This isn't "the" One Wire protocol, it's a single wire protocol that is very timing sensitive and also wiring sensitive.

@@rpavlik1 The only thing that's sensitive about DHT sensors is when you poll them too fast. The datasheet tells you the fastest they can be polled and I've never had an issue with a few feet of wire or "timing" issues reading the sensors. This video is just hocking the more expensive adafruit sensors that do the same thing with the same accuracy.

You're right. Just catch the rising edge in an ISR, along with a timestamp. Then reconfigure the processor to trigger on the falling edge. When that triggers, take a timestamp and calculate the difference between it and the previous capture. If it's longer than 50-60uS, then it's a one, otherwise.....

@@rpavlik1 true, it's not exactly the same, but it's not that much different in this respect.

@@tonyfremont I think that would be more complex than the Arduino library. I just had a look and they suspend all interrupts while reading from the sensor since the timing is rather tight. Since the max length message is 40 bits, that would be 80 interrupts total at 2 per bit plus a couple more to signal the start of a reading and then you still have to measure all of them to see what you got. If you had another interrupt fire during that time, you would be in trouble. There might be some speedy controllers that could handle it, but I'm not sure an 8-bit AVR is up to the task if you want to do anything else.

Yes, he can, you operating system

I use SHT40. it's actually tiny, and only requires a small cap. Maybe you are using a too -large board

Yes...the sht xx are the best solution...i lost my nerves too much with dht...

It isn't worth it. Overly complicated solution when there are better out there. A sensor that outputs measurements in I2C format is a much better solution. Cheaper, fewer component count, greater reliability and less complex software and a shorter development time. As engineers you are trying to optimise the solution, not make it more complicated than it needs to be.

​@@deang5622Configuring a micros peripherals to offload CPU time is not making things more complex than they need to be, it's making it exactly as complex as it needs to be. Also check out the cost of these I2C parts compared to the original single wire devices.

@@deang5622 Setting up DMA and a timer capture is like a handful of register writes and a short ISR. That's probably just as simple, not to mention just as easy to write as a simple I2C driver.

this is not a library

he is saying that your micro has to keep constantly waiting for the change, counting how long between the signal edges, and as such it cant do anything else that it might need to

​@@amyshaw893doesn't something as basic as a RPI pico have 4 cores and an esp32 has 2? You could do a different thread

@@alastor--radiodemon7556 sure, but an Arduino doesn't, which is what a lot of people will be using. Plus he wants to advertise the expensive adafruit board

Even with that, the data quality is so much worse than any modern sensor. There are plenty of libraries to talk to these, since they are popular because they used to be best performance/price in a humidity and temp sensor, but they still are cantankerous and prone to just not working. (Also there's enough variation between units that you might have code that works with one, but then you buy another and it doesn't work with that one.)

@@rpavlik1 Interesting. Didn't know that; thanks! Granted that terrible data is terrible data, but getting the ins and outs of the signaling could be quite valuable to someone. It could be a good troubleshooting exercise too. Why does one work and another not?

@@McTroyd if one wants to practice troubleshooting skills, sure. But not for practical usage 😁

Notice adafruit doesn't have breakouts for DHT sensors, only the ones the "recommend". I've never had an issue with them and have had them in service for years.

@@McTroyd The only way the quality is worse is that you can't constantly poll the sensor. Frankly, it doesn't matter for almost any application that fits this sensor's environmental requirements. You simply don't need to poll the temp sensor at 5hz for any practical reason. Even at .5hz you're generating way too much data for what you would likely practically use. 10-20 samples per min is plenty for almost any project and DHT sensors work fine for that. Reading the sensor is one thing, but you have to process the data and do something useful with it and on that scale, DHT11/22 are just fine.

Curious as to why? It seems people in the know are real fans of I2C and I'm a novice.

​@@Quietloudits a rather easy to implement serial buss that allows multiple devices to share the same buss by using a master slave system, so instead of the temperature sensor always sending out its information on the buss the master (usually your main controller) says hey id 123 "fromMaster" out into the buss so it doesn't matter where on the buss it is either. onse the slave device is done doing what it needs to do it can then send out a response on the buss for the master, for temperature that can be pretty much instant since it can continuously read temperature data and only send it once called but if for example you have a stepper motor connect to the I2C buss (would obviously need a interface between the two) the master controller could say move 100steps and once it done that it can respond that it have done its task, Obviously this is a rather simplistic explanation but I am happy to answer any questions you have as long as UKposts doesn't limit the notifications

If it's a choice between one wire and I2C then I'd go for the latter, but I2C in general is not as reliable as SPI.

That is true, but you still have the problem of blocking high priority interrupts etc if you start measuring multiple 28us periods purely in software. It's not that hard to use a timer to run these under interrupt using a timer with compare/capture though, assuming you have a spare one.

I'm pretty sure it can be implemented on the PIO blocks. Have you tried to do it?

Interesting place to put one I wonder what you're doing with it?

@@bland9876 I guess a toilet seat warmer?

Why do you have one near your toilet what does it have to do with anything

@@joey.g under the toilet, to detect if it's leaking

What kind of system do you have it hooked up. To your PC ...? What kind of software. Never heard of someone going to such extreme to monitor a toilet for leaks ..

Yes they do. I2c requires two wires though

The Galacy can read hymidity? Wow!

@@AureliusR Yess Humidity Temperature