Question How to interface DHT11 sensor with ELB-REV4?

Jun 12, 2019
1
0
10
I tried to interface DHT11 temperture sensor with ELB-REV4, kindly suggest which gpio should i connect it to.
 

OldSurferDude

Reputable
May 18, 2019
168
30
4,640
I have ten DHT-11. I placed them within 100cm of each other to determine the variance. seven were +/- 1C, but a two were +/- 2C, and one was +/- 4C of the average. In other words, the absolute temperature is unreliable. I didn't do a long term study, but I suspect that the part is a POS. The LM35 that is commonly used has similar part-to-part variation. Either one, you'll have to find a way to calibrate it.

I don't know this SBC, specifically. I don't think it matters, but there might be pins that are used specifically for some other device, No big deal to move it. If your SBC doesn't have a library for it, I used an Arduino script to "bit-bang" it. (definition of "bit-bang": high level control of a single pin, toggling it high/low for output and using a timing loop to observe the the input.) This script could be easily port to your SBC.
 
Jun 1, 2019
3
1
15
As per the data sheet for DHT-11 i see that it need 5V power which you can easily supply from the P9 header of the ELB-REV4. and the DHT-11 just needs a single GPIO pin to communicate with the host.
as per this datasheet
https://www.mouser.com/ds/2/758/DHT11-Technical-Data-Sheet-Translated-Version-1143054.pdf

the ELB-REV4 has to send a start signal, DHT11 changes from the low-power-consumption mode to the running-mode, waiting for MCU completing the start signal. Once it is completed, DHT11 sends a response signal of 40-bit data that include the relative humidity and temperature information to MCU. Users can choose to collect (read) some data. Without the start signal from MCU, DHT11 will not give the response signal to MCU. Once data is collected, DHT11 will change to the low- power-consumption mode until it receives a start signal from MCU again.

Data consists of decimal and integral parts. A complete data transmission is 40bit, and the sensor sends higher data bit first.
Data format: 8bit integral RH data + 8bit decimal RH data + 8bit integral T data + 8bit decimal T data + 8bit check sum. If the data transmission is right, the check-sum should be the last 8bit of "8bit integral RH data + 8bit decimal RH data + 8bit integral T data + 8bit decimal T data".

So it is simple to interface with ELB-REV4 and get the data on a single pin