Side-Projects

Sous Vide Arduino

After moving to NYC, we acquired an egg eating habit. While I scramble them most of the time, at some point we were starting to make soft boiled eggs daily when we managed to get our hands on some dark soy sauce.

Daily inconsistencies in quality didn’t go away much even after removing variables such as egg temperature by placing eggs on the counter, standardizing the amount of boiled water and the time spent in the water. Somehow the eggs would be over or under.. and also due to the initial high temperature, the outside whites would also be set while the inside whites hadn’t. When we did 4 eggs instead of 2, there was an even greater variation in outcome.

Obviously the thing most suited for the job is a sous vide machine and having built one in Jan 2014 with a proper PID controller, I wasn’t keen on building another until I realised how few parts I required from the plans here¬†and the code here. I already had 2 arduino UNOs on loan and the rest of the parts would be cheap as chips considering I already had the rice cooker. I would just strip out everything unecessary including the display, the buttons and hard-code¬†it just to make eggs at 60¬įC.

I had to stuff it into a small box that used to shelter pineapple tarts as I had nothing else.

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Notes:

  1. I particularly like how he did not implement a PID algorithm as they are really difficult to tune but rather wrote the code to operate the heating element according to how a human would operate it by switching the power on and off while doing some simple calculations about how fast the temperature was rising and falling. The setup really nailed the temperature in my tests and measurements with a Thermopen.
  2. Changed Piezo Pin from pin 13 to pin 7  so I could use pin 13/onboard LED as a status indicator
  3. Added a Status Indicator on PIN13. Flashes onboard LED to let user know what state the Arduino is currenty in
  4. Flipped RELAY_OUT_PIN from active HIGH to LOW for an active low relay I purchased. I think the original creator had a relay which activated when the voltage was high
  5. Hardcoded temperature to 60 deg celcius
  6. Aliexpress is crazy crazy cheap

Next improvement will be to control it from¬†Home Assistant¬†hosted on a raspberry pi so I can set it to make eggs remotely and switch it on when the time is right. I’m going to be using ESP8266s communicating over MQTT. The parts are slowly making their way from China.. ūüôā

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Side-Projects, Thoughts

Book: Avenue of Spies

Just finished this book a day or two ago. Reading biographies is interesting, especially of people in trying times. Random summary of thoughts

  • I didn’t know the germans basically waltzed into Paris in WWII
  • America didn’t join in WWII until pearl harbour
  • Sometimes taking decisive action early when things are starting to look bad is better than waiting till things are really bad
  • What goes around comes around
  • I found it interesting that the nazi soldiers being the ones in power¬†still feared for their lives at night when alone due to the threat of an uprising or being killed by unhappy citizens or the resistance
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Side-Projects, Stuff I Did

Altoid Tin Kid’s Electronics Kit

An Introduction to Electronics for Kids

Just trying to document the process I went through while building this for kids aged 5-8 years old.

Too young? Perhaps. But I’d rather they surprise me than find the kit to be too lame for their age.

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Deciding what to put in and how to build the circuit along with the container so it wouldn’t be complicated was tough! I selected these parts after a long process of looking around online at ebay, adafruit, sparkfun, Tinkersphere (in downtown manhattan) and Amazon. 3 kits cost a total of $40-50USD but the parts come in large quantities so it’s really cheap to do a couple more.

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In the end, I decided that a kit for kids should have a few guidelines:

  1. Everything needed to be as direct as possible. No switches, no jumpers on the breadboard, basically no logical jumps that require “if this then that, then that”. Power just goes to different components directly.
  2. The effects of applying power to the component should be obvious and hopefully attractive to kids. I chose a 5V piezo buzzer, a Green LED, a Flashing Multi-colored LED and a vibrating motor. Light, Sound, Motion.
  3. 3V might be more suitable than 5V via USB or 9V here so that¬†we won’t need to deal with resistors in series with the LEDs. I think the LEDs are over-powered but they are not burning out so I’ll hope my luck doesn’t run out.

What can they learn?

  1. Batteries have +ve and -ve poles
  2. Components have polarity as well, sometimes connecting it backwards works (like with motors) sometimes it doesn’t (like with LEDs and buzzers)
  3. When you add jumper cables into the mix to simultaneously power components, you can learn about connecting stuff in series and in parallel. A bit too advanced for younger ones though!
  4. Metal in the wires conduct electricity
  5. The symbols for the components as well as the RED/BLACK for + and – convention.

Any Risks?

There are a few risks I’ve identified here actually:

  1. Short circuits can get very hot, even at 3V. This is probably because the wire is so thin.¬†The hot glue I used to insulate the wire temporarily melted right off when I accidentally shorted it for about 5-10 seconds. The only way around this would be to permanently power the breadboard and short all the rows so that each side of the board is either +ve or -ve but then you’d have to leave the child to insert components which would surely result in breaking them.
  2. Small, small parts. To get around this I decided to just glue all the components to the board and mark out the rows of the breadboard that need to be connected. I decided not to hot glue all the unused rows in the breadboard so that perhaps in future there might be a bit more flexibility.
  3. The altoid tin itself conducts electricity which means the loose power cables could short out inside the tin. It doesn’t happen actually in real life but to be safe I just taped up the inside surface so it wouldn’t happen.

So that’s it! It’s really simple to build¬†but it really requires a lot of thinking about what you want to achieve as well as what is manageable and safe from a child’s perspective.

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Side-Projects, Stuff I Did

Completed – Hairpin Leg Side Table

The hairpin legs I ordered from modernlegs.com finally arrived at my place yesterday afternoon! They don’t ship outside the USA and I had to get someone to cart it home all the way¬†back from the states.

Proceeded to test-fit and assemble them and have pretty mixed feelings about the tables actually. They look a bit top heavy but definitely work as a side table placed beside a couch or armchair. Placed beside existing furniture, I think I like it.

Some pictures:

Yes, inspected by the TSA

Yes, inspected by the TSA


Bottom of the block

Bottom of the block


Positioning the legs.. no mater how I place it it's not far enough away from the center of gravity to be adequately stable :(

Positioning the legs.. no mater how I place it it’s not far enough away from the center of gravity to be adequately stable ūüôĀ


Modernlegs.com which hurried out my order and delivered it on time at short notice :) sorry! No shipping outside the USA.

Modernlegs.com which hurried out my order and delivered it on time at short notice ūüôā sorry! No shipping outside the USA.


Marked out the locations of the pilot holes.

Marked out the locations of the pilot holes.


All the legs mounted for a test fit

All the legs mounted for a test fit


All done and upright!

All done and upright!


not too sure if I really like it

not too sure if I really like it


Looks fine when placed beside a table though

Looks fine when placed beside a table though


Pencil, screw, bit and chuck key

Pencil, screw, bit and chuck key


The drill that has been in service forever

The drill that has been in service forever


Mounted the 16" legs on the bigger lump and it looks really good, much better than the 18" legs on the small block

Mounted the 16″ legs on the bigger lump and it looks really good, much better than the 18″ legs on the small block


This guy looks on jealously as the other 2 get all the attention

This guy looks on jealously as the other 2 get all the attention


A groupshot

A groupshot

 

 

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Some of the chainsaw marks still pretty clearly seen

Some of the chainsaw marks still pretty clearly seen


Some of the chainsaw marks still pretty clearly seen

Some of the chainsaw marks still pretty clearly seen

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