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Alternative 5Volt power supply for the UK
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Alternative 5Volt power supply for the UK

by g0hjq on Fri Oct 02, 2009 8:24 am

The kit arrived in England, safe and sound. It took 3 weeks in the post, and I had to pay the Royal Mail an aditional £5.80 UK Tax, plus a £8.00 handling charge (Totaling around US$21.95)

Thanks to the superb instructions, it was straight forwards to build in about 2.5 hours. It worked perfectly first time. I was very impressed how good it looks in the acrylic case, and also how compact it is. Thank you everyone at Adafruit.

The one thing I would like to change is the power supply. When plugged into a US-UK adaptor socket, it has a tendency to work loose, and looks ugly.

I have a number of good quality 5Volt 500mA USB Switch Mode adaptors that would be ideal. One side effect of this would be reduced heat disipation and lower power consumption. (the 5 volt regulator does get quite warm).

Has anyone tried modifying the clock to run off 5 volts? I suppose all I need to do is remove and bypass the 5 volt regulator, but would the high-voltage generator need modifying as well?

Gary G0HJQ
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Re: Alternative 5Volt power supply for the UK

by adafruit on Fri Oct 02, 2009 11:01 am

you really do need 9V for the boost converter

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Re: Alternative 5Volt power supply for the UK

by g0hjq on Wed Oct 07, 2009 8:31 am

After a bit of playing around, I did manage to get it working on 5 volts.

I replaced the 7805 voltage regulator with a wire link,
Replaced the Boost Coverter Inductor with one of 470uH,
Replaced the input protection diode with a wire link (otherwise the microprocessor voltage is too low)
Most important of all, placed a sticker on the back panel saying "5 Volt DC Only"

It seems to work fine, with good display brightness. All components, including the boost converter transistor and inductor run cool. The power consumption is around 150mA at 5 volts.

Gary.
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Re: Alternative 5Volt power supply for the UK

by bastard on Fri Oct 09, 2009 11:49 am

Hi,

g0hjq wrote:After a bit of playing around, I did manage to get it working on 5 volts.
...
The power consumption is around 150mA at 5 volts.


great! So powering by USB is now possible. One wallwart fewer.

Bye

Stefan
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Please be positive and constructive with your questions and comments.