SparkFun Forums

[Sky]

I'm researching my options for the most cost effective means of transmitting a single analog voltage measurement over a distance of 10 feet. A receiver would output the analog value. I'd hoped to find a single board solution - a transmitter with an analog input but found nothing.
Alternatively, I'll use an A/D converter with serial output onto the data pin of a transmitter. Is this a workable design? I don't have space for an antenna of more than one inch and I'd like a solution that doesn't require code. Being unfamiliar with some of the pros and cons of the various transmission protocols, can someone recommend a transmitter/receiver combination that could achieve this specification. I'd like to seta budget for the project of $40.

Any comments or advice would be greatly appreciated.

Sky

[lyndon]

IR? You could do this with a pair of Tiny85's transmitting and receiving an infrared signal. Other than that, the cheapest RF I can think of is again, a pair of Tiny85's and a cheap 433 MHz transmitter & receiver. If you FSK the signal it should be pretty easy to modulate/demodulate.

[jremington]

I'd like a solution that doesn't require code.

Use a voltage-to-frequency converter chip and a twisted wire pair. LM331 for example: http://www.ti.com/product/LM331/datasheet

[Sky]

IR? You could do this with a pair of Tiny85's transmitting and receiving an infrared signal. Other than that, the cheapest RF I can think of is again, a pair of Tiny85's and a cheap 433 MHz transmitter & receiver. If you FSK the signal it should be pretty easy to modulate/demodulate.

It needs to be RF, there isn't the line-of-sight for IR to work. Tiny85's look good though I'd like a product that doesn't require programming.

I'd considered using a LM311 for Voltage-to-frequency but there doesn't appear to be a matched frequency-to-voltage chip. If the pair weren't matched, it would require calibration to make Vin = V out.

Thanks for your input, much appreciated.