Spring (Europe)


Established in the 1960s, under the name Crow Electro Instruments, the company has been supplying British industry with quality transformers, wound components, wired assemblies, PCBs, cables, and test services for nearly fifty years.

In 2004, the core business was expanded to include design services. Over the next seven years, the company found its niche developing and then manufacturing a diverse range of products for a diverse range of customers, whilst continuing to offer its long-established services. At the same time, we developed the first of our own products, the very successful pump controller for the window cleaning industry.

In 2011,  To reflect the positive changes and direction we added the brand Spring (Europe) to reflect the changes that had taken place – to acknowledge that the company now was very different to what it had been back in 2004. The name was chosen for its positive connotations and range of meanings, ie new growth, a coil, a source of water. All of these are pertinent to our business and thus, the name Spring is a simple, elegant way of linking them all together.

This was quickly followed by a move to larger premises the extra space was much needed to allow the continuing growth of the business. Our focus as ever is to offer quality products and strive to meet and exceed our customers expectations.

Now the intention is to grow both arms of the business – the manufacturing of both our own and customers’ products under the name of Spring (Europe), and the design side under the name of Professional Applications. Giving each arm its own identity will help us focus on the needs of each more effectively whilst still allowing flexibility across both disciplines.

In other words, whether you come to us via Spring (Europe) or Professional Applications you will find the same thing: an experienced labour force and an expert design team who can cover the spectrum from simple assembly to turnkey projects. Our engineers will work to your exacting requirements, whatever your industry, quality systems, timescale or budget, basing our design process on your needs to produce a best of breed solution for your industry.


Contract Electronics Manufacture

We are able to offer all forms of electronic equipment manufacture, from components and sub-assemblies, to PCBs (both through hole and surface mount) and complete products, packaged and shipped to the customer. Above all, we pride ourselves on the quality of what we make and the support we give our customers.

Contract Electronics Manufacture

Electronic Design

Our design team can work with you on every aspect of your electronic design requirements. We have experience in analogue and digital PCB design, as well as small embedded firmware up to back end online servers. We also have expertise in UI and UX design in both embedded and PC applications.

Whether you need a blinking LED or a remotely operated, encrypted, world-spanning control system we can help.

Electronic Design

Product Design

We can guide you through the entire process of product development from idea to finished product. We will work with you to capture all the requirements and offer solutions on every aspect, from electronic hardware to injection moulded enclosure and packaging. Each step follows a tried and tested process, to ensure you get the product you want.

Product Design

Touch Screen Systems

When designing the cTouch 2, Spring had to design a product from scratch that would fit in with today's high-end consumer electronics. This product showcases our ability to work on every aspect of electronic product design, from custom PCB and firmware to custom enclosures and high-end graphical Uis.

The product has many advanced features: UPS (uninterrupted power supply) built in, ethernet, 10 inch TFT colour touch screen display with SBC (single board computer) to provide rich, fluid UI. We also provide an online update system accessible from the UI or via the web interface.


It was very important from the beginning that this device should blend in with other high-end consumer devices. With this design criteria in mind it was obvious we would require a custom enclosure, but with projected sales making this a low volume product, it was always going to be difficult. The final solution was to use a sheet folding process involving CNC routing and forming. The shape and fit were all designed in-house in CAD. Going for a forming process instead of injection moulding allowed us to reduce tooling costs and supply a full custom enclosure for a low volume product.

The touch screen panel is securely mounted in the lid along with the LCD. these two parts are bonded together to ensure there is no calibration drift over time.

To make mounting the unit simple, we included mounting holes for the 75mm VESA standard. We supply the unit with a stand of our own design. The stand is manufactured from 4mm steel, laser cut and formed, then powder coated.

Custom Electronics

Using an SBC is a sensible choice when dealing with large scale graphical displays. By utilising off the shelf components, you can save design time and speed up the time to market. However, the downside is that the physical shape or specification of the SBC may be changed midway through your production run. This can and will happen so we are always ready with alternatives. The second problem is that they will never have all the features you require, so it is sensible to incorporate an additional custom board. In this product, it takes the shape of a small PIC based circuit that talks to the SBC via serial (UART). This provides important features that the SBC lacks, each feature represents both hardware and firmware design.

1. RS485:  we use this to interface to various control networks and is an industry standard for controlling equipment.

2. Voltage regulation: for the SBC we take 12V (external PSU) down to 5V using an internal switch-mode supply. Designing switch mode regulators are more difficult than linear regulators, but achieving 90% efficiency and low heat operation is not possible with linear regulator designs.

3. UPS: once a power fail (loss of external PSU) is detected, we can switch over to the internal lithium battery. This will hold up the SBC for around two minutes, allowing the unit to wait to see if the power returns, or to perform an orderly shutdown.

4. RTC (real time clock): the SBC does not have a battery-backed clock on board, so this is important to set the clock time when no network connection is present.

5. LED notification: a small window at the bottom of the unit allows us to light up a row of RGB LEDs, giving another dimension of user notification.

Graphical UI

To stand out in the world of consumer touch electronics, considerable design time must be spent on the user interface. It has to be easy to use, intuitive and engaging. Using the Qt graphical library we were able to jump straight into designing and implementing the UI. All graphics were designed in-house using vector formats to support any resolution. The UI code was written in Javascript and QML while the back end code was written in C++. As the base OS is Linux, interfaces between the server code and OS were written using script files, to allow us to migrate the OS with minimal effort.

Web Inteface

Using a web interface to configure the unit facilitates remote configuration as well as allowing the users to download and upload configuration files from a computer.


Units can talk to each other using an SSL encrypted link, to provide remote control and status monitoring. As this feature uses standard internet technology, the remote unit can be in the room next door, or halfway around the world.

Touch Screen Systems

Earth Fault Indicator

The Earth Fault Indicator is a successful design that has been in production for a number of years. However, production processes have moved on and the original design was due for a comprehensive update. Primary objectives for the new design were:

1. Convert the through hole component design to a modern surface mount design. This significantly reduced costs, and production times by minimising labour

2. Change the design to fit in with a new range of Earth Fault Indicators that utilise a common PCB shape and common enclosure. This standardised the enclosures used and simplified the production process.

3. Modify the design to reduce the production test times. This was achieved by moving to a new type of connector that dramatically reduced test times by around 70%.

4. Use more cost effective components wherever possible to reduce the unit cost.

5. Simplify the design to reduce construction times and improve the ease of assembly. This was achieved by removing externally mounted switches and replacing them with internally mounted and yet still externally operated switches of a membrane type design.

6. Port the existing software from an older, expensive microcontroller that may become difficult to obtain in the future to a newer, readily available microcontroller that should be supported well into the future.

The end product is much easier to make and consequentally the price to the customer has been dramatically reduced.


Fusing your Pump Controller

Why is fitting a fuse important

A fuse(s) is needed in any electrical system (AC or DC). These protection devices react to the amount of heat being produced by electricity passing through wires and/or components. They are used so as to protect wires and components from the extreme heat produced should there be an electrical overload or short circuit.

When a short or overload occurs, the amps being drawn spike and this increases the heat produced in the wiring and components. When this occurs, a fuse or circuit breaker reacts almost instantly to stop the flow of electricity in the circuit and thereby stopping heat production.

You should never exceed the fuse rating advised by the manufacturer. For a fuse to open in a fault condition almost instantly (a few hundred milliseconds ) it can require a current of 2.2 to 3 times the rating of the fuse. We recommend 7.5 amp fuses so the actual current to open the fuse may be as high as 22.5 amps overrating the fuse is dangerous.

In very rare cases if a current is only slightly above or close to the rating of the fuse for prolonged periods there is not sufficient heat or current to blow the fuse, in this case, the heat can build up and cause the fuse to melt.

For example, a 15 amp fuse will happily supply current up to 15 amps but will not blow. (to blow it could require current of up to 45 amps) The fuse will however gradually get hot over time in testing at Spring I have seen a 7.5 amp fuse heat to 62C and not blow

Without PROPERLY-SIZED FUSES, this quick break in the circuit would not be possible, and damage to components and even FIRE could result.

If you are having a problem with fuses "blowing" please know that these devices are doing their job! It is important that you NOT replace a fuse or breaker with a higher-rated one. Check the circuit for shorts or overloads.

Damaged, rusted or worn connectors
Damaged cable
Bare cables touching
Poor connection (example would be insulation not stripped back)

Why then place the fuse close to the battery?

To reduce the risk of overheating in either the cable or device in the event of an electrical fault. The shorter distance current can travel between the battery and fuse means that the amount of cable that may get overheated is reduced to a minimum. For Example, It is possible the insulation on the red (positive) cable can become chaffed allowing the core or poorly installed cable to come into contact with the chassis creating a fault condition. Without a fuse fitted close to the battery, the wire will heat to red hot, burn off all the insulation and potentially cause a fire. Fitting a fuse close to the battery protects the cable run plus control and pump.

We recommend fitting cable into a conduit to provide double protection

It is the same with electrical goods, for example, you go out a buy a new Laptop or TV, the unit is supplied with a fused power lead. The Fuse is in the plug so it is close as physically possible to the power source in the case the wall socket. In both cases, the fuse is as close to the power source as possible to reduce the risk of
overheating and fire.

What then is the difference between DC (direct current) and AC (alternating current)?

A short history lesson most people know that Thomas Edison is the man credited with marketing Direct current power to the masses, However, what is less known is that his associate Nikola Tesla (https://en.wikipedia.org/wiki/Nikola_Tesla).

Tesla disagreed with the principle of large-scale DC as it requires every property to have its own generation plant. Tesler proposed AC was much more efficient as large stand-alone generation facilities could be built and the power could be transferred over long distances easily. Tesler, in fact, is responsible for the way power in
generated and transferred to this day.

Batteries, Fuel cells and solar cells all produce something called direct current (DC). The positive and negative terminals of a battery are always, respectively, positive and negative. Current always flows in the same direction between those two terminals. On the other hand, the power that comes from a power plant is called alternating current (AC). The direction of the current reverses, or alternates, 60 times per second (in the U.S.) or 50 times per second (in Europe, for example). The power that is available at a wall socket in the
United States is 120-volt, 60-cycle AC power.

The term positive terminal describes which of the two connection terminals on direct current (DC) equipment supplies or is meant to receive a positive electrical charge. DC power supplies always feature a positive to negative electron and always have a negative and positive terminal. Most DC appliances or machines also have a positive and negative terminal which should always be connected to terminals of same orientation on the power supply. Failure to do so can cause severe damage to the equipment and power supply. This positive/negative relationship is commonly known as the polarity of a supply or device.

Any source of direct current electrical power flows from a positive source to a negative source. This applies to the DC side of rectified power supplies, batteries, and Solar panel outputs. Each of these DC power sources features a positive terminal and a negative terminal. The permanent relationship between positive and negative
sides of DC power supplies is referred to as the polarity of the supply.

The universal colour code and symbol for a positive terminal is red and a plus (+) sign. The colour code and symbol for a negative terminal is black and a minus (-) sign. The polarity relationship, colour codes, and symbols for positive and negative terminals are also used on the devices powered by DC power supplies. The connection terminals on DC power supplies and devices will always be marked with one or both of these identifiers. When connecting DC devices to a power supply, it is crucial to observe the correct polarity. In other words, the positive terminals of the supply and device should be connected to each other with the same applying to the negative terminals.

In effect, the current can only travel in one direction around the circuit. Think of it as a one-way valve if you try to force the current the wrong way through the valve it will break and fail.

Our controls have a reverse polarity diode so in the event of reverse polarity the diode will blow, however, without a fuse the current can still flow onto the PCB Processor and pump drive stage causing further damage to the controller.

Fitting a fuse even in the event of reverse polarity will provide additional protection even as the current passes the wrong way around the circuit with the fuse now on the output part of the circuit it will still blow preventing further damage to the processor and pump drive stage as described above. The circuit is broken and current is no longer able to flow.

Please always be aware of Correct polarity when connecting your controller and please always ensure the correct rated fuse is fitted.

High current pump controller for soft washing

V11 High Current 

The V11 High Current (V11HC) is a more powerful pump controller designed for controlling pumps up to 30A. The V11HC is ideal for:

  • Solar panel cleaning systems
  • Soft washing pumps
  • Higher flowrate pump control
  • Soap or chemical injection control
  • Control of 1, 2 or 3 pump systems

The V11HC offers high power pump control, all of the features of our standard V11 Digital pump control and in addition can provide:

  • Flow control (0-99) of delivery pumps (up to  12V, 30A)
  • Booster pump control (12V, 30A)
  • Soap injection pump control (12V, 8A)
  • Remote Soap injection control
  • Flowmeter reading and display
  • Control up to 5 solenoid valves
  • Read upto 4 level switches

The V11HC is available as a very simple unit or can be configured to control up to three pumps (delivery, booster and soap injection pumps). The unit can be supplied with software configured for your application.

Standard features include:

  • Easy to use and simple to install
  • Copes easily with demanding daily use
  • Extends life of resin cartridges
  • Controls water flow accurately (0-99) and dependably
  • Advanced micro Dead End detection and retesting
  • Accurate battery voltage testing
  • Low battery cut off override function
  • Unit is sealed to IP65, stopping water ingress
  • Autofill RO ability (optional)
  • Charging ability (optional)
  • TDS display and control (optional)
  • Radio control (optional)
  • Hot water system control (optional)

Malibu Window cleaner makes use of V11 High Current controllers for two man system

windowcleaningmagazine Malibu Window Cleaner 

V11_High_Current - Data Sheet

High current pump controller for soft washing

110V - 220V AC pump controllers

V11M BPC 90-230Vac

The V11M BPC is the mains powered V11 unit, which can be used for mains booster pump control. This controller has a number great features as standard:

  • Provides simple RO system control
  • Controls your mains booster pump
  • Fills your tank automatically
  • Easy to use and simple to install
  • Copes easily with demanding daily use
  • Controls water production accurately and dependably
  • Unit is sealed to IP65, stopping water ingress

The unit is available as a simple mains powered RO controller to open a filling valve and drive a mains booster pump during filling then shut down the pump and close the valve when the tank is full.

Other functionality available include:

  • TDS measurement and display
  • High TDS cutoff or alarm
  • Flowrate measurement and display
  • Water pressure measurement and display
  • Water level measurement and control
  • Available with constant level control

V11M BPC - Data Sheet

110V - 220V AC pump controllers

Industrial peristaltic controls with timer

Accurate reliable liquid dosing controller, designed with ease of use and installation in mind. Ideal where controlled accurate dosing is required. Applications:

  • Dosing pump control
  • Chemical dosing
  • Detergent dosing
  • Chlorine dosing
  • Pesticide dosing
  • Fungicide dosing
  • Additive control
  • Water treatment control

Enclosed in hard wearing water resistant casing up to IP65. The 110/230V AC pump will run any 12V DC pump and peristaltic pumps with 3amp - 6amp - 12amp versions available. The controls feature a pre-programmable timer allowing you to set the dosing intervals which can be preset between 6 minutes and over four days.  Dosing can be set between 6 seconds and over 3 hours. Away for a few days? No problem set it and forget. These controls are the answer to automated dosing control and are highly versatile and hard wearing. Set the timer and walk away with a complete peace of mind. Spring are also able to offer a 12V DC dosing controller for DC powered applications. Supplied with full instructions and cables, making it easy to fit easy and to use.

Industrial peristaltic controls with timer
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