2 layers12.7 × 12.7 mm
2 layers20.6 × 28 mm
PPGUnit
akita11/PPGUnitPPG Unit
- Size
- 20.6 × 28 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 20
- Nets
- 12
- Pads
- 54
- Tracks, vias
- 141, 12
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 6 (file 20211014)
- Created
- 28 Jan 2026
- Updated
- 3 Feb 2026
Overview
PPGUnit is an open-source printed circuit board by akita11, from the akita11/PPGUnit repository on GitHub, published under the MIT licence. It is a 2-layer board of 20.6 × 28 mm with 20 parts on 12 nets, routed with 141 tracks and 12 vias.
It is built around the HT7533 and RT9193-1.8. Its parts include 6 capacitors, 4 resistors, 4 connectors, 2 ICs and 2 transistors.
Main components
2
HT7533
SOT-890℃~+70℃@(Ta) 1 100mA 100mV@(1mA) 10uA 24V 3.3V Fixed Positive Short Circuit Protection SOT-89 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSKEXINVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
RT9193-1.8
SOT-23-5-20℃~+60℃@(Ta) 1 1.8V 25uA 300mA 75dB@(1kHz) 7V Enable Fixed Positive SOT-23-5 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSTDSEMICVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
README
README.mdPPG Clip
M5Stack社の心拍センサユニットと機能的に互換のUnitです。 光学脈波(PPG)センサのMAX30100を使用し、光学脈波やSpO2、そこから心拍数の計測ができます。 またPPG Clip部品セットと組み合わせることで、透過型PPG計測装置をつくることができます。
※センサICのMAX30100は、再生品を使用している場合があります。基本的な測定には問題がないことは確認済みですが、新品とは多少の性能の差異がある場合があります。
使い方
M5Stack社の心拍センサユニットと機能的に互換ですので、そちらのソフトウエア(Arduino用ライブラリ、UIFlow等)がそのまま使用できます。
作り方
2枚の基板を、向きをあわせて、2組の4pピンヘッダではんだ付けします。 ピンヘッダの足は十分に短くカットしてください。
補足情報(I2C信号線について)
MAX30100のI2C信号線の端子の絶対最大定格は6.0Vです。 I2C信号線のプルアップ抵抗はGroveコネクタのVDD側(M5Stackシリーズでは5V)に接続されており、HレベルはVDD電圧（同5V）となりますが、絶対最大定格を超えません。 M5Stack社の心拍センサユニットでは、ここに電圧変換用の部品が入っていますが、I2C信号の波形を観測したところ、立ち下がり速度がかなり遅く、特に400kHz通信の場合には通信エラーが多発する現象が確認されましたので、この構成としています。
Author
Junichi Akita (@akita11) / akita@ifdl.jp
Parts
20| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | 4.7k | Resistor_SMD:R_0603_1608Metric | R1, R2, R3, R4 |
| 3 | Conn_01x04 | Connector_PinSocket_2.54mm:PinSocket_1x04_P2.54mm_Vertical | J1, J2, J3 |
| 2 | 0.1u | Capacitor_SMD:C_0603_1608Metric | C1, C2 |
| 2 | 1u | Capacitor_SMD:C_0603_1608Metric | C4, C5 |
| 2 | AO3400_C20628874 | libLCSC:SOT-23-3_L2.9-W1.3-P1.90-LS2.4-BR | Q1, Q2 |
| 2 | Jumper_2_Bridged | Jumper:SolderJumper-2_P1.3mm_Bridged_Pad1.0x1.5mm | JP1, JP2 |
| 1 | 10u | Capacitor_SMD:C_0603_1608Metric | C3 |
| 1 | 22n | Capacitor_SMD:C_0603_1608Metric | C6 |
| 1 | CON_GROVE | akita:CON_GROVE_H | CN1 |
| 1 | HT7533 | Package_TO_SOT_SMD:SOT-23 | U1 |
| 1 | RT9193-1.8 | libLCSC:SOT-23-5_L2.9-W1.6-P0.95-LS2.8-BR | U2 |
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Questions
How big is the PPGUnit PCB?
It measures 20.6 × 28 mm and has 2 copper layers, 1.6 mm thick.
What parts does the PPGUnit use?
20 parts, built around the HT7533 and RT9193-1.8. 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 PPGUnit KiCad files?
From the akita11/PPGUnit repository on GitHub, at the commit this page was made from: the board is PPGUnit.kicad_pcb and its schematic MAX30100sub.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the PPGUnit design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).