From early struggles to global success, a startup went from failed prototypes to selling thousands of DIY neuroscience kits worldwide. Sharing his journey of designing bio amplifier sensors to more innovations, Deepak Khatri from Upside Down Labs speaks to EFY’s Nidhi Agarwal.
Q. Can you elaborate on what your company does?
A. We design do-it-yourself (DIY) neuroscience kits for students and researchers to equip them with the tools to create human-computer interfaces (HCI) and brain-computer interfaces (BCI) easily. Our kits enable users to record biopotential signals such as electrocardiogram (ECG) from the heart, electromyogram (EMG) from muscles, electroencephalogram (EEG) from the brain, and electrooculogram (EOG) from the eyes. With open source demo code on GitHub and examples, users can collect data, apply filtering and detection algorithms to develop applications such as controlling a Mario game by blinking or moving a muscle. Additionally, BCI-based games allow users to trigger actions on a PC or control physical devices such as LEDs by focusing on specific elements.
Q. How unique is your DIY neuroscience kit?
A. We are the first and only company in India to provide affordable, open source DIY neuroscience kits, inspired by Backyard Brains in the US, which has been developing similar kits since 2010. We design, manufacture and distribute them. Our kits are largely compatible with theirs and can use their software, though we also have our own software stack called Chords. Everything is built from scratch and fully open source, allowing users to access design files and understand how each component of our DIY neuroscience kits is created.
Also, these are significantly more affordable—at least four to seven times cheaper than those from Backyard Brains or other international companies—while maintaining high reliability, with many research papers published using our sensors. Committed to open science, we provide all designs under an open source licence that requires proper credit to Upside Down Labs when creating anything based on our sensors. The licence details are available in our GitHub repository.
Q. How are electronics used in this?
A. The electronics in each sensor are designed from scratch. Most sensors use a quad operational amplifier, where the first stage consists of a custom-designed instrumentation amplifier. An additional amplifier is used for band-pass filtering, and the fourth amplifier is used for reference power supply generation. This structure forms the core of most bio-amplifier designs. Previously, there was a version called Biomp 1.5 that used a different topology, but the current designs follow this approach with a two-op amp instrumentation amplifier, one-op amp band-pass filter, and one-op amp power supply.
Q. Do you also offer custom solutions besides the DIY and neuroscience kit?
A. We do offer custom technology development services for a range of projects. Whether it is a government-funded university project, a social sensor for biopotential fitness from humans or animals, or even sensors for research on mouse and monkey brain activity, we can help. Our sensors are used in both industry and high-end research, such as prosthetic hand development with companies such as Symbionics and projects at IIT Kanpur, Indiana University, and others.
Q. How is the DIY neuroscience kit different from the other products you offer?
A. Yes, they are similar, but we simplify the process for those who already understand these sensors and want to focus on their experiments or applications. We provide a ready-to-use package that fits directly into their product or setup. For instance, we have a sensor designed for prosthetic hands that captures three-channel data from dry electrodes, sits under the prosthetic hand, interfaces with muscles, and outputs data. It has not been released yet. Users can connect it to any microcontroller or development system, or we provide a full system with the ‘brain’ for the hand, making integration seamless. This system has two sides—one connects to electrodes, and the other to the processing unit, which digitises signals for robotic control.
Students can use our DIY sensors by soldering or assembling them, connecting them to electrodes and development boards, programming them, and viewing signals on a browser or with Python. This hands-on process helps them learn where to place electrodes and how different body signals work. We offer sensors such as BioAmp EXG Pill with a three-pin cable for electrodes and a 2.54mm connector for microcontrollers, the Muscle BioAmp Patchy that attaches directly to the body and connects to Arduino, and the Muscle BioAmp shield, which is an EMG sensor with multiple LEDs, buttons, and ports for linking several sensors to Arduino using cables.
Q. How many products do you have now?
A. We have over seven sensors, multiple accessories, and more products in development. Our key product, called BioAmp EXG Pill, records various bio-potential signals such as ECG, EMG, EOG, and EEG. We also offer EMG sensors of different form factors. To support these, we have shields for connectivity and a range of electrode options, such as gold cup electrodes for EEG, snap electrodes for general use, and alligator clip electrodes for gel-electrode setups.
Our recent innovation, called Neuro Play Ground Lite, integrates the entire solution into an Adafruit feather-form-factor board. This board features six NeoPixel LEDs, three-channel bio-potential signal amplifiers, a user button, a reset button, battery management, USB and patient protection with wireless connectivity such as Wi-Fi, Bluetooth, Zigbee, and Thread. You can expand its capabilities through daughter boards called playmats to include a buzzer for audio feedback, a vibration motor for haptic feedback, a QWIIC connector for I2C, an on/off switch, and an electrode connector interface. The upper and lower boards connect seamlessly, allowing easy control. This is the only board of its kind, offering these features in such a small form factor at an affordable price. It includes built-in battery protection and management, supports USB-C charging and programming, and can be used for ECG/EMG/EOG/EEG data streaming, recording, and processing to create wireless HCI and BCI projects.
Q. Who is buying your products?
A. Actually, our target audience is quite broad. School and college students, researchers, and hobbyists are using our products to explore the field of neuroscience. They are learning how various biopotential signals are generated in the body and how to use them to solve various real-world problems.
We have found that people in design and art, including those in architecture, are using our sensors too. This includes users in both India and France, though they have not shared specific details on their usage. Some architects are using the sensors for their projects, but the exact applications are not clear. Additionally, there are research papers showing the use of our sensors in material science for designing new electrodes and conductive materials. Students are also using them for science fairs and their own research. A company called Incognito Blueprints uses our kits to help students build portfolios with science-based projects, which can improve their chances of getting into Ivy League colleges.
Q. What challenges have you faced in designing these modules and DIY kits?
A. Getting the first design to work was a big challenge. My first attempt at building a biopotential amplifier in 2016 failed. I had to break it down, understand the basics, and test different designs until I made a working circuit from scratch with simple parts such as op-amps, resistors, and capacitors. Manufacturing and scaling were also difficult. In 2018, I learned to design and etch my own PCBs, but turning prototypes into reliable products took more effort. When I launched my Tindie store, Upside Down Labs, there were no sales for around 18 months. Our first customers came in 2020, which motivated me to improve the products and production process.
Refining the BioAmp EXG Pill was another challenge. At first, I thought it could only record EMG signals, but after tweaking the design, I realised it could also record ECG and more. It took time to finalise the PCB, ensure reliability, and get it ready for production. Funding was also a hurdle. During my Google Summer of Code, my mentor, Drew Fustini and his company OSHPark from the US sponsored the first batch of perfect purple PCBs, but later, we had to raise money ourselves. Our crowdfunding campaign on Crowd Supply helped us grow, raising over $30,000 to date and selling more than $100,000 worth of BioAmp EXG Pills.
Q. How many products have you sold, and what is the total revenue?
A. Our products are sold in over 60 countries, with distributors in multiple regions. In the US, they are available on Mouser, Digikey, Amazon, and our Tindie store. They are also sold through Electronics For You Store, Robu, Amazon India, and the Government e-Marketplace (GeM). While the exact revenue cannot be shared, we have sold over 5000 kits alone.
Q. Coming to design, what key factors do you consider when designing a PCB for applications like ECG, EMG, and BCA? Is there any difference?
A. Yes, there is a difference. For introductory or educational soldering practice, we offer EMG sensor kits such as Muscle BioAmp Candy, built around the affordable LM324 (₹10–20), with easily available passive components. The single-sided circuit can be assembled on a breadboard or etched for around ₹200, with a total cost of ₹350 including electrodes and cables. We sell it for ₹499 to cover packaging and shipping, making it the most affordable DIY EMG sensor globally.
However, these kits are not suited for research due to susceptibility to noise from nearby power sources. For high-end devices, we use amplifiers with rail-to-rail input/output, high common-mode rejection, and low input bias current. Our bio amplifier chip features junction field-effect transistor (JFET) inputs, and we are transitioning to a version that supports 3.3V systems. While the TL084H or TL074H offered excellent performance at 5V, they are incompatible with 3.3V microcontrollers. For beginners, we recommend integrated circuits (ICs) with high common-mode rejection, low bias current, and voltage flexibility across 3.3V and 5V systems.
Q. Do you design, manufacture, and handle everything in-house?
A. Yes, everything is done in-house except for PCB manufacturing. We design the layout, including part footprints, and once the layout is ready, we send it to the PCB house. After receiving it, we conduct the first test. If there are issues, we use wires to fix the PCB. Then, we refine the layout, make it more compact, add necessary holes and solder pads, and send it back for another round of testing. Once it is final, we order the PCB panel. Using our in-house pick-and-place machine, we place the parts and start building the panels.
Q. What allows you to maintain performance and quality while keeping costs and size down?
A. In biopotential amplifier design, certain components are non-negotiable. The instrumentation amplifier stage, for instance, requires 0.1 per cent tolerance resistors to ensure high precision, despite their higher cost. The choice of amplifier is equally critical. For other sections of the circuit, standard 1 per cent tolerance resistors are sufficient. PCB quality also plays a vital role. We now use four-layer PCBs in our newer designs, which significantly enhance signal integrity and reduce noise compared to older one- or two-layer boards. These are essential considerations we consistently prioritise.
Q. How do you ensure flexibility and customisation in your biopotential amplifier designs?
A. For the design, we create a biopotential amplifier that can be customised for different uses. We provide a schematic with detailed information, allowing others to change the bill of materials and optimise it for their specific needs. The layout includes a quad op-amp for the instrumentation amplifier and a band-pass filter to isolate the signal of interest (such as EEG, EMG, or EOG).
On the back of the PCB, there are components that can be connected via solder bridges, allowing customisation. For example, users can adjust the gain and bandwidth of the band-pass filter or switch between different electrode configurations. This flexibility allows users to tailor the amplifier to their specific requirements, with some adjustments being possible by just adding solder bridges. When a company needs a custom solution, we design everything from scratch and create a new PCB based on the core design.
Q.What methods do you use to reduce noise and interference in EEG and EMG signals?
A. We use multiple layers of filtering both in hardware and software. On the hardware side, we apply double filtering: first, electrode input conditioning to remove resistor-capacitor (RC) interference, and then an on-board band-pass filter to eliminate alternating current (AC) interference. In software, we apply high-pass and low-pass filters to isolate the desired signal. This triple filtering method effectively reduces most noise. If your laptop is not connected to its charger, the bioimpedance will deliver data comparable to a $1000 competitor’s device.
Q. Do these kits use wireless or wired communication?
A. Most of the DIY neuroscience kits we sell are wired, and we offer strong software support for them. In the past six months, we focused on improving our Chords software, adding more Arduino example sketches, and enhancing documentation. I will show you a software example that works on any Chromium-based browser. We also offer Python support that works across all operating systems, through a website called Chords. This provides information on connecting and using the software. Once connected, you can visualise and interact with the signals. The system supports up to sixteen channels of data plotting, with filtering options for ECG, EEG, and EOG signals, all done directly in your browser. It is a simple setup: plug in the system, open the website, and start using it.
Q. Do you need to follow any standards for your products?
A. Yes, we follow certifications such as Conformité Européenne (CE) and Restriction of Hazardous Substances (ROHS), which include emission certifications. We also focus on patient protection, incorporating resistors and clamping diodes on the input electrode in our hardware. But again, since we are not in the medical domain and do not claim our product as medical, we do not need a medical certification, which is both expensive and time-consuming.
Q. What challenges are you facing in your swift growth as a startup?
A. We are a bootstrapped company, relying on sales to fund our growth and create new products. Currently, there are no major challenges. We are growing well and developing even better products. Our team has expanded from five to nearly 15 people in less than a year, and we are still growing.
Q. Are you about to launch any product?
A. We are all set to launch Neuro Play Ground Lite, which is a multichannel wireless biopotential signal amplifier supporting wireless connectivity options such as Wi-Fi, Bluetooth Low Energy (BLE), Thread, and Zigbee. It is designed for recording EMG, ECG, EOG, and EEG. It will soon launch on Crowd Supply.
Q. What are your plans for growth, and how are you investing in equipment, tools, team, or sales?
A. Currently, our primary focus is on improving software support, and we are expanding our team to achieve that. In the past six months, we have gone from having no custom software for our bio-potential amplifier to offering web application and software support in Python. We are also working on new projects involving wireless technology integration and other innovations. Most of our funding and research and development (R&D) are directed towards enhancing software support, with the remaining resources focused on designing new hardware.
Q. Is there any competition in this field right now?
A. There is no competition in the Indian market right now. One company did try to copy our product, but they shut down in 2024. Outside of India, there is one competition in the DIY Neuroscience domain called Backyard Brains, as I mentioned earlier. Some companies such as Sparkfun, Bitalino, and Olimex offer ECG or EMG sensors, but they focus on robotics and DIY electronics, not specifically on neuroscience.
Q. What are your plans for future?
A. We focus on designing new products and promoting open source technology. We need support in distribution networks and academic institutions for workshops on DIY neuroscience, especially basics. Our products are even used in Kendriya Vidyalayas in Pune, and we expect more schools to adopt them as awareness grows. While support is helpful, I believe it is more effective to share content and let others approach us. Going forward, we will continue launching products and moving forward.
