The voltmeterMAX1499 is - as you may expect by the name - a voltmeter based on the MAX1499 chip by maximinterated.
Started as a university project (v1) to be put into the student laboratories consoles as a highly accurat voltmeter (guess what: it never happend), it later got reworked (v2) to be used with a refrence voltage and two different seven-segment-display-boards.
- boards for the IC and the 'display' have to be seperate
- board dimensions not given, but as small as possible
- six seven-segments – one for the '-' and five for the digits
- multiple options for displaying (0kR for selection)
- decimals by chip
- decimals by user
- boards to be connected by male and female headers
- drills for spacers and mounting
- use smd parts
on X3: 5V DC (Vcc) on X1: 1.000V DC (testvoltage by signalgenerator)
Measuring the current consumption is a good tool to determin a correctly working board.
One seven-segment-element consumes 20mA on max brightness and all tiles lit. Six of them are used, so a current consumption of ca. 120mA is expected.
With R3=24kR and displaying 18882, the current flowing is 117mA. On idle, current consumption as expected of the datasheet.
estimated 45,00 € (per unit)
- PCBs 16.65€
- MAX1499 13.10€
- 7-Segments 1.00€-2.00€ (per segment-unit)
Connections:
- potentiometer for dimming (black/pink)
- Vcc (black/red)
- voltage to measure (black/orange)
- programming interface (brown/red/orange/yellow)
- moving decimal point
- using internal reference of MAX1499
- reading measurements over serial
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