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WiFi Sucks

Beating laid down by:itwasntme967, on 5/15/2017. Views: 43 | Votes: 0

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I currently am a trainee as an electronics technician at an rather well-known University in Germany. Our main tasks involve designing and producing circuit boards, most of them for the physicists at our institution. Since we are in training and there are not often suitable circuit boards for us, we also get rather "special" and out-of the ordinary tasks. This is one of them.

One day my instructor comes into the workshop and tells us we should get going on planing a measurement of time for a dog club.

They wanted to measure the time the dogs needed for running around a parcour which should be set up via two seperate photocells and the time should be displayed wirelessly on a base station.

My coworker ($CW) and $me get going, and soon we have the whole concept: We took an Arduino Uno, transformed the 12V signals of the photocells down to 5V, and hooked the Arduino to an antenna module, which worked at 2.4GHz.

The base station consisted of another Arduino, a third antenna module and an LCD-display to show the time.

Since at that time I was the one who knew the most about coding the Arduino (yes, even more than my instructor) $me was tasked with that whole deal.

Again in order to keep it simple $me just let the sending Arduinos sleep until they sensed the singnal from the photocell and transmitted either the "start" or "stop" signal. The base station would listen for these signals and after recieving the start, count the time and simultaniously displaying it.

To really make it wireless the sending Arduinos even got a huge powerbank to run off.

After a few days of trying we couldn't get the sending and recieving right, some times the thing would work perfectly fine, other times it had a delay of a couple of seconds and far more often than not it didn't work at all.

we knew the programming was working, since the base also had buttons to trigger it manually.

But the electrical part worked fine and since the only other option of failure was the programming $me got the blame.

Meanwhile the day of the first dog race drew near and we had to present at least SOMETHING, so we said "screw it", got some reeaally long aux cables, connected them up and called it a day.

The timekeeping worked like a charm, but our instructor was still not satisfied, since he REALLY wanted the thing to be wireless.

So we kept on testing and trying, played around with the test sketch which came with the library for the antenna, but the bloody thing just refused to work.

At this point we just gave up and assumed the antenna modules must heve been broken.

Our instructor didn't believe this and took the modules with him to test hem in his office, which was a few metres down the hallway.

Skipping to a few days later and we get told our instructor played with the modules and they worked like a charm.

We were in utter disbelieve and took the modules back to the shop - aannd - nothing.

They were struck silent.

After we brought the modules back to our instructor and walked down the hallway, we noticed, that just on the other side of the wall to our shop a router was hangning and happily blinking away...and sending data at 2.4GHz....the same bloody frequency the modules tried to communicate on.

We took them outside the range of any Wi-Fi onto a field and again they began to work like a charm.

TL;DR: if you work with wireless connections, always make sure there are no other devices operating in the same frequency range.

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