[clug] More info, please - was Re: Tridge's coffee contraption - photos

Alastair D'Silva alastair at newmillennium.net.au
Mon Nov 30 18:24:43 MST 2009

Hi Hugh,

Some suggestions to make the whole thing cheaper & better:

1. use a USB PIC, or software USB on an Atmel -
http://www.xs4all.nl/~dicks/avr/usbtiny/ . This replaces the MAX232 with a
couple of resistors. Since you now have a USB device, the transformer is not
needed for power. You can achieve the zero cross detection with an
optocoupler and a resistor divider network.

2. Add an analog input jack for the thermocouple, eliminating the multimeter
from the equation. Once could always add an LCD/LED display for temperature
readouts at a fraction of the cost of the multimeter.

3. Add another 240V output for direct control of the motor.

Some parts will be salvageable directly from the control of the breadmaker -
it likely already has a triac or relay for driving the motor, and possibly a
thermocouple as well. There may also be an LED display you can use for
temperature readouts.

Alastair D'Silva           mob: 0423 762 819
Networking Consultant      fax: 0413 181 661
New Millennium Networking  web: http://www.newmillennium.net.au
skype: alastair_dsilva     msn: alastair at d-silva.org
blog: http://alastair.d-silva.org

> -----Original Message-----
> From: linux-bounces at lists.samba.org [mailto:linux-
> bounces at lists.samba.org] On Behalf Of Hugh Blemings
> Sent: Tuesday, 1 December 2009 11:54 AM
> To: tridge at samba.org
> Cc: paulus at samba.org; Felix Karpfen; linux at lists.samba.org
> Subject: Re: [clug] More info, please - was Re: Tridge's coffee
> contraption - photos
> Hiya,
> > For those who may be interested, I've done a bit of a write up on the
> > power controlled coffee roaster at coffeesnobs. See:
> >
> >   http://coffeesnobs.com.au/YaBB.pl?num=1259627838
> >
> > It also includes a link to a much better circuit diagram than what I
> > showed at CLUG. Thanks to Hugh for the work on drawing up the
> circuit!
> Should add am going to take a crack at a PCB layout for the board in
> the next
> week or so and then we'll prolly organise to get a small run of boards
> done.
> Cheers,
> Hugh
> --
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> linux at lists.samba.org
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