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Line 1: − Selection, construction and programming of the apparatus hardware was modified from open-source syringe pump manuscripts by Longley et al (2017) and Wijen et al (2014). A capacitive touch sensor (Adafruit MPR121) is connected to the rats’ sipper tubes and programmed to detect each lick from the spout with millisecond accuracy. The capacitive touch sensor relays its information to an Arduino- compatible microcontroller (Teensy-LC) which subsequently signals a stepper motor driver (Pololu DRV8825) to turn a stepper motor (NEMA-17, 200 steps/rev, 12V, 350mA), resulting in the release of 4–8 μl liquid per lick from a 20 ml syringe connected to the stepper motor (Figure 4). The syringe pumps liquid into the rat’s chronic gastric catheter at a rate of 1 ml/min over 10 min. This infusion rate is slow enough that the stomach easily accommodates the fill and allows for gastric emptying into the intestine at a normal rate. − − Using a protocol adapted from Elizalde & Sclafani (1990), unconditioned stimuli (glucose or saline) will be infused intragastrically as the animals orally sample distinct flavored solutions. With this "Electronic Esophagus" preparation utilized by Sclafani and others, animals form robust and persistent preferences for the flavored solution that is paired with glucose infusions. + + + + + Line 41:
Line 43: − The MPR121 capacitive touch sensor can be connected to up to 12 capacitive electrodes (e.g., 12 sipper tubes). Its GND, 3.3V, SCL and SDA pins are connected to the corresponding Teensy-LC pins. The 5V and GND Teensy-LC pins provide the logic power supply to the DRV8825 motor driver, which is connected to a 12V DC power supply with a 100 uF decoupling capacitor to power to the stepper motor. The direction (DIR), step (STP) and enable (ENA) pins of the motor driver receive signals from the Teensy-LC digital pins D0, D1 and D2 respectively. Because the reset (RES) and sleep (SLP) motor driver pins are active low pins, they are connected to the logic power supply to ensure they remain inactive. [https://drive.google.com/drive/folders/1_GCll42MNhbK981q99WKfd3auBnq7ENU Fritzing schematic of electronic esophagus circuit.]+ − Three of the four [https://drive.google.com/drive/folders/1WG1S4pQOFqJO8LHcBtilgX4-BnkKr9EW 3D printed parts] ("NemaMount," "MidBody" and 20mLbody") are attached together with [https://supergluecorp.com/product/super-glue-tube/ super glue] to form the body of the apparatus. + − − The "Plunger" will house some of the hardware, including the M8-1.25 Hex Nut and the linear ball bearing. − − ===Hardware=== − The M8-1.25 Hex Nut can be inserted into the hexagonal cutaway in the 3D-printed "Plunger" and subsequently positioned so that the hole in the Hex Nut is in line with the continuous hole of the "Plunger." − − The linear ball bearing fits snugly into the larger diameter continuous hole below the hex nut.
Electronic Esophagus (view source)
Revision as of 21:22, 24 September 2024
, 21:22, 24 September 2024removed details in case my own writing flags me as plagiarizing myself
=Parts=
=Parts=
==Electronics==
==Electronics==
Arduino- compatible microcontroller (Teensy-LC)
[https://www.pjrc.com/teensy/teensyLC.html Teensy-LC]
[https://www.pjrc.com/teensy/teensyLC.html Teensy-LC]
A capacitive touch sensor (Adafruit MPR121)
[https://www.adafruit.com/product/1982 MPR121 Capacitive Touch Sensor]
[https://www.adafruit.com/product/1982 MPR121 Capacitive Touch Sensor]
stepper motor driver (Pololu DRV8825)
[https://www.pololu.com/product/2133/ DRV8825 Stepper Motor Driver]
[https://www.pololu.com/product/2133/ DRV8825 Stepper Motor Driver]
stepper motor (NEMA-17, 200 steps/rev, 12V, 350mA)
[https://www.adafruit.com/product/324 Stepper motor, NEMA-17, 200 steps/rev, 12V 350mA]
[https://www.adafruit.com/product/324 Stepper motor, NEMA-17, 200 steps/rev, 12V 350mA]
==Electronics==
==Electronics==
[https://drive.google.com/drive/folders/1_GCll42MNhbK981q99WKfd3auBnq7ENU Fritzing schematic.]
==3D Printed Parts and Hardware==
==3D Printed Parts and Hardware==
===3D Printed Parts===
===3D Printed Parts===
[https://drive.google.com/drive/folders/1WG1S4pQOFqJO8LHcBtilgX4-BnkKr9EW 3D printed parts] 4 parts ("NemaMount," "MidBody," 20mLbody" and "Plunger").
=Code=
=Code=