Bob Cassette Rewinder: Hacking Detergent DRM

> Proprietary cassettes for dishwashing machines? That's next level.

Although it is proprietary, to be fair on two points: there wasn't really any "DRM", it was literally just a one byte counter on an EEPROM so that a cartridge could digitally record the number of washes remaining, and the machine made no attempt to prevent this being changed. The manufacturer also did not prohibit the cartridges from being refilled by owners, this is in stark contrast to printer manufacturers.

I agree they could have done way more to make it easy for users to refill, although it's not prohibited it's completely impractical without some EE knowledge, and as the author says sending cartridges around the world is not a very efficient way of getting detergent back into these things. To be honest a better design would be no cartridges and a couple of reservoirs with level sensors (As you essentially suggested regarding measuring detergent level), since the machine already seems to be capable of pumping an accurate amount of liquid out of the cartridges they wouldn't even need to measure, just fill... I suspect the reason they didn't do this was for a more "consumer friendly" design where users have to do the least possible work, as it is more of a luxury product than a utility.

I'm not entirely convinced they are trying to make a serious margin on the cartridges, they work out about 3x the cost of the most expensive dishwasher tablet, but they have to send the thing back to france to be reprocessed and programmed... probably not at a scale to be very cost effective.

I do love the article though, it's great to be able to hack on stuff like this when the manufacturer made poor decisions.

> "all-in-one" tabs (1 tab = 1 wash) for my dishwasher,

Technology Connections explains why you actually want to use powder:

* https://www.youtube.com/watch?v=_rBO8neWw04

TL; DR: It allows for the pre-wash/rinse cycle to work properly and gets things cleaner, faster.

> Proprietary cassettes for dishwashing machines? That's next level.

Sony had proprietary cassettes for all kinds of products over the years, even when there were standards available (Betamax is the most famous but only one example)

I have 4 handheld voice recorders from the 1970s from my father. Philips, Norelco, Sony, and one other brand. All use the same size microcassette except the Sony. Fuck you, Sony.

The "Nespresso" businessmodel of cartridges is too environmentally unfriendly, and one of these days governments/EU will step in and crush it.

> It is interesting that this is in the UK

Not sure where you get that from, "Bob" is made/from Paris, France https://daan.tech/en/about-daan-tech/

In Western/South West Europe (Portugal, Spain, France), full-sized dishwashers are a bit more uncommon I think, especially in single/double room flats in bigger metropolitan areas where flat sizes tend to be in the smaller range. As an anecdote, I've lived in maybe ~20 places and only two of them had come with a dishwasher, only one of them was an apartment.

This is the first time I hear about "Bob" and my current place couldn't fit a full-size dishwater but in order to save time and water, I might actually get this. The price is a bit high for what it is though.

> I'm not sure what the market is.

Here's the 2019 data on dishwasher ownership in the UK [0]. More than 50% of two-adult households have them, rising to 64% for two-adult-two-children households. Retired single adult households have the lowest percentage (28%)

[0] https://www.statista.com/statistics/289337/distribution-of-d...

I've rented many flats and not a single one has had a dishwasher. I wish my current flat had one, washing dishes is the chore I hate the most.

How strange. I've lived in a dozen or so rented properties in the UK and only had a dishwasher in one of them.

For my own dishwasher I’m using a mix of Potassium hydroxide (Potash), Sodium hypochlorite (Bleach) and Sodium tripolyphosphate (Phosphates). This is strong stuff, so make sure hoses/tubes, seals and connections are compatible if anyone wants to try this.

Instead of rinse aid I’m using a 50% citric acid/water solution. The final rinse is at 85c or 185f. The stuff dries instantly. A built in fan/condensation system prevents moisture inside and outside the machine. I’m using two commercial grade peristaltic pumps for the chemicals. I have also considered an enzyme pre-wash; Protease and Amylase. The diswasher is commercial grade, but the racks and operation is just like a normal household dishwasher.

Drinking glasses come out spotless. Rinse Aid is not necessary. I hold them up to the sunlight for inspection and I see nothing.

Sodium hydroxide is only dangerous if concentrated. Diluted, and especially if it is mixed with wastewater, it'll just react with the various organics to form soap-like chemicals.

If anything, it'll help clean your sewage pipes!

PS: Most draincleaners are just a concentrated NaOH mixture. Consumers pour them down their drain all the time and nobody worries about this either...

You can have about the same experience with standard tablets though and none of the wasteful shipping and plastic cartridges. The dishwasher can be online (for those who want it) and report back the amount of washes (the backend can calculate the amount of washes per week to predict when you're going to run out) so that the manufacturer can send a new box in advance.

Does someone come into the house and change it out?

I spend a lot more time (still not much) loading and unloading the dishes than I spend acquiring and pouring powder, so I'm not sure what value I'm supposed to think this would provide.