The Bob dishwasher grabs your attention right away: it's ultra-compact, efficient, needs no extra plumbing, and looks great in any kitchen. But it comes with a catch: it relies on using special cartridges, 'Bob Cassettes' that control detergent dosage and maintenance cycles. GitHub user 'dekuNukem' bought a Bob unit in 2021 and, while happy with it, decided the cost per wash following the official route is too high. His solution? Hack the DRM on those cassettes and refill them.
We've seen DRM invade the world of coffee. It also did its thing obstructing train repairs. And our friends at HP have made it their way of life. DRM can mutate however it wants, but its ultimate goal is the same: control over software, hardware, and fundamentally over customers. What's next on the list? A dishwasher named Bob.
To be honest, Daan Tech didn't implement a very hard DRM. The dishwasher uses proprietary cassettes for detergent and maintenance, but it does allow you to pour detergent in manually very inconveniently when you run out, and the internet connection (mainly to order more cassettes online) is optional.
Daan Tech calculated it perfectly: the wash cassette (Pop) lasts 30 cycles, and the maintenance one (Rock 'n Roll) is used only once every 90 cycles. They sell a pack of four cassettes in a 3+1 configuration. Users can send used cassettes back to be refurbished, minimizing waste. So what's the problem?
How to refill and reset Bob dishwasher cassettes
For 'dekuNukem', it's about money. He paid 43 British pounds for a four-cassette pack (2021 price with a discount), including taxes and shipping, and figured that 48 pence per wash is too much. He decided to sacrifice one (in the name of DIY gods) and make a slight modification. Inside, he found a small PCB with an EEPROM storing only 256 bytes.
After dumping its contents, he found most of the memory was empty. After a wash and a second dump, he identified the value that tracks 'available washes'. He then found a detergent and rinse aid similar to Daan Tech's formula (with help from the Issues section). Using a syringe, he refilled the cassette, reset the counter to 30 washes, and it worked perfectly.
The final cost? 0.8 pence, 60 times cheaper. He also released his Bob Rewinder—a PCB that simplifies reading and writing the chip in cassettes. It's open source, but you can also buy it ready to use.
Official project site: Click here
