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Ben Heck’s Pill-Minder 2000 Episode -- Episode 237

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In this episode Ben and Felix set out to create a solution for people who may sometimes forget to take their pills. With the invention of the Pill-Minder 2000 users will be alerted not only when they forget to take their pills but also when they are supposed to take their pills in the first place.

 

Congratulations to Community member, , for having his build suggestion used in this episode! To watch the Ben Heck Show team discuss this build idea, watch this Top 5 Builds segment, HERE. Submit your suggestions HERE for a chance to have YOUR build idea featured on the show and win a Ben Heck Show t-shirt.

 

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  • There are a couple approaches that improve upon the resolution you were seeing.

     

    1. I suspect you were using a 10-bit ADC. Without adding external circuitry you could improve accuracy by oversampling at a higher sampling rate. For every 4x samples using oversampling you increase your resolution by 1 bit (doubles resolution). It is more effective than the averaging method you used (see page 5 of the referenced document). Since you are using an Atmel processor, here is a link to an Atmel reference on the subject. http://www.atmel.com/images/doc8003.pdf that your viewers can use.
    2. As an alternative, a single opamp can be used to null out the load cell when the empty pill box is present. A potentiometer or DAC (preferable) can be used to drive the amplifier's output to near zero when the pillbox is empty and the gain of the amplifier is set to 80% of the ADC's full scale input when the pillbox is full. For complete digital control a programmable gain amplifier (PGA) can be used. This method would probably be sensitive enough to not only tell how many pills are being added but what the weight of each is by using a calibration weight. For this application a calibration weight wouldn't be needed but one can be assured that differences in position of the box would be accounted for.
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  • There are a couple approaches that improve upon the resolution you were seeing.

     

    1. I suspect you were using a 10-bit ADC. Without adding external circuitry you could improve accuracy by oversampling at a higher sampling rate. For every 4x samples using oversampling you increase your resolution by 1 bit (doubles resolution). It is more effective than the averaging method you used (see page 5 of the referenced document). Since you are using an Atmel processor, here is a link to an Atmel reference on the subject. http://www.atmel.com/images/doc8003.pdf that your viewers can use.
    2. As an alternative, a single opamp can be used to null out the load cell when the empty pill box is present. A potentiometer or DAC (preferable) can be used to drive the amplifier's output to near zero when the pillbox is empty and the gain of the amplifier is set to 80% of the ADC's full scale input when the pillbox is full. For complete digital control a programmable gain amplifier (PGA) can be used. This method would probably be sensitive enough to not only tell how many pills are being added but what the weight of each is by using a calibration weight. For this application a calibration weight wouldn't be needed but one can be assured that differences in position of the box would be accounted for.
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