MEATER: The Only Wire-Free Smart Meat Thermometer on IGG - Page 1
Forum section: electronics / general

author: Kalidor
author_rank: Regular Contributor
timestamp: October 25, 2015, 08:23:08 am
content: https://www.indiegogo.com/projects/meater-the-only-wire-free-smart-meat-thermometerIs it possible that a battery and a WiFi & BT module can withstand cooking temperatures?

author: SeanB
author_rank: Super Contributor
timestamp: October 25, 2015, 08:40:31 am
content: Not for long, if you go for well done it will go above 140C and the battery and BT module will both fail, the battery probably explosively, which would be somewhat unhealthy in a gas oven with a naked flame and some volatile organic solvent vapour in a near ideal stoichiometric mix.

author: crispy_tofu
author_rank: Super Contributor
timestamp: October 25, 2015, 08:49:19 am
content: Not to mention the cycling of temperatures... wouldn't last for longAnd then there's the people that are going to say that the Bluetooth radiation would poison the food...

author: pbendel
author_rank: Contributor
timestamp: October 25, 2015, 09:00:50 am
content: Somebody should do a teardown on the probe, maybe TEG powered from the temperature difference from one end of probe to the other end. Maybe destructive testing, run a thermal oven hotter that a barbeque (or just use a barbeque) and see if anything fails...

author: Marco
author_rank: Super Contributor
timestamp: October 25, 2015, 09:52:48 am
content: The holder seems to be a charger, maybe they use capacitors to store energy? How much energy does it take to blip temperature say every 5 seconds? It's a pretty chunky piece of metal, you could put quite a lot of capacitance in there and the electronics can be in the tip at relatively low temperatures.I could see this working, but building it to 59$? That's quite an achievement.

author: crispy_tofu
author_rank: Super Contributor
timestamp: October 25, 2015, 09:55:34 am
content: Quote from: Marco on October 25, 2015, 09:52:48 amAccording to the Kickstarter, looks like it uses a AAA battery, which can 'recharge the MEATER up to 100 times'. (unless you're talking about the probe)There's a battery compartment on the back.

author: Marco
author_rank: Super Contributor
timestamp: October 25, 2015, 10:00:52 am
content: "Notch: Safe insertion line"Does that mean that if it's not inserted in a piece of meat that deep it's not safe?

author: crispy_tofu
author_rank: Super Contributor
timestamp: October 25, 2015, 10:07:11 am
content: Quote from: Marco on October 25, 2015, 10:00:52 amYep, it'll turn into a projectile.

author: mzzj
author_rank: Super Contributor
timestamp: October 26, 2015, 09:26:12 am
content: Quote from: SeanB on October 25, 2015, 08:40:31 amYou need only the antenna outside of the meat thus reducing the temperatures to below 100C.

author: mikerj
author_rank: Super Contributor
timestamp: October 26, 2015, 02:34:13 pm
content: Wonder how well it works in a microwave

author: Kalidor
author_rank: Regular Contributor
timestamp: October 26, 2015, 04:15:05 pm
content: Quote from: mikerj on October 26, 2015, 02:34:13 pmAs soon as the door is closed WLan & BT is blocked, no need to switch it on. You can try it with your phone.The backers with a microwave oven (combined) will probably complain.

author: kfitch42
author_rank: Frequent Contributor
timestamp: October 26, 2015, 08:33:49 pm
content: Quote from: Marco on October 25, 2015, 10:00:52 amProbably.I assume the battery is near the tip. This lets them use the meat as insulation to keep from causing thermal runaway in the battery. If they can get a battery rated for "industrial" temp range (125C) they might be OK. Cooking temperatures for meats (http://www.foodsafety.gov/keep/charts/mintemp.html) are below 100C. They probably only have a temp sensor (something like a K type thermocouple?) and the bluetooth antenna in the dark part that is not in the meat.

author: tom66
author_rank: Super Contributor
timestamp: October 27, 2015, 01:01:33 am
content: Does it need a battery? If the bluetooth part transmits only every minute or 30 seconds you could probably get acceptable performance from a bank of capacitors.A BLE module I have uses 15mA during transmit for around 1ms and sleeps the rest of the time. That's about 15uC for one transmission. Say you need to do 100 transmissions in every cooking session, excluding quiescent losses for now, that would mean you would need 1.5mC, or at 3V about 500uF. That's within the realm of a high temperature electrolytic, or even a few large format ceramic capacitors.

author: Bud
author_rank: Super Contributor
timestamp: October 27, 2015, 01:42:11 am
content: Quote from: Marco on October 25, 2015, 10:00:52 amThey've done their safety research to mitigate liability claims in case people used it as a rectal thermometer

author: Marco
author_rank: Super Contributor
timestamp: October 27, 2015, 11:17:06 am
content: Quote from: tom66 on October 27, 2015, 01:01:33 amI'd try 50V X7R ceramic capacitors derated to 12V, LoRa with an external BT/WiFi relay and put it together with 80Au/20Sn solder. That should make it pretty much indestructible.

author: fcb
author_rank: Super Contributor
timestamp: October 28, 2015, 07:05:37 pm
content: "DEREK - Your meat is ready!"What's not to love.

author: crispy_tofu
author_rank: Super Contributor
timestamp: October 28, 2015, 09:01:31 pm
content: Obligatory (sfw):

author: LukeW
author_rank: Frequent Contributor
timestamp: October 29, 2015, 12:43:36 pm
content: Quote from: crispy_tofu on October 25, 2015, 09:55:34 amEnergiser E92 AAA datasheet gives the nominal charge capacity as 1100 mAh (at 25C, 25mA discharge to 0.8V)So charge capacity of each probe should be 11 mAh, assuming 100% efficiency.

author: kfitch42
author_rank: Frequent Contributor
timestamp: October 29, 2015, 02:33:53 pm
content: Quote from: LukeW on October 29, 2015, 12:43:36 pmThe meater page says:QuoteI will take a swag at 1 transmission per minute. 48*60 = 2880 transmissionsQuote from: tom66 on October 27, 2015, 01:01:33 am2880 * 15mA*1ms = 43200(mA)(ms) = 43.2(mA)(s) = 0.012 mAhDid I foul up my math? That actually suggests that transmit power is not the limiter. Maybe they are doing 1 transmission per second. Or perhaps they need to transmit BLE at crazy high power (since they are likely to be in something resembling a faraday cage (oven or grill).

author: EEVblog
author_rank: Unknown
timestamp: November 03, 2015, 12:02:35 am
content: FYI, the user "meater" was a fake account with a bogus website. Banned.

author: Srbel
author_rank: Frequent Contributor
timestamp: November 10, 2015, 07:43:49 am
content: It should survive if this is true:https://ksr-ugc.imgix.net/assets/004/408/809/ebb99ce2817df79798740cec633ae3be_original.gif?v=1440979088&w=680&fit=max&q=92&s=d0a16615401d8f75b76d1113f1d7f5c3Only goes up to 75,5 oC?

author: amyk
author_rank: Super Contributor
timestamp: November 10, 2015, 08:33:31 am
content: There are ultra-high-temperature batteries available up to 200C:http://www.steatite-batteries.co.uk/electrochem-lithium-batteries.htmlProbably not cheap though, if you have to ask for the price...

author: Kalidor
author_rank: Regular Contributor
timestamp: November 11, 2015, 07:09:14 am
content: Quote from: amyk on November 10, 2015, 08:33:31 amThese are non rechargeable batteries, smallest size is AA.The contents of the batteries are highly toxic and require special disposal procedures, additionally they may explode if shorted.