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 ( web software ), so my models might be crappy and bad made.


Pictures and Videos

Saturday 9 August 2014

Ampere meter DIY

I always wanted to test my devices and find out what was the real current of each item.
The option was to buy a multi-meter that could do it, but because I bought an ampere meter display for 2 pounds on ebay, I wanted to make it easy to use.

I bought a small plastic box and fitted all the electronic inside, even the cable to connect the device to test.

I have used:
  • 2 crocodile clips to be able to clip any cable and measure the current.
  • 1 female and 1 male audio jack, to remove the cable and put it back in the box when it's done.
  • 1 ampere meter from ebay
  • 1 switch to turn on the power
  • 1 9V battery ( from the picture I used something else because I didnt have one )

The usage is streight forward, turn on the device from the switch, connect the cable and clip your device.
I have tested a DC motor to confirm that everything was working, and it worked!

Of course, with a 9v battery the box would be closed and easy to read.

When I have done with it, I just put the cable inside the box and put it somewhere.

Saturday 5 July 2014

Bike's lights

Since I got my bike, I had to carry around two lights when I was going to cycle on late nights. These lights were small but I was worried to leave them somewhere and cycle without lights.
I came up with a simple solution to make my own lights system and to install it on my bike.

The shopping list is very simple and small, also I could have bought less stuff:
- 4x white leds with wide angle and brighter
- 4x red leds with small angle and brighter
- 8x transistor to switch on and off
- 1x push button to change mode
- 1x arduino pro mini to control flashing mode
- 1x 3 AA battery holder


I wanted to get something very bright and have arduino to control these lights, but because it was using a lot of current I had to install some transistor.
I am not a genius in electronic, but probably my transistor wouldn't handle the amount of current of 4 leds, so I put one on each led.

An huge amount of hot glue was used to make it waterproof, I am sorry I made something very ugly, but the next version will be better!

I have coded 3 modes for my bike: both solid, front solid and back flashing, both flashing.
I could have used some small components and a 555 timer, but because I am very lazy and the arduino pro mini was very small, I decided to code it.

The whole electronics is fitted under the seat with some hot glue and good position in case I ride in a bumpy road.

The main switch, that you can reach with your hand, turn on the whole system and in few seconds I am ready to cycle.
I have used heat shrink to cover the cable and to make it less "mobile-bomb", people could think that I just made something dangerous!

The button to change the mode is located on the top bar, where you hands are.
I used a piece of plastic to make sure that it will be "water-proof", but only the first few rains will tell me if I have done a good job.

Final result
The big piece of glue is not good-looking stuff, I will try improve the whole system by using one single transistor and to drill 4 holes into the reflectors.
It will become less ugly and more stable while I am cycling.