Inside a scam fuel saver plug

I've featured a few of these devices in the past. All in the same case and being pushed on eBay, amazon, and all the other unregulated platforms during times of fuel poverty. It appears the recent greed-driven political idiocracy has caused another push of these devices onto the market to cash in on the fact that people are struggling financially.There are genuine engine-tuning devices available, but they are for specific cars and carry a high price tag to cover the development costs.These units claim to work with ANY car and "remap" the engine's parameters to boost performance while saving fuel. (That would be a massive software feat.) In reality they do NOTHING but waste power and blink lights.Some make an effort to look convincing by blinking the lights in a way that looks like bidirectional data communication, but others like this just flash an LED on and off to look like they are doing something. This particular unit is especially disappointing because it uses a microcontroller with full control over the three LEDs and could have looked so much more convincing with better software.The button in these units has two purposes. Firstly it gives an element of interaction, making the user think they have started the vehicle learning sequence.The second purpose is probably to facilitate fobbing customers off until they lose interest or are beyond the point they can open a dispute with the seller.The instructions with these units often imply that a minimum mileage or time is required for the device to learn and adjust the engine for maximum economy. If the customer then complains that there's no difference then they can ask if they pressed the button or suggest holding it in for ten seconds and then start the whole minimum mileage thing again.A subsequent test with an external resistor and supply showed that the zener diode is a 5.1V one, and the lower voltage readings were because the dropper resistor isn't passing enough current for the LEDs, so they drag the voltage down.The cost of these units varies dramatically, with the price starting at less than £2 on Aliexpress with no upper limit on eBay and amazon as the scammers either try to gouge as much money as possible, or use a high price to create the illusion of value. (Like the fashion industry.)Any positive reviews of these devices are either fake or from people who have bought one and then convinced themselves that it's doing something with the placebo effect.If you want one of these for the novelty value or as a handy source of an OBD2 connector, then here's a starter-link to everyone's favourite online purveyor of technical toys - AliExpress (not a sponsor). This is an affiliate link - which is kinda awkward with a product like this:-https://s.click.aliexpress.com/e/_c34wTCKPI'd guess that many of the scammers drop-ship items like this from AliExpress listings.If you enjoy my videos, supporting the channel on Patreon helps keep it independent of YouTube's quirks, avoids intrusive mid-video adverts, gives early access, bonus footage and regular quiet Patreon live streams.https://www.patreon.com/bigcliveAlternatively, for a single coffee contribution you can use PayPal:-https://www.paypal.com/paypalme/bigclive#ElectronicsCreators...https://www.youtube.com/watch?v=kvoC0uJ0COM