LED wristband

Google Groups
1

Hi all,

I am currently working on making a wearable electronics LED wristband, the
idea came from emfcamp, I though it would be cool if we had one.

Thing is, I am not really sure how to get it working and would appreciate
any help given, it would be awesome if someone can talk me through it so I
understand how the electronics behind it works.

Here is what I have so far:
LED strip snippit (with RGB+ pins)
an atmega328 DIL chip (from the shrimpit kit)
lots of wires.

I was talking to bob on sunday and he said it’s possible to get a
prototype(possibly on a pcb) before oggcamp. That would be awesome :smiley:

I will be at the hackspace on wednesday evening and can come on thursday
and friday to finish it off.

Thanks,

Nour

2

What we did for the LED strip used in our operation game was to run 12V
power and logic level signals to pods connected to the RGB strip. Each pod
then drove the strip using n-channel FETs to switch the ground lines to the
R, G and B.

Since the RGB strip uses a higher voltage than the pins on the atmega328
can handle, the FETs will provide the necessary buffering to protect it
whilst driving the LEDs.

I have some small n-channel FETs in my bits box if needed.

FYI, I attached the schematic for the pod design that we are using.On 29 September 2014 09:07, Nour Alomary nour.alomary95@gmail.com wrote:

Hi all,

I am currently working on making a wearable electronics LED wristband, the
idea came from emfcamp, I though it would be cool if we had one.

Thing is, I am not really sure how to get it working and would appreciate
any help given, it would be awesome if someone can talk me through it so I
understand how the electronics behind it works.

Here is what I have so far:
LED strip snippit (with RGB+ pins)
an atmega328 DIL chip (from the shrimpit kit)
lots of wires.

I was talking to bob on sunday and he said it’s possible to get a
prototype(possibly on a pcb) before oggcamp. That would be awesome :smiley:

I will be at the hackspace on wednesday evening and can come on thursday
and friday to finish it off.

Thanks,

Nour

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Ben Dooks, http://www.fluff.org/ben/ bjdooks@googlemail.com

lightpod.pdf (18.7 KB)

3

You have 2 real options for the strips, a) a common cathode/anode RGB
strip, iv done something similar to this, the circuit boards are a bit
rough, but they can give you an idea of what you need to do. The problem
youll face with this is most of the strips are designed to run on 12v for
the automotive market.

Your other option is neopixels, these run on 5v and act as a shift register
and youll be able to expand later to put patterns through the band. Problem
with this option is cost, neo pixel strips are ALOT more expensive than the
common strips, i got a 1m strip for £16 on ebay though that would probably
make 4/5 wrist bands. There are plenty of arduino libraries to use them so
it wouldnt be too hard to code for themOn Monday, 29 September 2014 09:07:21 UTC+1, Nour Alomary wrote:

Hi all,

I am currently working on making a wearable electronics LED wristband, the
idea came from emfcamp, I though it would be cool if we had one.

Thing is, I am not really sure how to get it working and would appreciate
any help given, it would be awesome if someone can talk me through it so I
understand how the electronics behind it works.

Here is what I have so far:
LED strip snippit (with RGB+ pins)
an atmega328 DIL chip (from the shrimpit kit)
lots of wires.

I was talking to bob on sunday and he said it’s possible to get a
prototype(possibly on a pcb) before oggcamp. That would be awesome :smiley:

I will be at the hackspace on wednesday evening and can come on thursday
and friday to finish it off.

Thanks,

Nour

4

Here is my ten pence…

I have used both led strip and neo pixels. They both have their place.

It all depends on what sort of functionality is required and costs etc.

My biggest input is I can help you make a PCB! Nathan will back me up that
its best idea once you get past the initial prototype stage it is well
worth the extra effort.

Have you used Eagle to input Schematic diagrams and design a PCB? If so we
can use the toner transfer method to manufacture a PCB in the etch tank. I
have written up a guide which is on the wiki:

http://wiki.hacman.org.uk/How-to_pcb

If you haven’t used eagle before I have made a basic how to guide on my
blog but you would need to apply it to your circuit:

If you want I can provide a bit of a face to face tutorial on Wednesday.

Cheers

AlexOn 29 Sep 2014 09:22, “Nathan Hickling” unfoundbug@gmail.com wrote:

You have 2 real options for the strips, a) a common cathode/anode RGB
strip, iv done something similar to this, the circuit boards are a bit
rough, but they can give you an idea of what you need to do. The problem
youll face with this is most of the strips are designed to run on 12v for
the automotive market.

Your other option is neopixels, these run on 5v and act as a shift
register and youll be able to expand later to put patterns through the
band. Problem with this option is cost, neo pixel strips are ALOT more
expensive than the common strips, i got a 1m strip for £16 on ebay though
that would probably make 4/5 wrist bands. There are plenty of arduino
libraries to use them so it wouldnt be too hard to code for them

On Monday, 29 September 2014 09:07:21 UTC+1, Nour Alomary wrote:

Hi all,

I am currently working on making a wearable electronics LED wristband,
the idea came from emfcamp, I though it would be cool if we had one.

Thing is, I am not really sure how to get it working and would appreciate
any help given, it would be awesome if someone can talk me through it so I
understand how the electronics behind it works.

Here is what I have so far:
LED strip snippit (with RGB+ pins)
an atmega328 DIL chip (from the shrimpit kit)
lots of wires.

I was talking to bob on sunday and he said it’s possible to get a
prototype(possibly on a pcb) before oggcamp. That would be awesome :smiley:

I will be at the hackspace on wednesday evening and can come on thursday
and friday to finish it off.

Thanks,

Nour

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5

Thank you all for getting back to me.

Since it’s just a prototype, and I would ideal to have it working for
friday, ordering new LEDs would be a disadvantage, but I would like to try
them out (when I get my next paycheck).
If it’s possible to get them working with the current LEDs that would be
great, I know that they won’t light up for long, and when/if 12V batteries
are used it will be a little big, but the whole point of it is a learning
experience so the next one would be an improvement/ much better.

Ben, I tried to get it working but it didn’t work for some reason on
sunday, I used new batteries for them too. Though would like to get one
working if possible.
Nathan, I have already started looking at neopixels, they look Awesome!
can’t wait to get my hands on some and start hacking away with them.
Alex, Yes, that would be great! Since this is the start and I’m just
getting used to playing with electrnoics and the hackspace, I think it will
have time to improve it and also get some neopixels and improve it.
last time I designed a PCB was about 5 years ago? in school D&T lesson,
haven’t done it since, though will have a look at the post, Thanks.
The f-2-f tutorial sounds awesome.

Thanks again!

Nour

6

We have a couple of variable power-supplies above the electronics bench
which are useful for testing.On 29 September 2014 13:31, Nour Alomary nour.alomary95@gmail.com wrote:

Thank you all for getting back to me.

Since it’s just a prototype, and I would ideal to have it working for
friday, ordering new LEDs would be a disadvantage, but I would like to try
them out (when I get my next paycheck).
If it’s possible to get them working with the current LEDs that would be
great, I know that they won’t light up for long, and when/if 12V batteries
are used it will be a little big, but the whole point of it is a learning
experience so the next one would be an improvement/ much better.

Ben, I tried to get it working but it didn’t work for some reason on
sunday, I used new batteries for them too. Though would like to get one
working if possible.
Nathan, I have already started looking at neopixels, they look Awesome!
can’t wait to get my hands on some and start hacking away with them.
Alex, Yes, that would be great! Since this is the start and I’m just
getting used to playing with electrnoics and the hackspace, I think it will
have time to improve it and also get some neopixels and improve it.
last time I designed a PCB was about 5 years ago? in school D&T lesson,
haven’t done it since, though will have a look at the post, Thanks.
The f-2-f tutorial sounds awesome.

Thanks again!

Nour

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Ben Dooks, http://www.fluff.org/ben/ bjdooks@googlemail.com

7

I have some spare NEO-pixels I could let you have as I won’t be using them.

I think we will be able to get your prototype working.

Cheers

AlexOn 29 September 2014 13:31, Nour Alomary nour.alomary95@gmail.com wrote:

Thank you all for getting back to me.

Since it’s just a prototype, and I would ideal to have it working for
friday, ordering new LEDs would be a disadvantage, but I would like to try
them out (when I get my next paycheck).
If it’s possible to get them working with the current LEDs that would be
great, I know that they won’t light up for long, and when/if 12V batteries
are used it will be a little big, but the whole point of it is a learning
experience so the next one would be an improvement/ much better.

Ben, I tried to get it working but it didn’t work for some reason on
sunday, I used new batteries for them too. Though would like to get one
working if possible.
Nathan, I have already started looking at neopixels, they look Awesome!
can’t wait to get my hands on some and start hacking away with them.
Alex, Yes, that would be great! Since this is the start and I’m just
getting used to playing with electrnoics and the hackspace, I think it will
have time to improve it and also get some neopixels and improve it.
last time I designed a PCB was about 5 years ago? in school D&T lesson,
haven’t done it since, though will have a look at the post, Thanks.
The f-2-f tutorial sounds awesome.

Thanks again!

Nour

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8

I went through the same sort of deliberations when i started building my
ambi-light clone.

I spent a long time (much to alex’s distaste) prototyping and seeing how
things reacted, alex has obviously recommended eagle, my 2 cents on this
one would be to look at design spark pcb, there is only a free version and
its a bit less limiting than eagle i find.
Its completely reasonable to have a board made and soldered all on
Wednesday evening, early on i made an isolated mosfet driver to do just
that that was designed, etched and drilled one night, it wouldnt take much
more to solder up and be ready.

In terms of getting it working for friday, you can reasonably run a
prototype on a 9v battery, the blue will be a bit washed and overall
brightness will be low, but youll get a nice example of what it will look
like. I can show you my board which I put together (its VERY rough) to give
an idea of what you can do, its built to handle ALOT more power than your
looking at, but it can be scaled back without too much issue.On Monday, 29 September 2014 13:31:49 UTC+1, Nour Alomary wrote:

Thank you all for getting back to me.

Since it’s just a prototype, and I would ideal to have it working for
friday, ordering new LEDs would be a disadvantage, but I would like to try
them out (when I get my next paycheck).
If it’s possible to get them working with the current LEDs that would be
great, I know that they won’t light up for long, and when/if 12V batteries
are used it will be a little big, but the whole point of it is a learning
experience so the next one would be an improvement/ much better.

Ben, I tried to get it working but it didn’t work for some reason on
sunday, I used new batteries for them too. Though would like to get one
working if possible.
Nathan, I have already started looking at neopixels, they look Awesome!
can’t wait to get my hands on some and start hacking away with them.
Alex, Yes, that would be great! Since this is the start and I’m just
getting used to playing with electrnoics and the hackspace, I think it will
have time to improve it and also get some neopixels and improve it.
last time I designed a PCB was about 5 years ago? in school D&T lesson,
haven’t done it since, though will have a look at the post, Thanks.
The f-2-f tutorial sounds awesome.

Thanks again!

Nour

9

Ben, Cool, can’t wait to get started on it.
Alex, Thanks, I promise i’ll return them after I’m done :smiley:
Nathan, cool, you don’t happen to have pictures of it right? Hopefully that
won’t happen with me since I have set myself a deadline and I’d be happy
with the minimum for now, after the weekend I can take it slow if needed
though, I know exactly what i want it to do, so it’ll be a matter of
getting it to do exactly that. I will check it out tonight when I get home.

Thanks! :smiley:

Nour

10

I wouldn’t say distaste…I didn’t really mind it’s just I could see you
struggling with wires flying of the breadboard and you spending more time
fault finding on the breadboard than getting it working [?]

Design spark is fine however most of the people at the hackspace use Eagle
so that’s the software someone will most likely be able to help you with.
Use whichever software you like…as long as it can print the design in
black and white reversed we can use it to make a PCB…

Cheers

AlexOn 29 September 2014 14:26, Nour Alomary nour.alomary95@gmail.com wrote:

Ben, Cool, can’t wait to get started on it.
Alex, Thanks, I promise i’ll return them after I’m done :smiley:
Nathan, cool, you don’t happen to have pictures of it right? Hopefully
that won’t happen with me since I have set myself a deadline and I’d be
happy with the minimum for now, after the weekend I can take it slow if
needed though, I know exactly what i want it to do, so it’ll be a matter of
getting it to do exactly that. I will check it out tonight when I get home.

Thanks! :smiley:

Nour

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