Digital Archive

  • I’ve been building some cabinets in the garage the last few days. I noticed that I was missing some data and dropping packets from the RF12 radios. Here is a...

    RF Interference

    I’ve been building some cabinets in the garage the last few days. I noticed that I was missing some data and dropping packets from the RF12 radios. Here is a...

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  • So a few days ago, the Jeenode stopped sending data. The beginning of this test can be found in this post. It stopped after sending 15,200 data points. That is...

    Eflite 120mAh test done!

    So a few days ago, the Jeenode stopped sending data. The beginning of this test can be found in this post. It stopped after sending 15,200 data points. That is...

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  • I want to build some small wireless sensor nodes that run off small LiPo batteries and use small solar cells to charge the battery. I found some small LiPo batteries...

    Testing the Eflite 120mAh battery with a minimal jeenode

    I want to build some small wireless sensor nodes that run off small LiPo batteries and use small solar cells to charge the battery. I found some small LiPo batteries...

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  • I’m testing a mini LiPo battery to see how long it will power a Jeenode. I bought this battery: It is listed as a 3.7V, 120mAh 1S 14C LiPo battery....

    Reading Lipo Voltage

    I’m testing a mini LiPo battery to see how long it will power a Jeenode. I bought this battery: It is listed as a 3.7V, 120mAh 1S 14C LiPo battery....

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  • The Si4221 has a digital received signal strength indicator (RSSI). You can set a threshold in the configuration and the pin will go low when that threshold has been broken....

    Reading the ARSSI pin on the Si4221/HopeRF 12B

    The Si4221 has a digital received signal strength indicator (RSSI). You can set a threshold in the configuration and the pin will go low when that threshold has been broken....

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  • Exciting news! Andy has created a new library for Arduino that includes DHCP. JCW has got it working on Jeenodes it appears. Follow it here. Code is available on Github...

    DHCP on the ENC28J60

    Exciting news! Andy has created a new library for Arduino that includes DHCP. JCW has got it working on Jeenodes it appears. Follow it here. Code is available on Github...

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  • Just a few notes about Silicon Labs chips and HopeRF modules. All the info is in the datasheets or online, but I like to keep use the blog to keep...

    Silicon Labs’ RF chips

    Just a few notes about Silicon Labs chips and HopeRF modules. All the info is in the datasheets or online, but I like to keep use the blog to keep...

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  • I’ve been trying to see how many packets are lost with a Jeenode I have on my roof about 50m from the receiver in side the house. There is a...

    RF12 packet loss

    I’ve been trying to see how many packets are lost with a Jeenode I have on my roof about 50m from the receiver in side the house. There is a...

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  • The antenna length for the 3 different frequencies can be calculated like this: Length(cm) = 7500/freq(Hz) Antenna size and frequency are inversely proportional. 433 1/4 wave = ~17.3cm 868 1/4...

    RF12B Antenna length/type

    The antenna length for the 3 different frequencies can be calculated like this: Length(cm) = 7500/freq(Hz) Antenna size and frequency are inversely proportional. 433 1/4 wave = ~17.3cm 868 1/4...

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  • So I’m toying with the idea to build my own Arduino clone with the RF12B transceiver. HopeRF sells the module in at least two physical formats (DIP and SMD) as...

    RF12B Modules…time to switch frequency?

    So I’m toying with the idea to build my own Arduino clone with the RF12B transceiver. HopeRF sells the module in at least two physical formats (DIP and SMD) as...

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