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Fabrication
Building your own Atmex board
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The Atmex board can be built by anyone who has even the most minimal
soldering experience. All parts are through-hole, and the board
only has 16 components to solder. It is also fairly inexpensive,
costing less than $10 |
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Purchasing
components
The
first step to using Atmex is to build an Atmex board! All the components
are available at Digikey. Making one PCB is not viable, but you can make
approx. half a dozen for reasonable cost (<$50) at 4PCB/Barebones
or Olimex. See the download
page for gerber files.
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| Name |
Manuf. |
Part Number |
Description |
Cost per |
(qty 25) |
Total Cost |
(qty 25) |
| IC1 |
Atmel |
ATTINY2313-20PI |
Microcontroller |
$2.26 |
$1.43 |
$2.26 |
$1.43 |
| IC2 |
T.I. |
MAX232N |
RS-232 level shifter |
$0.78 |
$0.65 |
$0.78 |
$0.65 |
| IC3 |
Any |
78L05 |
5V fixed regulator |
$0.20 |
$0.17 |
$0.20 |
$0.17 |
| SW1 |
Omron |
B3F-3120 |
Reset button |
$0.30 |
$0.27 |
$0.30 |
$0.27 |
| X1 |
Norcomp |
171-009-202-001 |
Serial DB-9 female |
$0.67 |
$0.58 |
$0.67 |
$0.58 |
| X2 |
CUI |
PJ-202AH |
2.1mm Power jack |
$0.38 |
$0.33 |
$0.38 |
$0.33 |
| X2 Alternate |
CUI |
PJ-600A |
2.1mm power jack (vertical) |
$0.45 |
$0.38 |
$0.45 |
$0.38 |
| D1 |
Any |
1N4001 |
Protection diode |
$0.03 |
$0.03 |
$0.03 |
$0.03 |
| LED1 |
Lite-On |
LTL-1KHPK or (LTL-4266N) |
Red LED |
$0.11 |
$0.09 |
$0.11 |
$0.09 |
| C3,C4,C5,C6 |
Xicon |
140-MLRL50V1.0 |
4 x 1uF Capacitors |
$0.08 |
$0.06 |
$0.32 |
$0.24 |
| C1, C2 |
Panasonic |
ECE-A1EKA220 |
2 x 22uF, 25V+ Capacitors |
$0.16 |
$0.10 |
$0.32 |
$0.20 |
| R1 |
KOA |
CFS1/4L151J |
150ohm resistor |
$0.02 |
$0.02 |
$0.02 |
$0.02 |
| IC1* |
AMP |
390261-6 |
Socket for IC1 |
$0.15 |
$0.14 |
$0.15 |
$0.14 |
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| PCB |
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$7.50 |
$5 |
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| Total |
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$12.75 |
$8.99 |
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Supporting
Hardware
You
might want to also buy one each of the following, to power and communicate/program
the board. Most are already available in labs or workshops, but you might
want to own a set for yourself. Any positive-center 7-12VDC adaptor should
be just fine, as should any reasonable-quality PC serial cable or USB/Serial
converter.
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| Description |
Manuf. |
Part # |
Cost per |
(qty 25) |
| 2.1mm plug |
Kobiconn |
170-2110 |
$0.57 |
$0.44 |
| Alkaline 9V Battery |
Energizer |
9V |
$2.00 |
$1.88 |
| 9V snap connector |
EPD |
123-5006 |
$0.33 |
$0.30 |
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| 9V DC adaptor, 2.1mm plug |
CUI |
DPD090020-P5P |
$3.68 |
$2.94 |
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| 2m serial DB9 cable |
Generic |
6' M-F DB9 Cable |
$2.30 |
$2.07 |
| USB/Serial adaptor for Macs, etc. |
Keyspan/etc. |
USB/Serial |
$17.95 |
$14.55 |
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Soldering
Notes
The
Atmex board is about as simple as any board you'll solder, but has some
interesting points to note, especially for beginners.
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- The (arguably) most important component to get right is the
protection diode, D1. This is the component that
protects the rest of electronics from plugging in the wrong power
supply. Getting this part wrong will result in fried chips and
much sadness. The 'arrow' in the picture points to the white stripe
on the diode.
- The electrolytic (cylindrical) capacitors also have polarity,
the white stripe on the capacitors indicates the negative terminal.
Whereas the pictures on the board indicate the positive terminal
hole.
- The LED and voltage regulator should go in the way that matches
their shape in the picture
- The DB-9 connector is kind of funky, it sandwiches the board
between the rows of connectors. To keep it secure, make sure it
fits snugly right against the board and use lots of solder on
every pin.
- Solder the MAX232 chip right in, keeping the notch on the chip
lined up with the one in the picture
- Solder in the socket for the Atmel, also noting which way the
notch goes. I don't suggest soldering in the chip directly.
- There are two options for the power plug, either one that is
horizontal (alongside the DB9 connector) or vertical (points up
from the board). Horizontal is more convenient and works with
the CUI wall wart specified above, but some bulky connectors might
not fit as well.
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