HFX – Electrical Test Set


Hui Gardens HFX electrical test set is the fusion of several basic electrical things that I’ve built while making other electronic things. It combines my HF1 – 100W Resistor Box, HF11 – 2 Wire RTD Simulator, the most useful parts of the HF2 -24V Variable DC Power Supply and more! I decommissioned the mentioned prototypes and repurposed almost all the parts including wires and resistors.

The Hui Gardens HFX features the following:

  • 24V adjustable DC power supply from 4x AA batteries (easy access) to loop power 4-20mA transmitters
  • 100W resistors including a 270Ω (close enough to a 250Ω resistor) for HART communication
  • 10 turn 2W potentiometers to allow for RTD simulation and 4-20mA simulation
  • 10W shunt to allow for high current measurement
  • Relay to take input and switch loads on and off and allow triggering of a frequency counter to test timing
  • 0.75″ spacing standard between banana jacks for double banana leads

I wanted something that can carry my Fluke 87V multimeter and be useful for things I test on a regular basis. I took a design cue from some of the high voltage equipment I see that allows for the meter and test leads to be stored in one case. Having a separate lead bag is really cumbersome and is prone to getting lost. I really like the brass wingnut chassis ground aesthetic. If it’s good enough for a 120kV hipot, it’s good enough for me!

Housed inside a Nanuk 920 hard case with a cut aluminum panel kit, the Hui Gardens HFX is pretty tough. The big red toggle switch cover is a must, the Chairman Mao emblem is an especially nice touch, but the best part is the custom 3d printed nameplate in brass.

HF61 – 5W USB Powered Amplified Speaker with Equalizer


Hui Gardens HF61 5W USB powered amplified speaker is the bigger badder version of the Hui Gardens HF6 with an added internal 4x AA battery pack and a 3 band equalizer. Sound output from this 5W speaker is enough to rattle the desk a bit. Protected by a Pelican 1030, the HF61 is still small enough to fit in the side pockets of most backpacks and the internal batteries makes it truly portable. There is still an option for external power if you have a USB port nearby. Ran out of power or don’t want lithium ion batteries exploding in your face? No problem, they’re just regular AA batteries, just swap in some new ones! If you’re finding that you can’t get enough juice out of your USB port to get the volume and bass desired without distortion or clipping, plug in a 9V or 12V wall adapter and crank it UP!

The 3 band equalizer allows for adjustment of treble, mid-range and bass via physical knobs. This dumb speaker has no extra “smart” bits, just plain and simple things to make good sound. At least better than what a laptop can muster. Crank it up a bit and watch this thing pound! Being a dumb speaker, it is impossible for the HF61 to spy on you. You can yell “HEY DUMBASS!” at it all you want and nothing is going to happen.

HF31 – Thermo Hygrometer Barometer with Solar Charger


Hui Gardens HF31 thermo hygrometer barometer is a rugged solar powered environment monitoring device. The HF31 makes use of the Bosch BME280 sensor for its thermometer, hygrometer and barometer functions to measure air temperature, humidity and station pressure. Dew point is calculated from air temperature and humidity and displayed on a hi-res OLED display.

Protected by a transparent Nanuk 310 case, the Hui Gardens HF31 can withstand the elements while housing a solar panel that charges two internal user replaceable NiMH AA batteries. The brains of the HF31 is an Arduino compatible Adafruit Pro Trinket (3V) for low power consumption. HF31 is field programmable via the FTDI cutout in the panel and can be adjusted and calibration date set if you know what you’re doing. The Hui Gardens HF31 is a portable weather station that can be strapped to the outside of a backpack or left in the snow.