Rechargeable Lithium Ion Sensor Custom PCB
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Updated to Rev 0.2:
- SMD capacitor footprint added (see first post)
- made sure no route is under the nRF antenna to prevent interference
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Updated to Rev 0.2:
- SMD capacitor footprint added (see first post)
- made sure no route is under the nRF antenna to prevent interference
@HenryWhite Just a suggestion.. you could break out the SDA/ SCL pins (A4/A5) to be able to use other Temp/Hum sensors like SHT21/ SI7021 boards. These work reliable, at lower voltages and are in the same price range as the DHT22 (but lack the plastic housing..)
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I think, on Rev 0.2 the download link for the board is wrong, it is the same as for Rev 0.1.
I think it is also imported that the antenna will not be covered by the shield pcb (see http://forum.mysensors.org/topic/1109/sensor-shield-for-arduino-pro-mini-3-3v-with-boost-up-regulator)
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I think, on Rev 0.2 the download link for the board is wrong, it is the same as for Rev 0.1.
I think it is also imported that the antenna will not be covered by the shield pcb (see http://forum.mysensors.org/topic/1109/sensor-shield-for-arduino-pro-mini-3-3v-with-boost-up-regulator)
@AWI: I will think about it
@Heizelmann said:
I think, on Rev 0.2 the download link for the board is wrong, it is the same as for Rev 0.1.
I think it is also imported that the antenna will not be covered by the shield pcb (see http://forum.mysensors.org/topic/1109/sensor-shield-for-arduino-pro-mini-3-3v-with-boost-up-regulator)
yeah the link is the same, i will update it. Did you made measurements to compare the range of the nRF when mounted onto the board and mounted sticking out? I'm not sure but I don't think this would make any difference, as there are no routes under the antenna or even a ground fill on the board.
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@AWI: I will think about it
@Heizelmann said:
I think, on Rev 0.2 the download link for the board is wrong, it is the same as for Rev 0.1.
I think it is also imported that the antenna will not be covered by the shield pcb (see http://forum.mysensors.org/topic/1109/sensor-shield-for-arduino-pro-mini-3-3v-with-boost-up-regulator)
yeah the link is the same, i will update it. Did you made measurements to compare the range of the nRF when mounted onto the board and mounted sticking out? I'm not sure but I don't think this would make any difference, as there are no routes under the antenna or even a ground fill on the board.
@HenryWhite said:
Did you made measurements to compare the range of the nRF when mounted onto the board and mounted sticking out?
No. With shield PCB I meant the ground fill. In your pictures I can not see if you leave this region out for filling. At least it is prophylactic.
What I tested is only this antenna modification. For me it really helps. May be this can be taken into account for the layout.
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@HenryWhite said:
Did you made measurements to compare the range of the nRF when mounted onto the board and mounted sticking out?
No. With shield PCB I meant the ground fill. In your pictures I can not see if you leave this region out for filling. At least it is prophylactic.
What I tested is only this antenna modification. For me it really helps. May be this can be taken into account for the layout.
@Heizelmann said:
What I tested is only this antenna modification. For me it really helps. May be this can be taken into account for the layout.
I plan to use this mod too. I'm curious if the additional wire(s) has/have to be straight or if you can twist it/them. If you use a single straight wire, it should already be compatible with the layout, the wire would be above the arduino.
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I have some thoughts about voltage.
A LiPo is 4.2 volt when it is 100% charged or when you have charged it for a few minutes, power will come from charger TP4056.
Do you use the regulator on Arduino board?
Can I use your files and modify it?
@flopp said:
Can I use your files and modify it?
Yes, absolutely.
But I don't think you need a voltage regulator. At least on the arduino I ordered there's already an onboard regulator which is rated for up to 12V DC input. -
I'm thinking of building the same kind of board for protyping sensors, also powered by Li-Ion or LiPo cells as I have plenty lying around :)
The TP4056 board will protect the cell if voltage drops bellow 2.8v. The arduino and nrf24 module should be fine at those values. This might not be the case for all sensors...
However when charging or at 4.2V the nrf24 module will exceed its 3.6V max input power. Did you manage to get your board working ? -
I'm thinking of building the same kind of board for protyping sensors, also powered by Li-Ion or LiPo cells as I have plenty lying around :)
The TP4056 board will protect the cell if voltage drops bellow 2.8v. The arduino and nrf24 module should be fine at those values. This might not be the case for all sensors...
However when charging or at 4.2V the nrf24 module will exceed its 3.6V max input power. Did you manage to get your board working ?@akumar said:
The TP4056 board will protect the cell if voltage drops bellow 2.8v. The arduino and nrf24 module should be fine at those values. This might not be the case for all sensors...
That's right, but for this case (which will only happen once a year or less (depending on configuration and used lipo battery) you have the battery measurement supported through mysensors onboard, which can tell you if the voltage drops below a certain level.
Also make sure to get the new tp4056 because the old and common one does not have a battery protection circuit!
@akumar said:
However when charging or at 4.2V the nrf24 module will exceed its 3.6V max input power.
No, the nRF24 is hooked up to VCC of the arduino, which has an internal voltage regulator. So the VCC output of the arduino should always be max. 3.3V, as long as the input is below 12V.
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If the arduino is outputing 3.3v that means that you are powering the arduino with the RAW pin, isn't it ?
If so make sure the linear voltage regulator on the arduino will be able to provide the 3.3v if battery voltage drops below 3.3v (so from 3.3v to 2.8v). I don't think they can boost the voltage from 2.8v back to 3.3v :( -
If the arduino is outputing 3.3v that means that you are powering the arduino with the RAW pin, isn't it ?
If so make sure the linear voltage regulator on the arduino will be able to provide the 3.3v if battery voltage drops below 3.3v (so from 3.3v to 2.8v). I don't think they can boost the voltage from 2.8v back to 3.3v :(@akumar said:
make sure the linear voltage regulator on the arduino will be able to provide the 3.3v if battery voltage drops below 3.3v (so from 3.3v to 2.8v).
That's not necessary - for this case you have the battery measurement circuit as mentioned in my previous post.
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@akumar said:
make sure the linear voltage regulator on the arduino will be able to provide the 3.3v if battery voltage drops below 3.3v (so from 3.3v to 2.8v).
That's not necessary - for this case you have the battery measurement circuit as mentioned in my previous post.
@HenryWhite said:
That's not correct. You are mixing up something. The RAW pin is for unregulated power input. With this you can bypass the internal voltage regulator. When you use the normal VCC input, the voltage will be regulated to 3.3V, if the input is (depending on arduino model) between 3.3V and 12V.
It is actually the other way around. From https://www.arduino.cc/en/Main/ArduinoBoardProMin :
If you're supplying unregulated power to the board, be sure to connect to the "RAW" pin on not VCC.
Power on RAW pin results in the regulator being in use.
Power on Vcc bypasses the regulator. -
@akumar said:
make sure the linear voltage regulator on the arduino will be able to provide the 3.3v if battery voltage drops below 3.3v (so from 3.3v to 2.8v).
That's not necessary - for this case you have the battery measurement circuit as mentioned in my previous post.
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@HenryWhite said:
That's not correct. You are mixing up something. The RAW pin is for unregulated power input. With this you can bypass the internal voltage regulator. When you use the normal VCC input, the voltage will be regulated to 3.3V, if the input is (depending on arduino model) between 3.3V and 12V.
It is actually the other way around. From https://www.arduino.cc/en/Main/ArduinoBoardProMin :
If you're supplying unregulated power to the board, be sure to connect to the "RAW" pin on not VCC.
Power on RAW pin results in the regulator being in use.
Power on Vcc bypasses the regulator.@mfalkvidd said:
Power on RAW pin results in the regulator being in use.
Power on Vcc bypasses the regulator.indeed. seems like I mixed up something there :D
I will update the eagle files when i have time to. -
So if I sum up, powering this node with a single Lipo cell will work by connecting the Lipo to the raw pin on the arduino. This will work from 4.2v to 3.4v. This is not that good for the battery life.
Using 2*AA batteries with a boost converter seems a lot easier...
I'm almost giving up on this idea : I liked the flat form factor of the lipos and they were solar pannel friendly. Is there a way to use a voltage regulator from 4.2v to 3.4v and then switch the circuit to a boost converter from 3.3v to 2.8v ? -
So if I sum up, powering this node with a single Lipo cell will work by connecting the Lipo to the raw pin on the arduino. This will work from 4.2v to 3.4v. This is not that good for the battery life.
Using 2*AA batteries with a boost converter seems a lot easier...
I'm almost giving up on this idea : I liked the flat form factor of the lipos and they were solar pannel friendly. Is there a way to use a voltage regulator from 4.2v to 3.4v and then switch the circuit to a boost converter from 3.3v to 2.8v ?@akumar It's the same problem as with all lipos. But you have to consider that it will take a really long time until the battery hits 3.4V or less. There are even smartphone batteries with 3000+ mAh which are very small.
Also it seems to be good for battery lifetime when the voltage does not drop that much compared to using a step-up converter below 3.4V.
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So if I sum up, powering this node with a single Lipo cell will work by connecting the Lipo to the raw pin on the arduino. This will work from 4.2v to 3.4v. This is not that good for the battery life.
Using 2*AA batteries with a boost converter seems a lot easier...
I'm almost giving up on this idea : I liked the flat form factor of the lipos and they were solar pannel friendly. Is there a way to use a voltage regulator from 4.2v to 3.4v and then switch the circuit to a boost converter from 3.3v to 2.8v ? -
Looking at discharge curves I can see that I should be able to squeeze 75% of the battery capacity if I charge it back when it reaches 3.3v. On a low power node this could work.
@flopp The reason I was mentionning 2.8v is because the battery protection module will kick in at this voltage. But you're right, no reason to go this far.Thanks !
