The thing seems accurate enough, but at the most inopportune times it refuses to sync and I really want to monitor the temp below the upper plate on my boka. I've only used this thermometer a few times and it is my second such unit. Has anyone been running a wireless thermometer long enough to establish any kind of reliability? I know you get what you pay for, but to be honest, all the wireless thermometers reviewed on Amazon have reports of the same type of problems. I also note that they all have a 100 foot range which means they're probably all using the same dodgey innards from the same Chinese supplier.
I'll rig up my Raspberry Pi to monitor the temperature, but I have a few hurdles to cross there first. It's going to double as my sous vide controller while I'm at it .
Is wireless connection the only option? Or you just want to collect data by your Rasbery?
In the last case you can use digital sensor DS18B20. It requires only two wires and can be connected directly to GPIO pin. You only need one 1 additional resistor.
Hey, thanks for that sambedded. I might order one of those sensors to play with, the main thing that has been holding me back is my raspi wifi USB goes to sleep and won't wake up. I don't want to have a monitor hooked up to the raspi, so I'd like to monitor it over wifi, probably ultimately through my android phone - so I need to sort wifi first. I'm also having trouble with an update trashing my raspbian install, so it's a little bit on the difficult side. In that respect I was chasing an interim solution with just a 'normal' wireless temp sensor. I might try another SD card with the raspi though and see if I can update and what happens with my wireless.
The raspi will make for a very cool modular sensor/controller. I'm sure someone has already done it, but it would be very interesting to replace the output valve with an electronic one and have it regulate. For my setup, I'd want it to open to a trickle maximum, and whenever the temp goes up a degree, shut the valve off and wait for equilibrium for a time, and open back up to the trickle. In principle it would be pretty damned easy if an electronic needle valve can be sourced. I could possibly connect a stepper motor up to my existing tap easily enough. You could then just switch the thing on and sit back and collect the output while relaxing and watching the show.
Another way would be to use a picaxe with the temp sensor and stepper motor. That would make for one incredibly cheap automatic regulator with parts readily available...
ebswift wrote:
I'd want it to open to a trickle maximum, and whenever the temp goes up a degree, shut the valve off and wait for equilibrium for a time, and open back up to the trickle. In principle it would be pretty damned easy if an electronic needle valve can be sourced. .
This simple algorithm should work. However due to column inertia you will get constant temperature fluctuation. And if you thermometer installed near dephlegmator you will get some tails in your output. So you need to install thermometer at lower 1/3 of of you column. This way you will have fluctuation only at the bottom, but upper temp should be stable till you milk out all ethanol.
I'm going to use similar method, but little bit more advanced - use PWM with 1min period controlled by PID algorithm. I ordered stainless still valves like this one - http://www.aliexpress.com/store/product ... 10379.html" onclick="window.open(this.href);return false;" rel="nofollow
Another way would be to use a picaxe with the temp sensor and stepper motor.
picaxe are very slow. I wold rather use Atmel AVR (Arduino for example) or even some board with ARM Cortex-M3. And stepper motor solution requires positioning sensor.
my raspi wifi USB goes to sleep and won't wake up.
Is it only WiFi goes to sleep or whole board? You probably need to adjust power management settings.
The temp fluctuation that I'm seeing is only 1 degree F, and anything beyond that is 'tailsy'. Temperatures are actually extremely stable within that range, and anything above that 1 degree or so means it either went too far into tails, or there's no more good stuff to grab. My column does seem to work OK, but I am only a learner and at this point have nothing to compare with. The lower thermometer does make sense though - an early warning system for impending tails. That's where the instability would definitely come into play - at this point, how unstable is an unknown for me for my column.
The picaxe is slow, but it's faster than I am at reacting to the situation. Using a stepper, I think I can 'calibrate' it to begin at the starting (off) position for the valve and have it simply move back and forth to that point provided there isn't slippage. It would be interesting to investigate the already tried and proven (and reliable) methods for operating a valve electronically.
Incidentally, I solved the problem of the raspbian image self-destructing after an upgrade. I used the bootcode.bin fix from here: http://elinux.org/R-Pi_Troubleshooting# ... on_display" onclick="window.open(this.href);return false;" rel="nofollow. Now that I've got upgrade working, what I've found with wifi is that it actually drops the connection after a time whilst the device itself is still working. I can scan for ssid's but the connection itself is dropped. I wish I had more time to play damnit!
I don't know how much more OT I can go on this . Ah well, it's my own topic I'm side-tracking. Anyway, the point of this post is the new m2 chips from picaxe may make things more interesting. There's apparently an in-built temperature sensor as well as much faster processing, much greater memory and parallel processing...
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