diff --git a/_board/hxr_sao_dmm.md b/_board/hxr_sao_dmm.md new file mode 100644 index 000000000..2b60bd291 --- /dev/null +++ b/_board/hxr_sao_dmm.md @@ -0,0 +1,57 @@ +--- +layout: download +board_id: "hxr_sao_dmm" +title: "SAO Digital Multimeter Download" +name: "SAO Digital Multimeter" +manufacturer: "HXR.DK" +board_url: + - "https://github.com/flummer/dmm-sao" +board_image: "hxr_sao_dmm.jpg" +date_added: 2025-02-24 +family: rp2040 +downloads_display: true +blinka: false +download_instructions: "https://github.com/flummer/dmm-sao/?tab=readme-ov-file#firmware" + +features: + - Display + - USB-C +--- + +This is a Digital Multimeter in the shape of an SAO (Shitty Add-On/Simple Add-on), designed specifically to assist in electronic badge and SAO development. + +This follows the 1.69bis version of the SAO standard ([Shitty Add-on standard](https://hackaday.io/project/52950-shitty-add-ons), [Simple Add-on standard](https://hackaday.io/project/175182-simple-add-ons-sao)) + +It is based on the RP2040 chip, includes a small OLED display, a rotary encoder for the main knob, a function button for sub functionality selection and two 2mm banana terminals for connecting probes for resistance, LED and continuity testing. + +A USB-C connector on the side allows easy modification of the firmware, and boot and reset buttons are also included for convenience, when updating or replacing CircuitPython. + +**CAUTION! THIS IS NOT A NORMAL MULTIMETER, AND DOES NOT INCLUDE THE PROTECTION FEATURES NORMALLY FOUND IN A DMM** + +If you would like to probe a live circuit, please check [the schematic](https://github.com/flummer/dmm-sao/blob/main/DMM%20SAO%20Schematics.pdf) first, and proceed only if you understand the implications, as improper use might result in a short circuit and harm either the multimeter, the device under test, a connected computer or a combination of those. + +**VOLTAGE OR CURRENT SHOULD NEVER BE MEASURED WITH THE PROBES OR TERMINALS ON THE FRONT** + +## Features + +- Resistance measurement (not the most precise, but should be OK in the range of 50-10K ohm) +- LED Tester (this will lit up the LED if the polarity is correct and show the voltage across it on the screen, 100 ohm resistor in series to 3.3v) +- Continuity tester with buzzer to indicate very low resistance +- Measurement of input voltage on the SAO port +- SAO Port GPIO monitoring (shown as either digital high/low or an analog voltage reading) +- I2C monitor (monitor or scan the I2C bus on the SAO port) + +## Technical Details + +- Raspberry Pi RP2040 controller +- 16MB SPI flash (W25Q128JVxQ) +- SSD1306 128x64 pixel 0.96" OLED display (white on black) +- Automatic power switching from SAO port to USB-C (both can be connected at the same time) +- Voltage boost circuit for operation on lower than 3.3v on the SAO port +- Maximum input voltage on the SAO port is 3.3v +- UART RX + TX connected to SBU pins on USB-C connector + +## Links + +- [hackaday.io page](https://hackaday.io/project/198892-sao-digital-multimeter) +- [Github repository](https://github.com/flummer/dmm-sao) diff --git a/assets/images/boards/large/hxr_sao_dmm.jpg b/assets/images/boards/large/hxr_sao_dmm.jpg new file mode 100644 index 000000000..9365c0e79 Binary files /dev/null and b/assets/images/boards/large/hxr_sao_dmm.jpg differ diff --git a/assets/images/boards/original/hxr_sao_dmm.jpg b/assets/images/boards/original/hxr_sao_dmm.jpg new file mode 100644 index 000000000..c48803b64 Binary files /dev/null and b/assets/images/boards/original/hxr_sao_dmm.jpg differ diff --git a/assets/images/boards/small/hxr_sao_dmm.jpg b/assets/images/boards/small/hxr_sao_dmm.jpg new file mode 100644 index 000000000..74f141605 Binary files /dev/null and b/assets/images/boards/small/hxr_sao_dmm.jpg differ