A Giant Show Product of E Ink Labels


A variety of brick-and-mortar retail chains have made the swap to digital shelf labels (ESLs) lately. Older ESL designs had LCD screens, however most trendy ESLs make the most of E Ink screens. As a result of E Ink screens solely eat energy when refreshing the show, they’re an ideal alternative for this utility. Retailers don’t must replace the tags typically, so the tag batteries final a really very long time. Every tag can stay in a “deep sleep” state till the retailer wirelessly updates the label info. Raphael Baron discovered a set of 25 of the ESLs on eBay and used their distinctive {hardware} to create this huge show.

In a retail retailer, administration can replace every ESL with a wi-fi configuration machine. Totally different ESLs make the most of totally different protocols. Every of Baron’s ESLs incorporates a Telink TLSR8359 SoC that has onboard BLE (Bluetooth Low Vitality) connectivity. The BLE connection would let administration replace the labels one by one. However Baron wished to replace the entire ESLs on the identical time in order that they might work as a single show. Connecting to every ESL, or “node” in Baron’s terminology, by way of BLE consecutively would take a very long time. Luckily, the TLSR8359 SoC additionally incorporates a regular UART serial port.

Baron used the UART ports to daisy-chain 20 nodes collectively. He connects to the primary node by way of BLE to ship the textual content. Node 0 then transmits knowledge to Node 1 by way of UART. Node 1 then does the identical for Node 2, and so forth. Not solely does this enhance transmission time, it additionally reduces the facility consumption for the 19 nodes that don’t must activate their BLE radios. Implementing that performance was not a trivial process and Baron spent a whole lot of time programming the SoCs to make this work. The nitty-gritty particulars of the code and Baron’s reverse-engineering course of can be found in his submit.

The 20 nodes slide right into a 3D-printed body in two rows of ten screens every. Baron hand-wired the UART connections between the nodes utilizing a nifty 3D-printed spool to measure out the correct wire lengths. The unique ESLs every had their very own battery, however Baron switched to powering all of them with a pair of AA batteries. That can make it simpler to exchange the batteries sooner or later and eliminates the necessity for charging.

To tidy all the pieces up, Baron enclosed the whole machine in a easy wooden field. He laser-cut that field’s panels from composite wooden sheet. The entrance panel has cutouts framing every ESL’s E Ink display screen. The one different exterior function is a programming header that Baron can make the most of sooner or later if he ever must replace the firmware. The lead to a minimalist show made up of 20 particular person screens, every of which shows a single character of a message.


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