Hi there this might sound stupid but please help me . Does anyone know how to make a pulse sensor a waterproof and water resistant one ?
If you're referring to heartrate sensors like those on pulsesensor.org, the simple answer is no.
There are two issues here. The first is whether the circuit could be fully waterproofed - the answer to this is yes. The second is harder, however - which is whether the sensor you refer to would be effective under water.
These sensors use a green light to detect changes in bloodflow, and they work poorly underwater even in commercial sensors. They are very sensitive to being jostled by water, and lose accuracy when there is water between the sensor and the skin.
There's a useful in-depth discussion of this here:
https://www.yourswimlog.com/best-waterproof-heart-rate-monitors-for-swimming/
If you need to measure heartrate underwater, you might have better luck with a chest strap sensor. These work by sensing elongation of a strap wrapped around the chest, and calculate heartrate based on those changes. Commercial versions are readily available and work well.
If all you're worried about is waterproofing the circuit for shallow water, this can be accomplished pretty easily. All elements would need to be encased in fully waterproof material. You could simply slip the whole thing in a waterproof baggie (google 'dry sleeve' or 'acquapac), or if you're up to it, build a silicon mold to encase the project.
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I am trying to evaluate the maximum power consumption of a MCU (Renesas RX72N or RX651). It's not battery powered and it's never run in sleep mode. I am thinking I can write a piece of benchmark code, in C of course, that should do a lot of complex calculations. While the MCU is executing the calculations, I can measure the current drawn by the MCU and deduce what's its maximum power consumption level. Is my understand correct? If so, do you think what kind of code I should write or is there already some open source code to use for the purpose?
Thanks in advance.
-woody
In general you just have to experiment. There is no fixed answer. First off check the datasheet, you certainly want flash on and all the peripherals out of reset. Fastest clock is probably good but understand that running from flash does not necessarily scale up, depends on the part (do they have wait states that have a table relative to processor clock speed).
Changing states burns power. So you want to try to flip as many as you can. But it could be that you want to flip gpio or other external pins rather than try to get the processor core to pull more power.
You will want a nice meter for this one that can measure milliamps or milliwatts.
Things like multiply and divide in theory take a good percentage of chip space, if they implement it in one clock, but some of these mcus naturally won't do that, the instruction will be multi clock or at times the chip vendor can choose (if they buy an arm core for example). But you may need to deal with data patterns to to get more consumption. For core stuff you probably want to do as much register based stuff vs read/save things to memory.
You probably want to write the test code in assembly language. Will want to start with an infinite loop, branch to self, measure power/current. Complicate the loop, additional memory cycles, or alu operations, see if you can detect a power difference (you may find that you are not going to be able to make much difference with the core). Depending on the mcu design you may/should get better execution performance running from ram, but it depends of course. ram tends to be faster in mcus than flash. then do things like flip gpio pins, leave them high, etc. If you have LEDs turn them all on naturally, etc.
There is no one answer for this, so no one benchmark nor one solution pushes any random chip the hardest. Assume that if possible to see a noticeable difference for a particular chip, that the test would be specific to that chip and not necessarily the same solution for other chips from the same company, much less chips from other companies.
I want to make home automation system for my final year project. One module of my project is light ON OFF on entrance, for that purpose I used IR sensor but the range of IR sensor is 20cm which is not suitable for my project, i need minimum 4 feet ranger to detect the human to turn ON OFF light. anyone suggest me to which sensor is best for that.
Thanks
You csn use what's called human sensor, it is very sensitive and provide the on off signal you need, low cost, easy to use ans small enough to fit inside any sensor enclosure.
I'm trying to get arduino uno to sequentially extract liquid from each of four chambers to a main chamber using solenoid vales, flowmeter, level sensors, and a centrifugal pump. process being open main tank solenoid valve, open valve one, extract quantity one, close valve two, delay 1 second, open valve two....
Does anyone know the best way to go about programming this? I have no coding experience outside of mathematic analysis. Trying to get it directly in the Arduino IDE. I'm also at the same time checking liquid levels and controlling temperature.
You should do one step at a time. Your project is pretty ambitious as a first project.
I would suggest going first for some small examples like letting a LED blink, using a button etc. to get a feeling for the IDE and C syntax.
When you feel confident enough with basic programs you can progress. I'd suggest to go one sensor/actuator at a time. Trying to communicate with it and verifying the data.
But keep in mind this won't be just a coding project but there will be a substantial mechanical/electrical part. Especially when dealing with liquids there are a ton of different hose diameters, voltage levels, etc.
You have to work out how to power the pump and valves safely, because the Arduino board can't handle greater currents.
If you really want to go into this project, you surely can. But keep in mind that this won't happen in a week. To get this working properly you probably will have to invest months and educate yourself not only on the programming side, but also on the electrical side.
I need a sensor which can detect chair occupancy. By googling I found that potential solution for this issue could be load sensors. However, the specifications of the most of the load sensors that are available online suggest that a sensor can measure up to about 50kg (https://www.sparkfun.com/products/10245).
Does this mean that I cannot detect when a person that weights over 50kg sits on the chair? Or this means that I just cannot measure accurately how much it weights?
I do not need information regarding the person weight.
Any particular reason why you are trying to use a load sensor, it sounds more complicated, they could brake easily if constant use of 50kg or more on them. It may be easier with a ultrasonic sensor and simply detect the occupancy if somebody is close to the sensor, or even a motion sensor could work as well.
I have not interfaced with this sensor before, but as seen from the specifications of the product, 50kg is its maximum reading.
You can use other sensors with higher range
or you can use another type of sensors to detect the person which does not depend on the weight as simple IR detector or distance sensors such as ultrasonic.
I have really work on a final year project in 4th year computer science. I need to calculate the blood pressure level of a human in a real time and alert to him.
Do we have any sensors for Ardino or Resbrry PI boards.
I have search on enter link description here but I have seen lots of sensors for heart rate but non of them for blood pressure.
Do you think is there any sensors available to get the blood pressures from ardino or rasberry PI ?
You've got a BIG project ahead of you. Automated blood pressure monitors are expensive medical devices, but I'll get you started.
Take a look at this link and think about the physical functions you must accomplish.
http://homepage.smc.edu/wissmann_paul/anatomy1/1bloodpressure.html
First, you have to build a pneumatic control system to inflate a blood pressure cuff and then slowly deflate it.
Second, you have to build an acoustic monitor to listen for the heartbeat below the cuff and a digital signal processing algorithm to detect the heartbeat.
For the first project look online for small pneumatic pumps and solenoid control valves. You will control these with the Arduino and a power transistor to switch the power on and off.
For the second project you will need to build a microphone and amplify that. You can find plenty of examples of microphones on the Arduino forum. The trick part will be designing the DSP filter to identify heartbeats and then count them. See Simon Monk's book, "Beyond Sketches" for an intro to DSP on the Arduino.
Get started and post some more and I'll check back to see if I can help on specific problems as you go forward.