Their expertise is accessible without the huge costs and barriers presented to small business by other CE specialists and test houses. Expect a friendly and knowledgeable team who ARITH-MATIC highly recommend and hope to continue working with as our business grows." Richard - Founder Background ARITH-MATIC is a British computational hardware project and startup. They craft a range of ultra cool homebrew hardware kits which beautifully dissect the complex mechanisms of computation. S1-AU Mk1 The S1-AU Mk1 is a 4-bit arithmetic unit. It is the first in a series of DIY hardware kits designed to pragmatically strip back the complex mechanisms of computation. Designed with 7400 series integrated circuits, this make-it-yourself kit contains all the through-hole components needed to build your own 4-bit arithmetic hardware and enables you to visually trace binary calculation through an array of onboard LEDs. Using 74HC173 registers for temporary data storage and a 74HC283 full adder for binary calculations, the assembled board enables an operator to perform 4-bit binary addition, subtraction and accumulation. The unit also performs basic logical operations to control the onboard flags. Along with the Operator’s Technical Manual, our beautiful PCBs will guide you through construction and operation. Find out more about ARITH-MATIC on there website "Gainspeed have provided a real lifeline for the ARITH-MATIC project and enabled us to complete compliance testing and CE Marking for our innovative electronics kits. Gainspeed understand the constraints on fledgling businesses and have gone beyond the call of duty to help us out. The team have always taken the time to help us understand, often confusing, CE obligations.