mandag 10. april 2017

DIY Bluetooth Adapter for any Headset

I recently bought a new headset that I'm mostly satisfied with. Except I would really like the convenience of streaming music wirelessly!
Instead of buying a more expensive headset, I cut the cord, and went to work to create a bluetooth headset adapter. 
That's what I'm showing you today.
At first I looked at all the parts needed to make an adapter from scratch. But realized I could get most of the circuitry needed in a much smaller package, by modifying a cheap pair of bluetooth earbuds.

Shopping list

These are the only points we care about to transmit music wirelessly. And they need to be wired from the bluetooth chip to the audio jack.

søndag 9. april 2017

Gift Away Your Heartbeat for Valentines Day! | Arduino Tutorial

All right people, I've got a pretty sweet project lined up, just in time for valentines day. I'm going to show you how to gift away your own heart!

This is how to use an ECG sensor along with an arduino to record your heart beat! This data will then in turn be used to make an awesome picture, so you can give away your heart to whomever you fancy! While this might seem complex from the start, the process itself is pretty straight forward and now I'm going to show you how to do it!

søndag 12. mars 2017

3D Printed Utility Desk Shelf

While living in tiny a dorm room you learn one trick right away - you have to use your vertical space!
To make use of a living space with small area you it's absolutely necessary to stack your items. This produces a challenge if you need a decent working area.
I, like most college students, picked up my furniture from IKEA. While my desk certainly was cheap it's somewhat lacking in working space. My computer would take up most of the desk which left little room for reading and note taking books.
This is the challenge I set out to solve!

I'm going to show you how to make your very own smart desk extender!
It's a clever solution where you get an level on your desk for your laptop, pens and other items to keep close, and even a second monitor.
This is also adds some smarts to your desk with utility features! The Smart Desk Space Extender comes with a phone grip and headset hook - both of which hovers your items above your desk. It also comes with cable managers making it easier to keep all cables out of your way!
The desk extender parts are 3D printed meaning you'll be using a robot to upgrade your working area. What exciting times we live in!

Click here for detailed build instructions.

fredag 3. februar 2017

Replacing machine parts with a 3D printed copy

I was recently tasked with fixing a washing machine using my 3D printer. This may certainly sound complicated, but was actually a small task. So the case was that I needed to make a replacement wheel for the lower drawer inside the washing machine. One of the original wheels had just disappeared so I was given one of the remaining wheels to make a copy.

The original wheel on the left and the copy on the right.

As you can see in the pictures above the new wheel looks really good. However this was far from what this mission required. The 3D printed wheel had to perform well.
The original wheel had an interesting design in the way it was put together. It consisted of two parts: the main wheel, and the axle. 
    The axle was made of plastic that gripped the front end of the wheel, but still let it slide in the middle of the axle. The back part of the axle had two plastic nubs that gripped onto a metal rod on the drawer in the washing machine. This was only fastened by the friction caused by the two nubs being pressed onto the metal rod.

What proved to be the main challenge was replicating the axle on a regular FDM 3D printer. FDM is an acronym for Fused Deposition Modeling, which basically means that a hot nozzle melts plastic in a precise pattern, and then melts another pattern on top of the first. This creates several layers that make up a solid object. FDM is the the most common type of hobby 3D printers.
    Because a FDM printer works in layers, it also means the finished object has a grain - analogous to wooden grain. And like wood grain, it is something to be wary of when using it as a material to hold a load. On a 3D printer, the grain is strongest along the X- and Y axis, these are the "flat" axes on the bed. This means the object is weakest on the Z axis, which is the upwards axis.

Finished copy of the most imported parts from the wheel.

The knowledge of the grain in a printed object should be used to make stronger objects when possible. But this knowledge was what made making the axle so difficult. Ideally the axle/metal rod holder would be printed on its side. This would mean it could withstand higher forces in the vertical axis after it was put in place. However, printing sideways would mean the metal holder would be made with support material, which would decrease their strength. There would be no use having the cart holder be strong to vertical forces, if one of the plastic nubs would break so it couldn't hold the cart in the first place!
    If the axle/cart holder was printed upright like in the picture above, the axle part would be very week to shock. Meaning it couldn't hold a lot of weight and could snap at any moment. Like the picture above is hinting at, my solution was to not print the axle at all, just the metal rod holder. Instead I would model the wheel and cart holder to use a M3x16mm machine screw as the axle. This would make it much stronger, and if I used a lock nut instead of a regular nut, the wheel would still spin freely.

I'm quite pleased with how the final model came together. While printing the wheel I paused the printer and put in a M3 nut. After starting the printer again it kept on printing above the nut, meaning it became fully integrated into the wheel itself. See the picture below.

 After the wheel was printed I fastened the screw really tight into the nut, from the front side of the wheel. This made the plastic wheel and metal screw act as one solid part. After the screw/axle was in place I just put on a couple of metal washers and the metal rod holder, before everything was put together with a nut on the end.

How the wheel was modeled with space for a M3 nut. After placing the nut during printing the printer would keep on adding plastic on top it.

torsdag 2. februar 2017


I always keep my eye out for small problems that could be improved my over engineering a solution to test my skills. My recent tutorial is no exception! I've attached a meter of LED strip under my bed, and it is of course controlled by an arduino.

The arduino is soldered onto a perf board along with an RTC module and a PIR sensor. The code is written to work as a wake-up and night light. The lights turn on in the morning, 06:30, to make it easier to wake up because the room is no longer dark. Then it turns off a couple hours later, when I'm out of bed.
    After this the lights turn on again in the evening before it turns off and goes into motion detect mode. The motion detect mode is on between 19:00 and 06:30. This means the lights turn on and stay on for three minutes whenever it detects movement between these hours. Perfect whenever I need to get out of the bed in the middle of the night!

Even though the LEDs are directed straight down to the floor, they still cast a lot of glowing light through out the bedroom!

Introduction at Instructables:
Today I'm showing you how to make your bed glow!

This works by having a LED strip hidden under the frame of your bed. This will give off a pleasant glow illuminating your room from downwards and up.

The lights are either activated by the time of day or when it detects motion. I've attached my code and made it easy to tweak and edit to suit your needs.

Now you will never be blinded by light if you wake up in the middle of the night again!

Let's get started!

Everyday Carry Sheet

Everyday I go out of the house I have some pre-determined items I'll always want at hand. Mostly stuff for making my interactions with different technology a lot easier. My problem was that I sometimes change bags depending on how many books I'll need that day.
So while I was changing bags I still needed the same technology tools every day. That's why I made a Everyday Carry Sheet!

This is a plastic sheet with elastic bands meant to hold all the stuff I might want on hand in a day. Now it only takes two seconds to change bags while keeping all my stuff. Just pull out the sheet from one bag, and dump it in another! It also has the benefit of keeping my stuff more organized and using less space in my bag.
Head on over to instructables to see how I made it!

Introduction at Instructables:
Today I'll be showing you how to make an Everyday Carry Sheet! This is a great way to keep all your essential items in one place that is easy to take out and chuck into whatever bag you're using on a specific day!

So what is this, you ask? Well when going to school I found myself carrying a set of items everyday. This I could need on any day regardless what I was going to do. I wanted an easy and organized way to carry all these items. So the Everyday Carry Sheet was born!

Let's get started!

søndag 28. august 2016

No Pump Automatic Watering

So I've been thinking a lot about automation with my kitchen plants. I don't like having to remember if they need water all the time. While this burden has been reduced with my Electric Soil Finger I would still prefer if everything took care of itself. Enter automatic watering!
There's already a lot of different solutions for automatic plant watering, but I all found them lacking in one aspec: You need to use a pump with special diameter tubing.
I would prefer not using a pump as that would require less power, be a lot more silent - a big pluss in a tiny dorm, and I won't have to buy several meters of tubing that fits the pump.

I solved both of these problems and actually won a prize for doing so! Instead of using a pump I had a servo react to sensor readings regarding soil moisture. The servo then opens or crimps shut a water tube to either let water flow or turn off the stream. Another improvement, I didn't have to buy a water tube. This system works with most tiny water tubes no special size. So I made my own water tubing by using the isolation of a power cord.

These improvements made this instructable my most popular yet with currently over 40.000 views! I also won a prize pack in the Low Water Challenge. Click here to read my full write up!

Introduction at Instructables:
In this instructable I'm going to show you how you can make your very own automatic plant watering system. The best part? This solution requires no pump!

The benefit of using an automatic watering system is that you avoid having your plants start to dry out, and you also wont accidentally soak your plants. The moisture is kept at the perfect level for your plants and you end up using less water!

There's a lot of different automatic watering systems out there. These seem to work great however there has always been something preventing me from building them. They all require a pump. Personally I would prefer not to use a pump because I think they are expensive and makes a lot of noise. I went to the drawing board to see if I could come up with something different!

This system uses a micro controller and soil sensor to monitor the water level of your plants. If your soil is starting to dry out the controller will counter this by watering the soil until it is sufficiently moist again.

Instead of using a costly and noisy water pump, we are going to use a servo to elegantly open and crimp a water tube. So cheap. So easy.

Let's get started!

I've been featured in an article! Gareth Branwyn from Make Magazine has written an article about this project. At the time of writing it's on the front page of or you can click here to read it.
Super exciting stuff!

onsdag 22. juni 2016

How to Harvest and Replant Tomato Seeds

For a about half a year I've had a few tomato plants growing in my window sill. They've grown really fast and got so tall I had to tie them up so they wouldn't fall over. Now I'm about to move and transporting the plants presented a bit of a logistics challenge. Then I figured, if I could just harvest the seeds I could very easily regrow plants when I've finished moving.
This is much preferable because that also means I won't have to fiddle as much with the plants when I'm moving, freeing up time for more important stuff.
I delved deep into several google searches before I found the best technique that worked for my kind of tomatoes. Then I aggregated the most important aspects into it's own tutorial that I shared online.

Introduction at instructables:
In this tutorial I'm going to show you how to harvest seeds from ripe tomatoes. Planting seeds and letting them start to sprout is a nice gift to give to someone who either loves plants, sustainability, or food!

This is a great project if you either have your own tomato plant, or is lucky enough to get a fully home grown tomato so you can start your own plant.

Let's get started!

Detailed Water Droplets from Spray Paint

The project I just made is a bit different as it involves no electronics, just paint. I used a technique to create really detailed water droplets from spray paint. The result looks really convincing so I'm pleased with how everything turned out!

Intro at instructables:
In this tutorial I'm going to show you how to spray paint these incredible detailed water droplets!

It's an incredible simple process to paint surfaces with these water droplets. You're sure to amaze the people you show your painted things to!

If you're anything like me, after learning this trick you'll be searching for what things you own that would like nice with a coat of painted droplets.

Let's get started!

DIY Electric Soil Finger

I've just made a small device I can use to get readouts on when to water plants. This works by measuring the conductivity of plant soil. The conductivity changes according to how wet the soil is. This information is read and mapped as servo positions to indicate on a gauge when it's time to water.

Intro at instructables:
Today I'm going to show you how to make your own electric soil finger!

What's an electric soil finger you say? Allow me to explain: This is a sensor for measuring the amount of water in plant soil. This will then in turn show you whether or not it's time to water your plants, or if they are very much happy with the amount of water they have right now!

The inspiration for this was that I was constantly sticking my fingers in my plants dirt to learn if I needed to water them. However, this only gave an idea of the water on the very top layer of soil, no good!

I wanted a deeper and more quantifiable measurement and thus the Electric Soil Finger was born.

Let's get started!

I entered this project in the Automation Contest over at instructables and I was lucky enough to win one of their runner up prizes! This prize includes an instructables t-shirt and a Teensy 3.2 microcontroller! Perfect for future projects with a lot of input/output handling.
I'll update with a picture of the prize when everything arrives.