2 layers152 × 88 mm
RFBitBangSMT
profdc9/RFBitBanger
A QRP digital transceiver created from readily available parts for off-the-grid maintenance
271 parts222
2 layers44.5 × 31.5 mm
KeychainAmp
whatwareweb/KeychainAmp1Audio amplifier on a keychain based on lm326
- Size
- 44.5 × 31.5 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 12
- Nets
- 16
- Pads
- 42
- Tracks, vias
- 28, 0
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 18 Jun 2026
- Updated
- 22 Jun 2026
Overview
KeychainAmp is an open-source printed circuit board by whatwareweb, from the whatwareweb/KeychainAmp repository on GitHub. It is a 2-layer board of 44.5 × 31.5 mm with 12 parts on 16 nets, routed with 28 tracks and 0 vias.
It is built around the LM386. Its parts include 3 capacitors, 3 resistors, 1 IC, 1 connector and 1 switch. It belongs with the audio and music boards of this library.
Main components
1README
README.mdParts
12| Qty | Value | Footprint | References |
|---|---|---|---|
| 2 | 4.7k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R1, R2 |
| 1 | .05uF | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C3 |
| 1 | 10 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R3 |
| 1 | 10k | Potentiometer_THT:Potentiometer_Bourns_PTA1543_Single_Slide | RV1 |
| 1 | 220uF | Capacitor_THT:CP_Radial_D6.3mm_P2.50mm | C2 |
| 1 | 4.7uF | Capacitor_THT:CP_Radial_D5.0mm_P2.00mm | C1 |
| 1 | 9V battery connector | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | BT1 |
| 1 | AudioJack3_SwitchTR | Connector_Audio:Jack_3.5mm_CUI_SJ-3524-SMT_Horizontal | J1 |
| 1 | LM386 | Package_DIP:DIP-8_W7.62mm | U1 |
| 1 | SW_SPDT | Button_Switch_THT:SW_Slide_SPDT_Angled_CK_OS102011MA1Q | SW1 |
| 1 | Speaker | TestPoint:TestPoint_Bridge_Pitch7.62mm_Drill1.3mm | LS1 |
Questions
How big is the KeychainAmp PCB?
It measures 44.5 × 31.5 mm and has 2 copper layers, 1.6 mm thick.
What parts does the KeychainAmp use?
12 parts, built around the LM386. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the KeychainAmp KiCad files?
From the whatwareweb/KeychainAmp repository on GitHub, at the commit this page was made from: the board is keychain-amp/keychain-amp.kicad_pcb and its schematic keychain-amp/keychain-amp.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the KeychainAmp design in my own project?
Its repository states no licence, so its author keeps all rights: ask whatwareweb before reusing the design.
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