My "Spirit"
The film “The Death of the Mars Rover ” in translation from Airstrike reminded me how in December last year I had seen / read a lot about the Mars rovers and made my “Spirit”.
It became interesting to me - what is it like to control the device at a distance, receive data from it and keep it alive? I was captured by the idea of experiencing all the difficulties of this process.
In about a day, I came up with such an apparatus - this is a cardboard box trimmed with sanitary tape. Inside was the “heart” of the Arduino Uno with the ATmega328 controller, the radio transmitter of 433Mhz RF link kit (the connection was one way, for the two-way software for me to implement in a program plan is quite complicated), an analog thermal sensor LM335Z, a digital temperature and humidity sensor DHT11, a battery 9V, and finally, the Nokia 5530 smartphone, used as a camera (the connection was made via Wi-Fi).
')
Under the terms of my plan, I attach this box outside the window, so much so that it is not visible. During the "mission" to touch her was impossible. In general, everything as close as possible to reality, but decided not to simulate a signal delay of 20 minutes for the first time. In principle, I calculated the resource of this device for about a week - the camera on its battery will work for several hours, and the battery should have provided all the electronics for a week with energy.
Although in the room tests the apparatus showed itself from the good side and worked without interruptions, the reality turned out to be cruel.
Day 1:
The device made a successful landing on the window sill. After power-up, the first data was immediately displayed on the computer screen of the Mission Control Center: the temperature sensor showed -3 degrees inside the hull, and the air humidity was about 40-50%. The camera regularly transmitted pictures for 3 hours, then its battery sat down and the connection with it was lost. Communication with the device itself was sometimes broken for a short time due to the fact that the transmitter and receiver are rather weak, and there is a brick wall and a glass unit between them. The unit worked normally all day. For the night I left him with some anxiety, because there was a strong wind outside the window, if anything happens, I cannot do anything.
Day 2:
When I woke up, I saw a blinking LED blinking happily on the receiver board - it means that the connection did not break off overnight. But a surprise was waiting for me on the monitor ...
The temperature sensor showed that the temperature inside the case is 60 degrees! And she slowly crawled up. I did not know that it could overheat and heat the air around. By definition, this can not be. Having thought it over, I decided that at such a temperature everything would have burned down long ago, which means that these are thermal sensor glitches. In any case, the mission could not be completed, according to the rules, it is completed only when the connection with the device is interrupted. The humidity sensor worked fine, which added to my confidence that nothing threatened the “window-siding”.
I went quietly for the night, the temperature by this time, allegedly, was 200C. Unpleasant, but not fatal ...
Day 3:
I woke up and immediately ran to the receiver. To my surprise, the LED did not blink. I looked at the receiver terminal - judging by the last temperature sent to 400C, the connection was interrupted at about midnight-one in the morning. I shook the receiver, attached an additional antenna. Nothing helped. After a short wait, it was possible to summarize - the device died, having worked on my planet 2 days from the planned 7th. "Mission" is over (or failed).
And now, the moment of truth - I take out a box. Everything froze (-15 outside), on the surface of a cardboard crust of ice. Opening it, I saw a lifeless charge. Everything is in place, no contacts are gone. I pulled the battery - it did not work. I connected via USB to my computer - it came to life. I checked the battery on the multimeter - it is zero. That is, apparently in the cold discharged faster than the estimated time, the device itself is intact.
This is how my apparatus died, and the cause of death is comparable to the cause of death of the Spirit rover. All this was, in fact, quite interesting due to the fact that you do not know what's going on with the device. You see only dry numbers and you make assumptions on them. I can imagine how interesting it is for people on the rover development and management team.
It became interesting to me - what is it like to control the device at a distance, receive data from it and keep it alive? I was captured by the idea of experiencing all the difficulties of this process.
In about a day, I came up with such an apparatus - this is a cardboard box trimmed with sanitary tape. Inside was the “heart” of the Arduino Uno with the ATmega328 controller, the radio transmitter of 433Mhz RF link kit (the connection was one way, for the two-way software for me to implement in a program plan is quite complicated), an analog thermal sensor LM335Z, a digital temperature and humidity sensor DHT11, a battery 9V, and finally, the Nokia 5530 smartphone, used as a camera (the connection was made via Wi-Fi).
')
Under the terms of my plan, I attach this box outside the window, so much so that it is not visible. During the "mission" to touch her was impossible. In general, everything as close as possible to reality, but decided not to simulate a signal delay of 20 minutes for the first time. In principle, I calculated the resource of this device for about a week - the camera on its battery will work for several hours, and the battery should have provided all the electronics for a week with energy.
Although in the room tests the apparatus showed itself from the good side and worked without interruptions, the reality turned out to be cruel.
Chronology of "flight":
Day 1:
The device made a successful landing on the window sill. After power-up, the first data was immediately displayed on the computer screen of the Mission Control Center: the temperature sensor showed -3 degrees inside the hull, and the air humidity was about 40-50%. The camera regularly transmitted pictures for 3 hours, then its battery sat down and the connection with it was lost. Communication with the device itself was sometimes broken for a short time due to the fact that the transmitter and receiver are rather weak, and there is a brick wall and a glass unit between them. The unit worked normally all day. For the night I left him with some anxiety, because there was a strong wind outside the window, if anything happens, I cannot do anything.
Day 2:
When I woke up, I saw a blinking LED blinking happily on the receiver board - it means that the connection did not break off overnight. But a surprise was waiting for me on the monitor ...
The temperature sensor showed that the temperature inside the case is 60 degrees! And she slowly crawled up. I did not know that it could overheat and heat the air around. By definition, this can not be. Having thought it over, I decided that at such a temperature everything would have burned down long ago, which means that these are thermal sensor glitches. In any case, the mission could not be completed, according to the rules, it is completed only when the connection with the device is interrupted. The humidity sensor worked fine, which added to my confidence that nothing threatened the “window-siding”.
I went quietly for the night, the temperature by this time, allegedly, was 200C. Unpleasant, but not fatal ...
Day 3:
I woke up and immediately ran to the receiver. To my surprise, the LED did not blink. I looked at the receiver terminal - judging by the last temperature sent to 400C, the connection was interrupted at about midnight-one in the morning. I shook the receiver, attached an additional antenna. Nothing helped. After a short wait, it was possible to summarize - the device died, having worked on my planet 2 days from the planned 7th. "Mission" is over (or failed).
And now, the moment of truth - I take out a box. Everything froze (-15 outside), on the surface of a cardboard crust of ice. Opening it, I saw a lifeless charge. Everything is in place, no contacts are gone. I pulled the battery - it did not work. I connected via USB to my computer - it came to life. I checked the battery on the multimeter - it is zero. That is, apparently in the cold discharged faster than the estimated time, the device itself is intact.
This is how my apparatus died, and the cause of death is comparable to the cause of death of the Spirit rover. All this was, in fact, quite interesting due to the fact that you do not know what's going on with the device. You see only dry numbers and you make assumptions on them. I can imagine how interesting it is for people on the rover development and management team.
Source: https://habr.com/ru/post/170683/
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