while the chronome requires a little more soldering then the arduinome, the build process is very similar. in designing the board, care was taken to lay out the components in a similar fashion to the common arduinome bibo boards. the major difference in the design of the chronome is the use of the arduino mega family of microcontrollers. the extra analog ports provided by the mega allows for not only the 64 pressure sensitive buttons, but also the addition of eight more continuous controls. the chronome shield pcb was designed with this in mind, and has a spot for attaching a 2×8 header pin connector to allow for easy hook up of additional sensors if you are so inclined.
basic info and parts
soldering video tutorials!
parts list:
- arduino mega
- (1) 8-pin female header connector
- (1) 2×8-pin female header connector
- (1) 2×10-pin female header connector
- 8, 16, and 20 wire ribbon cable
- see individual board sections below for more parts
what you’ll need:
- soldering iron
- solder
- flush wire cutters
upload the arduino firmware
before your arduino can become a chronome you need to take two very important steps. first you must change the serial number of the arduino, and then you have to load the firmware using the arduino IDE. make sure you have arduino installed before you start.
- change the serial number of your arduino mega
- the arduino firmware source code which is now hosted at http://www.sourceforge.net/projects/thechronome
shield
dimensions: 3.365” x 2.050”
parts list:
- circuit board
- (6) 8-pin straight header<
- (1) 6-pin straight header
- (1) 2×34-pin straight header
- (2) 2×8-pin straight header
- (1) 2×10-pin straight header
- (8) 670pF ceramic capacitors
- (1) 10k 9 pin bussed resistor network (8 res) **** this is only needed if you plan to use ADC 9-16
note: all headers can be made by ordering long single rows and snapping them to the appropriate size. the 2×34 just requires two individual rows of 34. see parts list
we have found it to be a good idea to use the mega as a place holder for the header pins. this ensures that the pins will line up with the mega when go to plug in your shield.
all other header pins go on the top side of the shield. after soldering the header pins, you’ll want to solder the eight 680pf ceramic caps (the brown things in the picture). they are not polarized, so it doesn’t matter which direction you put them in.
button pad
dimensions: 8.860” x 8.860”
parts list:
- circuit board
- (1) 8-pin straight header
- (1) 2×8-pin straight header
- (1) 2×10-pin straight header
- (4) TLC5940 LED driver chips
- (1) 1/4 watt 5.1k resistor (R8)
- (64) RGB LEDs (common cathode)
- (64) 1N148 diodes
- (1) 10k 9 pin bussed resistor network (8 res)
- (3) PNP transistor TO-92 package PN2907A ( Ic max 800mA, power max 625mW )
- (3) 1/2 watt 1K resistors (R1-R3)
- (4) 1/4 watt 6.25K resistors (R4-R7)
- (4) 0.1uF decoupling capacitors (C2-C5)
- (1) 470 – 1000uF electrolytic capacitor (C6 – this smooths the power supply, but we are currently testing smaller sizes so the value may change)
note: all headers can be made by ordering long single rows and snapping them to the appropriate size. the 2×34 just requires two individual rows of 34. see parts list
the LEDs go into the button board on the button pad side, with the longest leg going in the hole with square solder pad (see the above image).
once you’ve got the LED in the board, we found the easiest way to solder the pins (and avoid solder bridging), is to bend them all in the same direction and then fan the leads out from each other. you may want to hold the LED in place while soldering the first lead in order to get it as flat on the board as possible.
after soldering the LEDs, flip the board over and solder the button diodes. diodes will only allow current to flow in one direction, indicated by a black line on the diode itself. when placing the diodes, be sure to line the black line up with the silk screen graphic on the PCB (see above). the last column of diodes (next to the TLC5940 chips) face in the opposite direction
we have found it helpful to tape down one leg of the diode when soldering to the board. this allows for easy soldering of a whole column of diodes at once.
at this point you can populate the board with the rest of the parts. the transistors match the silkscreen graphic, while R1-R3 are the 1/2 watt 1K resistors.
after the transistors are in place, solder in the TLC5940 parts: sockets, 0.1uF decoupling capacitors (C2-C5), 6.25K resistors (R4-R7), 5.1k resistor (R8), and the 470-1000uF electrolytic capacitor (C6). C6 is an electrolytic and needs to go in the right direction. the positive/longer leg goes through the square hole (see above picture)
when inserting the resistor network, you’ll have to cut off the last pin (the last pin all the way to on the left <- in the picture). make sure the dot goes as shown above.
lastly, solder in the header pins. these should be facing the same direction as the diode side of the board.
once all the components are soldered in, insert the TLC5940 chips into the sockets. make sure pin1 of the TLC5940 (the end with the little half circle cut out in it) is facing towards the transistors (see above picture).
cables
when building the 8×1 cable, we found it worked better if we used a little solder to hold the wire in place
finally, when plugging the button board into the shield, we have tried to make it clearer how to align the cables. there should be numbers or txt by one side of each of the header pins, and the ribbon cables should line up with these. for example, in the picture above there is a number 1 next to the 8×1 header on the button board, and also a number 1 on the shield. the same grey wire should match on both boards.
that’s it, have fun!!!
we will be uploading more info here in the next few weeks, including Chronome Enclosure Files, and hopefully some software to get the chronome up and running quickly with MIDI enabled applications.
