Raspberry Pi CP Terrarium Controller Using Node-Red

CP Terrarium

My first project was an attempt to learn some programming, some 3D printing, some sensor design, and combine them with a longtime hobby of growing carnivorous plants.

A Raspberry Pi 3B+ is the main control device.

1) It controls turning the lights on and off to match sunrise and sunset anywhere. Mine is set up to match the photo-period of their natural habitat.

2) It monitors the temperature and humidity and displays them on a remote dashboard that can manually override the automatic control.

3) Water level is controlled with a homebrew designed/built sensor. The sensor’s plastic element was drawn on Fusion-360. It was 3D printed at Milwaukee Makerspace. Water level status is also displayed on the dashboard and can be remotely run.

4) Coding is done with Node-Red, a graphical programming tool.

Node-Red Code

The actual terrarium is an uncovered 10 gallon tank. It has two species of Drosera  ( Sundews, a sticky leafed plant) and a Cephalotus. (Albany Pitcher Plant) Lighting is provide by a small LED fixture. Humidity and Temperature monitored with a DHT22 sensor. Water level measured with a CMOS Schmitt Trigger voltage division sensor. Remote viewing and control is done with VNC.

Real world progress is coming along. Code has been finished (until I get a better idea and redo it again) and checked. Temp/Humidity sensor is in place. Right now it’s only monitoring and displaying. Adding a heater and cooling fan is in the future plans. 3D printed sensor has been fabbed. Assembly, electronic circuit building, and testing will be the next phase I approach. Following that will be the addition of a water pump or solenoid to automatically replenish the water level when it drops.

 

TLDR version: Raspberry Pi monitors or controls a CP Terrarium’s lights, temperature, humidity, and water.

Node-Red Dashboard

 

3D printed sensor

Maker Faire Milwaukee 2019 – Downtown!

If you haven’t heard the news yet, Maker Faire Milwaukee is back for 2019, and this year there’s a new location… We’ll be at the Wisconsin Center in downtown Milwaukee! (In fact, you may have already seen some of the digital signage around the Wisconsin Center District promoting the event, thanks to our old buddy Makey the robot.)

The downtown venue will bring new challenges, but we hope it brings new surprises (the good kind) and a new audience who might not have visited us before. We took a tour of the venue this week and it looks really nice, and so far we have no big concerns about the new location.

The other cool thing to share is an interactive map showing where people come from to attend Maker Faire Milwaukee. This shows both makers and attendees for 2017 and 2018. Neat! Who knew there were so many makers around Wisconsin and neighboring states.

If you want to join us this year and help make the awesome, we still need Makers and Volunteers!

Jellyfish Nightlight from a Football Helmet

   

Kathy H. entered an art contest where each contestant was provided half of a football helmet to be recycled into something artistic. It could be modified in anyway as long as the helmet was used in some manner. 

Having an idea to turn it into a jellyfish wall hanging Kathy asked another member to saw along the line she drew since she’s not skilled on all of the makerspace equipment.

In order to be able to hang it on a wall a back piece was made and attached with custom made L brackets.

After attaching the back the inside was spray painted gold and the outside was spray painted blue. The magenta shading was done by hand with a brush. Beads and ruffled ribbon were suspended from the inside with nylon string. The smaller beads were attached with hot glue. The ruffle along the outer edge was added with hot glue as well. Pearl beads and dimensional paint were also added to the outside. A tap light was attached inside with velcro. The lens of the light was colored with a hot pink permanent marker before attaching it.

Updated Filament Spool Holder for SoM

Big thanks to Tom Klein for a great modification of SoM’s filament spool holder!

The original design used to have a printed ABS top roller and I just pushed the roller against the flanges and finger-tightened the nut.  The problem was people kept taking it apart, so I added rubber bands to pull the roller down, and a nylock nut to prevent tool-free disassembly.  Then the rubber bands kept disappearing, and Tom came up with the idea of making a heavy top roller so the rubber bands wouldn’t be needed.  He cut a new, steel top roller on the lathe and it works great!  The bolt is just loose enough to let the roller slide up and down in the slot in the frame.  The roller is heavy enough that it just falls into position on the spool flanges.

Tangle-free filament spool holder

ShopWare and Markforged

We had a visit from ShopWare during our open night on Tuesday, January 29th, 2019. They thought we might be interested in seeing a Markforged 3D printer capable of printing with nylon, Kevlar, and carbon fiber. And they were right, we were interested!

They showed a few videos that featured the capabilities of very strong 3D printed parts, and then answered questions, and had a number of samples to pass around and show off. They also brought a Mark Two for us to take a look at.

One of the weird things about how the Mark Two functioned was that it homed the x and y after every layer it printed. It also lowered the z just a bit while it homed the x and y, then raised the z back up to meet the extruder (which was dripping a small bit of filament) before then starting a new layer. (None of us could figure out why it was doing that, or what benefit it offered, though we had some guesses.)

These appear to be some sort of brake lever, maybe for a bicycle or motor cycle. They were very strong. There was no flex at all when trying to bend them by hand. Typically parts printed with PLA or ABS feel pretty “breakable” but these seemed like you’d need some tools to break them. (I really wanted to crush one in the hydraulic press when no one was looking!)

Printed threads are no problem, and again, appeared to be very strong, and the ball joint moved pretty good.

The metal part was not printed on the Mark Two, but another Markforged printer. The part gets processed after it’s printed, so it shrinks a bit, but the software deals with sizing up your model before printing so it comes out the correct size when done. We’re pretty sure this part was “finished” a bit after printing as well, perhaps on a lathe, which would explain why the rounded part is polished while the flat hexagonal part is not.

While the extreme cold weather kept some members away, we had a pretty good turnout to welcome ShopWare, and for those who were there, got to see some cool technology we home to someday have a the space.