Machine Design

Inventor's Corner: Wireless test indicator measures blind holes

Our new column Inventor’s Corner showcases inventions that engineers have cooked-up in their spare time.

The wireless test indicator is designed to help toolmakers and lab technicians make accurate remote measurements. The idea comes from Dave Hoffman of Hagenhoff LLC, Canton, Ohio. The patented “Vyndicator” consists of two pieces — a stylus (sensor) and a receiver (display). The invention works something like a dial indicator but it is far more versatile because of the detached stylus. The device has a measurement range of 0.200 in. — five times that of a normal test indicator — and a transmission range of 30 ft.

The stylus unit (transmitter) contains a microprocessor that is connected to a linear sensor. The transmitter sends signals in packets to the receiver. The display unit (receiver) uses a second microprocessor that captures and decodes the signals. Signal packets contain data that describe the movement of the stylus. The receiver microprocessor decodes and displays the movement on an organic LED (OLED) display. Besides a digital readout, the display features a horizontal bar that expands and contracts to represent the movement and amount travel of the stylus.

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The wireless test indicator can reduce the amount of time spent in tasks such as centering a part on a milling machine. In addition, the device can serve in areas where it is dangerous for personnel to make measurements. The indicator also lets users take readings in locations where a traditional dial indicator would not be visible, as in a bore.

Resources: Dave Hoffman
From May to November: (330) 477-3019
From November to May: (623) 544-0679


Before the invention, machinists often had to use creative methods to get a dial indicator to the location to be measured — especially in blind areas or places where a dial indicator is rotated out of view. Hoffman says he got the idea while watching a machinist do involved and time-consuming measurements using a standard test indicator (a tiny dial indicator). “The thought popped into my mind that there should be an easier way to make these measurements,” he says.

Parker Hannifin, Babcock & Wilcock, JJB Engineering, Ansco CNC Specialists, and Cornwell Tools and Standard Engineering Group, all of the Akron, Ohio, area, and GM Lordstown, Ohio, are currently trying the wireless test indicator.

Are you (or do you know) an engineer who has come up with a sophisticated invention in your spare time? Want to get your idea showcased in Machine Design magazine? Contact [email protected] or (216) 931-9242.

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TAGS: Sensors
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