Summary of Miniscope v2f
This article describes Miniscope v2f, an ultra-low-cost oscilloscope using an STM32F042 microcontroller and an MCP6S21 programmable gain amplifier. The PGA upgrade resolves input leakage issues found in previous versions while increasing input impedance. The device streams 8-bit data at 480 kSps via USB to a PC GUI, offering eight voltage ranges up to 30V with a 1MOhm input resistance. It features a simple single-sided PCB design with minimal components.
Parts used in the Miniscope v2f:
- STM32F042Fx Microcontroller
- MCP6S21 Programmable Gain Amplifier (PGA)
- MCP1700 Voltage Regulator
- Mini-USB Socket
- Passive SMD Components
- Single-sided PCB
- Libusb Driver Software
- Win32 GUI Application
Extremely cheap low-speed PC/USB oscilloscope with STM32 (STM32F042) microcontroller – variant of miniscope v2e with input amplifier (MCP6S21 PGA) added. This is minor update, but input PGA fixes problem with input leakage of STM32F042 allowing increasing input impedance at the same time.
Quick specification
- follows miniscope v2a-d idea: very simple device streaming data in real time to PC; DLL and GUI (Win32) are handling all the functionality,
- sampling: 480 kSps, 8 bit, streaming via USB FS with libusb (32/64bit) used as driver,
- 8 voltage ranges (0..30V, 15V, 7.5V, 6V, 3.75V, 3V, 1.87V, 0.94V – PGA x1, x2, x4, x5, x8, x10, x16 and x32 respectively),
- input resistance: 1MOhm,
- noise: ~23mVpp (visible at two gain ranges with high sensitivity),
- record length: 4k to 1M defined in DLL (single screen); up to 512M samples (continuous!) when recording to file,
- firmware loading via USB (DFU bootloader embedded in ROM),
- low component count: MCU, voltage regulator, mini-USB and few passive SMD components on single-sided PCB.
BOM
Retail prices are from my local distributor, YMMV but listed prices are rather in top range.
- STM32F042Fx (MCU): $2 retail, $1 volume
- MCP6S21 (PGA): $1.40 retail, $0.80 volume
- MCP1700 (voltage regulator): $0.50 retail
- mini-USB socket: $0.55 retail
- other: < $2
For More Details: Miniscope v2f
- How does the new version fix input leakage?
The added MCP6S21 PGA fixes the input leakage problem of the STM32F042. - What is the sampling rate of this device?
The device samples at 480 kSps with 8-bit resolution. - Does it support multiple voltage ranges?
Yes, it supports 8 voltage ranges from 0.94V to 30V. - What is the input resistance of the oscilloscope?
The input resistance is 1MOhm. - Can I record data for long durations?
Yes, you can record up to 512M samples continuously when saving to a file. - How is the firmware loaded onto the device?
Firmware is loaded via USB using the embedded DFU bootloader. - What software handles the functionality?
A DLL and Win32 GUI handle all functionality by streaming data in real time. - Is the PCB single or double sided?
The design uses a single-sided PCB with a low component count.
