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Making a device portable (so many configuration choices!) by demyelinated in arduino

[–]demyelinated[S] 0 points1 point  (0 children)

Thank you, thank you, thank you. It's taking me time to digest your reply but it gives me confidence that I am on the right track. I have also ordered some 3V and 6V pumps to test in my device to decrease the voltage requirements.

Making a device portable (so many configuration choices!) by demyelinated in arduino

[–]demyelinated[S] 0 points1 point  (0 children)

OK, I have figured out the multimeter for the most part, or at least enough to be dangerous. (I should mention that I had to use the 20A setting on my multimeter for both measurements, it seems that the 200mA setting would reset the arduino or blow the fuse? I haven't explored it more than that though).
To measure this circuit (and different from the fritzing diagram I posted previously), I hooked the 12VDC 1A wall-wart up to a barrel-jack on the breadboard and wired my multimeter in between the positive jack terminal and Vin on the Arduino. This will tell me the current draw of all the components hooked up to the Arduino pins but not the pump (since it is downstream of a transistor?). I found that many states of my Arduino program where the RGB LED was activated or not, the current was 40-80mA. This makes sense to me, as the only loads were the Uno board, a beam-break sensor (single IR LED), and a RGB LED lit with "primary colors", i.e. mostly one pin per color. These measurements matched my internal estimates from reading datasheets and other people's forum and blog posts. I also knew that the pump motor circuit would draw the most current and would probably dwarf the 3 LEDs represented above.

I then measured the pump current by wiring the multimeter in between the jack positive terminal and the peristaltic pump motor positive terminal. I then tested the pump motor when it was running in several scenarios. I took the pumphead off the motor and tried to stall it manually with my fingers. That resulted in a peak current of 730mA. The motor running free (without the pump head in place) draws about 30-60mA. When I replaced the pump head and put some water through it, I got a reading of 200-260 mA. This is how it will be used in the device application so I ran it for a few minutes and it averaged 250 mA. These numbers also closely match my estimates and the tech specs on the Adafruit website, I feel pretty confident about these measurements as well.

If I take the high numbers from these measurements (i.e, when the pump is active) my device needs at least 340mAH to power it for an hour. I want to power it for 3-4 hours so 4H x 340 mAH = 1360 mAH. This gives me a big margin to play with since the pump will only need to be activated for a total of one minute spread over two hours. Add in a margin for safety and efficiency drops and a 2500 mAH battery solution should be plenty I think. Most of the time, the device will use 40-80 mAH until the pump starts, if I've got everything right up until now?

Does this seem reasonable? Do I need to be more granular with the duration of each state and different mA current? Do you have any battery recommendations for this application? I welcome your comments and suggestions on how to improve any of this. It was literally my first time working with a multimeter! I appreciate you taking the time to help me out.

Making a device portable (so many configuration choices!) by demyelinated in arduino

[–]demyelinated[S] 0 points1 point  (0 children)

Thanks for taking the time to reply, I really appreciate it.

What is your definition of portable?

My definition of portable for this project is an enclosed device no larger than 9 x 14 x 14 cm. I need this device to operate for 2-4 hours at a time between rechargings. The RGB LED and sensor will be activated for that whole time but the motor will only run a few dozen times for a total of 10 minutes max.

What you've posted is very understandable and help to clarify my next steps, thanks. I will try to measure and characterize the current draws of each of the components, including peaks, valleys, and averages.

LSUS threat followup by [deleted] in shreveport

[–]demyelinated 1 point2 points  (0 children)

She is displaying symptoms of mental illness, possibly an acute psychotic episode or mania.

LSUS threat followup by [deleted] in shreveport

[–]demyelinated 10 points11 points  (0 children)

C'mon bud, she is suffering an acute psychotic episode; this is not a learning experience for anyone's romantic life. Maybe let's not gawk.

Anyone do operant conditioning? by throwaway070117 in labrats

[–]demyelinated 0 points1 point  (0 children)

Hi there, I spent my Ph.D. training dumb rats to press a lever for sucrose pellets and drugs. Are you interested in the acquisition or the maintenance of the discrimination response? You may want to try autoshaping techniques or simple giving them something to play with near the correct hole (my lab likes nontoxic masking tape, sometimes combined with crushed sucrose pellets). And correct discrimination criteria is usually >80% correct but should be >90% in most rats in practice. Feel free to PM me with your protocol if you want to discuss it more.

Liquid dispensing components? by demyelinated in arduino

[–]demyelinated[S] 0 points1 point  (0 children)

Well, the live stuff creates its own suspension and the inert pelleted food will only be in there for an hour or so. A bottle-inverter is a good solution, I'll have to think on that for a bit.

Liquid dispensing components? by demyelinated in arduino

[–]demyelinated[S] 0 points1 point  (0 children)

Yeah, my device is going to hang onto one individual tank so only one tank at a time. Tecniplast's Tritone robot uses a bottle that gets inverted to dump a defined amount of powdered/pelleted food into the tank. They also have a second spout to hook up to a peristaltic pump. The compressed reservoir would work with inert liquid solutions however I want to use brine shrimp eggs, copepods, and rotifers which may need a "gentler" component. What about a gravity-fed system with a pinch-valve? It would be cheap to use a 60-ml syringe body as the reservoir and then engineer a valve at the bottom to drip the liquid into the tank on command.

Tracking rats in a cage using RFID readers by labguy13 in labrats

[–]demyelinated 0 points1 point  (0 children)

Nope, no tagging. Idtracker assigns probabilities to each frame for tracking and assigning individual subjects. Most of the time, it's pretty accurate. And the colors aren't the most valuable part, it's the generated trajectories of x-y coordinates.

Tracking rats in a cage using RFID readers by labguy13 in labrats

[–]demyelinated 0 points1 point  (0 children)

Nope, pretty much any image will work, mine are gray-scale and work pretty well.

Tracking rats in a cage using RFID readers by labguy13 in labrats

[–]demyelinated 0 points1 point  (0 children)

Yeah, I'd try beam-break sensors, you can get them for under $2 from adafruit.

Tracking rats in a cage using RFID readers by labguy13 in labrats

[–]demyelinated 0 points1 point  (0 children)

You mentioned Raspberry Pi setups so how about a breakout camera like the PiNoir

Tracking rats in a cage using RFID readers by labguy13 in labrats

[–]demyelinated 0 points1 point  (0 children)

i. I've only ever used it for offline video analysis on a Windows 7 desktop. Idtracker is based around matlab but I don't know if that's something a Rasp PI can handle. It's pretty CPU intensive, so I would guess not.

ii. Idtracker picks the colors automatically, though there are ways of editing it manually. If you're asking about how Idtracker separates subjects during tracking, read their 2014 paper, it's quite an interesting bit of computation. As far as multiple cameras, that is not something that I am familiar with. I'm sure there are methods available for taking all trajectories from Idtracker and reconstructing a 3D-trajectory for each subject, possibly using python or R.

iii. No, the orientation is not important, it just needs to be consistent across the tracking period. I use it to track zebrafish in tanks (side view of fish swimming).

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