How to go from Hardware Idea to Minimum Viable Product
We live in an age where a good idea is worth a fortune. Globalisation has made it much easier for people to bring their ideas to market successfully. The transition to a truly integrated global market gathered steam in the early 90’s. The liberalization of trade policy and growth of the internet both accelerated the flow of information, ideas and capital. In short, the phenomenon of globalisation has fostered a super efficient electronics marketplace.
Industry research methods have also evolved. Easy access to information and service providers have made entrepreneurship a more viable path to financial security. The explosive propagation of the Internet of things in recent times has fueled appetite for microcontroller technology and sensor miniaturization from hardware entrepreneurs.
A new hardware idea must be tested for feasibility before the development of an MVP (minimum viable product) commences. An MVP is a product with just enough features to validate the idea and gather user feedback in order to optimize the prototype development cycle. Collecting feedback via the MVP is less expensive and time consuming than developing a fuller product with more features.
The process of preparing an MVP is outlined below.
Philosophy of Minimum Viable Product (MVP)
The most receptive ideas today in the IT world are based on WiFi and cellular communication technology. As an example, let’s say your product idea is a “honeybee scale” that measures the weight of honey that bees produce in a hive each day and you want to be notified about this information on your phone thrice day at 9am, 3pm and 9pm.
Additionally, you also decide you want the following features embedded into your scale:
- rain sensor
- temperature sensor
- humidity sensor
- mini solar panels for battery charging
A rain sensor helps the beekeeper manage his/her beehive farm more efficiently since honey production is adversely affected by rainfall. Relocating the hives is one such decision the beekeeper can choose to make through regular rainfall tracking. Another pertinent factor that influences honey production is beehive temperature. Temperatures lower than 32°C or above 37°C are deadly for bees inside the beehive. A temperature sensor with programmed alerts is a vital tool for the beekeeper to make timely management decisions. For bees, humidity during the winter is more dangerous than the cold. Therefore it is essential for beekeepers to measure beehive humidity frequently to ensure their bees are healthy to survive the winter. An embedded humidity sensor with programmable alerts addresses this issue. Furthermore, a GPS sensor can be embedded in order to track the hive location. Finally, the scale requires a battery to power all these features, one that ideally charges itself through solar energy. These are all useful features that a beekeeper could embed into his/her honeybee scale.
But what if we later determine that these additional features aren’t required at all once the product hits the market? That could be a costly exercise that greatly affects the commercial viability of the product. This is why it is recommended to adopt an MVP method. In this case it’s a simple honeybee scale. While using the scale users will provide their own feedback about which features provide the optimal solutions for their needs.
So let’s start with this basic set of features for our MVP honeybee scale:
- weighing scale
- time set
- sending message
This is a clear example of an MVP. The prototype has just enough features that the beekeeper needs.
Minimum Viable Product (MVP)
From The Idea to The System Design
Embedded systems are everywhere around us today – you can find them in almost any building, car or electronics device. Therefore, the scope for innovation of the next big IoT tech product, gadget, smart home security device or smart medical device is vast. Now the MVP outline is in place, a hardware engineer has to design the system. What does this mean? The engineer will decide on the vital components for the device: micro controllers, communication modules, sensors, actuators, indicators, etc.
First off all, it is essential for the entrepreneur to relay to the engineer both the type and quality of connectivity available in the target geography where MVP will be used. In many cases, it boils down to deciding between GSM and/or WIFI. Let’s assume that our MVP users are not covered by WIFI signal but do have cellular connectivity. In this case, the user will be notified by SMS on his/her mobile phone. We now have a list of vital components for our honeybee scale MVP:
- Cellular modem module
- RTC module
- Lipo battery
- Load cell
- Passive components
Breadboard prototyping and software development
After the vital components are sourced for the system design, we place them on a breadboard and test the connections and functionality between the individual components. Simultaneously we commence the software design – in this case we only need to write microcontroller firmware. Some devices are accompanied by a mobile app or send the data to a cloud based terminal. In these cases software architecture is developed for the entire system. A simple state diagram maps the software logic for the device and is the basis for firmware development. After the state diagram is completed and the breadboard prototype is ready, we start the development of individual device functions: communication with the GSM module, communication with the RTC, reading data from the instrumentation amplifier for the load cell, etc. When all functionalities have been developed and thoroughly tested, we implement the main function of the device using previously developed functions for communication with other parts of the system. This method of prototyping enables us to develop robust firmware through a process of continuous testing and make design adjustments at any stage if required.
From breadboard prototype to the PCB design
You might ask yourself why we would design a PCB if the device is working just fine with the modules placed onto a breadboard. A breadboard circuit is typically used by engineers for validating a product concept and to get the rough idea of the final device. If the honeybee scale was put together using modules and wires, the quality and functionality of the device would be compromised. There are other issues as well. For example, 3D design for the casing would be very complex and expensive because of the surface area that modules and wires require relative to a PCB. Breadboard devices also have a low probability of obtaining certification for EMI (Electromagnetic interference). We mentioned this topic in the last blog Give form to your idea. To summarise, this method isn’t cost-effective when you want to produce limited quantities of electronics devices.
The first step in PCB development is electrical schematic drawing. We can start the PCB design once the schematic is complete. The schematic must take into account the arrangement of the PCB components
PCB design in progress
Today’s CAD software has the ability to simultaneously add components to a PCB design whilst drawing the schematic. The arrangement of components on the PCB depends on several factors. The first step is often deciding on the shape and size of the PCB. In some cases, the design of a casing dictates how a PCB will be designed. Next, we address the arrangement of components on the PCB.
Some electronics devices consist of a power supply circuit, a microcontroller with its components and an analog section of the circuit for signal conditioning. If we want the microcontroller to process the signal that is received from the weight sensor (load cell), it is necessary to prepare the signal properly so that the microcontroller can do the processing. In this case we need a suitable signal amplifying with a high degree noise reduction.
The next step thus entails forming component groups on the board depending on the functionality each group has.
- First group includes components that form the power supply circuit
- Second group includes components that form the circuit for signal processing
- Third group includes microcontroller and additional active and passive components
After we form these groups, it’s time to position the groups on the PCB. There are several parameters that determine the arrangement of the groups. Let’s take the temperature parameter for example. We know that the power supply circuit releases more heat than other system parts so we’ll position the power supply circuit in such a way that the temperature has minimal influence on temperature readings.
The temperature parameter is just one of the many parameters that impacts the positioning of component groups. When we’re done with the positioning of the groups, we route the components from each of the groups, paying close attention to the thickness, shape and length of these routes. The thickness, shape and the length of these routes is dictated by the electrical parameters and the parameters required by the plant where PCB production will take place. The parameters required by the factory are referred to as PCB design rules. These include:
- The minimum width of the laces
- The minimum and maximum size of the hole
- The minimum font size for the silk screen
- The minimum distance between the two routes etc.
Additionally, we optimize the general look of the PCB.
- Correcting the position of the elements
- Correcting the position of the element’s name
- Shortening routes, where possible,
- Logo placement, the drawings, the name of the designers, company’s name, etc.
Once the PCB is designed, we review the design in detail to scan and eliminate errors before generating Gerber files which will be sent to the PCB manufacturer.
After the PCB is manufactured, we assemble the discrete electronic components.
First, we prepare the discrete electronic components that correspond to the functions of the modules in the breadboard prototype. After the preparations are done, it is time to warm a solder iron and start the soldering of each component on the PCB.
After the board is assembled, we program the device with system logic. The firmware instructs the PCB to send an SMS conveying weight units three times a day at a defined precise time interval. In the future, we can select more use cases for the program. For example, we could choose a feature that would send an SMS with weight status when we dial the honeybee scale. So far, we have two options, but remember for now so we will use only basic program. The SMS timing feature will be powered by an RTC module optimized for discrete electronic components. After the device is programmed, we will test PCB several times to determined if the PCB design works correctly.
When we determined that the device works properly, we will move on to mechanical design of the honeybee scale.
Honeybee Digital Scale – PCB design
Design of mechanical parts includes
- The design of the casing for the electronics
- The design of the stand on which the Beehive is placed
For the first prototype of the casing we will use a casing box sourced from a hardware shop because it is a far cheaper alternative to 3D printing. For designing the stand, we can use a steel material but it is heavy for carrying and manipulation so in this case it is better to use an aluminium stand. Both materials have advantages and disadvantages. Aluminium is lighter than steel but it is more expensive than steel. So for the first mechanical design prototype we will package the electronics into box casing and the stand for the beehive will be designed to be made out of steel.
Ok, we got our first prototype of the beehive scale. After the scales have been placed on the apiary, it’s time to start the process of evaluation of the device and to get our first feedback from our beekeepers.
Honeybee Digital Scale – MVP
We just got our Minimum Viable Product
Overall, the MVP method is great for evaluating the feasibility of a product on the market at the early stages and is very popular today. With an MVP you can collect enough hard and soft data to evaluate and learn about your product and iterate the development in the direction that potential consumers want. Gathering insights with your MVP is far less expensive than developing a fully-fledged device with a bunch of features that may be eventually rendered redundant. Think big but start small.