DS18B20 reading wrong value [solved]
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DS18B20 reading wrong value [solved]
Hi,
I've a DS18B20 connected to GPIO-2 of a ESP01 with R78 installed but the reading is wrong :
1 Temperature - DS18b20 sensor 28-ee-e9-12-3-0-0-d6 12 GPIO-2 Temperature: 30.69
Expected temp is ~20 C, moving the DS18B20 to an ESP12 (GPIO-14) gives proper results, any idea how come ?
And YES a 4k7 is connected between Vdd and DQ as well as IDX has a non-zero value (on both ESP01 and ESP12).
Also tried GPIO-0 with same negative results.
Does it have something to do with the I2C scan at powerup ?
Second question, is a DS1820 supported as well or only DS18B20 ??
-ben
I've a DS18B20 connected to GPIO-2 of a ESP01 with R78 installed but the reading is wrong :
1 Temperature - DS18b20 sensor 28-ee-e9-12-3-0-0-d6 12 GPIO-2 Temperature: 30.69
Expected temp is ~20 C, moving the DS18B20 to an ESP12 (GPIO-14) gives proper results, any idea how come ?
And YES a 4k7 is connected between Vdd and DQ as well as IDX has a non-zero value (on both ESP01 and ESP12).
Also tried GPIO-0 with same negative results.
Does it have something to do with the I2C scan at powerup ?
Second question, is a DS1820 supported as well or only DS18B20 ??
-ben
Last edited by bennybubble on 18 Feb 2016, 10:52, edited 1 time in total.
Re: DS18B20 reading wrong value
You soldering DS18b20 directly to ESP? Esp heats up, it shows higher temperature
Re: DS18B20 reading wrong value
You soldering DS18b20 directly to ESP? Esp heats up, it shows higher temperature
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Re: DS18B20 reading wrong value
Nice thought but not anymore after 10 minutes ...
DS18B20 should give ~ 20 C.
-ben
DS18B20 should give ~ 20 C.
-ben
Re: DS18B20 reading wrong value
maybe something with the GPIO2, wich is TXD1
as an INPUT not so easy?
want to check this info?:
http://www.forward.com.au/pfod/ESP8266/ ... index.html
as an INPUT not so easy?
want to check this info?:
http://www.forward.com.au/pfod/ESP8266/ ... index.html
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- Normal user
- Posts: 44
- Joined: 31 Jan 2016, 21:05
Re: DS18B20 reading wrong value
Hi,
Good information! But in case of a DS18B20,GPIO-2 already has an external pull-up of 4K7 and is not pulled to ground during booting (as far as I know).
Couldit be realte to an initial I2C scan or is this not done on GPIO-0 / GPIO-2 ?
I'm planning to use the ESP01 in a PIR sensor and would like to add a temp sensor to it to measure the temp inside, just for fun !
Any good working alternatives (for a temp a sensor) ?
-antoon
Good information! But in case of a DS18B20,GPIO-2 already has an external pull-up of 4K7 and is not pulled to ground during booting (as far as I know).
Couldit be realte to an initial I2C scan or is this not done on GPIO-0 / GPIO-2 ?
I'm planning to use the ESP01 in a PIR sensor and would like to add a temp sensor to it to measure the temp inside, just for fun !
Any good working alternatives (for a temp a sensor) ?
-antoon
Re: DS18B20 reading wrong value
Two esp01 ?
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Re: DS18B20 reading wrong value
Good idea !
Only problem is that I cannot even get a single Ds18B20 to work on a ESP01 ...
Neither on GPIO-0 or GPIO-2.
-Ben
Only problem is that I cannot even get a single Ds18B20 to work on a ESP01 ...
Neither on GPIO-0 or GPIO-2.
-Ben
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- Normal user
- Posts: 44
- Joined: 31 Jan 2016, 21:05
Re: DS18B20 reading wrong value
It turned out that my ESP01 was bad, now using a 'fresh' one and all ok !
Re: DS18B20 reading wrong value [solved]
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