There’s a bunch of different electric scooters available nowadays, including those hoverboards that keep catching fire. [TK] had an older Razor E300 that uses lead acid batteries. After getting tired of the low speeds and 12 hour charge times, [TK] decided it was time to swap for lithium batteries.
The new batteries were sourced from a Ryobi drill. Each provides 18 V, giving 36 V in series. The original batteries only ran at 24 V, which caused some issues with the motor controller. It refused to start up with the higher voltage. The solution: disable the safety shutdown relay on the motor controller by bridging it with a wire.
With the voltage issue sorted out, it was time for the current limit to be modified. This motor controller uses a TI TL494 to generate the PWM waveforms that drive a MOSFET to provide variable power to the motor. Cutting the trace to the TL494’s current sense pin removed the current limit all together.
We’re not saying it’s advisable to disable all current and voltage limits on your scooter, but it seems to be working out for [TK]. The $200 scooter now does 28 km/h, up from 22 km/h and charges much faster. With gearing mods, he’s hoping to eke out some more performance.
An irritation-free razor that gives a close shave has been a dream for thousands of years. [Gillette] came close, and with multiple blades came even closer, but all razors today are still just sharpened steel dragged across the skin. This is the 21st century, and of course there’s a concept for a laser razor pandering for your moola. We recently covered the Skarp laser razor and its Kickstarter campaign, and today the campaign has been shut down.
The email sent out to all contributors to the Skarp campaign follows:
This is a message from Kickstarter’s Integrity team. We’re writing to notify you that the Skarp Laser Razor project has been suspended, and your pledge has been canceled.
After requesting and reviewing additional material from the creator of the project, we’ve concluded that it is in violation of our rule requiring working prototypes of physical products that are offered as rewards. Accordingly, all funding has been stopped and backers will not be charged for their pledges. No further action is required on your part. Suspensions cannot be undone.
We take the integrity of the Kickstarter system very seriously. We only suspend projects when we find evidence that our rules are being violated.
Although we will never know exactly why Kickstarter suspended the original Skarp campaign, the reason given by the Kickstarter Integrity Team points to the lack of a working prototype, one of the requirements for technology campaigns on Kickstarter. Interestingly, Skarp did post a few videos of their razor working. These videos were white balanced poorly enough to look like they were filmed through green cellophane, a technique some have claimed was used to hide the actual mechanism behind the prototype’s method of cutting hair. A few commenters on the Skarp Kickstarter campaign – and here on Hackaday – have guessed the Skarp prototype does not use lasers, but instead a heated length of nichrome wire. While this would burn hair off, the color of the wire would be a dull red when filmed in any normal lighting conditions. It is assumed the poor quality of the Skarp prototype videos is an attempt to hide the fact they do not have a working prototype.
Skarp’s move to Indiegogo has been lauded by some – mostly in the comments section of the Indiegogo campaign – and has been derided on every other forum on the Internet. Indiegogo is commonly seen as the last refuge of crowdfunding scam artist, but there are a few legitimate reasons why a campaign would choose to go to Indiegogo. Kickstarter is not available for campaign founders in all countries, and for some, debiting a card immediately, instead of after the campaign end like Kickstarter does, is a legitimate crowdfunding strategy.
But for a crowdfunding campaign to be suspended on Kickstarter and immediately move to Indiegogo? This almost never ends well. One of the most famous examples, the Anonabox, had its Kickstarter campaign suspended after it was found the creator was simply rebadging an off-the-shelf router. The Anonabox then moved over to Indiegogo where it raised over $80,000. Already the campaign for the Skarp Laser Razor has raised $135,000 USD from Indiegogo, after having its Kickstarter campaign raised over $4 Million. No, Skarp won’t be one of the most successful technology Kickstarter campaigns of all time. We can only hope it won’t be one of Indiegogo’s most successful campaigns.
At the end of the 19th century, [King Camp Gillette] had the idea of creating a disposable razor blade that didn’t need sharpening. There was one problem with this idea: metallurgy was not yet advanced enough to produce paper-thin carbon steel blades and sharpen them for a close shave. In 1901, [William Nickerson] solved this problem, and the age of disposable razors began.
This Kickstarter would have you believe there is a new era of beard technology dawning. It’s a laser razor called Skarp, and it’s on track to become one of the most funded Kickstarters of all time. The only problem? Even with relatively good documentation on the Kickstarter campaign, a demo video, a patent, and an expert in the field of cosmetic lasers, only the creators can figure out how it works.
Instead of using technology that has been tried and tested for thousands of years, the Skarp uses a laser to shave hairs off, right at the surface of the skin. You need only look at a billboard for laser hair removal to realize this is possible, but building a laser razor is something that has eluded us for decades. This patent from 1986 at the very least demonstrates the beginnings of the idea – put a laser beam in a handheld package and plunge it into a beard. This patent from 2005 uses fiber optics to send a laser beam to a handheld razor. Like anything out of the sci-fi genre, a laser razor is a well-tread idea in the world of invention.
But Skarp thinks it has solved all of the problems which previously block lasers from finding a place in your medicine cabinet.
[Salvatore Ventura] likes a close shave from an electric razor, and nothing shaves closer than a new set of blades. After shelling out for some sharp ones, the rechargeable batteries died so he set out to replace them with a couple of double A’s (not the ones pictured above as those are alkaline).
This fix actually increased the original battery life of the razor by about 30%. That’s thanks to a larger capacity than the battery that had come with the razor. But [Salvatore] didn’t get to enjoy the windfall for very long. One morning the charge light was blinking on the razor and it wouldn’t spin up at all. After testing the batteries with a multimeter he found that they had a full charge and figured it was the main board that had gone out.
The real question is, what is that board actually doing? A bit of study led him to the conclusion that it is just a charging circuit, and an on/off switch. He kissed the board goodbye, wired up the AA battery holders directly. Now he jams a paper clip into the recharging jack, shorting the pins to complete the circuit. He could even keep using rechargeables with an external charger if he was careful not to run them too low.
Hub motors put the power inside of the wheel. [Teamtestbot] goes deep into the hows and whys of building these motors, from parts, to windings, to the math behind the power ratios. The working example puts an electric motor inside the rear wheel of a Razor scooter. Past projects used belts to transfer the work of the motor to the wheel of the scooter. By integrating the motor and the wheel you end up with a much cleaner looking product. Check out the motor testing and the scooter test drive after the break.
For more tips on building your own electric motors take a peek at the Fly Electric page we covered back in November.