Component Layout

With around two dozen total components its hard to go wrong.1)  The chorder can be built on perfboard, stripboard, wirewrap or your can etch a pcb board.  If you create a layout, please send it to us, your layout may be just what someone else needs to help them build their board!  Please be sure to clearly state how you want to be listed when we post it.  From Name and email address (obfuscated by the wiki) to total anonymity, we will do our best to accommodate your request. Component numbers should match the ones used on the SpiffChorder hardware page.


click or select to enlarge

This layout is for a seven key chorder with no LEDs or ISP. It incudes pull-up resistors in a bussed resistor network.

The layout is for perfboard and wire but could be adapted to other methods.

For the largest version of the graphic, select it to enlarge, then select it again.

Component names and numbers match those used on the SpiffChorder hardware page.

wirewrap and solder, no board

click or select to enlarge

This layout if for a seven key chorder, no LEDs, ISP or pull-up resistors.

It uses two 28 pin DIP wirewrap sockets and either no perfboard or a piece of perfboard that is about 4×36 holes big (a little longer than the two sockets and only as wide as a socket).  The IC uses one of the sockets.  The components are all soldered into the other socket.  Then the sockets are connected using wirewrap. 

In practice all ground lines are brought together and soldered to the ground line of the USB cable and all VCC lines are brought together and soldered to the VCC line of the USB cable.

In like fashion, the lines for the keyswitches are brought out and soldered to one side of each of the key switches and a ground line is run to the other side of the key switches.

While a graphic is provided for reference, the wiring chart below should be used when doing the wrapping.  Check off each connection on the chart as you go.

For the largest version of the graphic, select it to enlarge, then select it again.

Component names and numbers match those used on the SpiffChorder hardware page.

First, insert and then solder the following components into a 28pin DIP between the pins indicated in Chart One.

Chart One
1  X1  28
2  272nd row left blank
3  C1  26
4  C2  25
5  245th row left blank
6  C5  23
7  R4  22
8  D2  21orientation is significant
9  R3  20
10  D1  19orientation is significant
11  R2  18
12  R1  17
13  C3  16
14  C4  15orientation is significant

Warning I have not yet wired up the wirewrap board, once I have (and as such confirmed that the wire chart below is correct) I will remove this warning -Greg

Next use a wirewrap tool to connect the pairs of pins indicated in Chart Two.  Consider your final placement of the sockets and make your lines long enough to accommodate.  With this layout you could place a small amount of non conductive material between the sockets and place them bottom side to bottom side once you have tested the circuit and trimmed the long pins on the sockets. Remember to take into account that you are turning the socket upside down when you wrap. Check your pin numbers carefully. Check off the boxes in the first column when you wrap them, check off the third column when you confirm the wiring with a continuity meter. You may find it helpful to use a little double sided tape to hold the sockets down to your work surface while wirewrapping. I will post photos with labels once I make this version of the chorder.

Chart Two
wired components    tested 
[ ]  CS-1  CS-4  [ ]
[ ]  CS-5  CS-23  [ ]
[ ]  CS-6  VCC  [ ]
[ ]  CS-8  GND  [ ]
[ ]  CS-10 GND  [ ]
[ ]  CS-11 GND  [ ]
[ ]  CS-12 VCC  [ ]
[ ]  CS-13 CS-14  [ ]
[ ]  CS-14 VCC  [ ]
[ ]  CS-15 GND  [ ]
[ ]  CS-16 CS-15  [ ]
[ ]  CS-18 CS-17  [ ]
[ ]  CS-18 USB-2  [ ]
[ ]  CS-19 CS-18  [ ]
[ ]  CS-20 CS-19  [ ]
[ ]  CS-21 USB-3  [ ]
[ ]  CS-22 CS-21  [ ]
[ ]  CS-23 GND  [ ]
[ ]  CS-25 GND  [ ]
[ ]  CS-26 GND  [ ]
[ ]  CS-28 CS-3  [ ]
[ ]  IC-2  CS-9  [ ]
[ ]  IC-4  CS-7  [ ]
[ ]  IC-7  CS-6  [ ]
[ ]  IC-8  CS-5  [ ]
[ ]  IC-9  CS-1  [ ]
[ ]  IC-10  CS-28  [ ]
[ ]  IC-12  SW-7  [ ]
[ ]  IC-14  SW-1  [ ]
[ ]  IC-15  SW-2  [ ]
[ ]  IC-16  SW-3  [ ]
[ ]  IC-17  SW-4  [ ]
[ ]  IC-18  SW-5  [ ]
[ ]  IC-19  SW-6  [ ]
[ ]  SW-1-7(GND) GND  [ ]
[ ]  USB-1 VCC  [ ]
[ ]  USB-4 GND  [ ]
key for Chart Two
CS-# component socket pin number, 28 pin dip holding the circuit components 
IC-# IC socket socket pin number, 28 pin dip holding the AVR atmega168 ic 
SW-# Switch number, each switch has 2 pins.  One pin is wired to the IC, the other to Ground
USB-#  The four lines of the usb cable (see SpiffChorder hardware
VCC  power from line one of the usb cable 
GND  Ground line from line 4 of the usb cable

1) Unless it’s 3am and the morning of a conference where you really want to have a new chorder to show folks, in which case experience tells me that it’s quite easy if not downright likly you’ll mess it up completely.
spiffchorder/sample_layout.txt · Last modified: 2008/05/21 14:51 by priestdo
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