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.
- 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.
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
Note: 3.3V voltage regulator can be used as well. It would change voltage ranges which may be compensated either by using software calibration function in GUI or recompiling DLL with changed fBasicSens value.
Eagle files: miniscope_v2f_eagle.zip
"Panelized" PCB printout for toner etching: miniscope_v2f_pcb_panelized.pdf
Firmware (Keil): miniscope_v2f_firmware.zip
DLL for miniscope v4: miniscope_v2f_dll.zip
Basic binaries in single archive (GUI + DLL + FW): miniscope_v2f_bin.7z
Big thanks to electronics-lab.com for featuring this project (as well as previous versions).