Bob Cassette Rewinder: Hacking Detergent DRM

My $1200 7 year old Miele dishwasher stopped working a few months ago, with the “Intake&#x2F;drain” light on red when starting a load. Dishwashers during the pandemic were sort of scare due to massive home remodeling demand, and the professional repair people would have cost $300 just to diagnose, so I went to try to fix it myself.<p>It turns out the water intake valve solenoid was jammed or gummed up somehow, as applying 120V to it directly had no effect. I went to find an OE replacement online only to find that they are $580, sold by only 2 places, and sold out. You need to be a certified Miele technician to buy them.<p>Given I knew the specifications from the model number and the printing on the solenoid itself wrt voltage and flow rate, I bought the cheapest replacement I could find on Amazon, spliced the wires into the existing harness and boom, it worked perfectly.<p>One thing I didn’t understand was why there were so many different inlet valves that all did the same thing. There were 120V AC and 12V DC versions but other than that the only difference was the water connector&#x2F;dongle&#x2F;bracket. It seemed absurd there would be so many but the reality is that actual solenoid is super generic and should only cost $20 and should be made to fit them all. Of course nobody really repairs things these days but I think this is the reason why. Even when the part could easily be standardized and replaced&#x2F;repaired like a light bulb, companies want you to buy a whole new one.

Actual news about hacking! It is interesting that this is in the UK ... i&#x27;m fairly sure most rents come with a full-sized dishwaster when furnished and all properties have the plumbing for one. I&#x27;m not sure what the market is. Especially that one of the main value adds was &quot;no mess&quot; when our dishwashers all accept pre-form tablets for detergent.<p>Anyway, I adore these kinds of blog posts. Tinkering, naughtiness and a big dollop of technical knowhow.

Loved the obsessiveness! FWIW the entire beer-brewing industry <i>runs</i> on NaOH for cleaning and sanitising. Disposing of it is not quite as environmentally-friendly as the dishwasher manufacturer seems to want you to believe -- in most places you&#x27;d be in serious trouble if you poured any significant quantity down the drain.<p>eta: I&#x27;ve just looked up the constituents of the dishwasher tablets we&#x27;ve been using, and yes, indeed, they&#x27;re mostly NaOH, an inert carrier (Na2SO4) and a variety of water-softeners, packaging films to keep everything in tablet form (but soluble) and a small number of helper enzymes, perfumes and whiteners. Looks like a teaspoon of NaOH might work justabout as well. :D

Proprietary cassettes for dishwashing machines? That&#x27;s next level. Also I don&#x27;t get the advantage that you don&#x27;t need to measure the detergent level, I have always used standard &quot;all-in-one&quot; tabs (1 tab = 1 wash) for my dishwasher, they cost around 0.15 Euro per wash and they only thing I need to add ever few weeks is salt (due to hard water). You can buy the tabs in large packs like 100 in one plastic bag and they are not individually packed (the packaging dissolves during the wash). No need for shipping back the cassette to refill or complicated recycling. We are reinventing the wheel again.

Ha, I thought that was going to be about a VHS head cleaner tape. Mine came with super-special head cleaning fluid in a tiny bottle. The bottle doesn&#x27;t last long, and you then have to buy another bottle of super-special cleaning fluid at a super-expensive price.<p>One whiff of the cleaning fluid - hmm, this smells like alcohol! Alcohol works great in it.<p>It also reminds me of back in college in the 70s where there were many audiophiles in the dorm. They&#x27;d buy super-special vinyl record cleaning fluid, because nothing but the best for their vinyl records. I just used liquid dish detergent, which works perfectly.

It&#x27;s great hack, but I bet that internet connection can be used to update the firmware.<p>Perhaps the updated version will use encryption, and it&#x27;ll be like the story in Unauthorized Bread:<p><a href="https:&#x2F;&#x2F;arstechnica.com&#x2F;gaming&#x2F;2020&#x2F;01&#x2F;unauthorized-bread-a-near-future-tale-of-refugees-and-sinister-iot-appliances&#x2F;" rel="nofollow">https:&#x2F;&#x2F;arstechnica.com&#x2F;gaming&#x2F;2020&#x2F;01&#x2F;unauthorized-bread-a-...</a>

While it comes across as an obvious cash grab, the cassette is a compelling feature if you consider that it does 30 washes and has its own memory of how many each has left. While it is 2x-3x the cost of traditional dishwasher pods, they are focusing on convenience — all the way down to automatic delivery and return — which deserves to be recognized as innovation in end-to-end product design, service, fulfillment, and product lifecycle.

Nicely done! Instead of a device to rewind&#x2F;reset the counter in the EEPROM periodically, I wonder how hard it would be to modify or replace the EEPROM with something that simply ignores any modification to the data (essentially making it read-only). That way, the machine thinks it&#x27;s decrementing the counter each time, but it always remains full. There&#x27;d be no need for a software reset.

Did you know you can just put detergent in the main compartiment? Why do you need such cassettes? Normally diswashers have something that dispenses it at a particular point in the cycle though. It&#x27;s a simple mechanism, no complex electronics involved in that either.

No matter what product you make, it seems that it&#x27;s impossible to earn money without using unethical proprietary practices. I guess the brand will argue that the products are &quot;hard to find&quot; and that it requires &quot;precise refilling&quot;.<p>And apparently it&#x27;s even true for such crazy good home products that really don&#x27;t get enough visibility.<p>I mean it&#x27;s the first time I discover this washing machine, and I want one. It&#x27;s almost like this hacking article was just designed as a disguised advertisement for this washing machine.

I think many product designers try to replicate the success of printer cartridges. I try to avoid buying any device that limits the input or supply especially those that require a cartridge.<p>It&#x27;s a clear method to milk consumers and they can hardly justify the benefit in most cases.<p>I even don&#x27;t buy the idea of capsule coffee machines. I like those that give you the option to use pads, but not those that only accept capsule. The environment impact is one reason, but I also want the freedom of choosing the supply and the having control on the running cost.

This is proper HN content!<p>I&#x27;m quite interested to learn what other household items could be replaced by getting commercial equivalents

The Bob Dishwasher is an interesting concept. Looking at their website it looks like it would fit 6 plates, 6 cups and a set of utensils. What’s the point of this? If you’re cooking for 6, you would have pots and pans which would have to be hand washed. Is 6 more plates and cups worth going through the effort of loading and turning on a dishwasher? Alternatively, I suppose it is more water efficient..

Great post! But so many poor posts about dishwashers in the thread. Ask anyone who services dishwashers (well outside the US at least) and they&#x27;ll tell you two things:<p>1) Don&#x27;t rinse first but if you do only use <i>cold</i> water. I have no idea why on earth dishwashers are connected to hot water in the US as this will make the first rinse work very poorly indeed. It is supposed to be cold to removed starches and dairy products...<p>2) Tabs are a no go but if you insist it should be soap only (not those 3-in-1 etc.) and should be broken in half. It will gunk up the machine in the long run otherwise.<p>I&#x27;d bet that dishwashers would need to be serviced or replaced half as often on average if everyone did this.

That Bob is actually a nice piece of tech, well thought off. A bit pricey, though. I like that ultraviolet disinfects option.<p>I am currently living alone, so my 2&#x2F;3 size (60cm wide) dishwasher stays for days in rinse&#x2F;wait mode, until it gets close to full to do an actual washing. It is not very good for tableware.<p>A friend of mine got a cheap chinese countertop dishwasher with form-factor of Bob, it is not that fancy, but still got color LEDs inside) She is totally happy with it, except small bits like draining used water into bucket with a hose. I can see Bob&#x27;s designers didn&#x27;t solve that too.

&gt; &quot;Over a year of daily washes, it would have cost £174 ($242) in Bob cassettes alone!&quot;<p>I was particularly struck by the this comment. So, the machine is small enough that he can have it as a countertop appliance, but it is also small enough that it gets fill with one day&#x27;s worth of dishes and needs to be run? So it&#x27;s a high price to pay for diswashing, especially when it seems the machine is not really doing a lot. It seems like it would be better to just wash the dishes yourself.

All cool and good, but I&#x27;d have stopped at step 1: Considering buying a dish washer with DRMed detergent. Sorry, but rewarding people with such outrageous proposals with a purchase is morally questionable in itself.

Really cool story.<p>I&#x27;d love to see an overview of what devices and software they used for the initial connecting to a computer, memory dump and memory modify.

The ROI for the effort probably wasn’t that great. But I can respect the obsession for the hack all the same. Sometimes it’s not about the dollars and cents, and if you let it be a hobby versus work that helps make it worth it.

&gt; What&#x27;s more, the 5L detergent can last well over 3 years of daily wash, while the rinse aid can last almost 12 years! Over those time you would have spent £2088 on Bob cassettes, and who knows if they will even be around then.<p>They certainly will be if even a small percent of their customers buy into their ridiculous subscription model. Look at those sweet, sweet margins!

At a dollar per wash, in a mini machine, It&#x27;s cheaper to buy plastic dishes and throw away after use then to buy this detergent!

The entrepreneur in me loves this idea. They are able to turn dishwashers into a subscription model.<p>I love the reverse engineering even more. A really step by step process, very well written. However I don&#x27;t understand this specific step here -<p>&quot;So my plan now is to read what&#x27;s inside the EEPROM. It seemed that a special connector is needed, but after rummaging around the parts bin, I found that it fits into a USB-A female socket just fine! Although I had to insulate the metal case so it won&#x27;t short on the PCB contacts.&quot;<p>Can anyone that understands explain how the EEPROM board can be plugged into a USB socket? Are they similar or is there some overlap? Once its inserted do I use USB protocol to read the data? This is the most interesting part of the whole thing for me. Wish the author explained this more, even if in a separate blog.

Dammit, there&#x27;s <i>one</i> tech company using my first name, and they mess it up with a harebrained DRM scheme for <i>soap</i>!? Maybe I should get out of tech. At least &quot;Daan carpentry&quot; won&#x27;t come up with results that make me instinctively close the tab...

&gt; Over a year of daily washes, it would have cost £174 ($242) in Bob cassettes alone! Imagine paying that much recurring cost for a dishwasher!<p>We pay at least half of that depending on store prices and whether or not we use name brand Cascade and Jet Dry.

I don&#x27;t understand one thing. Why not have a bottle refill system (like those ink tank printers) to have a supply of required chemicals?<p>Sure, you are adding a valve or two, perhaps a couple more sensors, but long term cost savings would be enormous.

Great article. I truly wish that companies that base their business model on environment destroying convenience would just die. But people love their convenience unfortunately.

Investors don&#x27;t want to invest in only HW. They want their MRR. This is all just going to get worse. We&#x27;ll start seeing everything coming with built in cellular soon.

I love reading these hacks!<p>Of course, from a pounds-and-pennies sense, the work he did, hacking the washer, was probably worth enough to buy a dozen of them.

Of course, in order to hack one of these Ter Bebbies, you have to buy one. Either way, Deputy Daan gets ya.<p>&quot;Dosing can be tricky...&quot; So can holding onto your sanity in today&#x27;s consumer world. After generations of TV advertising, reason is supposed to be the consolation prize.

I wonder how environment friendly that tiny dish washing machine and its detergent is. MAybe it can save some water instead of trivial manual washing, but how pollutant is that waste water?<p>Isn&#x27;t it better to manually wash those 2 to 6 dishes, 1 to 3 glasses and maybe 1 pan?

&gt; An eagle-eyed user flopp pointed out the value at 0xa1 is calculated as Washes left XOR 0x50, thanks! Not sure why they did it like this, but anyway!<p>Hilarious. Sounds like somebody&#x27;s manager overheard a conversation about one-time pads on the subway

&gt;&quot;I found a leftover board from pimping my microwave, and quickly threw together a contraption to read the EEPROM...&quot;<p>I found this particular line laugh out loud funny. This whole post was a great and a fun read. Cheers.

I love people hacking DRM shit like this as much as I hate DRM. It is so nice to see.<p>Sometimes it seems like the world has gone mad. Then you see something like this and realise, no, some other people out there are logical too.

I wish more appliances would would have some sort of refillable cartridges or containers (not DRM&#x27;d obviously). I saw some Japanese laundry washers have large containers for detergent.

I don&#x27;t understand how refilling for $0.86 per wash is better than the $0.67 per wash if you use their cartridges? Or how that becomes &quot;75 times cheaper&quot;. <a href="https:&#x2F;&#x2F;github.com&#x2F;dekuNukem&#x2F;bob_cassette_rewinder#cost-showdown" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;dekuNukem&#x2F;bob_cassette_rewinder#cost-show...</a><p>How does this math make any sense?<p><pre><code> With that, the total cost per wash is: 0.62p + 0.018p = 0.638p, or 0.87 US cent! We know from earlier that Bob Cassettes costs 48p (67c) per wash. Therefore, refilling it yourself is more than 75 times cheaper, resulting in a massive 98.7% cost saving compared to buying new! </code></pre> Huh?

Is anyone else bothered by tossing chemicals all over your dishes? I imagine this wouldn&#x27;t work or be feasible with a more health conscious detergent.

&gt; Once empty, you can leave it there and add detergents manually.<p>So you don&#x27;t have to buy their cassettes. You can just fill it like a regular dishwasher.

Hmm, so should we expect a future where washing machines and other appliances work like this but with actual DRM? That&#x27;s a dark thought.

Dishwasher Detergent DRM?<p>It would have never come into my mind that this is something that even exists.<p>What&#x27;s with the tabs you put into the little chamber, or which I&#x27;m just dropping into the cutlery holder since the chamber lid broke of. Aren&#x27;t they compatible or what?<p>----<p>For their website:<p>Is the use of a Bob cassette mandatory? No. However, to ensure optimal washing quality and higher Bob life durability we recommend using the Bob cassette.<p>Can I refill my Bob cassette myself? No.<p>We use a highly concentrated detergent formula which is not publicly available for sale.<p>So we have set up a way to collect used cassettes, clean them and refill them in our factory.<p>This allows us to offer you an optimal washing quality with a zero waste solution!<p>Seems fair to me.

Bob looks really cool. I&#x27;d 100% buy one and use the &quot;DRM&quot; detergent capsules until they went out of business, just to support them. $2K over 12 years is not enough to bother.

great work. I love projects like these. Having fun, saving money and thwarting what are effectively rent-seekers.

Pulled the sources.<p>Expecting DMCA take down in 3, 2, 1....

How I call it: &quot;Product as a Service:&quot; you buy something, but still don&#x27;t own it.

I usually buy Dawn dish soap. It really works well. A machinist friend of mine said they use it as a degreaser at work.<p>A few weeks ago while standing ten deep in Safeway, I read the label.<p>Right on front, they listed at least 11 ingredients. Nothing looked outrageous, but I thought about all the times I didn&#x27;t rinse that well.<p>I now stoped using it on my dishes.<p>I think the lawyers told them to list the ingredients in bold print?<p>Anyhoo--I now rinse much better than before, and on the lookout for just plain soap.