Category: Uncategorized

Vortex cannon

Driving a vortex of air.

Vortex cannons are interesting in relation to fluid dynamics, if it can be done with air, then can the same principles would apply for other fluids. The fuel powered ones are hail cannons, I’d have to look more.

Hydraulic cylinders use a fluid to pump to a large cylinder to a affect a more forceful change on a small cylinder. The opposite could be used to quickly affect a large compressible fluid like air.

LED Grid

Fast refresh a grid of LEDs.

I have 6, 5M 30LEDs/m WS2812B strips and if connected in a grid that would be 900 LEDs. I haven’t cut my strips yet, I have a 288 LED test strip first. Next would be if you can output a control signal on more than one digital pin at the same time. The Photon controller is 120Hz and there is some direct port access, toggling with pinSetFast() pinResetFast() is faster than my oscilloscope can handle.

They seem to have straightforward timing based on a state machine. It seems like there is a library I can start with.

Any idea on how Oscilloscope rating relates to time divisions?

Guitar

A wireless MIDI controller.

References: Wireless MIDI, Jamstik

The Particle Photon run Arduino code that is connected to one long or a few ThinPots along the neck, and a laser/LED harp could go across the sound hole. Given the thickness of 2.5 cm (1 inch) of the pots I’m looking at making my own, I need to research, it seems like a conductor, a spacer, and a resistor layer is what you’d need. I have thin copper tape, I’d need to find the rest. Wireless MIDI is definitely possible on many platforms.

Quadcopter

Control and GPS.

The Particle Electron with Asset Tracker shield enables cellular data, GPS, and an accelerometer, control the ESCs I have connected to the brushless motors and I’m off. There is still the PID control that I need for stable hovering, then I can try directional movement. With GPS I could take it to place where unattended drones are allowed, and have it follow programmed waypoints.

I have the Electron working logging temperature and humidity.

Current build:
250mm quadcopter frame
25560 battery holder
12A ESC
EMAX MT2204 motors 2 x CW and 2 x CCW, the opposite sides are spinning the same way.
I have some SR-HC04 ultrasonics and got distance but not a stable flight using a different micro.

  1. Assumption, common RC timing is 50Hz:
    1 sec / 50 Hz = 0.020 second = 20ms period
    it is controlled with 1ms (1/20) low and 2ms(2/20) high
    ESC and digital servo timing is 300Hz
    1 sec / 300 Hz = 0.00333 seconds = 3.33ms period
    it is controlled with 0.166ms (1/20) low and 0.333ms(2/20) high
  2. Digital Servo control and timing is the same 300Hz the more frequently it updates, the more responsive it can be.
  3. Test at 300Hz with buttons to increase and decrease. Test at other frequencies, but it will not be under load they heat up using frequencies not supported, that would be worse under load.

Home Gardening

A personal greenhouse.

References: FarmBot, Plantbot, pH probe

I would want ideal plant growth, while testing for taste.
Seeds can germinate with paper towel and some water, I wonder how direct you could get it to sprout, some rock wool maybe. A filter for the bubble air pump. The more variables you can control the more you can test for.

Light amount, spectrum, time of day.
pH of water
Oxygen water & air
CO2 water & air
Circulation amount water & air
Nutrient amounts

A different spectrum of light at times of day, a light at 60Hz and our eye doesn’t notice it blinking. Wonder if photosynthesis acts the same as the reactions in our rods/cones and it stops mattering at a certain refresh rate.

Lighting, I have a very large grow LED and liquid cooling, better with a large fanless heatsink.
Hydroponics, I have the 3″ mesh pots.

Needed:
ph sensor, ph up and down
liquid nutrients
a way to circulate air, I have a few pumps which may do
germinante seeds, rock wool may work

 

2D Icing Printer

References: Syringe extruder, PancakeBot™

Once I had control of a simple shape I would implement use an open source firmware to control motion, and investigate more on the software to allow user text or drawings to be ‘printed.’

So far:
I have used my CNC more to make the stepper mounts and the wood blocks.
I made a C++ header with a class for the DVR8825 module.
Constructed a two rail gantry out of 10mm drill rod and linear bearings, used GT2 timing belt with 30 teeth on the stepper and a pair of fanged bearings on the other side.

Cookie cutter

Custom cutter

There are straightforward ways of doing this. I don’t think I’ll venture into metal casting at home, but I can make a CNC cut a simple 2D shape. Material selection is the question, I cut softer metals but a cutter has a lot of negative space. I may do a thinner metal outline and then a supporting structure or handle.

Ideas:
Fruits
Animals
Ninja
Smile tooth
Fossil bones
Halloween: ghost, skull, skeleton
An open source superhero logo