Tuesday, 5 May 2015

3D Printed Chain Guard

I changed my Crank of my bike recently and it didn't have a chain guard to protect my jeans to get smashed and dirty.
The options were to buy one online that means 10-12 GBP or to get a 3D model online and print it with my "already paid" filament.
I went on Google and found one model that looked good and big enough for main Crank but when I tried on my bike, it was too small.  What I have done is to measure the right diameter and increase the size to match my 12 cm disk.


I have shared the model, even if it is not the correct ratio, but people could improve it and print it.



Final result with 4 M4 screws

Friday, 13 February 2015

Leds Jacket

In my little part of Switzerland, there is a huge celebration for the carnival that can last for over a month, and one of the way to enjoy this event is to dress up, party and enjoy the night.
My project fits into the "dress up" step, where I made my own costume leds jacket that react with the sound and has different modes.

- 1x old jacket
- 1x arduino
- 1x spectrum sparkfun or MSGEQ7
- 1x microphone
- 1x Lipo battery
- 1x 9v battery
- 1x lot of meters of leds ( addressable are better )
- few step down 5v ( if you run a lower voltage leds compared to the battery )

You have to be creative, I decided a bit randomly how to place my strip of leds and based on that you have to think what kind of animation you can display.

Best way to stick your leds on the jacket is to saw them a bit every 20-40 cm then put a piece of fabric on the top to avoid people grabbing the strip or get stuck somewhere.

If you are lucky enough, you will have a jacket with more than one layer of fabric, so you can run cables inside the jacket without touching them when wearing the jacket, and remember to find one with some big pocket inside to store battery and arduino.

The microphone is the tricky one to place, it took me a while to stick in the right position but with some sewing and hot glue everything stayed in position.

Remember, try to find the best position to fit everything and close to inside pocket to avoid to pull any cables that will stop the fun.

The battery is up to you, in my case I decided to use a 5v addressable leds that will consume 3.2 A and one lipo 4S 4000 mah to power them. The battery life is about 6-8 hours but it can be extend by lowering the brightness via code.

In addiction, I had to use 3 step down 5V, be sure to use a switching converter to avoid any lose on the conversation. I bought few of them from HobbyKing and they are UBEC converter.

Dont forget to have two batteries, one for the Arduino ( can be a 9v battery ) and one to power the LEDs, this because you might want to have all the possible current to the LEDs and avoid any "power down" or "frying arduino" due to the higher current.
It might sounds silly but it's just less work to do and much more safe.

I got a fuse in my jacket between the battery and my leds strips, just in case there are any shorts, I wont burn =).

I am not a great guy in terms of design and animations, so I had to watch some youtube videos to get some inspiration. I have implemented 4 modes on my jacket and 6 mode for the brightness&control.
The 4 modes shuffle every 60 seconds and they do react with sound or when I change to manual, they read random values to replaced the microphone. 

I have implemented the green button to switch between 6 modes: Microphone, Microphone 50% brightens, Microphone 20% brightness, Manual, Manual 50% brightness and Manual 20% brightness.

To have a quick access to the operation of the arduino, I soldered a switch to turn it on and off.



Wednesday, 7 January 2015

Watering system

I bought a plant, a Christmas tree ( actually two of them ), because I felt like I had to decorate my desk at work, but I was failing to water it regularly and I came up with a plan.
I decided to check on ebay for a very small and cheap pump, a soil sensor, a small arduino and few
other bits.

Wiring of transistor may change based on your model 

Pump system
The pump system was pretty straight forward, one pump, a tube and wrap it around the plant.
I decide to make holes in the tube and close the end of it, in this way the water would come out uniform and gently instead of flooding. the terrain.

In addition, I designed 4 pins to hold the tube down to the soil and point the water against the middle instead of having some random ray of water coming out of the pot.

Soil sensor
The soil sensor was the easy bit, just stick the "fork shape" into the soil and read the analog input from the chip, nothing very difficult, a part from the missing datasheet.
My chinese sensor was giving me 1024 when the soil was dry and almost zero when everything was wet.

** Note ** The soil PCB broke down after 1 week, so better if you stick two wires in the soil

I wrote down some code to make sure to trigger the pump only in a specific value, adding a delay ( in case the sensor will fail ) and a max pump time ( in case the sensor will be slow to read the current change of the soil conductivity.

Box and Tank
I had to keep everything clean and nice to look, so I designed two boxes: one to put all my electronics in and the second to keep 0.6L of water.
Very simple basic, nothing too complicated, I wanted to use a simple bottle as tank, but was very unattractive.

Source code
You can find one copy of my source code and 3d models on my github:  *** Soon ***


Tuesday, 6 January 2015

Bosch kettle - Reduce beep noise

I got a Bosch Styline Kettle and I am happy with that, it does the job and pretty quick. There is one small thing that is annoying me, it is the horrible beep noisy that it makes when I start and when it finishes the job.
Unfortunately, using a normal screwdriver to unscrew the 4 screws below the platform wasn't possible, I had to buy a special tool to access the inside of it.

The tool bit to unscrew these special ones was "Spanner (snake eye): 4, 6, 8, 10", I reckon I used the number 6 but better to get a set as I did. You can find one on Ebay for about 8 pounds.

Find the buzzer
This is what it looks like inside the base of the Bosch Kettle, simple PCBs, and you can spot the annoying buzzer on the right side.

Fix it!
Applying a bit of tape on  the top of the buzzer will reduce the noise and still notify when it has done the job.


Saturday, 6 December 2014

XLED bike lights version 2.0


In my previous project Bike lights I managed to create my personal lights, but these were very ugly.
I have tested my current setup for few months, under rain, cold, washing my bike, etc... everything went good and I had no issues.
The next step was to improve the position of the lights, a new design for the enclosure and change type of leds where needed.

One light wired up, my configuration had two of them.


The case that contains the leds, is full of glue as the previous one, but of course the outside doesnt look like a piece of glue as the old one.
I designed, with tinkercad, the new enclosure to fit on the top of the reflector and 3d printed in black.

The front leds( white ones) were upgraded because the previous ones had a wider angle and didnt have enough light.

The transistor was upgraded to a bigger one from the previous design. I had one on each led and now I got only one in each case.


The design was very simple, just 4 holes to allocate each led and a small side to slide on the top of the reflector.
I had to drill manually the hole to hold the case.

Final result

Sunday, 2 November 2014

Halloween ghost


Here we go, Halloween has arrived and I have to make something for it! Below you can find my first sketch that I have done in a pub ( and in the end of this post, something that should look like that).
In few words, what I wanted to create was a simple ghost that will interact with people by walking close to it.
The interaction should be an inflatable arms and flashing eyes & mouth.

- Few yellow leds
- Few red leds
- Few transistor
- Ghost cover ( bought one from poundland shop )
- Few shopping bags that match the color of your ghost
- Two powerful fans
- A lot of batteries :)

Making arms

The inflating of arms was something tricky to achieve, because I had to find a good material and very light.
By hot glueing a shopping bag around the fan and make a relative small tube, I managed to inflate two arms.
I was using a very powerful fan with double prop and  6 batteries to get 9 volts.

Flashing leds
My flashing system was made with 2 transistor and few leds.
I used one transistor to flash the eyes ( red leds ) and the second one to flash the mouth ( yellow leds ). I have avoided to use a 5 volt regulator and connected  everything into the Arduino.
You should be careful to use this method, because your Arduino might shut down due too much current drained from the leds. I was lucky and my Arduino didnt shut down :)

One issue that I found while the ghost was working at the party, was some interference with the IR sensor, probably due to colored lights or else.
One solution would be to use a sonar sensor instead.

Arduino was shutting down after the fans were on. This happened because my fans were draining too much power and the arduino lost power and reset itself.
One solution would be to solder a bigger capacitor, so the Arduino would run for the short drop of power.
Second solution, the one that I chose because I had a spare battery hold, was to use another power source to power the Arduino. You could try with a 9V battery or just 4 batteries holder.

Images and videos

Wednesday, 29 October 2014

Marble dispenser

This is another challenging project that took over all my free-time but it made me achieve something that I couldnt think that I was possible to do.
The marble dispenser was a machine that interacts with Twitter and streaming a live feed from a webcam.

Watch the final result:

The bigger problem was to make an automatic marble dispenser without any human interaction to make it works.
The first idea was to make something like the candy vendor machine, with a rotator dispenser and hook it up with a motor
Of course, as every simple thing, this didnt work as I wanted. The problem was to make a container that wouldnt let marbles stuck in the container.

The solution came after few days, after a bit of brain storming and a good beer.
The container solution couldnt have made in the short time that I had, but a pre-order columns with marbles placed in a row, this was the way to go.

It might look odd but in the end, it worked and I had less trouble to make sure that one marble was released when the system needed.

Twitter integration
It might sounds strange to connect a marble dispenser with Twitter, but the reason is simple. The idea was to ask questions on Twitter and make a visual action from people's answers.
The visual action was to position two marble dispensers and drop one single ball for each answer received. Here it comes the bottom part of the marble dispenser, where I made one simple system to release only one at the time.

Bottom part
The release mechanism is very simple, it has two main parts:
- The little brick that drag only one marble at the time
- One servo motor that moves the brick

In the picture above, you can see that the brick ( in red ) has a small hole where you can fit a bracket ( in red ) and connected to the servo motor.
The main enclosure ( in orange ) fits the servo and the brick, the motor rotates from 170 to 85 degrees to make sure that the marble is released.

LCD count
To keep track of each answer and have visual reading, I used one of the 7 segments from AdaFruit.
This little guy is super easy to use and the library save you hours of coding or understanding how to send the right number to the IC.

I have used one low resolution webcam from Logitech, even because I was streaming a 640x480 because Raspberry pi can't handle a full hd streaming to Ustream.
The resolution maybe let people down, but the cool feature was to have a visual access for people not physically  at the installation.

Source code
I am sharing some of the code from the whole installation and STL files in case you would like to print the same thing.
The code might be not the perfect one you have ever seen but it works, so please dont judge me.
Also this was my first attempt to create something very sophisticated in 3D using TinkerCad.com ( web software ), so my models might be crappy and bad made.


Pictures and Videos