Draught Guardian · Hospitality tech / IoT
Draught Guardian
A hospitality-tech startup that monitors beer pours, volumes and loss came to BMEC for a modest hardware revision - a more robust version of what they already had. We told them the honest answer: a surface revision wouldn't fix the real problems.

- Client
- Draught Guardian
- Engagement
- Discovery + full redevelopment
- Delivery
- PCB + firmware in ~6 weeks
- Scale
- Hundreds into thousands of units
- Cost impact
- ~10x unit-cost reduction
The challenge
The device connected over GSM - the single biggest cost driver, demanding SIM management and data plans for every deployment, a choice inherited from before Wi-Fi was reliably available. And deployed under bars and in fridges, it kept failing from water ingress.
Neither problem registered as a problem to the client. They had normalised both constraints and asked us only to make the existing design a little tougher.
The client expected a minor revision. We proposed a fundamental rethink - and the business impact was an order of magnitude beyond what the original brief would have produced.
What we did
- 01
Challenged the brief
A systematic discovery phase surfaced that the GSM module was the most expensive component, and that its original justification no longer held. We recommended a full architectural pivot - more change than the client had anticipated, because it was the right answer.
- 02
Re-architected the product
Custom ESP32-based PCB to fold Wi-Fi and Bluetooth into one chip and delete the cellular module; a Bluetooth-connected mobile app to replace the fragile embedded interface; and a fully potted enclosure to kill the water-ingress failure mode.
- 03
Built on proven foundations
Our Deep Core firmware libraries - Wi-Fi, Bluetooth and MQTT stacks already field-validated across other deployments - went straight into the product, with over-the-air updates for the whole fleet.
- 04
4-to-1 revision
A later iteration replaced the single-flow-meter node with a four-meter variant, cutting the cost per monitored tap by a further 2 to 4 times.
More work
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