This item comprises the two PCBs (main board and control surface) that form the basis of my open-source ARPIE MIDI Arpeggiator project https://www.tindie.com/products/hotchk155/arpie-midi-arpeggiator-kit-1/ and two programmed microcontroller ICs (ATMega328p and PIC12F1822)

The boards are high quality factory made PCBs with plated through holes. Surface mount parts on the reverse of the upper board (74HC595D x 2) are included and pre-soldered.

If you are an advanced electronics tinkerer and/or want to build multiple ARPIEs this item may be a better bet for you than buying the pre-packaged kit with all the components. Perhaps you already have components or want to take advantage of cost savings and economies of scale in sourcing your own parts.

You can remove the microcontrollers from the kit and reduce the price (select product option) if you want to source and program them yourself. Firmware is freely downloadable but programming hardware is needed. Firmware source code available on Github

• AtMega328 Firmware - INO source file
• PIC12F1822 Firmware compiled HEX file BoostC source code for PIC also on Github

Additional parts required:

Other parts you will need are:

• R1, R2, R3, R4, R18 – 5 x 220 Ohm resistor
• R5, R6, R7, R8, (R21) – 5 x 1.5k resistor. Do not add R21 unless you experience problems with “off” step LEDs flickering or lighting dimly
• R9, R10, R13 – 3 x 10k resistor
• R11, R12, R14, R15, R16, R17, R19, R20 – 8 x 1k resistor
• D1, D2 – 2 x 1N4148 Diode
• D3, D4, D5, D6 – 4 x 1N4001 Diode
• C1, C2, C3, C4, (C9) – 5 x 100nF Ceramic Capacitor. C9 is optional and allows auto-reset during firmware upload.
• C5, C6 – 2 x 33pF Ceramic Capacitor
• C7, C8 – 2 x 4.7uF Electrolytic Capacitor
• X1 – 16MHz Crystal
• TR1 – 2N3904 NPN Transistor
• IC Sockets – 1 x 28 pin, 1 x 14 pin, 2 x 8 pin
• IC1 -ATMega328P Microcontroller with firmware (see above)
• IC2 – PIC12F1822 Microcontroller with firmware (see above)
• IC3, IC4 – 2 x 6N138/6N139 High Speed Opto-Coupler
• IC5 – 7805-TO220 +5V Voltage Regulator
• LEDs – ARPIE uses a row of 16 blue LEDs on the control surface PCB. The control surface has 4 other indicator LEDs (suggested red) and the main board has 3 diagnostic LEDs (suggested green).
• 20-pin Female DIL header
• 20-pin Male DIL header with long pins (25mm or more) connects the boards
• 6-Pin Female SIL Header – solder female header in the position next to TR1.
• 6-Pin Male SIL Header – solder in the “Serial Prog” position
• SPDT slide switch (power)
• Battery Holder
• 2 x M2.5 nuts + bolts
• 2.1mm DC power socket
• 4 x M3/25mm Female/Female Standoff Pillars
• 8 x M3/6mm machine screw