of big bill Low to High
2C. Use VoIP for voice calls Cheap calls to back home Low
3. Buy a travel data package $1.00 to $0.35 per min based on plan Unlimited 120MB to 800MB included based on plan Full capability with controlled price Low Med
4. Get a local SIM card Variable minutes included Variable texts included Variable data included Full capability; same as local phone High Med

Tuesday, June 2, 2015

How to correctly use a bike tube patch kit

A recurring theme in bicycle discussions is the use of patch kits to fix flat tires. Some people claim they work poorly and are unreliable, while others claim they are great and last forever. Who is right? I'll go ahead and agree with the latter, that they are very reliable and will last as long as the rest of the tube will, but only when used correctly. I think many people do not use patch kits correctly, which is the root of the problem! (Tuning up your bike and not sure if everything is being covered? See my tuneup checklist.)

Instead of just saying "follow the instructions in your kit" in an article on fixing flats, let's review a little more in depth with the most common type of patch kit, which uses vulcanizing glue (all the vulcanizing kits are pretty much the same, though I've heard good things about the Rema Tip Top TT-02).

Typical bicycle patch kit

Thursday, May 14, 2015

Bike Tune-up Checklist Reference

When a friend wants you to look over his or her bicycle so they can get riding again, what do you look for? Online and in books I've seen some regular maintenance schedules and daily pre-ride checks, but what about initial evaluation of an unknown bike? I've combined the best info I could find along with my personal experience tuning up bikes for friends and family to create this handy checklist!

Obviously pages could be written about each of the items on this list, and indeed they have been in a variety of books and web sites. My favorite online reference is Sheldon Brown's site, and for a more organized and comprehensive physical book, I use The Bicycling Guide to Complete Bicycle Maintenance & Repair (according to reviews, don't buy the ebook version). This book got me started in bike maintenance so it holds a special place in my heart, but has still stood the test of time.

The work listed here would typically cost $75-150 at a Chicago bike shop, so learning to do it yourself definitely pays off.

Monday, November 17, 2014

Knog Blinder—How to Fix Broken Mounting Strap

The Knog Blinder 4 is a great rear blinky bike light—super bright, cool flashing modes, and USB rechargeable.  But the Achilles' heel of these bike lights is the attachment band, as confirmed by the repair needs around the internet. (Same issue with the Knog Frogs!) A few of these sites have hinted at fixes, and certainly the 3D-printed cover is a good go at it (I tried it and it works!), but when I had two of these lights' straps fail on me I had to find a simpler / smaller / cleaner solution.

Knog Blinder with broken strap on right side
Knog Blinder with broken strap on right side
It turns out all it takes is a few minutes with some snips, a zip tie, and two small o-rings.  The result is a mounting mechanism that works very similarly to the original but if it breaks it is easily fixed!

Sunday, November 9, 2014

Saeco Vienna Plus—How to Fix and Replace the Dosing Microswitch

The Saeco Vienna Plus is a great, relatively inexpensive (especially refurbished) automatic espresso machine!  After 6 months I started to have a problem where the bean grinding step would time out after grinding and grinding.  This led to compacted grounds and a clogged grounds chute -- the immediate fix was to open up and clean out the grinder.  This distracted me for a long time from real troubleshooting and determining the true root cause of the problem.  It turns out that the dosing microswitch was getting stuck / gummed up after sitting still from morning to morning.

Saeco Vienna Plus

Saturday, January 4, 2014

How to Install a Fusion Drive into a Mac mini Running Mavericks

In order to speed up my computer without the expense of a large SSD, I just finished installing a DIY Fusion Drive into my 2011 Mac mini with great success. (This should work for Yosemite as well with minor modifications). I didn't expect the need to write about it but there were enough lessons and deviations that I'll describe them. Originally the Fusion Drive was released using Mountain Lion so most write-ups have not been updated for the newer OS X Mavericks. 

Assumptions: You have a working 2011 Mac mini running OS X Mavericks with a single HDD and want to install a second drive (an SSD) internally to make a Fusion Drive.

First, the hardware, which I ordered all from Amazon. I chose:
  • Mac mini dual drive kit from iFixit ($30) because I liked the included tools better than the similar kit from OWC (note: if prices are wonky, just order from the manufacturer directly or choose the other brand)

Saturday, July 20, 2013

How to Make a Raspberry Pi Laptop with a Discontinued Moto Lapdock


Update 2/27/17 -- To clarify, this project uses the Raspberry Pi 1 Model B

The Raspberry Pi is a cheap, multi-purpose Linux computer great for education and maker projects. It is pretty bare-bones so if you are not careful you can end up with a rat's nest of cables just to turn it on and experiment. A solution that can turn the Pi into a compact laptop-style setup is to use a Motorola Atrix or Bionic Lapdock, originally designed to dock with their line of Android phones. But why limit to a particular phone? A Lapdock is simply a nicely-packaged group of components available via USB and HDMI that you would end up connecting to your Pi separately anyway:
  1. Display (1366 x 768)
  2. Keyboard
  3. Trackpad
  4. USB hub
  5. Stereo speakers
  6. Portable battery pack
  7. Power supply
Raspberry Pi with Lapdock in action
Raspberry Pi with Lapdock in action

Wednesday, July 17, 2013

An Arduino-based synthesizer

One of the first projects I made with the Arduino was this synth called the "Auduino".  It consists of five potentiometers wired to the five analog inputs and one digital PWM output used for audio.  The code came directly from the project site.  Check it out in action:

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