User:Gsuberland

Hi, I'm Graham! I also go by gsuberland and Polynomial.

Interests

• Electronics (particularly if it has a lot of LEDs or sensors)
• Security
• Cryptography
• Demoscene
• Stage lighting

Prior Projects

Projects that I've previously worked on:

ManyMQ

Large breakout board for up to sixteen MQ-series MOX sensors (e.g. MQ-2, MQ-3, MQ-7). Designed a long time ago but as of August 2024 the design is being refreshed for potential deployment in the hackspace.

EMF Camp 2022 & 2024 - Air quality sensors

Air quality infrastructure at EMF Camp 2022 and 2024.

Original 2022 (mk1) design featured an MH-Z19D sensor and SHT32 temperature/humidity sensor, and an ESP8266 devboard. Power over USB micro. OLED screen for realtime data. Sends data over MQTT. Cheap and simple.

Updated 2024 (mk2) design is much fancier. Powered over USB-C with a buck-boost regulator to provide a stable 5V primary rail, since USB voltage regulation is garbage. SCD40, SGP30, and SHT35 sensors onboard for CO2, TVOC/eCO2, temperature, and humidity. Supports PMSA003 or MH-Z19D as an optional add-on. Still running ESP8266 to save firmware redevelopment time, but with a much cleaner codebase.

Each design has a custom laser-cut acrylic enclosure.

A modified version of this is (as of August 2024) being considered for use in the space. See Air Quality Monitoring Pledge Drive for details.

EMF Camp 2024 - NullSector Hexpansion

Custom "Polybius Biotech Employee Authenticator" hexpansions for the Tildagon badge at EMF2024, commissioned by the NullSector team. Dimmable LEDs plus an EEPROM for custom behaviour. Also built a programmer jig for batch programming.

EMF Camp 2022 & 2024 - Hexlight installation

Large (2x2m) lighting installation consisting of 14 hexagonal panels that individually light up. Each panel is driven with 12V over XT60 connectors. Panels laser cut from MDF and acrylic, with over Displayed in Nullsector at EMF 2022 and EMF2024. Driven by a pair of Switchen8r MkII boards.

EMF Camp 2022 - Infopoints

Electronic infopoints commissioned for Nullsector. Has a dimmable Polybius logo plus a ring of RGB LEDs, an ESP32 with external WiFi antenna, and composite video output for driving a mini CRT.

EMF Camp 2022 - Jellyfish

A few hundred custom PCBs for Elsmorian's jellyfish installations. Each has a ring of RGB LEDs to light up segments of the jellyfish tentacles.

Switchen8r

8-channel PWM driver boards. Each board is capable of switching around 15A per channel (although the total limit per board is lower, around 50A) with fast MOSFETs for high bit depth PWM. Has two XT-60 power inputs that can be used in parallel or as an input/output for daisychained power when stacking boards. MOSFET gate drive voltage is selectable between direct (for 10-18V supply), regulated 12V (for >18V supply), or external (for <10V supply). The MkI design used a custom push-pull BJT gate driver, whereas the MkII revision moved to a dedicated gate drive IC per MOSFET.

I also designed a chainable SIPO latching shift register breakout to plug into these boards, allowing an arbitrary number of stacked boards to be driven from just three lines (DCK, DIN, RCK) for cases where minimising pin count is more important than high PWM frequency.

I have a ton of the Switchen8r Mk1 and Mk2 boards, so if you want any let me know.

HoRuS485

A series of high reliability redriver boards for transmitting WS2812-like RGB LED data over differential RS-485 for outdoor use, with data transmitted over Cat6 cables. Supports four parallel channels and has current shunt monitoring. Designed for an LED installation in a metal gazebo which I never finished.

Hackspace Electronics Inventory

Sorting, re-labeling, and cataloguing all of the electronic components we have in the space. See Electronic Components Inventory (2019/2020).

Contact

• Mastodon: @gsuberland@chaos.social
• Twitter: @gsuberland (defunct)
• Web: poly.nomial.co.uk