Reader Device Research Articles

Developments in electronic low vision aids: Assistive technology 3

In the third article in this series, Bill Harvey focuses on electronic reader devices and software and their adaptability for those requiring vision support and then describes some of the ever-growing number of apps aimed at supporting the visually impaired with reading.

A Brief Training Program to Support the Use of a Digital Pill System for Medication Adherence: Pilot Descriptive Study.

BackgroundDigital pill systems (DPSs), which comprise ingestible radiofrequency sensors integrated into a gelatin capsule that overencapsulates a medication, can directly measure ingestion events.ObjectiveTeaching users to operate a DPS is vital to ensure the collection of actionable ingestion and adherence data. In this study, we aim to develop and pilot a training program, grounded in the Technology Acceptance Model, to instruct individuals on DPS operation.MethodsA two-part training program, comprising in-person and text message–based components, was used with HIV-negative men who have sex with men with nonalcohol substance use, who had enrolled in a 90-day pilot demonstration study using the DPS to measure adherence to pre-exposure prophylaxis. We assessed the number of responses to text check-ins, the number and types of episodes where technical support was requested, the resolutions of such issues, and engagement with the program over the study period. Participant feedback on the program was evaluated through qualitative user experience interviews.ResultsA total of 15 participants were enrolled in and completed the program. Seven technical challenges related to DPS operations were reported across 5 participants. Most commonly, participants requested support connecting the wearable Reader device with their smartphone, charging the Reader, and operating the mobile app. A total of 6 issues were resolved asynchronously or in real time via phone; 1 required in-person evaluation and resolution. Preliminary qualitative findings indicate that both the in-person and remote follow-up components of the training program were perceived as acceptable. Suggested improvements included repeated DPS refresher sessions at in-person follow-up visits and enhanced written materials for the independent resolution of technological issues.ConclusionsA brief two-part DPS training program, drawing from individuals’ experiences and from the Technology Acceptance Model, can provide valuable insights for users. The program also identifies and addresses several areas of actual or potential challenges related to operating a DPS and allows for the resolution of such issues within the first week of DPS use.

Rapid point-of-care testing for SARS-CoV-2 virus nucleic acid detection by an isothermal and nonenzymatic Signal amplification system coupled with a lateral flow immunoassay strip.

An outbreak of a new coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), began in December 2019. Accurate, rapid, convenient, and relatively inexpensive diagnostic methods for SARS-CoV-2 infection are important for public health and optimal clinical care. The current gold standard for diagnosing SARS-CoV-2 infection is reverse transcription-polymerase chain reaction (RT-PCR). However, RTPCR assays are designed for use in well-equipped laboratories with sophisticated laboratory infrastructure and highly trained technicians, and are unsuitable for use in under-equipped laboratories and in the field. In this study, we report the development of an accurate, rapid, and easy-to-implement isothermal and nonenzymatic signal amplification system (a catalytic hairpin assembly (CHA) reaction) coupled with a lateral flow immunoassay (LFIA) strip-based detection method that can detect SARSCoV-2 in oropharyngeal swab samples. Our method avoids RNA isolation, PCR amplification, and elaborate result analysis, which typically takes 6–8 h. The entire CHA-LFIA detection method, from nasopharyngeal sampling to obtaining test results, takes less than 90 min. Such methods are simple and require no expensive equipment, only a simple thermostatically controlled water bath and a fluorescence reader device. We validated our method using synthetic oligonucleotides and clinicalsamples from 15 patients with SARS-CoV-2 infection and 15 healthy individuals. Our detection method provides a fast, simple, and sensitive (with a limit of detection (LoD) of 2000 copies/mL) alternative to the SARS-CoV-2 RT-PCR assay, with 100 % positive and negative predictive agreements.

Design and Development Of Lecturer Attendance System Using Radio Frequency Identification (RFID)

Lecturer attendance record is required by the university to know the presence of lecturers in teaching in class. In general condition, lecturer attendance is recorded on the attendance sheet, or input to web application accessed on a class computer. However, there are some problems in its implementation so that at the end, lecturer presence is carried out using a manual form where the academic staff needs to re-enter the lecturer attendance data into the applications. Based on the above, the authors designed and developed a lecturer attendance information system to record lecturers' attendance using radio frequency identification technology by implementing a near field communication card (NFC Card). The device used to record and read presence data during lectures, by tapping an Mi-fare NFC card to an NFC reader / writer device. The flow of this research method begins with a literature study of NFC card, observe the flow of lecture attendance process and data recorded into lecturer attendance sheet, analyzing the database design, the system design which has compatible with NFC reader and writer devices, designed system interface and continue to develop system. The result is system consists of master data, system attendance, verification and reporting module. The results show that NFC card implementation is more practical for lecturers in conducting lecture attendance and NFC card could be tapped out into an NFC device at a maximum distance up to 7 cm with the reading angle relative to NFC reader/writer with range 00 until 300 can read NFC Card.

Long-Term Stability of the Electronic Sensor Component of a Digital Pill System in Real-World Storage Settings.

Background: Digital pill systems comprise an ingestible sensor integrated into a gelatin capsule that overencapsulates medication allowing real-time measures of medication ingestion. These systems may improve the manner in which medication adherence can be assessed and supported. Objective: In this investigation, we tested the durability of the ingestible sensor as part of a clinical trial to measure the feasibility and acceptability of the system to measure adherence to once daily tenofovir disoproxil fumarate/emtricitabine (NCT03842436). Methods: Digital pills not dispensed during the study were stored in a pharmacy. Seventeen sensors were selected from digital pills stored for at least 12 months and activated in a simulated gastric environment. A radiofrequency spectrum analyzer and the reader device used in the clinical trial to capture ingestion events were used to measure activation of emitters. A passing evaluation was defined as an energized emitter within 30 minutes of immersion, ability to broadcast a signal for 10 minutes, and successful acquisition by the reader. Results: All ingestible sensors passed the stability test. Mean activation time in simulated gastric fluid was 3.33 minutes (SD = 1.47); emitters remained active for a mean of 47.72 minutes (SD = 1.78). These parameters matched guidelines defined in the ID-Cap system requirements for use in patients. Conclusions: Ingestible sensor components of the ID-Cap system were therefore stable after long-term storage.

Bioluminescence in G Protein-Coupled Receptors Drug Screening Using Nanoluciferase and Halo-Tag Technology.

Here we describe the stepwise application of bioluminescence resonance energy transfer (BRET)-based conformational receptor biosensors to study GPCR activation in intact cells. This technology can be easily adopted to various plate reader devices and microtiter plate formats. Due to the high sensitivity of these BRET-based receptor biosensors and their ability to quantify simultaneously receptor activation/de-activation kinetics as well as compound efficacy and potency, these optical tools provide the most direct and unbiased approach to monitor GPCR activity in a high-throughput-compatible assay format, representing a novel promising tool for the discovery of potential GPCR therapeutics.

IoT Based Vehicle and License Authentication Device

Technology has become a part of human life with everyday changes and IOT plays a vital role in real life application technologies such as authentication and detection When integrating real life used objects with IOT devices will save time and make things easier and Nowadays carrying documents everywhere we go and identifying legal vehicles has become a problem for everyone so to overcome that problem we use technology to store them virtually so for accessing the data whenever required quickly we use the IOT based Authentication devices. Transmission control protocol and Internet protocol were used to centralize the database of vehicles and users and RFID reader device is used to read the RFID tags which are attached to the vehicle and just by reading the tag the device can detect whether it is a register vehicle or not and a finger print module with buzzer is used to authenticate the user license and all these components are connected to Arduino UNO which is connected to the system through USB This idea helps in saving the time and results in less traffic The mechanism and functionalities of components are discussed in detail in the semina.

Amplification-free detection of SARS-CoV-2 with CRISPR-Cas13a and mobile phone microscopy

The December 2019 outbreak of a novel respiratory virus, SARS-CoV-2, has become an ongoing global pandemic due in part to the challenge of identifying symptomatic, asymptomatic, and pre-symptomatic carriers of the virus. CRISPR diagnostics can augment gold-standard PCR-based testing if they can be made rapid, portable, and accurate. Here, we report the development of an amplification-free CRISPR-Cas13a assay for direct detection of SARS-CoV-2 from nasal swab RNA that can be read with a mobile phone microscope. The assay achieved ∼100 copies/μL sensitivity in under 30 min of measurement time and accurately detected pre-extracted RNA from a set of positive clinical samples in under 5 min. We combined crRNAs targeting SARS-CoV-2 RNA to improve sensitivity and specificity and directly quantified viral load using enzyme kinetics. Integrated with a reader device based on a mobile phone, this assay has the potential to enable rapid, low-cost, point-of-care screening for SARS-CoV-2.

Upconverting nanoparticle reporter\u2013based highly sensitive rapid lateral flow immunoassay for hepatitis B virus surface antigen

Detection of hepatitis B Virus surface antigen (HBsAg) is an established method for diagnosing both acute and chronic hepatitis B virus (HBV) infection. In addition to enzyme immunoassays (EIAs), rapid diagnostic tests (RDTs) are available for the detection of HBsAg in resource-poor settings. However, the available RDTs have inadequate sensitivity and therefore are not suitable for diagnosis of patients with low levels of HBsAg and for blood screening. To provide a high-sensitivity RDT, we developed a lateral flow immunoassay (LFIA) for HBsAg utilizing upconverting nanoparticle (UCNP) reporter. The UCNP-LFIA can use whole blood, serum, or plasma and the results can be read in 30 min using a reader device. When compared with a commercial conventional visually read LFIA, the developed UCNP-LFIA had a Limit of Detection (LoD) of 0.1 IU HBsAg/ml in spiked serum, whereas the LoD of the conventional LFIA was 3.2 IU HBsAg/ml. The developed UCNP-LFIA fulfills the WHO criterion for blood screening (LoD ≤ 0.13 IU HBsAg/ml) in terms of LoD. The UCNP-LFIA and conventional LFIA were evaluated with well-characterized sample panels. The UCNP-LFIA detected 20/24 HBsAg-positive samples within the HBsAg Performance Panel and 8/10 samples within the Mixed Titer Performance Panel, whereas the conventional LFIA detected 8/24 and 4/10 samples in these panels, respectively. The performance of the assays was further evaluated with HBsAg-positive (n = 108) and HBsAg-negative (n = 315) patient samples. In comparison with a central laboratory test, UCNP-LFIA showed 95.4% (95% CI: 89.5–98.5%) sensitivity whereas sensitivity of the conventional LFIA was 87.7% (95%CI: 79.9–93.3%).

Ultrasensitive and Robust Point-of-Care Immunoassay for the Detection of Plasmodium falciparum Malaria.

Plasmodium falciparum malaria is widespread in the tropical and subtropical regions of the world. There is ongoing effort to eliminate malaria from endemic regions, and sensitive point-of-care (POC) diagnostic tests are required to support this effort. However, current POC tests are not sufficiently sensitive to detect P. falciparum in asymptomatic individuals. After extensive optimization, we have developed a highly sensitive and robust POC test for the detection of P. falciparum infection. The test is based on upconverting nanophosphor-based lateral flow (UCNP-LF) immunoassay. The developed UCNP-LF test was validated using whole blood reference panels containing samples at different parasite densities covering eight strains of P. falciparum from different geographical areas. The limit of detection was compared to a WHO-prequalified rapid diagnostic test (RDT). The UCNP-LF achieved a detection limit of 0.2-2 parasites/μL, depending on the strain, which is 50- to 250-fold improvement in analytical sensitivity over the conventional RDTs. The developed UCNP-LF is highly stable even at 40 °C for at least 5 months. The extensively optimized UCNP-LF assay is as simple as the conventional malaria RDTs and requires 5 μL of whole blood as sample. Results can be read after 20 min from sample addition, with a simple photoluminescence reader. In the absence of a reader device at the testing site, the strips after running the test can be transported and read at a central location with access to a reader. We have found that the test and control line signals are stable for at least 10 months after running the test. The UCNP-LF has potential for diagnostic testing of both symptomatic and asymptomatic individuals.

A novel wireless implant for central venous pressure measurement: First animal experience

Background/ObjectiveCentral venous pressure (CVP) serves as a surrogate for right atrial pressure, and thus could potentially predict a wider range of heart failure conditions. The purpose of this work is to assess CVP, through an implantable sensor incorporated with a novel anchor design, in the inferior and superior vena cava of an animal model.MethodsTwo animals (Dorset sheep) were implanted with sensors at 3 different locations: inferior vena cava (IVC), superior vena cava (SVC), and pulmonary artery (PA). Two sensors with distinct anchor designs considering anatomical requirements were used. A standard PA sensor (trade name Cordella) was deployed in the PA and SVC, whereas a sensor with a modified cylindrical anchor with various struts was designed to reside in the IVC. Each implant was calibrated against a Millar catheter reference sensor. The ability of the central venous sensors to detect changes in pressure was evaluated by modifying the fluid volume of the animal.ResultsThe sensors implanted in both sheep were successful, which provided an opportunity to understand the relationship between PA and CVP via simultaneous readings. The mapping and implantation in the IVC took less than 15 minutes. Multiple readings were taken at each implant location using a hand-held reader device under various conditions. CVP recorded in the IVC (6.49 mm Hg) and SVC (6.14 mm Hg) were nearly the same. PA pressure (13–14 mm Hg) measured was higher than CVP, as expected. The SVC waveforms showed clear beats and respiration. Respiration could be seen in the IVC waveforms, but not all beats were easily distinguishable. Both SVC and IVC readings showed increases in pressure (3.7 and 2.7 mm Hg for SVC and IVC, respectively) after fluid overload was induced via extra saline administration.ConclusionIn this work, the feasibility of measuring CVP noninvasively was demonstrated. The established ability of wireless PA pressure sensors to enable prevention of decompensation events weeks ahead can now be explored using central venous versions of such sensors.

Excess body fat increases the accumulation of advanced glycation end products in the skin of patients with type 1 diabetes.

The process of protein glycation described by Brownlee et al. is a crucial pathogenic mechanism in the development of chronic complications of diabetes. To assess advanced glycation end products (AGEs) in the skin of patients with type 1 diabetes (DM1) and excess body fat (EBF) accumulation. The study group consisted of 227 DM1 patients (121 women and 106 men) whose mean age was 31 ±9.2 years; the mean duration of diabetes was 12 ±7.7 years; and the mean HbA1c was 8.9 ±1.8%. The inclusion criteria were as follows: age 18-65 years, DM1, and lack of acute inflammations and uncontrolled chronic diseases. The exclusion criteria were: anemia (hemoglobin (Hb) <11 g/dL), chronic kidney disease (CKD) (glomerular filtration rate (eGFR) <30 mL/min/1.73 m2) and elevated aminotransferase levels (more than twice the upper normal limits). Total adipose tissue content was assessed using the electrical bioimpedance method, with the Tanita BC-418 MA analyzer (Tanita Corp., Tokyo, Japan). The Tanita ViScan AB 140 (Tanita Corp.) was used to evaluate visceral fat tissue (VTF). The content of glycation end products in the skin was assessed using a DiagnOptics AGE Reader device (type 214D00102; DiagnOptics, Groningen, the Netherlands). The group with normal body fat (NBF) consisted of 123 subjects, whereas 104 subjects had EBF. No significant statistical differences were found between the NBF and EBF groups with regard to age, duration of diabetes, current HbA1C value, and tobacco use. A significantly higher AGE score was observed in the EBF group. Increased body fat affects the amount of AGE in the skin, which correlates with a higher risk of developing chronic diabetes complications.

Influence of electromagnetic radiation emitted by daily-use electronic devices on the Eyemate\xae system in-vitro: a feasibility study

BackgroundEyemate® is a system for the continual monitoring of intraocular pressure (IOP), composed of an intraocular sensor, and a hand-held reader device. As the eyemate®-IO sensor communicates with the hand-held reader telemetrically, some patients might fear that the electronic devices that they use on a daily basis might somehow interfere with this communication, leading to unreliable measurements of IOP. In this study, we investigated the effect of electromagnetic radiation produced by a number of everyday electronic devices on the measurements made by an eyemate®-IO sensor in-vitro, in an artificial and controlled environment.MethodsThe eyemate®-IO sensor was suspended in a sterile 0.9% sodium chloride solution and placed in a water bath at 37 °C. The antenna, connected to a laptop for recording the data, was positioned at a fixed distance of 1 cm from the sensor. Approximately 2 hrs of “quasi-continuous” measurements were recorded for the baseline and for a cordless phone, a smart-phone and a laptop. Repeated measures ANOVA was used to compare any possible differences between the baseline and the tested devices.ResultsFor baseline measurements, the sensor maintained a steady-state, resulting in a flat profile at a mean pressure reading of 0.795 ± 0.45 hPa, with no apparent drift. No statistically significant difference (p = 0.332) was found between the fluctuations in the baseline and the tested devices (phone: 0.76 ± 0.41 hPa; cordless: 0.787 ± 0.26 hPa; laptop: 0.775 ± 0.39 hPa).ConclusionIn our in-vitro environment, we found no evidence of signal drifts or fluctuations associated with the tested devices, thus showing a lack of electromagnetic interference with data transmission in the tested frequency ranges.

Portable Low-Cost Fluorescence Reader for LFA Measurements

A portable device for measuring fluorescence signals from a lateral flow test strip was developed. The aim was to build an easy-to-use, affordable reader device for fast, quantitative analysis of point-of-care tests, made mostly of commercial off-the-shelf components. The device is capable of exciting fluorescent labels with 532 nm and 650 nm lasers and collecting the emitted fluorescent light with a camera. Core of the device is a Raspberry Pi Zero W wireless single board computer that controls the Raspberry Pi camera v2 module and lasers. The computer can also perform the image analysis and communicate the results to a mobile phone application acting as a user interface. Sensitivity of the device was characterized by sweeping the imaging parameters and comparing the performance with a high-grade fluorescence reader. Using dummy LFA samples, it was found that the device is able to detect signals from analyte concentrations that are relevant in biological samples. Image exposure time of $500~\mu \text{s}$ was enough to read a distinguishable signal. The manufacturing costs were estimated to be below 100 euros per device in mass production.

Second window near-infrared dosimeter (NIR2D) system for radiation dosimetry

Fiber-coupled scintillation dosimeters are a cost-effective alternative to the conventional ion chambers in radiation dosimetry. However, stem effects from optical fibers such as Cerenkov radiation incur significant errors in the readout signal. Here we introduce a second near-infrared window dosimeter, dubbed as NIR2D, that can potentially be used as real-time radiation detector for clinical megavoltage beams. Lanthanide-based rare-earth NaYF4 nano-phosphors doped with both erbium and cerium elements were synthesized, and a compact 3D printed reader device integrated with a photodetector and data acquisition system was designed. The performance of the NIR2D was tested using a pre-clinical orthovoltage radiation source and a clinical megavoltage radiation source. The system was tested for dose linearity (100, 200, 600 MU), dose rate dependency (100, 200, 400, 600 MU min−1), and energy dependency (6, 10, 15 MV). Test results with the clinical linear accelerator demonstrated excellent dose linearity and dose rate independency when exposed to 6 MV linac beams—both data follows a linear trendline with R2 > 0.99. On the other hand, the NIR2D was energy dependent, where the readout dropped by 9% between 6 and 15 MV. For stem effects, we observed a finite Cerenkov contribution of 1%–3% when exposed between 100–600 MU min−1 (6 MV) and 3%–6% when exposed between 5–15 MV (600 MU min−1). While the stem effects were still observable, we expect that enhancing the current optical setup will simultaneously improve the scintillation signal and reduce the stem effects.

Sensor-based filament fabrication with embedded RFID microchips for 3D printing

Composite filament materials with embedded sensors are increasing in demand to create 3D printed hierarchical sensor structures in a cost-effective and scalable way for the development of wearable and geometry-conforming sensing devices. Traditional methods of encapsulating sensors with polymers are implemented through techniques such as adhesive bonding and potting. For microelectronic device encapsulation, the plastic moulding technologies are employed. However, final products from these methods have geometry constraints and are not easily customizable. This paper presents a methodology of fabrication of polymer filaments embedded with 550-µm radio-frequency identification (RFID) chip using extrusion process for 3D Printing applications. The fabricated filament (3 mm diameter) is manufactured with a 1.5 mm extrusion nozzle specifically designed for this process and controlled by an RFID reader. The RFID sensor filaments produced by this extrusion encapsulation technique were successfully used to produce objects on an existing Fused Deposition Modelling (FDM) 3D printing machine. Such filaments and printed devices are wireless, battery-less, flexible, customizable, and repairable, and hence are advantageous in new sensor applications including the internet of things (IoT). The 3D printed objects produced via this process will have the ability to sense the environment and communicate with reader devices due to their unique embedded RFID codes. This development will subsequently open new avenues for meeting the growth in IoT demands forecast as a pillar of industry 4.0.

Rapid noninvasive detection of bladder cancer using survivin antibody-conjugated gold nanoparticles (GNPs) based on localized surface plasmon resonance (LSPR).

Bladder cancer is diagnosed by the use of several biomarkers, including survivin. This protein has an important role in the cancer progression by controlling the rate of cell apoptosis. Findings show that there is no survivin in normal tissues, whereas the level of survivin expression increases in tumor cells. The purpose of this study was to specify the reactive antibodies to survivin protein as a biomarker to determine the bladder cancer stage with ELISA method and using GNPs conjugated with survivin antibody. The serum and urine samples of patients with bladder cancer were collected among those referred to Sina Hospital, Tehran, Iran. The survivin protein level was measured in the serum and urine by ELISA technique and in the urine by GNPs conjugated with survivin. Based on the results of ELISA, the serum and urinary levels of survivin increased significantly in T3 and T4 stages of the disease (high grades), compared with the healthy individuals. Also, using conjugated GNPs, survivin protein was detected in the urine specimens of patients at all grades (low and high grades). Our findings showed that using the ELISA technique, the increased level of survivin could be identified in high grades of bladder cancer, but using anti-survivin antibody-conjugated GNPs, bladder cancer can be detected in early stages. The applied method was found to be a rapid tool, dependent on visible color changes and colorimetric detection, without any need for reader devices.

PORTABLE HEAT METERING SYSTEM DESIGN

In modern construction practice, more than half of buildings in operation require modernization of thermal insulation. However, in order to select an effective insulation system, it is necessary to know the actual thermal and technical characteristics of structures and parameters of the building internal environment. The paper analyzes methods and equipment for evaluation of the thermal performance of outdoor enclosures. The advantages and disadvantages of the main devices recommended by the regulatory documents for field research are shown. According to the data obtained, a heat engineering complex is developed for conducting field studies of heat and humidity of wall structures and microclimate of building premises. Software improvement together with Arduino reader device allow monitoring both at stationary and non-stationary thermal conditions of external enclosures and indoor climate parameters in field conditions.

Modeling of magnetic thermal noise in stable magnetic sensors

Low-frequency noise is a critical issue in magnetic tunneling read sensors. In this work, a mechanism of low-frequency noise generation due to asymmetric oscillations is analyzed using the Langevin equation applying both biharmonic and approximated skew normal distribution energy potentials. Both models show a high degree of correlation between low-frequency noise and fluctuations of resonance oscillation amplitude only when oscillation asymmetry is present. Furthermore, the low-frequency spectrum approaches a 1/fα profile as asymmetry increases. To investigate the effect of asymmetry in magnetic read sensors, a macrospin model was developed and validated by comparison with a full micromagnetic simulation. This macrospin model was used to study low-frequency noise by introducing asymmetry via shape anisotropy of the reader. The presence of this effect of low-frequency noise generation in reader devices is confirmed with this model, and its effect with varying temperature and damping constant is investigated.

Attitudes and Response to a Smartphone-Based Digital Pill Intervention to Enhance PrEP Adherence Among Men Who Have Sex With Men With Stimulant Use

Background Digital pills contain a radiofrequency emitter and gelatin capsule that over-encapsulate a study medication. The radiofrequency emitter, activated by the chloride ion gradient in the stomach, transmits a signal to a wearable Reader device following ingestion. The Reader relays ingestion data to a smartphone app and cloud-based server, allowing for real-time verification of ingestion events and adherence measurement. Digitized pre-exposure prophylaxis (PrEP) may improve outcomes in populations with suboptimal adherence related to substance use. Stimulant use is particularly prevalent among men who have sex with men (MSM) and is associated with increased HIV risk behavior and transmission. We conducted seven focus groups with MSM who use stimulants (N=16) to inform the development of PrEPsteps, a novel smartphone-based adherence intervention respondent to data from digitized PrEP and designed to augment adherence. Objective To inform the specification of the design, content, and delivery of the smartphone-based PrEPsteps adherence system via focus groups with HIV-negative MSM who use stimulants. Methods Seven focus groups were conducted with HIV-negative MSM reporting stimulant use (eg, cocaine, methamphetamine) in the past six months. Participants self-reported medical history, substance use and sexual activity. Focus groups explored responses to digital pill technology, willingness and barriers to use, content and timing of adherence messaging, and three intervention components: (1) abbreviated cognitive behavioral therapy (CBT) adherence counseling (LifeSteps); (2) contingent reinforcement/corrective feedback; and (3) substance use-related Screening, Brief Intervention and Referral to Treatment (SBIRT). Focus groups were transcribed and analyzed using applied thematic analysis. Results Sixteen individuals participated in focus groups. All were male; age ranged from 24 to 63 (mean 39.9, SD 14.1) and most self-identified as gay (N=13). Participants were primarily non-Hispanic or Latino (N=12); 10 identified as white, two as black, and four as multiracial. Most had at least a college degree (N=14). Twelve participants were taking PrEP, 5 of whom reported missed doses in the past two weeks. Number of sexual partners in the past three months ranged from 1 to 200 (M=28.1; SD=50.9). Fifteen participants reported using stimulants during the last 30 days. Participants viewed digital pills as a tool to enhance PrEP adherence and accountability. They expressed a willingness to use the digital pill and identified physicians, family members, and partners as people with whom they would share adherence data. The Reader was viewed as the most difficult technological component to use, although participants also described the device as itself an adherence reminder. Participants identified customizability as a valuable aspect of the technology; message and reminder content, structure, and scheduling were all considered customizable. With regard to the intervention, participants were accepting of and willing to interact with corrective feedback messages linked to a brief CBT LifeSteps booster session. Conclusions PrEPsteps, a smartphone-based adherence intervention, was viewed as acceptable by HIV-negative MSM who use stimulants. Individuals perceived corrective feedback notifications to be the most helpful component of the system, and expressed a strong preference for customizability across the intervention.