HandBat is a handheld Ultrasonic Radar device that sends out pulses of UltraSound and listens for Echos, like a Bat. It is intended for use by vision-impaired people or navigation in the dark.
Handbat is housed in a low-cost ($3.97) Rayovac Floating Lantern case from Walmart.
It is made from 5 parts:
- A YourDuino Robo1 Microcomputer (Or similar Arduinos)
- An Ultrasonic Sensor
- A small Beeper
- A Battery Holder for 4 AA batteries
- "Rainbow" cable (Cablemaker) strips
These parts are widely available on Ebay, Sparkfun.com, Adafruit.com, YourDuino.com etc.
A kit with the needed parts is available HERE:
Step 1: How HandBat Works
The completed HandBat (above) contains the YourDuino/Arduino microcomputer and battery holder inside the lantern case, the UltraSonic Sensor mounted on the front lens, and the beeper on the outside of the case.
Here is a good Educational article we have written about Ultrasonics and EchoLocation: Understanding the Science Behind the Ultrasonic Distance Sensor (click this link)
In use, the HandBat is held by the user and pointed in front of them and around to find out how close objects are. The maximum range is 2 meters (about 6 feet). The user listens to the beeper which tells how close objects are with different tones and rates of beep.
- 2 meters to 1 meter the tone is lower and the beep rate is slower and increases towards 1 meter.
- At 1 meter the tone changes higher and slower, then faster towards 25 cm, when it changes to a high pitch
- From 25 cm down to 2 cm the beeps get faster and faster and small distances can be sensed.
Note: A Kit of parts to build the Handbat (Not including the $4 Walmart Lantern!) is available HERE.
Step 2: What HandBat is Made Of: Mechanical
Above are all the parts of the HandBat before being assembled into the case:
The YourDuino Robo1 and the battery case are wired to opposite sides of a 3 by 4 inch piece of strong cardboard or foamcore.
The Ultrasonic Sensor is glued to the front lens and the beeper is glued to the case and connected through two drilled holes.