JakeStew
JakeStew
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Interesting stuff. Any updates? Did the experiment produce any results? I've never heard of 3.5 week semesters. Don't see how that could work well. I remember getting burned on transferring from a quarter system to a semester system based coll…
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> much of the planned hardware (A/D, processor, etc.) is still not finalized. I would suggest avoid the past weak points of the current hardware then. Don't fool around with proprietary bluetooth solutions, use wifi. Now would also be a good…
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> CE Certification for medical devices cost estimates are in the tens of thousands of dollars. So OpenBCI has not pursued this. A FDA 510k might be as cheap as $2,000. Might be something to look into. The problem might be having to get a ne…
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Microchip loves to change around those stupid header files. Every 3rd release seems to break something for me. Usually you can fix this by doing some defines at the top of your code.
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One guy on a website I came across was working with the ADS1299. His idea was to use SATA cables as connectors. The idea is that these are a good cheap source of tightly specd wiring and the conenctors are readily available. You might try someth…
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Probably best to not be using cables in the first place. Just stack the boards with headers connecting them.
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Curious what the fixation with the Arduino IDE is?I switched some of my work from PICs to cheap Arduino boards and the Arduino IDE was REALLY disappointing to me. It just doesn't have any of the modern IDE features I've grown to rely on, and is fra…
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Having small decoupling caps will smooth out the high frequency noise the best, while larger caps smooth out the lower frequency noise better. Many engineers just string out a handful of caps of various sizes to get clean power. Otherwise you'd b…
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> Does seem like 5.2V should be enough, if it is indeed LDO. You never know. Calling something a "LDO" depends on a number of factors other than just the voltage dropout vs. current. A LDO can have dropout voltages anywhere from below 0.2v to…
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The EEG channels are deferentially amplified. The output value is the *difference* between the (+) and (-)/reference electrodes for each channel. There are no rails in this setup. If the (+) channel is not connected to a (-)/reference channel the…
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I skimmed it. Seems like BS to me. Check out the graphs on their simulation of drift. Seems like they're claiming that a TINY percentage of drift will somehow distort a square wave into a trapezoid. Doesn't make any sense to me. Maybe I don't h…
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"When a drift is detected, you will see a progress bar moving on the left or right (not enough or too many samples). When the drift reaches a threshold, an automatic correction is done : the Acquisition Server removes or duplicates some samples, and…
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I'm just doubting the difficulty of padding 6 samples into 250. It wouldn't be re-sampling as every data point, except the extra 6, would be real, unchanged data. Only 6 would be interpolated from the nearest points. The straight line interpolat…
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So what happens at the end of 1 sec when the program has received 250 instead of 256 samples?I'd think it would be pretty lame if it just crashed and burned from that. I still think you're overstating the difficulty of padding a lousy 6 samples …
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High frequency whine is usually capacitors charging. Perhaps your power system output cap is undersized or under filtered and is charging/discharging constantly.
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I would think that it would not really be that hard to convert 250 to 256 sps. Every 42 samples you pad with an interpolated sample.You could spline it or use some other fancy method (I'm no math expert). Or you could probably come up with a simpl…
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Please post back to let us know how they work out! If they work well this might just be something that will work well for some applications.I suggested the round tips because from my experience with larger size pogo pins the spring tension was fair…
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I wouldn't want to add overhead with LUA or NodeMCU for such a simple project.The ESP8266 has a C compiler, which would be the normal way to program for it. The wifi stack is integrated. All you really have to do is write normal code for it and…
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WiFi modules cost around $4 now that the ESP8266 modules are out there, so I don't see any reason to settle for BT and all the headaches and limitations it entails.I'm currently working on a unit that will use the ESP8266 for everything, essentially…
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You might try something called a "pogo pin". Sometimes they are also called a "spring test probe". You can find them on ebay for next to nothing. They come in a variety of qualities and tip sizes/styles. Many of them are very small. Basically …
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Or you could use all silver, or gold plate your earrings. You might check around with your local jewelers and see what they'd charge for a 24k gold flash. It only takes about 5 minutes.
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BMI stands for Body Mass Index. You should check your acronyms, especially in the medical field, before naming a project. The problem is that it will confuse people and you'll never be able to get search engines to find you.
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Yes, trying to randomly or constantly poll with other stuff going on would not work well at all.Microchip has pretty good RTOS support though if we really don't want to do basic housekeeping ourselves. Just using an interrupt for the data acquisiti…
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I still don't understand what you're trying to say. There's no difference between the two methods other than potentially saving a timer on the uC and avoiding a few clock cycle penalty if you try to get the data early. You're only saving a couple…
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Your ISR should be reading and storing the data in a ring buffer then exiting. The main loop will use this data as needed. If your main loop does not use the data before the buffer is filled the data will be overwritten by new incoming data. …
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Whatever works! All depends who you want clocking the cycle. No matter which way you do things you only have 1/256th of a sec to do your calculations or you'll quickly overrun your ring buffer, so I don't see any real advantage either way. I pro…
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So I assume that the occurrence of this is controlled by the sample rate set in the ADS1299 registers?I'm still a bit confused about the implementation. How is there any advantage or difference between polling at 256 Hz or getting interrupts at 256…
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I'm not understanding the logic of using interrupts, can you explain more on this? Seems to me that it's not a standard interrupts vs. polling argument since you're not polling the status of anything, just requesting the new data when ready for it…
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Anyone have any comments on the following type of cap?You can find this by searching ebay for "eeg cap". They are selling for around $15. They look pretty cheesy, but then again if they work well then it would be well worth it.
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I just came across the ESP8266 SoC WiFi chip. This chip is available on a variety of "WiFi Serial Link" boards now for very cheap (<$5). Looking into this things just seem to get better and better. The firmware is open source and there is a…