Bubble Display Alarm Clock

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Bubble Display Alarm Clock

Postby Markus Gritsch » Sun Jun 01, 2014 5:36 am

Hi,

recently some vintage bubble displays popped up at various places [1][2], so I felt the urge to build another bedside table alarm clock, this time a really tiny one, roughly the size of an AAA battery:

IMG_3538_1600x1200_85.jpg

Since I already built two previous alarm clocks [3][4], the build was straight forward. Here is the simple schematic:

Schematic.png
Schematic.png (5.93 KiB) Viewed 8450 times

Here the parts used:

IMG_3484_1600x1200_85.jpg

And here how the wiring was done:

IMG_3486_1600x1200_85.jpg

Please find the source code attached.

A video is also available on YouTube: http://youtu.be/PlNQiXvsbPA

Have fun,
Markus

[1] https://www.tindie.com/products/BBTech/ ... t-display/
[2] https://www.sparkfun.com/products/12710
[3] viewtopic.php?f=56&t=2126
[4] viewtopic.php?f=56&t=2784&p=28231#p53277
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Re: Bubble Display Alarm Clock

Postby McLaren » Wed Jun 04, 2014 10:58 pm

Hey Markus, an impressive project. Thank you.

Mind if I ask the source for the miniature speaker, please?

TIA. Cheerful regards, Mike
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Re: Bubble Display Alarm Clock

Postby Markus Gritsch » Thu Jun 05, 2014 1:17 am

McLaren wrote:Mind if I ask the source for the miniature speaker, please?

Sure, I saw it being used in this nice project: http://blog.zakkemble.co.uk/diy-digital-wristwatch/

Google for ABMT-801-RC. I bought mine from Farnell.

Don't expect too much in terms of sound quality from such a small speaker, though.
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Re: Bubble Display Alarm Clock

Postby Vicaro » Fri Jun 13, 2014 5:54 am

Hi Markus,

Thanks for putting your clocks up on the net. I picked up a couple of the the HP Bubble displays as soon as I saw them and had been wanting to use them in a clock but hadn't the means so your design + code is fantastic.

I had a couple of questions, if that's OK:

1) - The schematic has a couple of caps, notably one by the buzzer, but the built item doesn't seem to neither does the photograph of 'parts'. Should the caps be used?

2) - The voltage from a single AAA is below spec for the chip, display, & buzzer. Doesn't this matter?

3) - You don't have a resistor in series with the LED, would it be good to put one in, if part+room available?

Also I'm envious of your neat tac buttons as I weary of the ubiquitous black round rod type, do you have a part # or source for them - also the LED which looks a nice rounded edge shape for free mounting, all the rectangualr ones I've seen are very hard edged.

Thanks again, Vicaro
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Re: Bubble Display Alarm Clock

Postby Markus Gritsch » Fri Jun 13, 2014 6:16 am

1. The buzzer capacitor from the schematic is visible as the two SMD caps between the LED and the buzzer on the board.

2. The AAA sized battery is an AAA sized LiFePo4 battery, rated at 3.4 V. I bought mine from here http://www.ebay.com/itm/2-10450-3-2V-20 ... OC:AT:3160
Love them.

3. The white LED is rated for 3V, which the output of the microcontrolled is not able to provide at such high currents (20 mA). Since the output does not get damaged, everything is fine and resistors are futile :)

4. These are the buttons I used http://imall.iteadstudio.com/im120731002.html

The LED is a standard 5 mm white LED with round head where I filed away most of the plastic :)
Last edited by Markus Gritsch on Fri Jun 13, 2014 2:24 pm, edited 1 time in total.
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Re: Bubble Display Alarm Clock

Postby Vicaro » Fri Jun 13, 2014 2:16 pm

Aha, missed the smd cap there. Thanx for being patient with my 'duh'' moments :-). Thanx, Vicaro
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Re: Bubble Display Alarm Clock

Postby chiruru » Thu Jun 19, 2014 4:35 am

Hello,

So cool post, Thank you.

I'm testing your product, and I wonder that why need SHINING mode?
And Why measure the voltage while the LED is shining?

And I want to find out so pretty LED like you. Where did you find out it?

Thanks,
SB YIM.
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Re: Bubble Display Alarm Clock

Postby Vicaro » Tue Aug 05, 2014 8:56 am

Hi Markus,

Finally sourced all parts with the exception of battery: The speaker has got to be the world record for tiny :-)

Re batteries, could I ask how you recharge these - do you use a dedicated LiFePo4 charger?

Regards, Vicaro
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Re: Bubble Display Alarm Clock

Postby Markus Gritsch » Tue Aug 05, 2014 2:21 pm

I do not have a dedicated charger. Instead I hook up the battery to my bench power supply, set the voltage to 3.6 V and limit the current to 200 mA for the AAA sized cell. This way the battery is first charged with a constant current of 200 mA and then with a constant voltage until it is fully charged (charge current below 1 % of constant current, i.e. <2 mA).

This might not be as convenient as using a dedicated LiFePo4 charger, but since the battery lasts (for this application) about 2 years, it is not that much of a hassle to me :)

Cheers,
Markus
Last edited by Markus Gritsch on Wed Aug 06, 2014 1:36 am, edited 1 time in total.
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Re: Bubble Display Alarm Clock

Postby Vicaro » Tue Aug 05, 2014 8:04 pm

I'd wondered if something like this was OK so this information is great. 2 years is very a long time - these Texas Instrument ICs are impressive and some are available as samples.

Thanks once again for such a detailed and useful reply, regards, Vicaro
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