Tag Archives: hack

DIY Crock Pot Sous Vide System

On a visit to some friends I became aware of the whole topic of Sous Vide “under vacuum” (SV) cooking, the concept of using a controlled water bath to cook food (particularly meats) at low(er) temperatures for more consistent and desirable results. High end restaurants have been doing this for a while. At the time, Sous Vide systems were quite expensive but some home cooks were doing ingenious hacks to simulate a professional SV cooker by using hot water in beer coolers, etc. In that discussion, I mentioned that I thought one of the small computers I was toying with for home automation (HA) could make a simple & cheap SV system with some other basic parts.

It took me some time to come back around to the whole SV idea myself. Not too long ago I came across a great deal on some London Broil at Market Basket and that served to get me going on setting up my own SV system using parts I had already at the house from my previous HA projects. While there are now some SV immersion systems on the market for under $200, I thought I had everything needed to make one on hand. I figured I could try it out and see what I thought of SV cooking without spending any more money. Here’s what I came up with.

DISCLAIMER: This post is just to document what I did. I’m a hobbyist and know almost nothing above my tinkering. I DO NOT MAKE ANY ASSURANCE THAT THIS IS APPROPRIATE FOR HEALTH OR SAFETY CONSIDERATIONS. YOU ARE RESPONSIBLE FOR YOUR OWN FOOD HEALTH DECISIONS AND FOR USING ELECTRICITY RESPONSIBLY. I WILL NOT BE HELD LIABLE FOR ANY ACTION YOU TAKE TO FOLLOW THIS SAME PATH AND ANY DAMAGE THAT MAY RESULT. YOU HAVE BEEN WARNED! But should you make some delicious food as a result please comment to let me know!

OK, with that out of the way, here’s a photo of my solution:

My DIY Sous Vide System

The major parts here are:

  • standard Crock Pot slow cooker
  • Programmable Power Controller, consisting of:
    • CAI WebControl PLC (Programmable Logic Controller) unit
    • DS18B20 1-wire temperature sensor, embedded in a stainless steel probe
    • AC to 9v DC power adapter
    • 5v “Arduino” relay board
    • Misc. breadboard wires, low voltage wires and a PC 12v fan connector
  • 110v home wiring components:
    • Light switch
    • Power outlet
    • Appliance power cable
    • Misc. wires and connectors

Update 5/29/2016:

I’ve now been using this set up successfully for nearly a full year. Today I’m doing a SV Leg of Lamb for later finishing on the BBQ grill. Other meals have included lots of chicken, pork and beef – each one has turned out really well (I’ve yet to do fish, but will try it soon). I’ve not posted my PLC code up to now because I was awaiting it becoming stable – which I think I can now consider it, as it’s pretty much worked unchanged since day1 – so here it is. A bit of explanation:

HEAT_ON is a subroutine to energize the power relay, HEAT_OFF does the opposite.
HEAT_MAIL informs me of changes in state of the power relay.

Using the WebControl PLC’s General Setup page, various values can be set to control the program:
UROM1 is the desired set point (degF *10), so 1360 is 136.0 deg
UROM2 is the lower offset (degF * 10), so 8 is 0.8 deg – this controls the amount of swing in the actual temperature and will need to be tweaked for a given crock pot. This determines the actual point at which the heat will be turned on.
UROM3 is to enable or disable the power relay. 1 enables.
UROM4 is to enable or disable the email notices. 1 enables.

START
SET VAR1 0
TSTEQ TS1 0
EMAIL EM1
SUB UROM1 UROM2 VAR1
TSTLE T1 VAR1
CALLSUB HEAT_ON
TSTGE T1 UROM1
CALLSUB HEAT_OFF
END

HEAT_ON:
TSTEQ OP2 0
SET VAR4 -1
TSTNE UROM3 1
SET OP2 0
TSTNE UROM3 1
RET

SET OP2 1
SET VAR2 T1
TSTEQ VAR4 -1
CALLSUB HEAT_MAIL
SET VAR4 0
RET

HEAT_OFF:
TSTEQ OP2 1
SET VAR4 1
SET OP2 0
SET VAR3 T1
TSTEQ VAR4 1
CALLSUB HEAT_MAIL
SET VAR4 0
RET

HEAT_MAIL:
TSTNE UROM4 1
RET

TSTEQ VAR4 -1
EMAIL EM2
TSTEQ VAR4 1
EMAIL EM3
RET

I’ve also set up a script on a Raspberry Pi on our network which I use for data logging of each batch. At 10 minute intervals it captures the relay state and current bath temperature into a .csv file via a URL get from the WebControl. I can use this data for tweaking the UROM2 value above and for modifying my recipes going forward.

I’m very pleased with the system now and may be extending it to control more than one bath. For instance, today I was wanting to do both a pork loin and the lamb leg at the same time. There’s not enough space in the crock pot for both, despite the temperatures being able to be the same (but duration differing). With some code changes and multiple probes & relays I could control several baths.

I may also be creating an internal web portal on the pi which could provide real-time graphing and settings management for the SV set up, so I don’t have to look up what UROM values mean what each time! 🙂 This will be more important if/when I extend it to multiple baths, as only the UROM values have a built-in web interface on the WebControl unit.

Hack: Recycled Scrubbies!

We love to save money and the environment. Aways great when you can get a two-fer, and here’s one!

Do you need non-scratching scrubbing pads for cleaning around the house? Did you know that the woven plastic netting from vegetable packaging like this onion bag works wonderfully? No need to buy scrubbies when you can make them yourself from something you aready have!

Just cut the woven material away from the product labeling and you’re set to go (it used to be easier when the bags used to have simply ties – before they started bonding plastic labeling to the netting – but I haven’t found any brand that doesn’t do it now). Avoid the other non-woven plastic “netting” bags that are sometimes used (where they simply slit a flat sheet of plastic and stretch it into an open net form) as these have sharper edges and may scratch.

Be sure to test it someplace inconspicuous to be sure it doesn’t scratch the surface in your application. I find these work great for cleaning out grubby pots and the kitchen sink. If they get messy just toss ’em in the recycling bag after rinsing them out and grab a new piece – they don’t “cost” anything, after all! 🙂
2015-05-20 20.29.34

Silencing a Harbor Freight Item 93575 Safe

Harbor Freight sells a pretty decent safe for secure storage of selected items in the home, their item number 93575. With the right discount coupon the cost was about $24, just a couple of dollars more than their smaller safe but, IMO, of much better quality/construction.

I wanted to use this for a discreet situation where the safe’s very loud keypad beep would be a distinct disadvantage. Others had posted solutions on the product review pages that involved totally silencing the beep through squirting super glue into the speaker or de-soldering it from the board.

Mine is a simple solution with what I believe are two distinct advantages: ability to adjust the volume to retain some of the feedback capability, and reversibility – the ability to undo the change and return the safe to factory condition in case you’d need to return it for some reason.

What I did was to insert a small screw into the opening in the speaker housing, which I screwed down carefully and slowly until it reached the volume level I wanted. This worked great and has remained the same for several weeks now. See the following photos for how to do it.

Motley Fool: Immoral or Incompetent?

I have to say I feel quite let down.

When I first started investing to save for my retirement (quite some time ago) I came across material from the Gardiner brothers, a.k.a. the “Motley Fools”. The information was funny and empowering, helping me to learn more about this important topic. One of their key principles was that you could get your best performance using low cost mutual funds/index funds and bypass all the shenanigans that Wall Street tried to sell you. They were lauded for their ethical approach to investing and straightforward talk.

Well over the years they seem to have strayed from this index fund advice, and I was riding along with them by becoming a member of fool.com. They had a good privacy policy and claimed to not give away your email address. However, they started sending out these incredibly long emails pitching their own various newsletters and advisory services, and I still hung on despite starting to feel uneasy. Others have written about this change and some took them to task for it. But their “CAPS” experiment was interesting, and I could easily delete the emails, so I still stuck around.

Well, a short time ago I started getting SPAM messages sent to the email address I gave them. Owning my own domain, I am able to give out unique virtual email addresses to anyone I wish — in doing so, I can track down just what I’m ticked off about and going to relate to you here. So understand that my email address with fool.com is only known by me and them.

These new SPAM mailings are coming from very shady pitches for penny stocks, etc. They are the standard dregs of the internet masking as investment advice at best, and are potentially identity theft schemes at their worst. And here’s the kicker: these are being sent to the unique address I gave fool.com – which exists in reality in no place but their own servers.

So I dutifully sent an email to their provided address for such things (PrivacyPete@fool.com), and waited. And waited. It has now been a loooooooong time (nearly a year ago now) and nobody has got back to me about this. So this leaves me with just two possibilities (is there any other?):

  • Motley Fool is violating their own privacy pledge and has starting selling their mailing list, or
  • Motley Fool’s account management has been hacked, proving their incompetency in protecting subscriber information.

Either of which is totally unacceptable. I’m a Fool no more.