Pebble half (partial) assembly: Pre-installed parts ... and the remainder for the mini-conference
Andy Gelme
On the basis that the hardware assemble session(s) will be 2 x 45
minnutes ... the following rough break-down is proposed ...
- 15 mins: Introduction
- 20 mins: Build stage 1
- 20 mins: Build stage 2 (split by break)
- 20 mins: Build stage 3
- 5 mins: Conclusion
The 3 build stages aren't super-challenging, we need to ensure that
everyone completes their hardware and that it works, for later
presentations. For those more competent attendees, we can have other
"exercises", e.g. putting something onto their prototype area.
The build stages are ...
1) LCD
~~~~~~
Within 20 minutes, attempt to have a big win by getting "Hello World"
(or equivalent) onto the LCD screen. The Arduinos will either come
pre-installed with Aiko (those brought by us) or we'll quickly download
the firmware into Arduinos brought by attendees. No time to waste (at
this stage), helping people get their Arduino IDEs and USB going (we'll
do that after the hardware build).
Attendees who are racing ahead and have their Arduino IDE going can
play around with programming the LCD ... or maybe get a head start on
plugging their ZigBee in (which will have enough pre-assembled parts on
the Pebble PCB to function immediately).
p.s. I wonder if we can "sell" a company name / URL to display ... to
the highest bidder ... are you listening Nathan :)
2) Input buttons and potentiometer
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This second section will get some discrete components, buttons and a
potentiometer on the board. The preloaded Aiko software will perform
some obvious actions, when these buttons are pressed and the
potentiometer twiddled. This way we can use the firmware as a
self-testing mechanism.
3) Sensors and relay outputs
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Install the discrete components, LDR, temperature sensor and
remaining relay parts. Once again, the firmware will have the facility
to test sensor input (on the display) and drive the relays.
Mitch has suggested / offered to build some simple LED test harnesses
for the relays ... to clearly demonstrate that they are working.
Hopefully, this amount of soldering with both give attendees a "taste"
of assembling a PCB ... and give them some first-hand familiarity with
the Pebble hardware, before going on to software sessions that use the
Pebble.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Here is a complete list of Pebble parts, with "*" to indicate whether
the component is pre-installed onto the PCB ...
Partial assembly
----------------
* Components to pre-install on PCB
- Components to be assembled during the mini-conference
1) General parts
~~~~~~~~~~~~~~~~
* 2x 8-pin male header strip
* 2x 6-pin male header strip
* 100 KOhm resistor (near relay outputs)
2) ZigBee
~~~~~~~~~
* LED (red)
* 100 Ohm resistor
* 2x 10 KOhm resistor
* 100 nF capacitor
* 10 uF capacitor (place horizontally)
* LC1117V33 voltage regulator
* 2x 2 mm ZigBee female header
3) LCD screen
~~~~~~~~~~~~~
* 4 row x 16 column LCD screen
* 2x 16-pin male header strip
* LED (green)
* 100 Ohm resistor
* 100 KOhm resistor
* 100 nF capacitor
- 10 KOhm variable trim-pot
- 16-pin IC socket
- 2x 16-pin female header strip
- IC4094 8-bit shift register (plug into socket)
4) Buttons
~~~~~~~~~~
- 2x 10 KOhm resistor
- 22 KOhm resistor
- 39 KOhm resistor
- 4x buttons
5) Variable input
~~~~~~~~~~~~~~~~~
- 10 KOhm variable resistor (potentiometer)
6) Light sensor
~~~~~~~~~~~~~~~
- 10 KOhm resistor
- LDR
7) Temperature sensor
~~~~~~~~~~~~~~~~~~~~~
- 4.7 KOhm resistor
- DS18B20 1-wire temperature sensor
8) Relay outputs
~~~~~~~~~~~~~~~~
* 2x 1N5819 diode
* 2x 14-pin IC socket
- 2x Reed relay
- 6-pin male (white) lockable connector (Molex)
- 6-pin female (white) lockable connector (Molex)
- Pins for female Molex connection
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andyg (geekscape)
Yesterday, I built up a half-assembled Pebble ... and then ran through
completing it, in the 3 proposed Build stages, timing each one ...
On Dec 29, 6:30 pm, Andy Gelme <an...@geekscape.org> wrote:
> The 3 build stages aren't super-challenging, we need to ensure that
> everyone completes their hardware and that it works, for later
> presentations. For those more competent attendees, we can have other
> "exercises", e.g. putting something onto their prototype area.
>
> The build stages are ...
> 1) LCD
> 2) Input buttons and potentiometer
> 3) Sensors and relay outputs
Each stage took me around (or less than) 10 minutes ... including
testing each stage with an Arduino running Aiko.
I'm presuming that we'll need to cater for new-comers that will take
longer ... and there may need to be a small amount of talk /
presentation time for each section, so this conservative schedule will
hopefully allow everyone to complete everything ... even if a mistake
or two is made.
However, there will be attendees who can race through these stages and
will have time on their hands. So, we'll need to have some strategies
to keep them occupied, e.g. ...
- Some coding exercises for the hardware stage that they just
completed.
- Working on something in the Pebble prototype area (maybe bring some
additional components and bread-board).
- Playing around with ZigBee and building up a mesh-network of
Pebbles. Note: The Zigbee circuitry will be complete and tested on
the half-assembled PCBs.
> Partial assembly
> ----------------
> * Components to pre-install on PCB
>
> 8) Relay outputs
> ~~~~~~~~~~~~~~~~
> * 2x 14-pin IC socket
Luke has made a convincing argument that we should ditch the relay
sockets ... and they won't be included in the half-assembled kits.
The attendees will be directly soldering the relays on to the Pebble
PCB.
cheers andyg (@geekscape)
Jonathan Oxer
> Each stage took me around (or less than) 10 minutes ... including
> testing each stage with an Arduino running Aiko.
Perfect.
> However, there will be attendees who can race through these stages and
> will have time on their hands. So, we'll need to have some strategies
> to keep them occupied, e.g. ...
If there's time to develop a couple of extra exercises that's fine, but
I'd put this as a low priority. If people have 5 minutes here or there
to fill in that's not a serious problem, and they can switch to helping
other people or whatever.
> Luke has made a convincing argument that we should ditch the relay
> sockets ... and they won't be included in the half-assembled kits.
Hooray!
Thanks Luke.
One of the things on my list of suggestions for the next design
iteration is to switch to a proper reed relay footprint.
Cheers :-)
--
Jonathan Oxer
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Luke Weston
> One of the things on my list of suggestions for the next design
> iteration is to switch to a proper reed relay footprint.
>
You mean a DIP footprint that only has the outside 8 pins populated?
I actually originally had that on the board layout, but someone
suggested, at some point in the past, that it be changed.
Jonathan Oxer
> You mean a DIP footprint that only has the outside 8 pins populated?
Yes, exactly.
> I actually originally had that on the board layout, but someone
> suggested, at some point in the past, that it be changed.
I don't remember that, but perhaps it was because of the suggestion to
use DIP sockets. But if the sockets are being dropped (which I fully
agree with) then I think it should be done as you originally intended.
Neater and more self explanatory.