Has it really come to this? Are we really at the point that dishwashers have proprietary detergent cartridges that you’re locked into buying at inflated prices?
Apparently so, at least for some species of the common kitchen appliance. The particular unit in question goes by the friendly name of Bob, and is a compact, countertop unit that’s aimed at the very small kitchen market. [dekuNukem] picked one of these units up recently, and was appalled to learn that new detergent cartridges would cost an arm and a leg. So naturally, he hacked the detergent cartridges. A small PCB with an edge connector and a 256-byte EEPROM sprouts from each Bob cartridge; a little reverse engineering revealed the right bits to twiddle to reset the cartridge to its full 30-wash count, leading to a dongle to attach to the cartridge when it’s time for a reset and a refill.
With the electronics figured out, [dekuNukem] worked on the detergent refill. This seems like it was the more difficult part, aided though it was by some fairly detailed specs on the cartridge contents. A little math revealed the right concentrations to shoot for, and the ingredients in the OEM cartridges were easily — and cheaply — sourced from commercial dishwashing detergents. The cartridges can be refilled with a properly diluted solution using a syringe; the result is that each wash costs 1/75-th of what it would if he stuck with OEM cartridges.
For as much as we despise the “give away the printer, charge for the ink” model, Bob’s scheme somehow seems even worse. We’ve seen this technique used to lock people into everything from refrigerator water filters to cat litter, so we really like the way [dekuNukem] figured everything out here, and that he saw fit to share his solution.
Soap cleans clothes better than magnets. There, we are spoiling the ending so don’t accuse us of clickbaiting. The funny thing is that folks believe this is plausible enough to ask magnets experts so often that they dedicate a blog entry to comparing magnets and soap. Since you already know how this ends, let’s talk about why this is important. Science. Even though some magnet retailers, herein referred to as [the experts] can easily dismiss this question as fanciful or ridiculous, they apply the scientific method to show that their reasoning is sound and clean evidence is on their side. [The experts] detail the materials and techniques in their experiment so peers may replicate the tests and come to the same results themselves. We do not doubt that the outcome would be equally conclusive.
The experiment includes a control group which processes dirty clothes without detergent or magnets, one group with only magnets, one group with only detergent, and one group with both. White clothing was soiled with four well known garment killers and manually agitated in a bin of warm water. We guessed that magnets would be on par with the control group, and we were pleased to be right. [The experts] now have a body of work to reference the next time someone comes at them with this line. The only question now is if tricky spouses used science to get nerds to do the laundry.
In this age of spin, keeping facts straight instead of jumping to heartfelt conclusions is more vital than ever. We are all potentially citizen scientists so testing a conspiracy is within everyone’s grasp.
Continue reading “Magnets Versus Laundry Detergent”
No matter how mad your 3D printing skills may be, there comes a time when it makes more sense to order a replacement part than print it. For [billchurch], that time was the five-hour window he had to order an OEM part online and have it delivered within two days. The race was on — would he be able to model and print a replacement latch for his dishwasher’s detergent dispenser, or would suffer the ignominy of having to plunk down $30 for a tiny but complicated part?
As you can probably guess, [bill] managed to beat the clock. But getting there wasn’t easy, at least judging by the full write-up on his blog. The culprit responsible for the detergent problem was a small plastic lever whose pivot had worn out. Using a caliper for accurate measurements, [bill] was able to create a model in Fusion 360 in just about two hours. There was no time to fuss with fillets and chamfers; this was a rush job, after all. Still, even adding in the 20 minutes print time in PETG, there was plenty of time to spare. The new part was a tight fit but it seemed to work well on the bench, and a test load of dishes proved a success. Will it last? Maybe not. But when you can print one again in 20 minutes, does it really matter?
Have you got an epic repair that was made possible by 3D printing? We want to know about it. And if you enter it into our Repairs You Can Print Contest, you can actually win some cool prizes to boot. We’ve got multiple categories and not that many entries yet, so your chances are good.