The Count
About the The Count PCB
The Count is an open source AVR/Arduino PCB design by rabidaudio, published on GitHub under the MIT license. It is a 2-layer board measuring 15.2 × 128.5 mm, with 50 components from 30 distinct parts.
Its main chip is the ATmega328P-PU, from the AVR/Arduino family. Other key parts include the L7805 and SM460281N. By type, the board carries 19 connectors, 13 resistors, 6 capacitors, 5 ICs, 3 switches and 3 diodes.
It belongs with the audio designs in this gallery.
From the project
My custom synthesizer work
- BPM from 15 to 400 - two outputs with relative rates - 3-digit LED 7-segment display - swing control - tap tempo - CV in - pause - save/load/reset settings
Main components on the The Count
The Count bill of materials (BOM)
50 components, 30 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | ATmega328P-PU | DIP-28_W7.62mm | U1 |
| 1 | L7805 | TO-220-3_Vertical | U2 |
| 3 | SM460281N | SM460281N_ARKLED_0.28mm_CC_7-segment_LED | U3, U4, U5 |
| 1 | 16MHz | Crystal_HC50_Vertical | Y1 |
| 1 | AVR-ISP-6 | PinHeader_2x03_P2.54mm_Vertical | J1 |
| 1 | EURORACK_CONN_10 | EURORACK_10_IDC | J2 |
| 3 | Conn_01x05_Female | PinSocket_1x05_P2.54mm_Vertical | J3, J5, J7 |
| 3 | Conn_01x05_Male | PinHeader_1x05_P2.54mm_Vertical | J4, J6, J8 |
| 1 | Conn_01x07_Female | PinSocket_1x07_P2.54mm_Vertical | J9 |
| 1 | Conn_01x07_Male | PinHeader_1x07_P2.54mm_Vertical | J10 |
| 1 | CV_IN | Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | J11 |
| 1 | BEAT_OUT | Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | J12 |
| 1 | DIV_OUT | Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | J13 |
| 1 | SCREW1 Cinch Connectivity Solutions Johnson | eurorack_screw_hole | J14 |
| 1 | BEAT_OUT Cinch Connectivity Solutions Johnson | thonkiconn_hole | J15 |
| 1 | DIV_OUT Cinch Connectivity Solutions Johnson | thonkiconn_hole | J16 |
| 1 | CV_IN Cinch Connectivity Solutions Johnson | thonkiconn_hole | J17 |
| 1 | KNOB Cinch Connectivity Solutions Johnson | knob_hole | J18 |
| 1 | SCREW2 Cinch Connectivity Solutions Johnson | eurorack_screw_hole | J19 |
| 2 | SW_Push | SW_PUSH_6mm | SW1, SW2 |
Show 10 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | Rotary_Encoder_Switch | RotaryEncoder_Bourns_PEC11R_Vertical_Switch | SW3 |
| 2 | LED | LED_D3.0mm | D1, D2 |
| 1 | 1N4148 | D_T-1_P5.08mm_Horizontal | D3 |
| 1 | 10u | CP_Radial_Tantal_D4.5mm_P2.50mm | C1 |
| 3 | 10n | C_Rect_L7.0mm_W3.5mm_P5.00mm | C2, C5, C6 |
| 2 | 22p | C_Rect_L7.0mm_W3.5mm_P5.00mm | C3, C4 |
| 6 | 10K | R_Axial_DIN0207_L6.3mm_D2.5mm_P2.54mm_Vertical | R1, R4, R5, R10, R11, R13 |
| 5 | 1K | R_Axial_DIN0207_L6.3mm_D2.5mm_P2.54mm_Vertical | R2, R3, R6, R7, R8 |
| 1 | 180K | R_Axial_DIN0207_L6.3mm_D2.5mm_P2.54mm_Vertical | R14 |
| 1 | 100K | R_Axial_DIN0207_L6.3mm_D2.5mm_P2.54mm_Vertical | R15 |
The Count design files
The KiCad project lives in the rabidaudio/synthesizer repository on GitHub; these links point at the commit this page was built from.
- Layoutclock/clock/clock.kicad_pcb
- Schematicclock/clock/clock.kicad_sch
The Count: common questions
What microcontroller does the The Count use?
The The Count is built around the ATmega328P-PU, from the AVR/Arduino family.
How big is the The Count PCB?
The The Count measures 15.2 × 128.5 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the The Count?
50 components, from 30 distinct parts. The full bill of materials is listed on this page.
Where can I download the The Count design files?
From the rabidaudio/synthesizer repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the The Count design in my own project?
Yes, under the terms of its MIT license, which rabidaudio chose for the repository.
Can I test firmware for the The Count without the hardware?
Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug AVR/Arduino firmware against it before you order a PCB.
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