Universal AvoMeter (AVO Meter) 7 Mk. II (2) Braille

In the mid-1950s, efforts to integrate the visually impaired into technical fields gained significant attention. As highlighted in the September 1956 issue of Wireless World, various radio factories, including Pye's TV Construction Ltd., actively employed blind operators in assembly work. These operators used specialised tools such as Braille-adapted micrometers, gauges, wiring diagrams on plastic sheeting, and notably, a new Braille Avometer. This innovation enabled blind technicians to work alongside their sighted colleagues effectively, exemplifying the practical application of tactile measurement aids in professional environments.

Braille Avometer Model 7

• Introduced in 1956, modified for use by visually-impaired servicemen.
• Based on a standard Avometer Model 7 Mk II with a "feeler mechanism" pointer swung from the meter movement, enabling tactile interaction.
• Braille range markers are moulded above the arc of the scale window for each range.
• Range selector switches have Braille moulded markings and milled grooves to allow positioning by touch.
• Braille markings are placed on the front face rather than the knobs.
• Housed in an aluminium case, robust and reliable with a two-switch range selection and a mechanically operated cut-out linked to the meter movement.
• Used a 1 mA meter movement.
• The design facilitated usage by blind users through tactile identification of ranges and scale reading.
• The model 7 Braille retained traditional features such as mirror scale and "smiley" meter scale.
• Power supplied by a 1.5V cell plus two 4.5V batteries for high resistance ranges.

See also the Braille Avometer Model 8.

Here you find 86 models, 83 with images and 41 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
All listed radios etc. from Avo (Brand), Automatic Coil Winder and Electrical Equipment Co., Avo Ltd; London